Detecon Opinion Paper Photonic Packet Switching and the Evolution of Optical Networks

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Photonic Packet Switching

and the evolution of optical networks

2008 / 10


Opinion Paper 1 Detecon International GmbH

Table of Contents

1 Executive Summary.............................................................................................2 2 Introduction..........................................................................................................4

2.1 Electronic Domain – A Bottleneck coming closer ........................................4 2.2 Optical Domain - Escape Pot and Solution .................................................5

3 Photons invading Circuit Boards .........................................................................6 3.1 Photonic Integrated Circuits – The Optical Chip..........................................6 3.2 The Nanophotonic Market for Telecommunications ....................................7 3.2.1 Motivation ....................................................................................................7 3.2.2 Market & Forecast .......................................................................................8 3.2.3 Key Players ...............................................................................................13

4 Photonic Packet Switching ................................................................................15 4.1 Generic Overview ......................................................................................15 4.2 Specific Example from R&D ......................................................................17 4.3 Current Challenges & Considerations .......................................................19 4.4 Hybrid Solution: Optical Burst Switching ...................................................20

5 OPEX Considerations for a hypothetical 100Tbps Node...................................21 5.1 OEO Approach ..........................................................................................21 5.2 OOO Approach..........................................................................................22 5.3 Correction & Comparison ..........................................................................23

6 Summary ...........................................................................................................24 7 Literature ...........................................................................................................26 8 The Authors .......................................................................................................27 9 The Company ....................................................................................................28



1 Executive Summary

Optical nanotechnology (Nanophotonics) is finding its way into telecommunications. Recent advances in the field of fabrication technologies on the nanoscale triggered a leap forward in the development of components used for optical communication. The market is at the dawn of a new era. First products - packed with state-of-the-art nanophotonics - have hit the Telco market in 2008 and large-scale mass production is expected to follow soon. As a result, the next generation of optical networks will differ significantly from today’s optical networks:

Bandwidth allocation will be of greater scalability & flexibility, and capabilities for dynamic & remote reconfiguration will enjoy large improvements. But most important, these functionalities are going to be provided directly in the optical layer. It minimizes (or even eliminates) cost-intensive optical-electrical-optical conversions. Hence, the future optical networks will be fully transparent to data rates, formats, and signal protocols.

This is perfect timing and is music to the ears for operators & carriers. They are well aware of the fact that ever increasing bandwidth demand is creating a new performance bottleneck; the switching electronics at the core network’s nodes. The magic keyword is PICs (Photonic Integrated Circuits). They are the optical counterpart of electronic integrated circuits and stem from extensive R&D in the field of nanophotonics. PICs are promising candidates to kill 2 birds with one stone: a significant increase in node bandwidth capacity and at the same time reducing operational expenses.

Within the PIC family and along the path of photonic evolution, a new species of optical switches will appear; wavelength routing applying photonic packet switching (PPS). Photonic packet switching is aimed to unfold the capacity and functionality advantages provided by the optical layer and not supported by available electronic router solutions. And contrary to circuit-switched based Reconfigurable Optical Add-Drop Multiplexers (ROADM) the PPS goes one level deeper. Due to its high speed switching capabilities, a PPS does not switch entire data streams; it is rather able to switch single packets within the stream.

However, maturity for mass production has not been reached yet. From this point of view the market is still in its burgeoning stage. Nevertheless, forecast for many high-performance low-power consuming nanophotonic network devices is less than 4-5 years. This is shorter than the life cycle for most of the telecommunications network equipment. Operators/carriers who currently consider purchasing equipment or upgrading their networks should keep this in mind.



Besides the (theoretical) technological superiority, all-optical switching is also likely to enable advantages on the business side. The major impacts are:

Increased flexibility and dynamic re-configurability: Packet based switching takes place on the lowest possible layer adding a high degree of flexibility in application design to core networks. The core network can be changed or reconfigured in a dynamic way following sudden demand and environmental changes.

Increased reliability and reduced complexity: Photonics tends to be more reliable than electronics leading to reduced maintenance costs, hence lowering OPEX. With its ability to act as a multi-degree all-optical wavelength cross connect (multiple inputs, multiple outputs) the PPS reduces the complexity of a network by consolidating management and transmission into the optical layer. It virtually removes the need for higher client layers, hence, lowers CAPEX as well.

Reduced footprint and power consumption: Estimations on the power consumption of pure photonic switching devices is – even in worst case scenario – still one order of magnitude lower than traditional electronic telecom network core equipment. This also includes the footprint of the equipment. It scales down the number of units for supplemental equipment as well (uninterruptible power supplies, air condition etc.). Savings in terms of OPEX are obvious and confirm the overall trends with environmental friendly, low-power consuming Green ICT solutions.

Enhanced revenue streams: The benefit of networks based on intelligent control plane extends beyond survivability and lower OPEX/CAPEX costs. It enhances revenue streams. An intelligent optical control plane enables real-time inventory management and supports the delivery of services on demand. It carries an increased revenue potential as new services can be directly created. The next generation of optical networks can handle much more data as well as much more services (and a variety of services), therefore can support more clients.

This paper addresses CTO’s and technology strategists of the Telco industry. It discusses the current status of photonic packet switching, its impact on networks, and the benefits & drawbacks from a technological perspective. It will also reflect on the current market situation, the economics, the trends & forecasts as well as new & existing players. The paper will give guidance on value propositions and roadmap of this new technology in the light of Telco operators and service providers as well as users of large transmission capacities.

Optical networking is the future, on both medium- and long-term perspectives. And nanophotonics is the driving force behind it. We would like close the summary by citing a statement given by Intel: „Today, optics is a niche technology. Tomorrow, it’s the mainstream of every chip that we build“.



2 Introduction

2.1 Electronic Domain – A Bottleneck coming closer

The full performance potential of optical communication networks is still curbed. With respect to its high bandwidth capabilities of 40Gbps/channel (and beyond) the restriction comes from converting optical signals to the electronic domain and the limitation of electronic processing performance of routers. Manufacturers are well aware of the challenges to provide packet forwarding at wire speed with minimum packet size. From this point of view, electronics impose a bottleneck on the data rate which could be available via fiber optics.

A large number of telecommunication operators are operating IP/MPLS core/backbone networks with point to point DWDM links between the core nodes. At every node the optical signal may need to be converted to the electronic domain (Figure 1). In worst case, sending information from point A to point B requires a fourfold optical-electrical-optical (OEO) conversion.

The constantly increasing demand for more/higher bandwidths forces operators to expand their telecom networks. In case of point-to-point DWDM solutions an expansion/upgrade unavoidably results in increased complexity. Furthermore, OEO conversions and associated electronic processing yield in additional cost at a service provider’s POP. More space to accommodate a larger number of racks & shelves and additional power and cooling would be necessary to operate the active electronic components. A coarse estimation/comparison for footprint and power consumption is given in Chapter 5. From a perspective of OPEX and CAPEX it is obvious that upgrading the core of a network by following the OEO approach is simply not future proof enough.

