ummer is the time many vaca-tioners head to Europe, butgoing abroad is all business forRSoft Design Group. In June,

RSoft made two significant announce-ments regarding their expansionoverseas. First, the companyannounced a distribution and R&Drelationship with AlpsTelecommunications Software (ATS).Then, just weeks later, RSoft openedits newest office, RSoft DesignEurope, in the UK.

ATS is a start-up company found-ed via the I3P Incubator at thePolitecnico di Torino, Italy. The com-pany is distributing RSoft's system-level tools — including OptSim™ andLinkSIM™ — and its network-level tool,Artifex™, across the European Union (withthe exception of France). RSoft will con-tinue to directly sell MetroWAND™both domestically and abroad. RSoftproduct distribution in France will con-tinue to be handled by OPTOPRIM.RSoft and ATS also entered into a con-sulting relationship where ATS will col-laborate on research and developmentwith RSoft on RSoft's system-level tools.These agreements will significantlyenhance RSoft's sales channels in Europeand allow for the continued develop-ment of its system tools to better servecurrent and future RSoft customers.

Dr. Vittorio Curri, CEO of ATS, notes, "Thedistribution agreement we have signedis a great opportunity for both RSoft

Design Group and ATS. RSoft will be ableto take advantage of the well-knowntechnical skill of ATS' people, as well asto their experience in the market seg-ment. ATS will benefit by being a part-

ner of a company with deep market pen-etration and well-funded future plans.The ATS team, including myself, is real-ly delighted that the distribution agree-ment has been added to the collabo-ration contract already in place betweenATS and RSoft."

Back in England, RSoft Design Europehas been set up to sell RSoft's compo-nent design tools — includingB e a m P R O P ™ , F u l l W AV E ™ ,BandSOLVE™, GratingMOD™, andLaserMOD™ — in the EU. The newoffice will also allow RSoft to providetechnical support directly to the Europeancommunity, while further strengthen-ing RSoft's presence abroad.

John Horgan has been appointed gen-eral manager of RSoft Design Europe.

John has more than 18 years of expe-rience in sales, marketing, and techni-cal support in the electro-optics andphotonics industries. Most recently,John was the telecom products manager

at Optima Research Ltd., RSoft'sformer European distributor, wherehe dealt almost exclusively withRSoft's component design tools.(For more information, see "MeetJohn Horgan" on page 4.)

The new European office, as wellas the two ATS agreements, pro-vide the base by which future busi-ness can be grown throughout theEuropean Union, reinforcing RSoftDesign Group's position as the

market leader in the design, simulation, and optimization fields.

WHAT’S INSIDE

N F O E C , B o o t h 8 0 9 • E C O C , B o o t h 6 9 4 • L E O S , B o o t h 3 3 • S e p t e m b e r 2 0 0 3

Volume 2 Number 2

RSoft Design Group Heads To EuropeNew European Office And Partnership With ATS Increases RSoft's Presence Overseas

FullWAVE Version 3.0 Steps Up ToThe Challenge Of Photonic Devices’Complex Design Requirements

Meeting The Need For Speed:BandSOLVE Upgrade AcceleratesPhotonic Band Structure Calculations

RSoft Opens Its First EuropeanOffice: Meet John Horgan

GratingMOD Is Embraced ByGovernment, Universities, AndPrivate Industry

Breaking Down The Wall BetweenSimulation Of Electrical And OpticalDomains

Availability Analysis Is The Key ToReducing Network Operating Costs

In Brief

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hotonics engineers have increasinglycomplex design needs, especially in rap-idly developing areas of photonic crystal-related research and applications, as well

as in new areas where the FDTD method can be fea-sibly applied, such as micro-diffractive devices, sur-face plasmons, biophotonics, and VCSEL cavity design.The latest version of FullWAVE™ steps up to these designchallenges. Version 3.0 adds new functionality forboth 2D and 3D modeling which simplifies data meas-urement and post-processing, includes extended mate-rial models for anisotropic and metallic materials, andadds additional excitation types.

