Fiber.optics.tutorial

7/31/2019 Fiber.optics.tutorial

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Fiber Optics For BroadcastVideo Applications

Eric FankhauserV.P. Advanced Product Development


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Fiber Optics

Need for Fiber Optics technology isconstantly increasing

Driven by increasing data rates

Declining implementation cost

Many advantages

Extremely High Data Carrying Capacity

Low signal attenuation

Free From Electromagnetic Interference Lightweight


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Presentation Overview

Technologies / Building blocks available Lasers

Receivers

Fiber Multiplexing

Switching

System Design Considerations Application Examples


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Technologies Available

Transmitters (Light Sources) LEDs - 850/1310nm

Used with MMF up to 250Mb/s

Short distances


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FP and DFB Laser Spectrum

FP laser Emits multiple evenly spaced wavelengths

Spectral width = 4nm

DFB laser Tuned cavity to limit output to single oscillation / wavelength

Spectral width = 0.1nm

O

pticalOutput

Power(mW)

FWHM=4nm

O

pticalOutput

Power(mW)

FWHM=0.1nm

Wavelength(nm)

Wavelength(nm)

FP Laser Output DFB Laser Output

A B


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Which Laser Type is Better?

Fabry Perot Ideal for low cost pt-pt

MMF or SMF

Not suitable for WDMdue to +/- 30nm variation

Dispersion is a seriousissue at Gb/s rates

Distributed Feed Back Used in wavelength

division multiplexingsystems

Less susceptible todispersion than FP laser

Used for medium andlong haul applications


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Technologies Available

Receivers (Detectors) PIN Photodiodes

Silicon for shorter s (eg 850nm)

InGaAs for longer s (eg 1310/1550nm) Good optical sensitivity

Avalanche Photodiodes (APDs)

Up to 50% more sensitivity than PIN diodes Primarily for extended distances in Gb/s rates

Much higher cost than PIN diodes


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Multi-Mode

50/62.5um core, 125um clad

Atten-MHz/km: 200 MHz/km

Atten-dB/km: 3dB @ 850nm

MMF has an orange jacket

Single-Mode

9um core, 125um cladding Atten-dB/km: 0.4/0.3dB

1310nm/1550nm

SMF has a yellow jacket

Laser

Laser

Muliti Mode

Single Mode

Core

Cross section

Cladding

LED

Laser

Muliti Mode

Single Mode

Core

Cross section

Cladding

CoreCladding

Fiber Types


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Degradation In Fiber Optic Cable

Attenuation Loss of light power as the signal travels

through optical cable

Dispersion Spreading of signal pulses as they travel

through optical cable


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Attenuation Vs. Wavelength


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Light Propagation

Light propagatesdue to total internalreflection

Light > critical anglewill be confined tothe core

Light < critical anglewill be lost in thecladding


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Bending Loss

Bends introduce an interruption in thepath of light causing some of the opticalpower to leak into the cladding where it

is lost Always keep a minimum bending radius

of 5cm on all corners

When bundling fibers with tie wrapskeep them loose to avoid introducingmicro bending into the fiber


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Dispersion - Single-Mode

FP and DFB lasers have finite spectral widths andtransmit multiple wavelengths

Different wavelengths travel at different speeds over fiber

A pulse of light spreads as it travels through an opticalfiber eventually overlapping the neighboring pulse

Narrower sources (e.g DFB vs. FP) yield less dispersion

Issue at high rates (>1Ghz) for longer distances (>50Km)

Time

Transmitter Receiver


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Dispersion - Multi-Mode Fiber

Modal Dispersion

The larger the core of the fiber, the morerays can propagate making the dispersion

more noticeable

Dispersion determines the distance asignal can travel on a multi mode fiber


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Advances in Fiber Optic cable