Typical telecommunication network

Figure 1: Illustration of OEO conversions at the core nodes of a network (red line). Source: Detecon



A more attractive approach is to transform the network core nodes to an all-optical solution without electronic conversion. The core network becomes transparent meaning the nodes are then independent of data rate, format or protocol transported across the network.

2.2 Optical Domain - Escape Pot and Solution

Historically, economic efficiencies and technological performance improvement in backbone networks have often been achieved by substituting photonics with electronics. This trend started with replacing regenerators, installed every 40-80km, with in-line optical amplifiers. The benefit materialized in decreased power consumption, reduced number of components, and facilitated & accelerated network upgradeability. The introduction of optical amplifiers solved many problems on interconnects (e.g. physical fiber). However, one challenge had not been resolved/addressed yet. The electronic bottleneck likely to occur at the network nodes, the point where switching and routing takes place.1

Focusing on nodes, Reconfigurable Optical Add-Drop Multiplexers (ROADM) and Micro-Electro Mechanical Systems (MEMS) were recently introduced. This reconfigurable solution enabled carriers & operators to lower operational and capital costs for their optical networks and is currently the most popular form of photonic solution in networks. A ROADM and/or MEMS can route optical wavelengths through the core network without converting the signal to the electronic domain. The concept is commonly known as optical networking/switching or wavelength/lambda routing. The latest generations are multi-degree ROADM and offer any-port-to-any-port interconnectivity. Compared to the predecessor, simpler versions such as wavelength blockers (single-input, single output) or wavelength selective switches (WSS, single input, multiple output), the multi-degree ROADM supports both meshed and ring network topologies at interconnection nodes.

However, switching wavelengths is similar to circuit switching in the electronic domain as a dedicated path must be established first between source and destination. Apparently, using an approach related to circuit switching has a negative impact on the bandwidth efficiency, routing performance, and network utilization. Data traffic across a network is of statistically bursty nature, a behavior for which TDM is sub-optimal. Carriers and operators are moving away from TDM towards packet switched networks where routing/switching decisions are made “on-the-fly” (= data signals are already in the way).

The question arises, how to further minimize the electronic bottleneck at the nodes. One promising candidate is photonic packet switching (PPS) which will be the content of Chapter 4. However, before getting there, a brief introduction shall be given to photonic integrated circuits (PIC) as the PPS technology belongs to this group of devices.

1 The necessity for OEO conversion at networking nodes is rapidly changing. Recent advancements enable agility in

the photonic layer through a combination of optical switching, gain-flattened amplifiers, Ultra Long Haul optics,

dispersion compensation, and full-spectrum tunability. These technologies make it possible for wavelengths to be

purely optically networked up to several thousands of kilometres via intermediate multidirectional nodes, thereby

bypassing the OEO transitions at intermediate nodes.



3 Photons invading Circuit Boards

3.1 Photonic Integrated Circuits – The Optical Chip

Photonic Integrated Circuits (PICs) are the optical counterparts of today’s Electronic Integrated Circuits (EICs), following the same approach to move towards System-on-Chips (SoC, see Detecon/Intel, 2007 “Convergence on a Chip”). The goal of photonic integration is similar; to combine multiple optical functions together on the very same material/substrate (in almost all cases a semiconductor wafer). The driving motivation is to generate savings in manufacturing cost, material cost, space, power consumption and increase reliability. The integration includes passive functions such as waveguides, filters, switches, multiplexers, couplers, variable optical attenuators and active functions such as lasing, modulation, PIN detection, and amplification.

The basic principle of enabling light signals/pulses to propagate in a controlled fashion is optical wave-guiding. In many cases the waveguides is simply a strip of material on top of the microchip. As the refractive index of the material is higher than the surrounding air, light which is injected into this guide remains inside (Total Internal Reflection = TIR).

PICs are aiming to mimic all functionalities of today’s electronic circuits. Hereby, nanotechnology plays a fundamental and crucial role. Without the advances in fabrication technology none of recently demonstrated optical on-chip components (such as splitters, modulators, buffers, etc…) would have been possible. Hence the fabrication quality of these nano-photonic components is crucial. The light would have been simply scattered out of the waveguide due to high surface roughness and/or lack of precision in manufactured component geometry. Meanwhile, PICs have been demonstrated the capability to guide & switch light in the picosecond regime (1 picosecond = 10-12 seconds and equals 1 THz switching speed).

There is a reason for the strong activity in the field/market of PIC. On chip optical connections could be 100 times faster and use one-tenth as much power as predicted by IBM. Although photonic integration has much in common with micro-electronic integration, a major difference is the variety of devices and device-principles in photonics.

Of course, compared to the mature and well established electronic IC Technology, PIC is still in an early stage. State of the art PICs today provide about 50-230 components/functions per chip. State of the art electronic ICs offer more than one billion combined functions per chip. Nevertheless, the commercial market entry is predicted to be very soon. With respect to the above mentioned advantages (speed and power consumption), PICs impose a serious threat to electronics for specific applications, and might be even of disruptive nature. However, the first commercially available generation of PICs will not be entirely based on optics. It will be more like a hybrid version, partly optics, and partly electronics. For this reason one of the major goals of those companies focusing on PIC (Chapter 3.2) is to guarantee fabrication compatibility with CMOS technology (Complementary Metal Oxide Semiconductor). Therefore, a majority PIC architectures is either based on InP or Silicon both with individual pro and cons and to be chosen depending on the functionality of the PIC (for instance, InP is known to own better physical properties with respect to lasing, detecting, and, amplifying).



With a PIC the electronics is (theoretically) removed, and a single optical fiber comes closer to its potential of economically and efficiently carrying data and performs terabit aggregate switching speed. This is beyond current electronic switching technologies. Typically, IP routers can process individual channels within a WDM link at 2.5-40Gbps. Therefore, some hundred of switching line cards & module interfaces would be required to terminate a single fiber carrying e.g. 4Tbps.

Figure 2 on the right illustrates the design space for electronic and all-optical cross connects. As electronics is reaching its limits (by means of performance and in particular feasibility) the design space for optical cross-connects appears - at least by today’s view - fairly unlimited. Another approach industrial R&D is also drawing its attention to is Optical Time Division Multiplexing (OTDM). Although not yet widely implemented also here PIC technology will increase the per-channel data rates. It should be noted that TDM in the electronic domain is approaching it limits and OTDM technology will even further increase pressure on resolving the currently existing electronic bottleneck at the network nodes.

3.2 The Nanophotonic Market for Telecommunications

3.2.1 Motivation

As noted earlier, the driver for operators & carriers to look for innovations in the field of optical communications is simply the exploding demand for bandwidth. Customers today are generating a lot of pressure, they are easy to disappoint and difficult to satisfy; a challenging situation and one reason for strong customer fluctuations among service providers. The end-consumer does not care about the deployed network technology, he simply expects flawless high-quality video streaming, fast downloads and peer-to-peer applications; all combined with an abundant number of other simultaneously running online activities. The past years have shown - together with forecasts for the years to come - that our life and the way to communicate is rapidly moving into the digital ether.

2 The figure is a forecast which is expanding input data from IEEE Communications Magazine, March 2002.

Design space for electronic vs. all optical cross-connects

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Figure 2: With respect to number of ports and data rates optical cross connects cover a design space which is at least one order of magnitude larger than for electronics.