A FullWAVE FDTD simulationproduces large amounts of data,and it is important to providea convenient and sophisticatedinterface to extract useful data.FullWAVE utilizes time moni-tors — which make measure-ments as a function of timeduring a simulation — for thispurpose. This concept has beenexpanded in the latest version,so users now have access to allthe data produced by the FDTDalgorithm. Measurements cannow be made of specific fieldcomponents, allowing for almostlimitless post-processing options. In addition to the fielddata, several common electromagnetic parameterssuch as power, the Poynting vector, and energy den-sities in both the spatial and temporal domain can berecorded. Additionally, the frequency analysis optionshave been expanded to include both FFT and DFTanalysis. This provides users with added functionalityand allows for spectrum analysis at arbitrary frequen-cies.

Version 3.0 introduces support for anisotropic mate-rials. The refractive index of materials can now bedefined by an arbitrary index tensor, which allows forthe design and simulation of structures that dependon birefringent effects. Support for dispersive materi-als has also been improved. The Drude and Lorentz dis-persion models are now implemented, and allow forimproved simulation of metallic structures.

FullWAVE Version 3.0 also includes support for multi-ple launch fields with different spatial and temporal char-acteristics. This includes parameters such as position,wavelength, direction, polarization, and temporal exci-tation. Additionally, linear, circular, and arbitrary polar-

izations are now available. Thisallows for improved simulationof real-world excitation types.

While FullWAVE can be used asa stand-alone solution, it canalso be easily integrated withother RSoft device design toolssuch as BeamPROP™,G r a t i n g M O D ™ a n dBandSOLVE™ because of theshared RSoft CAD-layout inter-face that allows hybrid simulationon complicated photonicdevices.

As the only commercial photonic FDTD tool with a par-allel computing feature, FullWAVE's clustering capa-bility has been significantly improved in terms of sim-ulation capability, display, and post-processing. Theseadvancements make FullWAVE the only feasible sim-ulator for large-scale 2D and 3D modeling. Additionalperformance improvements in this new version makeFullWAVE the fastest, most memory-efficient tool onthe market.

FullWAVE Version 3.0 Steps Up To The ChallengeOf Photonic Devices' Complex Design Requirements

Figure 1. FullWAVE simulation results of a photonic band gap-based channel-dropping filter.

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he latest versionof RSoft DesignGroup’s photonicband structure

tool, BandSOLVE™, introduces twonew simulation modes providinggreater speed in calculation.BandSOLVE 1.2, released August,2003, now supports both inversionsymmetry and mode-seeding.

Most useful photonic crystalstructures display inversionsymmetry — if all spaceis inverted, the refrac-tive index distribu-tion is unchanged.For example, inmany 2Dstructures,thetransfor-mation x➝ -x, y➝-y produces an identi-cal structure. This seemingly sim-ple symmetry has a direct impact onthe eigenmodes of the photoniccrystal, in that their expansion in planewaves is real, instead of complex.New code that takes advantage ofthis difference can now produceidentical results in as little as 45percent of the time previouslyrequired. For large 3D problems,this timesavings is a huge advantageto the user. BandSOLVE 1.2 supportsinversion symmetry in one, two, orthree dimensions and activation ofthe feature requires only a singleswitch.

Similar or even better time effi-ciencies are realizable using theother new addition to BandSOLVE1.2: mode-reseeding. In band struc-ture work, engineers are invariablyrequired to solve numerous similarproblems. For instance, in con-structing a single band structure, aneigenvalue problem is solved formany wave vectors within theBrillouin zone. If the various wave

vectors are closely spaced, themodal solutions

are verysimilar in form.Therefore, the results atone wave vector often representa good first guess, or seed, for thesolutions at the next wave vector.Reseeding is remarkably effective,providing typical speed-ups of bet-ter than 100 percent. Moreover,the closer the scan in wave vector,the greater the improvement. High-resolution scans actually finish fasterthan low resolution scans! As usualin BandSOLVE, all the work is done

for the user — mode seeding isactivated with a single mouse click.

BandSOLVE 1.2 includes numerousother enhancements, including newmeasurements of polarization frac-tions and the McIsaac mode classfor photonic crystal fibers, and facil-ities for more flexible organizationof measurements. Considerableattention has been made to improv-ing BandSOLVE’s unique dual-modeinterface to the FDTD engine for cal-culating metallic and dispersive

band structures. Finally, an enhanced

ModeVIEWERprovides more

powerful data

browsing and new options forexporting graphs and mode profilesin a variety of image and animationformats.