SMF Reduction in the water peak

Reduction in loss per Km

Corning SMF28e Lucent AllWave

MMF Higher bandwidths

Most manus going to 50um, graded indexfiber


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Optimizing Fiber Usage

Multiplexing

TDM Time Division Multiplexing

WDM Wave Division Multiplexing


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Multiplexing - TDM

Done in the electrical domain

Can TDM Video+Audio+Data OR Many

Videos, Audios, Datas Increases efficiency of each wavelength

Max # of signals based on max link rate

TDMMultiplexed signal

Signal 1

Signal 2

Signal 3

Signal 4

TimeDivisionMultiplex

Signal 1

Signal 2

Signal 3

Signal 4

TimeDivision

De-multiplexSingle-mode Fiber


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Multiplexing - TDM

Latest developments in TDM No synchronization required between signals All

signals 100% independent

Low latency (


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Wavelengths travel independently

Data rate and signal format on eachwavelength is completely independent

Designed for SMF fiber

Signal 1

Signal 2

Signal 3

MUX

Signal 1

Signal 2

Signal 3

DEMUX

WDMMultiplexed signal

Single-mode Fiber

Signal 4 Signal 4

Multiplexing - WDM


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Multiplexing - WDM

WDM

Wave Division Multiplexing Earliest technology

Mux/Demux of two optical wavelengths

(1310nm/1550nm) Wide wavelength spacing means

Low cost, uncooled lasers can be used

Low cost, filters can be used

Limited usefulness due to low muxcount


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Multiplexing - DWDM

DWDM

Dense Wave Division Multiplexing Mux/Demux of narrowly spaced wavelengths

400 / 200 / 100 / 50 GHz Channel spacing

3.2 / 1.6 / 0.8 / 0.4 nm wavelength spacing Up to 160 wavelengths per fiber

Narrow spacing = higher cost implementation

More expensive lasers and filters to separate s

Primarily for Telco backbone Distance

Means to add uncompressed Video signals toexisting fiber


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Multiplexing - CWDM

CWDM

Coarse Wave Division Multiplexing Newest technology (ITU Std G.694.2)

Based on DWDM but simpler and more robust

Wider wavelength spacing (20 nm) Up to 18 wavelengths per fiber

Uses un-cooled lasers and simpler filters

Significant system cost savings over DWDM DWDM can be used with CWDM to increase

channel count or link budget


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CWDM Optical Spectrum

20nm spaced wavelengths


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DWDM vs. CWDM Spectrum

1470 1490 1510 1530 1550 1570 1590 1610

Wavelength

dB

1.6nm Spacing


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Optical Routing - Definitions

Optical Routers Optical IN , Optical OUT Photonic Routers Optical IN & OUT but

100% photonic path

OOO- Optical to Optical to Optical switching Optical switch fabric

OEO- Optical to Electrical to Optical

conversion Electrical switch fabric

Regenerative input and outputs


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Photonic Technologies

MEMS (Micro Electro-Mechanical System)

Liquid Crystal

MASS (Micro-Actuation and Sensing

System )
http://www.lucent.com/pressroom/images/Lambda3.jpg


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MEMS Technology

Steer the Mirror Tilted mirrors shunt light in various directions

2D MEMS Mirrors arrayed on a single level, or plane

Off or On state: Either deployed (on), not deployed (off)

3D MEMS Mirrors arrayed on two or more planes, allowing light to

be shaped in a broader range of ways

Fast switching speed (ns)

Photonic switch is 1:1 IN to OUT (i.e. no broadcastmode)
http://www.lucent.com/pressroom/images/Lambda3.jpg


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Liquid Crystal Technology

Gate the light No Moving Parts

Slow switch speed

Small sizes (32x32) Operation based on polarization:

One polarization component reflects off

surfaces Second polarization component transmits

through surface


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MASS Technology

Steer the fiber

Opto-mechanics uses piezoelectric actuators

Same technology as Hard Disk Readers and

Ink Jet Printer Heads

Small-scale opt mechanics: no sliding parts

Longer switch time (


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OE EOOE EOOE EOOE EO




X

EQEQEQEQEQEQ

EQEQEQEQ

EQEQEQEQ

EQEQ

CPUMonitoring

Interface

LocalIndication

Fiber

Inputs

ElectricalInputs

FiberOutputs

Electrical

Outputs

OEO Technology

High BWElectrical

XPNT


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OEO Routing

Optical Electrical conversion at inputs/outputs Provides optical gain (e.g. 23 dB)