Source: Detecon 2



Photonic Integrated Circuits and advances in optical interconnects have the potential to kill two birds with one stone: a significant increase in bandwidth capacity and at the same time reducing operational expenses (see Chapter 5 for a comparison of electronic and optical nodes). For operators & carriers this is music to the ears; the ultimate solution to ease existing and upcoming pressure points.

Consequently, the question arises if such ‘almighty’ photonic components/devices are already commercially available. The answer is “yes, but actually no”. It’s true, the PIC technology has left basic R&D a while ago and has now even hatched out of applied research laboratories entering the commercial stage. The first products have hit the market in this very year 2008. However, mass production has not been reached yet. From this point of view the market is still in its burgeoning stage and accordingly has not achieved the same maturity level as their electronic counterparts do already offer. But with respect to fast-paced advances in Nanotechnology (the breeding ground for any innovation with PICs), the market is expected to take off very fast. And in case the cost/bandwidth (price per bit) advantages are beneficial – even after subtracting the hype around nanophotonics - analysts agree upon that the impact of PICs is going to be of very disruptive nature for today’s market of electronic telecommunications components.

The race has just begun and it is not only between optical component vendors but also with electronic component vendors, the current ‘top dogs’ of the market. They are ramping up as well. Impressive advances have been demonstrated in the field of microchip technology yielding in low-power consuming multi-core processors. However, bandwidth limitations due to copper links as well as on-chip global wiring scaling problems have not been fully resolved yet (see Detecon Paper: Convergence on a Chip, 2007). It is worth mentioning that the International Technology Roadmap for Semiconductors ITRS has identified optical interconnects as a promising candidate to address these scaling problems. Again, without nanophotonic technology this would not be possible at all.

This chapter will draw it attention to the current situation of the PIC market (and beyond) as well as forecast predictions on how this young technology field will grow. The rule is simple: What manufacturers/vendors do not have on their roadmaps will hardly materialize as a product and will not find its way into the network of operators/carriers. The approach of this chapter is actually to give a larger overview about the optical market in general, to briefly review current technologies, and eventually to focus on activities in the (nano)-photonic telecommunications community with an estimate of when such products will hit the market. The overview will therefore not be restricted to photonic packet switching devices as it is just one single product within a potentially much larger market seeded by nanophotonics. This overview will enable to enhance the intuition of a companies’ management level in which direction telecommunication technology is most likely moving in the years ahead.

3.2.2 Market & Forecast

In general, the market for optical network equipment is prosperous and profitable. However, as new technologies are introduced older ones slowly vanish, mostly driven by the earlier mentioned demand for higher bandwidth, the usual product life cycle.



OXE: Transmission technologies such as SDH, SONET as well as node technologies like Digital Cross Connects (DXS, DCS) are predicted to experience a turning point in their Compound Annual Growth Rates (CAGR). While still positive in 2007, the market growth reverses into negative values from 2008 on, yielding in CAGR of -4% to -10% in the year 2011 (not shown). This trend reflects the fact that circuit-switched based technologies are steadily perishing.

In contrast to this, some other market segments are expected to have strong growth such as Optical Exchange Equipment (OXE). OXE is defined as any kind of network equipment for nodes which can handle traffic in the optical layer only, hence does not depend on higher client layers anymore. Figure 3 shows that the market for OXE will double between 2007 and 2011 and exceeding 2 billion dollars. This corresponds to a CAGR of 20%3. Similar growth is expected for transmission technologies such as long-haul DWDM & MWDM, reaching 4.5 and 2.5 billion dollars with CAGR of 9% and 14% in 2011, respectively (not shown).

The take-home message is that financial investments for network upgrades and new network deployments are clearly shifting to technologies which are capable of higher bandwidths with an optical layer largely independent from higher ones. Accordingly, manufacturers of network equipment are putting large efforts to develop and implement more intelligence & management capabilities into the optical domain covering both sides, interconnects as well as nodes.

ROADM: The latest and most popular generation of multiplexers for optical networks is the Multi-Degree ROADM. They fall into the category of OXE and as mentioned in Chapter 2.2, offer any-port-to-any-port interconnectivity and support mesh & ring network topologies at the nodes. The MD-ROADM is the closest one can get in terms of almost-unlimited flexibility, and, in addition, no conversion to the electrical domain is necessary anymore.

3 Note that OXE includes circuit-switched technologies.

Optical Exchange Equipment

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Figure 3: The OXE segment covers any kind of node equipment for handling traffic within the optical layer, hence, do not depend on

higher client layers. CAGR is predicted to be 20%. Source: Dataquest 2007



Although the current generation of MD-ROADM is quite powerful in terms of bandwidth, it is nevertheless somewhat curbed in scalability due to it circuit-switched based principles and the corresponding inflexibility to respond to random traffic bursts. A packet-based solution - at the optical layer – would remove this last barrier and fully unleash the potential provided by optics. Nevertheless, MD-ROADMs are currently state-of-the-art and, accordingly, in high demand. Figure 4 presents the MD-ROADM market and it projection until 2012.

The Average Selling Price (ASP) of MD-ROADM follows standard life cycle behavior and is declining throughout during the years (CAGR = -12%). However, the number of units sold is sharply rising (CAGR = + 60%). The combination of both numbers positions the revenue of the MD-ROADM market at a strong CAGR of +41%, reaching an estimated 130 million US$ in 2012. Note the low unit number for 2007 (Figure 4, 87 units). This is explained by the fact that MD-ROADMs have entered the market only a few months earlier in 20064. In 2010 we can expect colorless, directionless, 20 degree ROADMs again demonstrating the high degree of flexibility that ROADM technology adds to an optical network.

4 Note that in the optical community a clear non-ambiguous terminology is still not fully established. While some vendors/carriers use ‘MD-ROADM’ and ‘WSS’ interchangeably, others use the term ‘photonic cross-connect’ to clearly distinguish from Optical Cross Connects (OXC) which may still depend on OEO conversion. MD-ROADM are sometimes also called multi-degree wavelength cross connects (WXC).

The Multi-Degree ROADM Market

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Figure 4: Although the Average Selling Price (ASP) for MD-ROADM is decreasing, the overall revenue still rises due to a large demand for

deployment (increasing number of Units sold). It clearly indicates the move of networks towards optics, Source: Ovum 2008



Nanophotonics: Of course, there is a benefit in discussing the OXE market and in particular MD-ROADMs as this kind of equipment is currently available in the market. However, far more interesting is to determine the timeline and success rate of new devices/applications in the years to come, the ones which are fueled by innovations in nanophotonic technology. The performance of PPS – and more important its reproducibility - largely depends on manufacturing quality. The requirement for high quality is a tough one as it scales down to the dimensions of the ‘nanoworld’. For some applications this level of reliability has recently been achieved and as a result first nanophotonic based components have entered the market.

