Fiber to the Antenna Fiber Certification...ORL is the ratio of reflected to transmitted optical power levels for the end-to-end fiber link. This represents the combined amount of reflected

Fiber to the Antenna

Fiber Certification

Summer 2018

2© 2018 Viavi Solutions Inc.www.viavisolutions.com

FTTA Installation Webinars

• Fiber Inspection and Connectivity• Cable and Antenna Test• Fronthaul Installation Test• Fiber Certification

For more information, visit viavisolutions.com/ftta

http://www.viavisolutions.com/


Fiber Up the Tower – Interconnects

BBU and Fiber Patch Panel

Junction Box

RRU/RRH

Fiber Trunk Cable

Tx & Rx Fibers

RRU/RRH Jumper

RRU = Remote Radio UnitRRH = Remote Radio HeadBBU = Base Band Unit

Front haul Physical Layer CharacteristicsFiber Type : Singlemode or MultimodeConnector Type: Duplex LC/PC


4© 2018 Viavi Solutions Inc.www.viavisolutions.com 4© 2017 Viavi Solutions Inc.www.viavisolutions.com

Inspection




Inspect Before You Connect!Fiber inspection/cleaning of the patch cord and bulkhead sides are SIMPLE steps with immense benefits. Connectors behind the bulkhead are frequently dirty and problematic.

4 Connect2 Clean1 Inspect 3 Re-inspect

SUBJECTIVE INSPECTION

???

2.4um

3.0um

8.6um

FAIL

OBJECTIVE INSPECTION

IEC 61300-3-35 Sets Requirements for Connector Quality

Dirt, oil, pits, scratchesnot seen

VS

VS

• Tools need to be automated and adhere to the defined standards• Move away from subjective to objective assessment



MPO




First – What is MPO?

MPO (Multi-fiber Push On) is a connector for ribbon cables with 12 to 96 fibers (field usage is 12 or 24 fibers). Connectors for singlemode fiber have angled ends to minimize back-reflection, while multimode fiber versions typically have flat ends.

Fan-out/Break-out MPO cableOR native support in SFP



Fiber Plug & Play or Plug & Pray?

Particle of Dirt

Air Gap

1

2

3

45

6

7

8

9

1011

12

Dirt

Back Reflection

Insertion Loss

CONTAMINATION is the #1 source of troubleshooting in optical networks.

Responsible for around 80% of failures



Insertion Loss (IL)




Insertion Loss (IL)• IL testing assesses how much optical power is lost across an optical link. If there is too

much link loss, an optical receiver (SFP or QSFP) will not function correctly. • Losses are due to fiber losses, splice and connector losses• When testing MM fiber, LS must be encircled flux compliant • Referencing (or zeroing) is key for accurate or realistic results

- Takes out losses due to patch cords leaving only the fiber of the installation• Design docs will specify total allowable link loss (or link budget) that cannot be exceeded

Light Source Power MeterPin

Pout

IL (dB) = Pin (dBm) – Pout (dBm)



A Word On Referencing

Tx FiberRx Fiber

Loopback Device

Light Source

Power Meter

1 cord reference

3 cord reference(using loopback device as 3rd cord)

jumper cords/cables – reference fibers are best

Light Source

Power Meter

1

1 2

LS PM

LS

PM



Causes of IL• Contributors to link loss include fiber attenuation and loss through mated

connectors or splices. - Contaminated, damaged, or poorly mated connectors are the most common

sources for excess link loss (~80%). - Stress on the fiber by over-bending, pinching, or kinking (typically found in

RRU enclosures, junction boxes and fiber trays) is also a frequent source of problems. Microbend loss

Macrobend loss



Optical Return Loss (ORL)




Optical Return Loss (ORL)• ORL is the ratio of reflected to transmitted optical power levels for the end-to-end

fiber link. This represents the combined amount of reflected light from all the link components - connectors, splices plus the Rayleigh backscattering from the fiberitself.

• ORL usually only measured on SM fibers• Flat connectors will need terminating • Angled connector doesn’t need any termination

ORL (dB) = 10Log (PT/PB) (≥0)

PAPC PPC PAPC PAPC

PT

PF PF PF

ORL Meter(CombinedLS & PM)

PT: Output power of the light source

PAPC: Back-reflected power of APC connector

PPC: Back-reflected power of PC connector

PF: Backscattered power of fiber

PB: Total amount of back-reflected power



Causes of ORL• The largest contributor to reflected optical power is air gaps and connectors.

Exceeding ORL limits can cause data errors, increase system noise, and can sometimes damage transmitters in higher-power environments.



Optical Time Domain Reflectometry (OTDR)




OTDR Testing & Certification It’s the single most important tester used in the installation, maintenance & troubleshooting of fiber plant

T-BERD/MTS-2000 OTDR with FTTA-SLM

Most versatile of Fiber Test Tools• Detect, locate and measure events at any location on the

fiber link• Identifies events & impairments (splices, bends,

connectors, breaks)• Provides physical distance to each event/ impairment• Measures fiber attenuation loss of each event or

impairment• Provides reflectance / return loss values for each reflective

event or impairment• Manages the data collected and supports data reporting



OTDR Testing & Certification

Tx Feeder

Receive Lead

Rx Feeder

Launch Lead

Loopback Device

AB

CD

E F



Interpreting OTDR traces with Smart Link Mapper (SLM)Making OTDR results easy to read

Dedicated FTTA-SLM



Wavelength Division Multiplexing (WDM)




Types of WDM Networks

CWDM channels are spaced 20 nm apart DWDM channels are spaced ~0.4 to 0.8 nm apart