High BW, rate agnostic electrical switching at core

SD, HD, Analog Video (digitized), RGBHV, DVI Fast switching (


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Regeneration - Optical vs Photonic

Photonic is a lossy device that provide nore-amplification or regeneration

Signal coming in at23dBm leaves at

25dBm OEO router provides 2R or 3R (re-amplify,

reclock, regenerate)

Signals come in at any level to25dBm Leave at7dBm (1310nm) or 0dBm (CWDM)


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Applications - Design Considerations

Types of signals Signal associations

Fiber infrastructure

Distance/Loss

Redundancy

Remote Monitoring


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Types of Signals

SDI

HDSDI

ANALOG

DVB-ASI

RGB

RS232/422/485

GPI/GPO

10/100 ETHERNET

GBE

FIBER CHANNEL

70/140 MHz I/F

L-BAND

CATV

SONET OC3/12

T1/E1

DS3/E3

AES

ANALOG

DOLBY E

INTERCOM

OPTICAL

ROUTING

WDM

CWDM

DWDM

VIDEO

AUDIO

CONTROL

DATACOM

RF

TELECOM

MULTI

WAVELENGTH

MULTI

FIBERORFacilityLINK - Fiber Optics Platform

SPLITTERS

+

PROTECTION

SWITCHING


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Design Considerations

Signal associations Video, audio, data

Together or separate - Issues

Fiber infrastructure MMFor SMF Many fibers or one fiber

Single clean run for your use (e.g. put in for you)

Leased fiber (multiple patches, fusion splices)

Distance/Loss Total path loss = (fiber+connectors+passives)

Distance can be deceiving - patches, connections,fusion splices


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Fault Protection Protection against fiber breaks

Important in CWDM and DWDM systems

Need 2:1 Auto-changeover function withswitching intelligence

Measurement of optical power levels on fiber

Ability to set optical thresholds Revert functions to control restoration


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Remote monitoring is key due to distance issues Monitor

Input signal presence and validity

Laser functionality and bias

Optical Link status and link errors

Pre-emptive Monitoring

Input cable equalization level

CRC errors on coax or fiber interface

Optical power monitoring

Data logging of all errord events

Error tracking and acknowledgment



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Diagnostics Interface


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Design Examples Single Link

SDI @

270Mb/s

HDSDI @

1.485Gb/sHD OE

Dispersion

40 Kms

SDI @

270Mb/s

HDSDI @

1.485Gb/sHD EO

SD OE40 Kms

SD EO-7dBm @ 1310nm

-23dBm

-32dBm

Loss Budget

-7dBm @ 1310nm

SD HD HD

FP DFB

TX Power (dBm) -7 -7 0

RX Sens (dBm) -32 -23 -23

Available Budget 25 16 23

Distance (Km) 40 40 40

Fiber Loss(0.35dB/km@1310)

14 14 14

Connectors 4 4 4

Connector Loss 1 1 1

Total Loss 15 15 15

Headroom 10 1 8

SD HD HD

FP DFP

FP Line width (nm) 4 4 0.2

Dispersion (ps/nm.km) 2 2 2

Distance (km) 40 40 40

Dispersion (ps) 320 320 16

RX Jitter Tolerance (UI) 0.4 0.4 0.4

RX Jitter Tolerance (ps) 1480 270 270

Headroom (ps) 1160 -50 254


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Post House Facility link - Legacy

E to O

SDI @

270Mb/s

HDSDI @

1.485Gb/s

HIPPI @

1.2Gb/s

E to O

O to O

O to O

O to E

Location #1 Location #2

O to ERS422

2 Kms

1510

WDM

1530

1550

1570

1510

1530

1550

1570

SDI @270Mb/s

HDSDI @

1.485Gb/s

HIPPI @

1.2Gb/s

SDI @

270Mb/s

HDSDI @

1.485Gb/s

HIPPI @

1.2Gb/s

O to E

E to O

E to O

O to O

O to O

1510

1530

1550

1570

1510

1530

1550

1570

SDI @

270Mb/s

HDSDI @

1.485Gb/s

SONET OC3

@155Mb/s

HIPPI @

1.2Gb/s

E to ORS4221310

1310

SONET OC3

@155Mb/s

SONET OC3

@155Mb/s

SONET OC3

@155Mb/s

1310

1310

1310

1310

1310

1310

CWDM M4 CWDM D4

CWDM M4 CWDM D4

WDM

O to E

ATM

Switch

ATM

Switch

ATM

Switch

O to E

ATM

Switch


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Post House Facility Link New