For example:

Reliability: Infinera has reported 80 million failure-free field operational hours with their PIC components. Already today, they have commercially available nanophotonic integrated products capable of 100Gbps per fiber (the chip is as small as a credit card). The PIC has 10 lambdas modulated at 10Gbps each. For next year a 400Gbps chip with 10 lambdas at 40Gbps each is announced. In 2018 a 4Tbps chip is expected which will put 40 lambdas, each at 100Gbps, onto one fiber.

Performance: Bell Labs researchers, in partnership with Alcatel-Thales’ III-V Lab and the optical solution company Kylia, have achieved successful transmission of 16.4Tbps of optical data over 2550km (164 lambdas at 100Gbps).

Silicon and InP are popular semiconductor materials but differ strongly in their physical properties. A viable short-term approach could be that companies introduce hybrid structures (different semiconductor materials combined on one chip) to achieve all functions the PIC is aimed to perform. As not all functions of EICs can be reproduced by PICs, this hybridization would go beyond optical components but also include electronic circuits in order to combine the full range of functionalities (e.g. active and passive ones). The near future PIC therefore would be a blend of optics and electronics based on different semiconductor materials; eventually being CMOS compatible to achieve economics-of-scale for mass production. In the framework of switches one could call this a ‘translucent hybrid PIC-based PPS’.

However, in the long run the future market will gather around silicon-based nanophotonic structures/devices as they show flawless compatibility with CMOS fabrication techniques of today with a high degree of expertise (stemming from electronic manufacturing). Also, recent publications suggest promising work-around with respect to lasing thresholds of the material. This particular field within nanophotonics is called Silicon Photonics. The immediate market will again succeed with hybrid approaches. To gain insight on when such nanophotonic components will reach a maturity level to enter mass production is of significant importance.



Figure 5 therefore gives a brief overview on some important functions within the field of

Optical Interconnects (Intra-Inter chip and board/backplane optical connections)

Data- and Telecom (switches, filters, waveguides, amplifiers, transceivers, etc…)

It shows the time-line (2007- 2015) for 6 selected fields/applications where nanophotonics will have a strong impact. The 4 different colors present the different stages of development:

The forecast is based on the MONA roadmap funded by the European Commission (MONA = Merging Optics and Nanotechnologies). For more than 2 years the knowledge from 300 industry and research experts from 27 different countries of the European Economic Area but also from and specialists Korea, Taiwan, Japan, and USA were collected, discussed and elaborated. Interviews took place covering the field of material development, equipment manufacturing, and technological applications. The MONA project was held in collaboration with the MIT (Massachusetts Institute of Technology) which had already worked on a Silicon Photonics roadmap (Opto-Electronic Integration in Silicon Working Group).

Industry is performing intensive work & research in the Datacom & Telecom field as agility and transparency (see also Chapter 4.1, Generic Overview) has been identified as the main challenge for future network deployments.

Roadmap of Nanophotonic Impact on Telco landscape

Optical Interconnects CAGR = 25% (2006-2009) with US$ 800M in 2009

2007 2008 2009 20152010 2011 201420132012 Chip to Chip link

All Si link

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Datacom &Telecom CAGR = 13% (2006-2009) with US$ 2.5B in 2009

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All Optical Devices (switches, amplifiers, add/drop filters…)

Passive PIC (waveguide, splitter, delay,…)2007 2008 2009 20152010 2011 201420132012

2007 2008 2009 20152010 2011 201420132012

Figure 5: According to the Roadmap Chip-to-chip links as well as optoelectronics integration for transceivers has reached the ‘photonics’ market in 2008. The market size of optical interconnects and

Datacom &Telecom is expected to be as large as 3 billion US$ in 2009. Source: MONA 2008

Basic R&D Applied R&D Mass ProductionFirst Products



As can be seen, first products with respect to optical interconnection between chips have been announced in 2008 and mass production is expected for next year. The same applies for active PICs for Datacom & Telecom. In 2009 the photonic/electronic integration will have gained a maturity level suitable for mass production. Passive PICs are about to follow in 2-3 years from now. Note this is less than a life cycle for network equipment, generally 4-5 years. Operators/carriers who currently consider purchasing equipment or upgrading their networks should keep this in mind. The most challenging application are - as mostly sophisticated - switches and add/drop filters on the nanoscale; the all-optical devices. The PPS belongs to this group. First products are expected for 2012. The CAGR for the group of optical interconnects is 25% while applications for Datacom & Telecom will reach 13%. The market size for 2009 is estimated to be 0.8 billion US$ and 2.5 billion US$, respectively.

A note with respect to the given timelines: As the market for manufacturer equipment for telecommunication is fast-paced and highly competitive, it cannot be excluded that in the meantime - while ‘waiting’ for nanophotonics to reach its maturity level - new advances and proposals for network transmission technology might emerge. One highly discussed candidate is P-OTN (Packet Optical Networks), a blend of packet network data technologies (e.g. Ethernet, MPLS) with optical network transmission technologies (e.g. WDM and ROADM). P-OTN is seen as one of the hot topics in optical networking in 2008. However, Nanophotonics will - without any doubt - also find its way into P-OTN. The near future situation of nanophotonic has been adequately described by the senior vice president of Intel Corporation's Digital Enterprise Group: „Today, optics is a niche technology. Tomorrow, it’s the mainstream of every chip that we build“.

3.2.3 Key Players

A large number of companies and start-ups around innovative photonics have entered the scene some years ago. But only a few survived the burst of the telecom bubble. However, some players survived and other newcomers were bold enough to enter the scene. We want to stress again that only those companies whose products are CMOS compatible will have a realistic chance to gain commercial success. One of the largest challenges still remains in fabrication of photonic telecommunication components. Naturally, a manufacturing process for photonic devices (such as PIC) which can be combined with existing techniques used in the electronic semiconductor sector is the most promising approach. Hence, the choice of material is an important key decision.

The following list shows currently known global key players in the field of photonic components for telecommunications.



Players (alphabetically sorted):

• 3S Photonics www.3sphotonics.com • Bell Labs (Alcatel Lucent) www.Alcatel-Lucent.com/BellLabs • Bookham www.bookham.com • Ericsson www.ericsson.com • Enablence Technologies www.enablence.com • Hewlett-Packard www.hpl.hp.com • IBM Corp. www.research.ibm.com/photonics • Infinera www.infinera.com • Intel Corp. www.intel.com/technology/silicon/sp • JDS Uniphase Corp. www.jdsu.com • Kotura Inc. www.kotura.com • Kylia www.kylia.com • Lightwire Inc. www.lightwire.com • Luxtera Inc. www.luxtera.com • NeoPhotonics www.neophotonics.com • PGT Photonics www.pgt-photonics.com • Sun Microsystems Inc. www.sun.com/servers/hpc • Translucent Communications www.translucentinc.com • US Conec Ltd. www.carolinasphotonics.com



4 Photonic Packet Switching

4.1 Generic Overview

Summarizing the three major trends in optical communication, the continuous increase in bandwidth, packets replacing circuits, and photonics replacing electronics it is clear that optical networks will be steadily evolving into Photonic Packet Switching (PPS) generations of networks. In a nutshell, the goal of PPS is

offering the same services as electronic packet switched networks provide

but performing at much higher speeds

avoiding any OEO conversions (in the data plane), and

preserving transparency of the payload data

Packet switching was introduced to increase efficiency of transporting bursty traffic across a network, a kind of traffic pattern TDM based technologies can only deal with in a sub-optimal manner.

