Light Path Networking 1 Light Propagation Light propagates

Light. Path Networking 1

Light Propagation Light propagates due to total internal reflection n Light > critical angle will be confined to the core n Light < critical angle will be lost in the cladding n 2

Fiber Types n Multi-Mode: supports hundreds paths for light. n Single-Mode: supports a single path for light 3

Fiber Types Multi-Mode n 50/62. 5 um core, 125 um clad n Atten-MHz/km: 200 MHz/km n Atten-d. B/km: 3 d. B @ 850 nm n MMF has an orange jacket Single-Mode n 9 um core, 125 um cladding n Atten-d. B/km: 0. 4/0. 3 d. B 1310 nm/1550 nm n SMF has a yellow jacket 4

Attenuation Vs. Wavelength 5

Degradation In Fiber Optic Cable n Attenuation n n Loss of light power as the signal travels through optical cable Dispersion n Spreading of signal pulses as they travel through optical cable 6

Technologies Available Transmitters (Light Sources) n LED’s - 850/1310 nm n n n Used with MMF up to 250 Mb/s Short distances <1 Km Semiconductor Lasers – 850/1310/1550 nm n n VCSEL’s, Fabry Perot and DFB 1310/1550 can be used with MMF or SMF Short to long distances Low to High data rates (Mb/s to Gb/s) 7

FP and DFB Laser Spectrum n FP laser n n n Emits multiple evenly spaced wavelengths Spectral width = 4 nm DFB laser n n Tuned cavity to limit output to single oscillation / wavelength Spectral width = 0. 1 nm 8

Which Laser Type is Better? n Fabry Perot n n Ideal for low cost pt-pt MMF or SMF Not suitable for WDM due to +/- 30 nm variation Dispersion is a serious issue at Gb/s rates n Distributed Feed Back n n n Used in wavelength division multiplexing systems Less susceptible to dispersion than FP laser Used for medium and long haul applications 9

Technologies Available Receivers (Detectors) n PIN Photodiodes n n Silicon for shorter ’s (eg 850 nm) In. Ga. As for longer ’s (eg 1310/1550 nm) Good optical sensitivity Avalanche Photodiodes (APD’s) n n n Up to 50% more sensitivity than PIN diodes Primarily for extended distances in Gb/s rates Much higher cost than PIN diodes 10

Dispersion - Single-Mode n n n FP and DFB lasers have finite spectral widths and transmit multiple wavelengths Different wavelengths travel at different speeds over fiber A pulse of light spreads as it travels through an optical fiber eventually overlapping the neighboring pulse Narrower sources (e. g DFB vs. FP) yield less dispersion Issue at high rates (>1 Ghz) for longer distances (>50 Km) 11

Dispersion - Multi-Mode Fiber Modal Dispersion n The larger the core of the fiber, the more rays can propagate making the dispersion more noticeable n Dispersion determines the distance a signal can travel on a multi mode fiber n 12

Attenuation n It is the reduction of light power over the length of the fiber. n n n It’s mainly caused by scattering. It depends on the transmission frequency. It’s measured in d. B/km ( ) 13

Chromatic Dispersion (CD) n Light from lasers consists of a range of wavelengths, each of which travels at a slightly different speed. This results to light pulse spreading over time. n n It’s measured in psec/nm/km. The chromatic dispersion effects increase for high rates. Source www. teraxion. com 14

Transmission Bands n n Optical transmission is conducted in wavelength regions, called “bands”. Commercial DWDM systems typically transmit at the C-band n n n Mainly because of the Erbium-Doped Fiber Amplifiers (EDFA). Commercial CWDM systems typically transmit at the S, C and L bands. ITU-T has defined the wavelength grid for x. WDM transmission n n G. 694. 1 recommendation for DWDM transmission, covering S, C and L bands. G. 694. 2 recommendation for CWDM transmission, covering O, E, S, C and L bands. Band Wavelength (nm) O E 1260 – 1360 – 1460 S C L U 1460 – 1530 – 1565 – 1625 – 1675 15

Single Mode Fiber Standards I n ITU-T G. 652 – standard Single Mode Fiber (SMF) or Non Dispersion Shifted Fiber (NDSF). n n The most commonly deployed fiber (95% of worldwide deployments). “Water Peak Region”: it is the wavelength region of approximately 80 nanometers (nm) centered on 1383 nm with high attenuation. 16