BandSOLVE 1.2 is being demon-strated at the RSoft booth — stopby to see these latest enhance-ments firsthand.

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Meeting The Need For Speed:BandSOLVE 1.2 Accelerates Photonic Band Structure Calculations

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Defect mode for the

photonic crystal slab with

line defect shown in crystal

lattice. The simulation speed of

large 3D problems such as this

one benefit from BandSOLVE

1.2's support of inversion sym-

metry.

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Meet John Horgan:

John Horgan is the general manager of RSoft Design Europe,which opened in June. John has a degree in Applied Chemistryand a professional teaching qualification from Cambridge University.He has been involved in the sales and marketing of electro-opticsand photonic products for more than 15 years. John previously workedas a software engineer, writing code for analytical instruments beforemoving into the field of fast laser diagnostics. Since then, he hasworked for numerous European distributors, most recently atOptima Research as a product manager for RSoft's design toolsthroughout Europe. John spends his weekends racing motorcycles.

For more on the opening of RSoft Design Europe, see the cover storyin this issue.

RSoft Review: Why do you think the time is right for RSoftto open this new office?

John: The European office being opened now gives RSoft amuch higher profile in Europe. It is a bold move that shows

RSoft is very firmly here to stay.

With business in the telecom sector still generally depressed,it is more important than ever to maximize our chances of win-ning greater market share while also serving our existing cus-tomers to the very best level we can offer. By establishing a newsales and support base now, we will be perfectly positioned tohit the ground running and take full advantage of any oppor-tunities that arise as the market improves.

Although the telecom market is still suffering from the after-effects of over-production, there is some light on the horizon.For example, research and development in the area of photoniccrystal devices and fibers is currently showing some excitingsigns of growth. RSoft's BandSOLVE™ and FullWAVE™ toolsare specifically suited to work in this area. As researchers beginto produce better and more cost-effective designs using toolslike ours, companies will resume production of photonic devicesand fibers and that will hopefully pull the telecom industry backon its feet.

Much of this work is being undertaken by European univer-sities and companies, and part of the European office's func-tion will be to form working relationships with engineers inthese establishments in order to develop our tools along opti-mum lines.

RSoft Review: What will be the primary priorities of RSoftDesign Europe?

John: In addition to EU sales of our device-level tools, expand-ed European training is another important goal that will enableus to be more responsive to our European customer demandsfor training and support. In short, we are literally taking ourproducts and services to our customers, and the end resultshould be to the mutual benefit of everyone involved.

This expanded effort will help our partners in Europe whilecontinuing to improve our customer reach and solidifyingRSoft’s position as the global leader in its field.

RSoft Opens Its FirstEuropean Office

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ratingMOD™ is a pas-sive device analysis anddesign tool specifical-ly tailored for inte-

grated waveguide and fiber gratings.The newest member of RSoft's com-ponent design tool suite, GratingMODapplies a variety of powerful modesolvers and fast analysis techniques forsimulating gratings with nearly arbi-trary waveguide cross-section, chirp,and apodization. Advanced synthesiscapabilities include augmented Layer-Peeling for generating gratings frommeasured spectra, and a sophisticat-ed preconditioning feature that allowsthe input spectra to contain only ampli-tude. It can perform time-domainanalysis, handle dispersion, performmultimode and cladding mode analy-sis, and account for side coupling andvertical coupling. Extensive post-pro-

cessing features are also available.

GratingMOD uses the same user-friendly CAD layout tool as the other

tools in RSoft's device tool suite.Special graphical objects allow for

easy construction of complicated peri-odic structures. These structures canalso be parameterized, allowing fordesign optimization through auto-mated batch simulations. A signifi-cant advantage of this commonalityis that a GratingMOD layout can alsobe simulated directly by the other pas-sive device tools, such as RSoft'sBeamPROP™ and FullWAVE™.

For example, a grating designer canuse the synthesis module to create agrating that performs according tosome measured response, use theanalysis module to verify this per-formance, and, finally, use BeamPROPor FullWAVE to assess the fringingeffects or how the device might per-form with defects or misalignment.Additionally, the ability to simulate adesign with multiple tools helps tofilter out mistakes in the design pro-cedure.