The definition of a PPS-based network is an optical network capable of providing packet-switched services at the optical level. This should not be confused with wavelength routing or optical switching. Although for both switching/routing is done without OEO, PPS performs packet-switched services while the latter is based on a type of circuit-switching. Figure 6 illustrates the concept and function of a generic PPS node.

Typical Photonic Packet Switching node

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O/E

Figure 6: Typical node and functions required at a Photonic Packet Switching node. Source: Detecon



Input-Output: The different wavelengths are switched at different sections. For instance, all the “red” wavelengths entering from input 1 to 4 are optically (‘photonically’) switched in the upper section by using a 4X4 switch fabric. The number of inputs to the switch fabric corresponds to the number of input fibers while the number of wavelengths corresponds to the number of switching sections. After switching, the different wavelengths from the different sections are multiplexed into the output fibers again. Depending on the type of switch fabric used, amplification might be required after the switching process. As the packets travel through the node, they are not converted to the electronic domain, hence transparency is being preserved.

Buffer: The function of the buffer is to store a packet entering the node until the header has been processed and the switch fabric had been set up correctly. The length of the buffer depends on the time it takes to process the header and the time necessary to configure the switch fabric. The synchronizer’s function is to align the packets in time before entering the switch fabric, but only if the switch fabric requires synchronized packets.

Electronic Control: The function of the electronic control is to process the packet’s headers and control the photonic switching node. To accomplish this, a small percentage of the incoming optical power is split off. In the above figure four optical fibers enter the node each carrying four lambdas. After de-multiplexing the wavelengths, a portion of the optical power is tapped off (indicated by the black line) and converted to the electronic domain. There, only the headers are processed and the control signals are send to control the buffer, the synchronizer and the switch fabric.

Header: Most PPS proposals assume that the packet’s header is transmitted separately from the data payload and at a lower speed. The reason for the lower speed is simply to make it feasible for the electronics to process. Electronics is reaching its information processing capacity limits for beyond 40-100Gbps. Optics does not yet have the computing power to perform the control functions required at the PPS node. Photonic header processing in the future will be possible using e.g. NOLM (Non-linear Optical Loop Mirrors) or TOAD (Terahertz Optical Asymmetric De-multiplexer) technologies. To achieve carrier class availability, the scope of functions for header processing should include:

the route for the packet,

length of the packet,

prioritizing packets based on class of service,

maintaining topology information,

performance monitoring,

header rewriting, and

fault localization and bridging.

Switch Fabric: The most important building block of the PPS node is the switch fabric (right hand side within the switching sections in Figure 6). The photonic switches that are being used in wavelength routing (e.g. MEMS) can switch in the microsecond range. MEMS is therefore well suited for photonic switching in the cross connect domain, however, on the level of packet-switching this switching speed is not sufficient. To be capable of switching e.g. between IP packets, a photonic switching technology is required that is - at least - in the nanosecond to picoseconds regime, hence one million times faster. The following list gives an overview of currently available switching fabric technologies:



Opto-Mechanical switches use moving (rotating or alternating) mirrors, prisms, or holographic gratings to deflect light beams. The major limitation is the slow switching speed (micro-second), major advantages are low insertion loss and low crosstalk.

Electro-Optic switches use electro-optic materials to alter their refractive indices. The most promising technology to realize electro-optic switching is integrated optics. High switching speeds (nano-second range) are possible with electro-optic switches.

Acoustic-Optic switches use sound waves to deflect optical signals (Bragg deflection). The power of the sound waves controls the intensity of the deflected light while the angle of deflection can be tuned via the sound frequency. Switching speeds in the nano-seconds are feasible.

Magneto-Optic switches use magneto-optic materials that change their optical properties under the influence of a magnetic field and can switch in the nano-second range.

Opto-Optic switches where the light path of one light beam is controlled by another light beam. In such an all-optical switch, this is done by using the nonlinear optical response of the material (nonlinear = the response of the material does not scale proportional to the manipulating force). IBM has announced to have built a switch on a chip-level that can control the propagation of optical information by using light pulses instead of electrons. With this approach, picosecond switching times are possible.

4.2 Specific Example from R&D

Most of the efforts on PPS focus on the component level. Results from various industrial and academic research facilities have shown that photonic packet switching is indeed possible.

One example is to use the Active Vertical Coupler Optical Cross-Point Switch (AVC-OXS)5 as the switching fabric in a PPS node. The AVC-OXS has 4 optical inputs and four optical outputs. The top view of the AVC-OXS can be seen in Figure 7 on the right. Each of the 4 inputs consists of passive waveguides with a width of 3-5μm and separated by 500μm and are used to guide the light into the OXS. The 4 outputs also consist of passive waveguides, again separated with a distance of 500μm.

5 Developed by the University of Bristol, UK

Active Vertical Coupler Optical Cross-point Switch (AVC-OXS)

Figure 7: A 4x4 input-output optical switch with 16 cross-points. Source: Van der Merwe



They intersect perpendicularly with the input waveguides. These passive waveguides are made from InGaAsP. The 4 input and output waveguides are deposited on top of an InP substrate and intersect, similar to a chess board, at 16 locations.

A three-dimensional picture of a 2x2 AVC-OXS is shown in Figure 8. On top of each of the waveguide intersections, an active layer is deposited. Together with the passive lower waveguide it forms an active vertical coupler. Active in this sense means that the material can be manipulated to impose either a significant loss or gain on the incoming optical signal. With an external power source the loss & gain and refractive index can be modulated by injecting an electrical current. As shown in the inset of the figure, one active vertical coupler is on top of the input waveguide, the other on top of the output waveguide (white). A total internal reflection mirror (indicated as TIR) cuts the corner of the active waveguides right above the cross point. This intersection (=cross point) actually represents the switch cell.

The switch cell can be operated in ON / OFF state. The injection of carriers into the active region turns the device ON. The following happens: The electrical current injects electrons into the active waveguide, generates gain and lowers the refractive until it matches the value of the bottom passive waveguide. As the index is now the same, the input light signal can propagate upwards into the active waveguide (‘coupling’, see also the bended arrow in the inset of the figure). This occurs at the first cross-point being in the ON state. The TIR mirror then redirects the light signal towards the output where it is coupling back into the lower passive waveguide. The light exits the OXS at the specific passive output waveguide.

The AVC-OXS successfully operated in various PPS scenarios and demonstrated promising results with Bit Error Rates (BER) of less than 10-9. The tests and experiments used packets similar to those in Figure 9. Three different lengths (payload lengths) of packets are used. The header of the packet is at 155Mbps and the payload is at 10Gbps. Header and payload is separated by a guard time. The header contains information about the desired output port of the packet as well as the length of the packet. Total length of the header was 8bits.