AES

E to O

O to E

SDI @

270Mb/s

HDSDI @

1.485Gb/s

E to O

O to E

Mux + EO

OE+Demux

O to E

E to O

Location #1 Location #2

RS422RS422

2 Kms

SDI @

270Mb/s

HDSDI @

1.485Gb/s

GBE

AES

Gbe

RS422 RS422

Analog VideoAnalog Audio

1310

CWDM

M16

CWDM

D16

Gbe

O to E

E to O

Demux+OE

EO + Mux

Analog Video

Analog Audio

Mux + EO

OE+Demux

Analog Video

Analog Audio

Demux+OE

EO + Mux

10/100 10/100

Mux +EO

Demux +OE

10/100 Mb/s

Ethernet

Demux +OE

Mux + EO

Analog Video

Analog Audio

10/100 Mb/s

Ethernet

GBE

Fib STL


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Coax to Fiber

Coax to Fiber

Coax to Fiber

Coax to Fiber

CH 1

CH 2

CH 3

CH 4

AudioMux

SDIVideo

with

Embedded Audio

6 AES

Audio

for

Radio

Fiber to Coax

Fiber to Coax

Fiber to Coax

Fiber to Coax

NTSC Enc

NTSC Enc

NTSC Enc

NTSC Enc

AudioDemux

Analog

Video

and

Audio

Fiber STLMonitoring

Points

6 AES

Audio

for

RadioMonitorin

g and

Control

Cat 5 to Fiber Fiber to Cat 5

BROADCAST CENTER CN TOWER

X
http://www.evertz.com/proddesc/7765AVM-4(FS).html


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RF Over fiber optics -Applications

Typical Satellite Application With SNMP Monitoring

LB EO LB OE

LB OE

SatelliteReceiver

Vertical

Horizontal

LNBPower

L-Band Downlink (950Mhz 2250Mhz)

IF OEC or Ku

Up ConvIF EO

Video Mod

IF Uplink (70/140Mhz)

HPA

LB EO

RemoteSNMP

Monitoring& Control

SatelliteReceiver

SatelliteReceiver

SatelliteReceiver

SatelliteReceiver

BPX-RF DA8-RFRouter

SatelliteReceiver

SatelliteReceiver

DA-RF

BPX-RF

Video Mod

DA-RF

BPX-RF

Ethernet/ SNMP

Ethernet/ SNMP

Ethernet/ SNMP


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Large Video MAN Fully protected

RSK

Pac TV

RSH

OneWilshire

VideoMan Nodes Layout

DT11/17/03

25 mi

25 mi

KNBC KRCAKVEA

BT

DirectTV

KCBS CNN9 Net

Australia

Intelsat

JapanTelecom

FoxSports

VYVXFiber

KSCI

KTTV

RSE

Fox

NCTC

4 mi

0.5

10.5

10.5

1.5

0.5

0.8

Extra 2.3

2.3 2.92.3

7.3

Ent ..Tonight

KTLA

CBS2.1

1.5 1.1 1.11.1

2.7

E!

0

0.5

6.2

0.7

Globesat

0.75KMEX

7.25

8 mi

5.5 mi

11 mi

13.5 mi

9.8 mi

KABCProspect

8 mi5.5 mi

LA Zoo

TVGaming 7.25 Dodger

Stadium2.5

5.75

7.5

KABCCircle seven


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Summary

Fiber is an ideal transport medium

No magic involved in using fiber

optics Many solution options available

Proper upfront system design

upfront prevents many headaches


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Questions

Eric [email protected]

www.evertz.com
mailto:[email protected]:[email protected]

Documents

Fiber.optics.tutorial