Single Mode Fiber Standards II n ITU-T G. 652 c - Low Water Peak Non Dispersion Shifted Fiber. 17

Single Mode Fiber Standards III n ITU-T G. 653 – Dispersion Shifted Fiber (DSF) n n It shifts the zero dispersion value within the C-band. Channels allocated at the C-band are seriously affected by noise due to nonlinear effects (Four Wave Mixing). 18

Single Mode Fiber Standards IV n ITU-T G. 655 – Non Zero Dispersion Shifted Fiber (NZDSF) n n Small amount of chromatic dispersion at Cband: minimization of nonlinear effects Optimized for DWDM transmission (C and L bands) 19

Single Mode Fiber Standards ITU-T Standard Name Typical Attenuation value (C-band) Typical CD value (C -band) Applicability G. 652 standard Single Mode Fiber 0. 25 d. B/km 17 ps/nm-km OK for x. WDM G. 652 c Low Water Peak SMF 0. 25 d. B/km 17 ps/nm-km G. 653 Dispersion. Shifted Fiber (DSF) 0. 25 d. B/km 0 ps/nm-km G. 655 Non-Zero Dispersion. Shifted Fiber (NZDSF) 0. 25 d. B/km 4. 5 ps/nm-km Good for CWDM Bad for x. WDM Good for DWDM 20

Multiplexing - WDM Multiplexed signal Signal 1 Signal 2 MUX Signal 1 DEMUX Signal 3 Signal 2 Signal 3 Single-mode Fiber Signal 4 Wavelengths travel independently n Data rate and signal format on each wavelength is completely independent n Designed for SMF fiber n 21

Multiplexing - WDM – Wave Division Multiplexing n Earliest technology n Mux/Demux of two optical wavelengths (1310 nm/1550 nm) n Wide wavelength spacing means n n n Low cost, uncooled lasers can be used Low cost, filters can be used Limited usefulness due to low mux count 22

Multiplexing - DWDM – Dense Wave Division Multiplexing n Mux/Demux of narrowly spaced wavelengths n n Up to 160 wavelengths per fiber Narrow spacing = higher cost implementation n 400 / 200 / 100 / 50 GHz Channel spacing 3. 2 / 1. 6 / 0. 8 / 0. 4 nm wavelength spacing More expensive lasers and filters to separate ’s Primarily for Telco backbone – Distance Means to add uncompressed Video signals to existing fiber 23

Multiplexing - CWDM – Coarse Wave Division Multiplexing n Newest technology (ITU Std G. 694. 2) n Based on DWDM but simpler and more robust n Wider wavelength spacing (20 nm) n Up to 18 wavelengths per fiber n Uses un-cooled lasers and simpler filters n Significant system cost savings over DWDM n DWDM can be used with CWDM to increase channel count or link budget 24

CWDM Optical Spectrum n 20 nm spaced wavelengths 25

DWDM vs. CWDM Spectrum 1. 6 nm Spacing d. B 1470 1490 1510 1530 1550 1570 1590 1610 Wavelength 26

x. WDM Technology Dense WDM 0, 8 nm 1470 1490 Fine channel spacing, 0. 8 nm typical • High precision stabilization of Lasers • High component cost /nm 1550 Coarse WDM • • Wide channel spacing, 20 nm typical • Lower precision of Lasers • Significantly lower component cost 20 nm 1510 1530 1550 1570 1590 1610 /nm 27

DWDM Migration Capacity Expansion 1470 1490 1510 1530 1550 1570 1590 1610 /nm • Each CWDM channel can be utilized with 8 DWDM channels • Resulting maximum system capacity: 8 x 8 = 64 DWDM channels • CWDM and DWDM channels can be mixed • Soft migration path 28

DWDM Migration CWDM to DWDM Channel utilization 2, 5 Gbps : 8 ch DWDM ch 2 : ch 8 CWDM DWDM ch 1 CWDM & DWDM ch 8 • 8 channel DWDM system per CWDM channel • Soft migration path • Mixing of CWDM and DWDM channels • No interruption of CWDM channels 29

Amplification CWDM vs. DWDM 80 km Requires 1 amplifier per wavelength CWDM wavelengths C-band (DWDM wavelengths) L-band n n n { { EDFA 1 EDFA amplifies all wavelengths in the C-band Requires 1 amplifier per wavelength EDFA: Erbium-doped Fibre Amplifier DWDM is typically used for longer distance transport, because EDFA amplifiers enable very long spans more cost-effectively than CWDM. Amplifiers typically cost approximately US$ 20 k or more 30