3D view of switch cell

Figure 8: At the cross-points incoming light signals can be redirected via manipulating the refractive

index of the material. Source: Van der Merwe

A packet used for the PPS experiments

Figure 9: Header, guard time and payload for a data stream being read from the OXS. Source: Van der Merwe



These types of packets were generated and send to three of the AVC-OXS’s inputs synchronously. Processing of header and switch configuration requires about 114ns. For this, about 20 meters of optical buffer are integrated to compensate for packet delay. Its purpose is literally to ‘wait” for electronics to process. However, as mentioned in Chapter 4.1, new technologies will soon resolve this bottleneck as well.

4.3 Current Challenges & Considerations

When discussing, evaluating, and describing the PPS technology it is advisable to raise some self-critical questions. Points to be addresses are for instance:

How beneficial is it to have another high speed L1 packet-switch layer underneath an already existing packet switch layer (e.g. Layer 3, IP)? Will it be able to provide a better link utilization at all?

In today’s networks when packets arrive at the core, the traffic streams have already been processed via multiplexing and become less bursty in nature6. Having in addition an optical packet layer underneath the electrical packet layer may not help too much, since traffic – as just mentioned – has already lost a great part of its bursty behavior, thus has become more suitable for circuit switching. The statistical properties of the traffic (whether in the aggregation or core) have a very large influence on the success of PPS. PPS is only recommended for bursty core traffic patterns. As it is very likely that statistics of traffic won’t change in the core network of today and tomorrow the favorite switching method will be packet switching at the optical layer. However, within the community it is still an open question and needs to be studied/ monitored more closely.

How will PPS functionality be introduced into an exciting optical network? More importantly, how are protection, restoration, and management integrated into a network which is running entirely optically - even at the nodes?

Today, for all-optical networks, the primarily used technology is P-OTN (Packet Optical Transport Network). Management and control is performed by a dynamic optical control plane, e.g. GMPLS or G.ASON. These technologies have proven to transport packets on a carrier class level across optical networks. For the current state of PPS there are neither protocols nor recommendations available. The best successful approach would be to seamlessly migrate or extend current standards to PPS, instead of introducing new protocols specifically aimed at PPS.

Will Ethernet (PBT), NG-SONET/SDH and IP/MPLS act as replacement drivers for an IP/DWDM layer approach?

The answer is mostly likely to be “yes”. However, it will be restricted to the core transport network as here the largest demand for bandwidth and switching speeds are. IP/MPLS, Ethernet and NG-SONET/SDH type networks will still dominate in metro networks.

How will the challenge of “no optical RAM” and contention be resolved?

6 When looking at nodes, all packets coming from different inputs and destined for the same output are grouped together – thereby making the traffic smoother, in other words, less bursty for the next node.



Packets in the optical domain cannot be stored and retrieved yet in the same way as possible with electronic RAM. Although industrial R&D has successfully demonstrated the controlled delay of optical packets it is not yet commercially available. In an optical buffer one can store optical packets for only limited time but not retrieve them instantaneously on-demand. The need to dynamically store packets is actually to avoid contention. It occurs when two packets, owning the same wavelength but coming from different input ports, are destined to the same output port. Interference and loss of data would be the result. Hence, to overcome contention is one of the major challenges in PPS networks. Candidates for buffer-free switching are deflection routing (hot potato routing) or remaining in the wavelength domain. If dealt properly, it removes the need of storing or buffering optical packets.

Should the header remain constant throughout a PPS core network or if be rewritten at the nodes?

Deleting and rewriting the header at each node introduces the requirement for more electronics precision. However, it could be avoided by using traffic engineering together with an intelligent header technology which supports the payload throughout the PPS core network. This means only one header is required for the packet to be switched across the PPS network, no header rewriting necessary.

What are the design considerations and constrains if an “all-optical” PPS network is introduced?

Routes in the PPS network will not have similar signal quality. Due to linear and non-linear signal impairments in optical fiber networks, it may be advisable to initially design or limit the all-optical network to several sub-networks of limited geographic size which are optically isolated from other parts of the optical layer. Linear impairments for optical signals include for example (but are not limited to) amplifier spontaneous emissions, polarization mode dispersion, chromatic dispersion, polarization dependant loss, independency of signal power and affect wavelengths individually. Some of the non-linear impairments include: four-wave mixing, optical Kerr effect, self-phase modulation and stimulated Raman scattering. Also operational considerations like fault isolation suggests limiting the size of “transparent” domains (switching on the optical layer 1) as to ensure that all potential routes own adequate & comparable signal quality in all circuits.

4.4 Hybrid Solution: Optical Burst Switching

Current and ongoing R&D is also dealing with hybrid solutions to overcome drawbacks of PPS, simply because of technology has not evolved far enough yet. One candidate is Optical Burst Switching (OBS).

OBS combines the best of circuit switching and packet switching while avoiding their shortcomings to transport various lengths of packets or “bursts” with very efficient protocols across the optical network. A header is send over the optical network to reserve bandwidth or a path. The payload or burst follows with no electronic conversion and also no optical buffering is required. However, OBS is susceptible to traffic congestion in the core network. A combination with either lambda routing or also PPS with dedicated wavelengths for ROADM, PPS, and OBS) might be a favorable approach to resolve this shortcoming.

Matisse Networks has introduced an optical burst switching solution which is offered as a metro solution. Underlying technology takes advantage of optical amplification technology.



5 OPEX Considerations for a hypothetical 100Tbps Node

The purpose of this chapter is to perform a rough comparison in footprint and power consumption between the OEO approach and the of OOO approach. PPS equipment is not available on the market yet and therefore an exact comparison is not possible. However, for the sake of giving some ballpark figures, the following estimations should be accurate enough. The power consumption and space requirement will be evaluated for a hypothetical 100Tbps node.

5.1 OEO Approach

The equipment of 2 large market players will be used as examples. Juniper offers a high capacity IP/MPLS core router solution using the TX Matrix platform together with four T640 platforms. The TX Matrix is the central switching and routing element that interconnects up to four T640 chassis into a single routing entity with 32 slots and a sustainable throughput rate of 2.5Tbps.

Juniper:

The Juniper TX Matrix platform consumes 2.976kW of power and has dimensions 44x113x76cm (one shelf).

Each of the four Juniper T640 platforms consumes 4.517kW of power and has dimensions 44x95x79cm (one shelf).

Together the system uses 21.044kW of power and the space of five shelves/chassis to switch 2.5Tbps. With respect to the goal to achieve 100Tbps, one would need 40 of these systems to build a node capable of switching 100Tbps. This 100Tbps system will then consume 841.76kW of power (excluding room air-conditioning) and use 200 shelves.

Cisco:

The Cisco’s CRS-1 platform operates on the same principle. It consists of line card shelves containing the 40Gbps interfaces together with route processing cards, and shelf control cards. There is also the fabric shelf that connects multiple line card shelves.

• shelf is 60x213x104cm in dimension and consumes 9.1kW of power.

The system can scale into a 92Tbps switching node by connecting 72 line card shelves with 8 fabric shelves. This will mean 80 shelves are required and 859.04kW of power needed.



5.2 OOO Approach

With the OOO approach, the costs would be strongly dependent on the used switch fabric as well as the complexity of the electronics. For this comparison values from experiments as shown in R&D and described in the previous chapter will be used. It should be sufficient enough to project the potential values the OOO approach may have when introduced to the market. For the sake of minimizing the uncertainty given by this “hypothetical” transformation of values from a test/lab environment into a commercial level, a correction factor will be introduced. More details on this are given in Chapter 5.3.