GratingMOD is under constant devel-opment, and the next release willincorporate a variety of new features,including integration with LinkSIM™and OptSim™. Gratings, such as FiberBragg gratings (FBGs), have foundapplication in almost every part ofoptical networks, from performingtasks such as sensing, gain equaliza-tion, add/drop coupling, and disper-sion compensation, to optical timedomain reflectometry (OTDR) andchannel filtering. GratingMOD's abil-ity to communicate with LinkSIMallows grating designers to not onlydesign the physical characteristics ofFBGs, and other such gratings, but toverify how they will perform in anoptical system. Similarly, the design cri-teria for a grating may be extracted

from the system analysis, and passedto GratingMOD for synthesis.

GratingMOD Version 1.1 is scheduledfor release this autumn.

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GratingMOD Is Embraced ByGovernment, Universities, AndPrivate Industry For Analyzing AndSynthesizing Complicated GratingProfiles

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Figure 1. WDM multi-channel gratingspectrum.

Figure 2. 3D profile of a single apodized grating section.

Figure 3. 1D profile of several grating sections.

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Breaking Down The Wall Between Simulation Of Electrical And Optical DomainsOptSim's New SPICE Interface Makes It Easy

he performance of optical transmission sys-tems is simulated in the optical domain, whilethe electrical performance of transceiver com-ponents such as laser drivers is simulated in

the electrical domain. This complete separation leads tohigher development costs because the design of laser driv-ers and transceivers requires modeling and simulation inboth domains.

To optimize the transceiver circuit design for the lowest costand maximum performance, thelaser must be modeled accuratelywith the laser driver in the electricaldomain as well as the optical domain.Accurate electrical circuit-level mod-eling of the laser has always repre-sented a time-consuming and diffi-cult challenge for high-speed circuitdesigners. Because of the over-whelming complexity of an advancedelectrical circuit-level model for thelaser, the most common approach isthe use of a simple resistor capacitor model. This simple lin-ear model completely neglects the laser's substantially non-linear behavior, and doesn’t take into account laser charac-teristics like threshold current, turn-on delay, power satura-tion, and other important phenomena. These significantlimitations cause inaccurate simulation results of the electricalcircuit design, leading to poor designs and the need for

costly and time-consuming design-test-redesign cycles.

The OptSim SPICE Interface™ has been developed to addressthis problem by bridging the gap between the electrical andoptical domains. For example, with the OptSim Best-Fit LaserToolkit™, the user can generate the best mathematicalmodel for the laser based on the data sheet characteristics.This model, which is now shared between the electrical andoptical domains, can then be used for both optical systemsimulations as well as accurate electrical circuit simulations

via the OptSim SPICE Interface. Thiscapability finally provides the circuitdesigner with the power to simulatethe true load and driving conditionsof the laser in the context of the laserdriver circuit simulation. In addition,the impact of various electrical designscenarios on the optical system per-formance can be accurately deter-mined through simulations in OptSim.Other potential applications for thiscapability include the determination

of the laser driver design's influence on the pulse distortiondue to chromatic dispersion in the fiber, and investigationof signal integrity and electromagnetic interference issues.

With OptSim's new SPICE Interface, high-speed circuit design-ers can break down the wall between electrical and opticaldomains. –

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LinkSIM/OptSim Integration Update

Since the acquisition of ARTIS' intellectual property — including OptSim — was announced in January, RSoft has been workinghard on integrating its LinkSIM™ software with OptSim. Some technology from each tool has already been incorporated into theother in their most recent releases. RSoft is on target for a merged product with a new, advanced interface by the end of 2003.The new product will be fully compatible with both OptSim and LinkSIM, providing a seamless upgrade for users of both tools. Inaddition, it will include exciting new features solidifying its position as the leading tool for optical transmission system design andvalidation. A demo of the new tool is on display at our booth, so stop by and see the future today!