DWDM enables a much higher density, therefore a better usage of the fiber

8 CWDM Channels in the S+C+L band

Wavelength

Up to 96 DWDM Channels in the C Band

18 CWDM Channels



DWDM over CWDM Channel Expansion

DWDM

1550 nm

1570 nm

1510 nm

1530 nm

1590 nm

1490 nm

1470 nm

1610 nm

1550 nm

DWDMCW

DM

1547.72 nm

1548.51 nm

1549.32 nm

1550.12 nm

1550.92 nm

1551.72 nm

1552.52 nm

1553.33 nm

1570 nm

1510 nm

1530 nm

1590 nm

1490 nm

1470 nm

1610 nmCW

DM

1547.72 nm

1548.51 nm

1549.32 nm

1550.12 nm

1550.92 nm

1551.72 nm

1552.52 nm

1553.33 nm

To increase the capacity of an existing CWDM fiber optic network ,1530nm and 1550nm channels can be used to insert DWDM wavelengths.

Expanding CWDM networks with DWDM channels enables to achieve a much higher data transport capacity and connect more subscribers using the same fiber optic cable and infrastructure between the network sites

Example of 8 DWDM channels added to an existing 8-channel CWDM network



RAN Deployment ScenarioArchitecture

Cell SiteMobile

Switching Center

BSC/RNC SGW/MME

Backhaul

Dis

trib

uted

RA

NRRU

(Radio Radio Unit)

BBU(Baseband Unit)

FTTA (Fiber to the

Antenna)

Central Site

Mobile Switching Center

BSC/RNC SGW/MME

Cen

tral

ized

RA

N

Backhaul

RRU

BBU Hotel

FTTA

xWDM

Cell Site

Fibers



Services with xWDM

The risks• Longer wavelengths (L-band) more sensitive to bends• Delayed service/wavelength turn up• Repeat truck rolls – at own cost (contractors)• SLA penalties if you take down other services

Challenges• Validating specific wavelength routes and individual losses• Turn-up or troubleshooting without disrupting other

services/wavelengths• Number of fibers and wavelengths, total test time

What to test• At specific CWDM & DWDM wavelengths

• OTDR and LS • Verify individual power levels – channel test• Validate End-to-End Losses through MUX and DEMUX



Workflow & Reporting




Report Generation – Proof and Protection.

Birth Certificate – Prove Day 1 Fibre Performance and Quality of Work

Inspection and LossOTDR and Inspection



Pulling It All Together

Meter is properly set up• Firmware version• Configuration• Options deployed

Job is properly defined• Required tests• Proper limits• Named correctly

Job is properly executed• All assigned jobs completed• All tests performed/job• All tests passed

Data is properly managed• Collected upon meter sync• Organized per your org structure• Centrally available

Proper reporting available• Emailed on defined cadence• Custom/ad-hoc reports anytime• Per tech/group/region/division/…

Proper meter is available• Right model• Right options• Valid calibration



Conclusion




FTTA - Connector Certification / Losses / OTDR• Inspect and clean fiber end faces• Inspect and clean loopback device, reference

jumpers & light source

• Perform reference loss measurement• Connect loopback device• Perform loss measurement

• If no signal – use a VFL to validate continuity

• Inspect & clean Launch cable and connect to the OTDR

• Inspect & clean Receive Cable & Non Reflective Termination and connect

• Perform OTDR Measurement

Ste

p 1

Ste

p 2

Ste

p 3

Ste

p 4



Macrocell/FTTA Cell Site Deployment Solution

BBU

Junction Box

RRU/RRH

Fiber Trunk Cable

RRU/RRH Fiber Jumper

Front-haul

Backhaul

Junction Box

Rad

io

BB

U



VIAVI SmartOTDRWhite Papers• Deploying Reliable FTTA Networks• Important Factors for choosing an OTDR• Macrobend detection using an OTDR

Product Briefs and Brochures• FTTA-SLM application for T-BERD/MTS OTDR Platforms• Essentials of Fiber to the Antenna: Fiber Certification

Posters• Heterogeneous Network Testing• Understanding OTDR

More on viavisolutions.com/cellsiteinstallation

VIAVI OTDR Test Educational Resources


https://www.viavisolutions.com/en-us/literature/deploying-reliable-fiber-antenna-ftta-networks-white-paper-en.pdf

https://www.viavisolutions.com/en-us/literature/important-factors-choosing-optical-time-domain-reflectometer-otdr-white-paper-en.pdf

https://www.viavisolutions.com/en-us/literature/macrobend-detection-using-otdr-white-paper-en.pdf

https://www.viavisolutions.com/en-us/literature/ftta-slm-application-t-berd-mts-otdr-platforms-product-solution-briefs-en.pdf

https://www.viavisolutions.com/en-us/literature/essentials-fiber-antenna-fiber-certification-product-solution-briefs-en.pdf

https://comms.viavisolutions.com/lp-cmp?cp=vi95823&th=std&lang=en&_ga=2.160951549.1728293022.1526990961-158356058.1524239628&brw=pushsafari

https://comms.viavisolutions.com/lp-cmp?cp=vi45254&th=std&lang=en&_ga=2.4205367.524018432.1526990956-158356058.1524239628&brw=pushsafari

http://www.viavisolutions.com/cellsiteinstallation


Questions

Contact Doug Clague:[email protected]


www.viavisolutions.com


Documents

Fiber to the Antenna Fiber Certification...ORL is the ratio of reflected to transmitted optical power levels for the end-to-end fiber link. This represents the combined amount of reflected