PPS:

Packets are sent in 1μs timeslots (see also Chapter 0). The timeslot is divided into 25ns guard time in the beginning of the timeslot, 25ns guard time between header and payload as well as 25ns guard time at the end of the packet. Typically 25ns of time is reserved for the header in which 16 bits at 622Mbps can be transmitted. The payload occupies the rest of the packet, 800ns and is transmitted at 100Gbps. This corresponds to 80Gbps of information being transmitted on one wavelength through the node.

The node given in Chapter 6 has 4 fibers entering and leaving the node. Each fiber has 4 wavelengths yielding in 4x4 = 16 optical data streams. As described in Figure 6, the node would then operate with 4 sections (= covering the 4 wavelengths) having switching and controlling units for each wavelength. In principle a section does represent a line card as all the above functions can be manufactured and integrated onto a single line card. The node would therefore equal 4 line cards. The optical PPS node would have a switching capacity of 4 sections serving all 4 fibers each carrying 4 wavelengths per fiber yielding in 1.28Tbps (4x4x80Gbps).

This node represents a “small” switching node. However, considering DWDM technology of today, the node has the potential to be expanded to e.g. example 32 input fibers each carrying 64 wavelengths. The switching capacity would reach 163.840Tbps and is based on the same calculation as for the small node; 32 input fibers x 64 wavelengths x 80Gbps. In such a larger node one will require about 64 line cards (= number of wavelengths). This corresponds to 4 shelves.7

The power requirement of such a node is calculated from the electronic control circuit board plus the power required configuring the switch fabric. Form the research and tests presented in chapter 0, about 5.28W of power is required to process the header and configure the switch fabric per wavelength on each fiber. For the small node (4 input fibers with 4 lambdas) the total power requirement is about 84W. The larger node with 32 input fibers and 64 lambdas will approximately consume 10.813kW.

7 We assume 16 line cards fit into one shelf. The ‘small’ node with 4 cards would therefore correspond to a quarter filled shelf.



5.3 Correction & Comparison

The comparison is not exact but rather a ballpark figure. It serves to get a reasonable feeling for the OOO-PPS approach. However, the following should be kept in mind:

OEO:

With OEO approximately 840-860kW is required and 200/80 shelves to deploy the equipment. Note that these numbers are likely to decrease within the years as photonic integration will probably have a beneficial impact on the OEO approach as well.

The market roll-out of PPS still requires a few years. For the sake of fair comparison, the calculated numbers for the OEO approach must therefore be corrected downwards to cover advances in power consumption in electronics (triggered by newly developed low-power multi-core processor technologies, see Detecon/Intel “Convergence on a Chip”, 2007). Both technologies - OEO and OOO - should be streamlined to the same timeline, otherwise even a simple ballpark figure might fail.

OOO:

The optical packet structure is different compared to the OEO example and making it difficult to draw an exact comparison.

With the OOO approach no contention resolution techniques are considered. This may result in additional hardware and more complex electronics increasing power consumption. In case a different switch fabric is used the power will also be affected.

The projection of values from a test/lab environment into a commercial level contains a clear risk of uncertainty.

Therefore, the results for power consumption of the OEO approach will be scaled down by a 300% to accommodate above mentioned points. In the same way, the OOO values will be scaled upwards by 300%.

The comparison is summarized in Table 1. Even after the applying above corrections, the savings in space and power when deploying PPS-OOO nodes is almost one order of magnitude. This leaves no room for discussion. It also reflects and confirms prediction made by IBM, stating that “On-chip optical connections could be 100 times faster yet consuming only one-tenth of the power”.

OEO and OOO node comparison

Technology Switching Capacity Space Requirement Power Requirement

OEO by Juniper equipment

100Tbps 200 Shelves @ 44x113x76cm

280kW (down-scaled by factor 3)

OEO by Cisco Equipment

92Tbps 80 Shelves @ 60x213x104cm

290kW (down-scaled by factor 3)

OOO potential 163Tbps 4 Shelves @ 60x213x104cm

36kW (up-scaled by factor 3)

Table 1: Summary of space and power requirement for a hypothetical 100Tbps node



6 Summary

No doubt, bandwidth demand is rising and will keep rising. This places a high demand on the core nodes. Their electronic bottle neck – as of today – will simply not hold this demand. The migration to an all-optical backbone has more benefits than only high bandwidth support. This includes space and OPEX (less power + maintenance required) saving. Operators should take on the challenge and design their “Next Generation” optical core network architecture to easily include/extend it with PPS technology, combined with wavelength routing functions to ensure a highly efficient, reliable, and dynamic network.

Photonic packet switching is a special application within the field of photonics and combines the high capacity of optical technology with the flexibility of well established packet switching. It is regarded as a very promising candidate for all-optical networks in order to withstand the battle against increasing bandwidth demand and complexity of future networks. Photonics with respect to telecommunications is actually copy & pasting from electronics. With this, it has the advantage to evolve on a much shorter timescale rather than developing new functionalities from scratch. Photonics, as used in communications, is therefore a fast-paced technology sector, in particular supported by advances in nanophotonics. Components such as PIC and PPS will facilitate & accelerate the availability of extremely high bandwidths and enabling to leverage the efficiency of future all-optical fiber networks.

Although PPS offers much higher capacities than today’s electronic packet switching it will not completely take over and networks will not evolve within the next week into an “all-optical” network. Enhanced hybrid versions (operating on the electronic and optical level) will come first. The electronic domain is (still) required to perform BER, QoS, protection & restoration functions in the optical network. It is currently difficult and costly to achieve functions such as performance monitoring, sub-lambda grooming, advanced and flexible protection schemes, and dynamic line equalization on a photonics level.

But interestingly, it will be the current superior “intelligence” of electronics that will even support efficient & fast implementation of PPS. From this point of view, electronics is “paving the way for its own killer”. A good solution may be the approach to merge all 3 switching technologies into one core node as shown in Figure 10. Specific wavelengths could be used as all-optical circuit switching and only use the ROADM in the core node. Other wavelengths can be assigned to carry packet data and be either optically or electronically switched in the core node. The whole setup can be controlled with the dynamic control plane.

Functionality required in next generation core node

ROADM

PPSDXC

ROADM

PPSDXC

Figure 10: The next generation of optical network should have several switching technologies included in their core

nodes. (DXC – Digital Cross Connect) Source: Detecon



But the success of PPS strongly depends on the statistical nature of data traffic in the core. However, as it is bursty by nature, PPS-based technology is believed to have a good chance to penetrate the Telco equipment market. PPS will first be implemented in the core of the network pushing the IP/MPLS network away from the core into the metro network. While transmission and switching should be done photonically, the routing and forwarding will still be performed electronically. And it indicates that telecommunication networks will undergo decentralization as the “intelligence” will also migrate from the core into the metro network leaving only transmission and physical switching for the core network.