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Availability Analysis Is The Key ToReducing Network Operating Costs

etwork operators are under continued pres-sure to cut costs in today’s down market, soconfiguring their equipment cost-effective-ly to meet all service level agreements (SLAs)

becomes critical. To address this need, RSoft’s MetroWAND™Version 3.1, announced in July, has added the capability toperform availability analysis and calculate end-to-end serv-ice downtime. The availability analysis feature in MetroWANDcan be used by network service providers to model and ana-lyze the reliability of different network architectures such asring, mesh, point-to-point, and architectures with or with-out digital cross connects. In addition, equipment with sim-ilar functionality (such as add/drop multiplexers) can bemodeled for different reliability configurations. These relia-bility values can be used to cost-effectively configure the equip-ment in the network to meet all SLAs.

Given a network component’s failure characteristics — meantime to failure (MTTF) and mean time to repair (MTTR) —its availability is estimated. The tool can be used to input fail-ure characteristics of various network components includ-ing tributary cards, plug-ins, cross-connects, cable, andmore. If the user specifies routing based on maximum avail-

ability, the availability values are first used to perform max-imum availability routing. MetroWAND computes and orderspaths based on highest availability (most reliable path) whilemaintaining all other service constraints. Once the requestsare routed through reliable paths, the software calculates end-to-end path availability through a series combination of theavailability of all components the signal passes through.Next, end-to-end service availability over diverse paths by aparallel combination of path reliability is computed.

The availability values are then converted into downtime min-utes per year and displayed in the working path window asshown in Figures 1 and 2. The user could also study the impactof availability on the services by classifying the services basedon their downtime. For example, the number of services whichhave downtime of less than a minute per year, between 200-300 minutes per year, and those which have downtimegreater than 300 minutes are plotted in a graph.

An economic turnaround may be on the horizon, but evenduring a telecom recovery network operators will be chargedwith maintaining cost efficiencies. MetroWAND 3.1's avail-ability analysis features help service providers keep networkoperating costs at a minimum, while meeting customerSLAs. –

Figure 1. MetroWAND interface.

Figure 2. Service availability information.

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P h o n e : 9 1 4 . 9 2 3 . 2 1 6 4E m a i l : i n f o @ r s o f t d e s i g n . c o m We b : w w w . r s o f t d e s i g n . c o m

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VISIT US AT:

NFOEC 2003, Booth #809September 8-10, 2003Orlando, FL USA

Visit RSoft at our booth and join us for the followingsessions:

• Wednesday, September 10th: 1:30 PM - 3:00 PM"Link-Level Design, Analysis, and Simulation of Multimode Data Communication Systems" (Session B5: Video and Data in the Valencia Ballroom B/C)

• Wednesday, September 10th: 3:30 PM - 5:00 PM"The Impact of Ring vs. Mesh Architecture on Your Evolving Metropolitan Network" (Session B6: Metro Network Evolution in the Valencia Ballroom B/C)

• Thursday, September 11th: 8:30 AM – 10:00 AMRSoft's Brent Whitlock chairs Session F7: "Transmission over Fiber"

ECOC 2003,Booth #694September 22-24, 2003Rimini, Italy

LEOS 2003, Booth #33October 28-30, 2003Tucson, AZ USA

In The Media

A demo version of RSoft's LinkSIMoptical communications system simu-lation software is being bundled witha new textbook authored by HaroldKolimbiris. The book, "Fiber OpticsCommunications," is published byPrentice-Hall and is available now.

•RSoft is featured in the article"Simulation saves money on design,manufacture" in the August 2003FibreSystems Europe(www.fibers.org).

•Oxford Intelligence (www.oxint.com),an international business intelligenceand research group, chose RSoft tobe profiled in its CorpTracker service,which is available to subscribers atwww.corptracker.com. CorpTrackershowcases select companies that areexpanding operations in Europeand/or North America.

•VentureReporter interviewed RSoftCEO Dr. Robert Scarmozzino for its"Software Mergers & Acquisitions Q12003" report, published in April2003. The report is available to sub-scribers at www.venturereporter.net.

RSoft TrainingSeminarsVisitwww.rsoftdesign.com/support/traing.cfm for the latest details on our training semi-nars around the country. Can't find aconvenient location or time? We'll cometo you. E-mail us at info@rsoftdesign.comfor information on setting up RSoft train-ing seminars in your office, or evenonline.