The ongoing OEO vs. OOO debate will continue for some time. But one thing is sure: NextGen optical networks will require both technologies. A marriage between electronic routing functions at the edge and photonic networking/switching in the core will deliver a more operationally agile, cost-effective core networking solution. Moving the network to include more photons and fewer electrons puts a high exclamation mark on Green IT, a very important concept these days among operators worldwide. To take full advantage of Green IT a clear differentiation between hype and reality will be necessary.



7 Literature

Agarwal, A. Garrett, K. and Giernatowicz, P.: Wavelength Management Devices for Dynamically Reconfigurable Networks, Lightwave Europe June 2003

Bishop, D. Giles, R. and Austin, G.: The Lucent Lambda Router: MEMS Technology of the Future Here Today, IEEE Communications Magazine March 2002

Chu, P. Lee, S. and Park, S.: MEMS: The Path to Large Optical Cross Connects, IEEE Communications Magazine March 2002

Dulkeith, E. Kellmereit, D. and Schmidt, D.: Convergence on a Chip – Potential Opportunities for Telco Industry, Detecon consulting GmbH 2007

Lightwave Magazine, http://lw.pennnet.com/

Listanti, M. Eramo, V. and Sabella, R.: Architectural and Technological Issues for Future Optical Internet Networks, IEEE Communications Magazine September 2000

Perrin, S.: Photonic Integration & the Future of Optical Networking, Heavy Reading vol. 6 March 2008

Ramaswami, R and Sivarajan, K.N.: Optical networks, a practical perspective, 2002

Saleh, B.E.A and Teich, M.C.: Fundamentals of Photonics, 1991

Strand, J. Chiu, A and Tkach, R.: Issues for Routing in the Optical Layer, IEEE Communications Magazine February 2001

Van der Merwe, J.S.: The Design of an Electro-Optic Control Interface for Photonic Packet Switching Applications with Contention Resolution Capabilities, 2006

Yoo, M. Qiao, C. and Dixit, S.: Optical Burst Switching for Service Differentiation in the Next-Generation Optical Internet, IEEE Communications Magazine February 2001,

Optical Expo 2008 – Dallas, Texas, USA

MONA (Merging Optics and Nanotechnologies): A European Roadmap for Photonics and Nanotechnologies, March 2008

Perrin, S.: Silicon Photonics: A Market takes Shape, Light Reading, Aug2008

Perrin, S.: The Future of Optical Transport Networks: 40G & the Road to 100G, Heavy Reading vol. 5 No.15, Nov 2007

Amber Jenkins: The Road to Nanophotonics, Nature Photonics, Vol2, May2008

Cooperson D. And Redpath I., Optical networks unit volume, ASP, and revenue history and forecast, 2005-2012, Ovum 2008

Kjeldsen P. Juan F., Akiyoshi I. and Tina T., Optical Transport Systems, Worldwide, 2002-2011 (2H07 Update),

Dataquest Inc, 2007 TPACK A/S: P-OTN: Packet Optical Network Transformation, June 2008



8 The Authors

Stefanus van der Merwe is Business Analyst for Detecon International GmbH in the Competence Practice Information Technology since 2007. His studies at the University of Pretoria in South Africa and University of Bristol in the United Kingdom resulted in a master degree in Electronic Engineering with a strong focus on optical fiber networks and photonic packet switching networks. Through numerous international projects and research experience, he has gained substantial knowledge of the trends and future demands of fiber optic telecommunication networks. The emphasis of his work lies in the development of solutions for telecommunications companies, including fixed access network design and transport network design. Stefanus van der Merwe can be reached at [email protected]

Dr. Kai Grunert is head of the group Fixed Access and Transport Technologies. The focus of his work is on the field of migration and integration of existing or future access networks in an NGN scenario which is optimal for the network operator. He studied engineering in Munich and earned his doctorate in engineering (Dr.-Ing.) at the Technical University of Berlin. He has 15 years experience in managing, leading and supervising telecom fixed network operator projects. He is international recognized for strategic telecommunication projects worldwide with special focus on wire line operators in Europe, Middle East and Asia. Kai Grunert can be reached at [email protected]

Dr. Eric Dulkeith is member of the Strategy & Innovation Group in Detecon’s Silicon Valley office in California. The main focus of his activities is on innovation management and business development of converging technologies & markets. Before joining Detecon, he worked at IBM Watson Research Center in New York on the analysis of future optical on-chip communication architectures. He was awarded the degree of Ph.D. in Physics from the University of Munich (LMU) for his work on nanosensor technology. He is the author of numerous publications and has given more than 30 written/oral contributions for international technology magazines, conferences, and workshops. Eric Dulkeith can be reached at [email protected]

Daniel Kellmereit is head of the Strategy & Innovation Group for Detecon in the US. His key focus areas are marketing & sales strategies, strategic partnerships and alliances, growth strategies, next generation fixed and mobile technologies & services as well as corporate development and market entry planning. Before working for Detecon, he was co-founder and CTO of EFM Technologies. He also consulted clients in information technology, communications, and media at Roland Berger Strategy Consultants. Mr. Kellmereit holds an MBA from Northwestern University, Kellogg School of Management. Daniel Kellmereit can be reached at [email protected]



9 The Company

Detecon International GmbH

Detecon International is a leading worldwide company for integrated management and technology consulting founded in 2002 from the merger of consulting firms DETECON and Diebold. Based on its comprehensive expertise in information and communication technology (ICT), Detecon provides consulting services to customers from all key industries. The company's focus is on the development of new business models, optimization of existing strategies and increase of corporate efficiency through strategy, organization and process improvements. This combined with Detecon's exceptional technological expertise enables us to provide consulting services along our customers' entire value-added chain.. The industry know-how of our consultants and the knowledge we have gained from successful management and ICT projects in over 100 countries forms the foundation of our services. Detecon is a subsidiary of T-Systems, the business customers brand of Deutsche Telekom.

Integrated Management and Technology Competence

We possess an excellent capability to translate our technological expertise and comprehensive industry and procedural knowledge into concrete strategies and solutions. From analysis to design and implementation, we use integrated, systematic and customer-oriented consulting approaches. These entail, among other things, the evaluation of core competencies, modular design of services, value-oriented client management and the development of efficient structures in order to be able to distinguish oneself on the market with innovative products. All of this makes companies in the global era more flexible and faster – at lower costs.

Detecon offers both horizontal services that are oriented towards all industries and can entail architecture, marketing or purchasing strategies, for example, as well as vertical consulting services that presuppose extensive industry knowledge. Detecon's particular strength in the ICT industry is documented by numerous domestic and international projects for telecommunications providers, mobile operators and regulatory authorities that focused on the development of networks and markets, evaluation of technologies and standards or support during the merger and acquisition process.

Detecon International GmbH Oberkasselerstr. 2

53227 Bonn Telefon: +49 228 700 0

E-Mail: [email protected] Internet: www.detecon.com

Detecon Inc., Strategy & Innovation 128 Spear Street, 4th Floor

San Francisco, CA 94105, USA Phone: +1-703-476-4800

E-Mail: [email protected] Internet: www.deteconusa.com

Documents

Detecon Opinion Paper Photonic Packet Switching and the Evolution of Optical Networks