How Much Capacity ? 100 Gbps Duo-binary Wave-locker++ 1 b/s/Hz 16 symbol levels – 4 bits per symbol required. 256 symbol levels – 8 bits per symbol required. 40 Gbps NRZ/CS-RZ/ Wave-locker+ 10 G overlay 0. 4 b/s/Hz Duobinary Wave-locker+ 16 symbol levels – 4 bits per symbol No issue NRZ 0. 1 b/s/Hz Reduced reach Wave-locker NRZ 0. 2 b/s/Hz Reduced reach No ROADMs Wave-locker+ 0. 4 b/s/Hz 100 GHz 50 GHz 25 GHz 10 Gbps 0. 8 b/s/Hz 31

Optical Routing - Definitions Optical Routers – Optical IN , Optical OUT n Photonic Routers – Optical IN & OUT but 100% photonic path n OOO- Optical to Optical switching n n n Optical switch fabric OEO- Optical to Electrical to Optical conversion n n Electrical switch fabric Regenerative input and outputs 32

Photonic Technologies MEMS (Micro Electro-Mechanical System) n Liquid Crystal n MASS (Micro-Actuation and Sensing System ) n 33

n n n MEMS Technology Steer the Mirror Tilted mirrors shunt light in various directions 2 D MEMS n n n 3 D MEMS n n n Mirrors arrayed on a single level, or plane Off or On state: Either deployed (on), not deployed (off) 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 broadcast mode) 34

Liquid Crystal Technology n n n Gate the light No Moving Parts Slow switch speed Small sizes (32 x 32) Operation based on polarization: n n One polarization component reflects off surfaces Second polarization component transmits through surface 35

MASS Technology Steer the fiber n Opto-mechanics uses piezoelectric actuators n Same technology as Hard Disk Readers and Ink Jet Printer Heads n Small-scale opt mechanics: no sliding parts n Longer switch time (<10 msec) n 36

OEO Technology Fiber Inputs Electrical Inputs OE OE OE OE EQ EQ EQ EQ High BW Electrical XPNT X EO EO EO EO Fiber Outputs Electrical Outputs Monitoring Interface CPU Local Indication 37

OEO Routing n Optical <> Electrical conversion at inputs/outputs n n High BW, rate agnostic electrical switching at core n n n SD, HD, Analog Video (digitized), RGBHV, DVI Fast switching (<10 us) Full broadcast mode n n Provides optical gain (e. g. 23 d. B) One IN to ANY/Many outputs Build-in EO / OE to interface with coax plant n Save converter costs 38

Regeneration - Optical vs Photonic n Photonic is a lossy device that provide no reamplification or regeneration n n Signal coming in at – 23 d. Bm leaves at – 25 d. Bm OEO router provides 2 R or 3 R (re-amplify, reclock, regenerate) n n Signals come in at any level to – 25 d. Bm Leave at – 7 d. Bm (1310 nm) or 0 d. Bm (CWDM) 39

Applications - Design Considerations Types of signals n Signal associations n Fiber infrastructure n Distance/Loss n Redundancy n Remote Monitoring n 40

Types of Signals Facility. LINK - Fiber Optics Platform VIDEO AUDIO MULTI WAVELENGTH OR SDI HDSDI ANALOG DVB-ASI RGB MULTI FIBER AES ANALOG DOLBY E INTERCOM OPTICAL CONTROL DATACOM RF TELECOM WDM CWDM DWDM RS 232/422/485 GPI/GPO 10/100 ETHERNET GBE FIBER CHANNEL SPLITTERS + PROTECTION SWITCHING ROUTING 70/140 MHz I/F L-BAND CATV SONET OC 3/12 T 1/E 1 DS 3/E 3 41

Design Considerations Fault Protection n Protection against fiber breaks n Important in CWDM and DWDM systems n Need 2: 1 Auto-changeover function with “switching intelligence” n n n Measurement of optical power levels on fiber Ability to set optical thresholds Revert functions to control restoration 42

Design Considerations n n Remote monitoring is key due to distance issues Monitor n n Input signal presence and validity Laser functionality and bias Optical Link status and link errors Pre-emptive Monitoring n n n Input cable equalization level CRC errors on coax or fiber interface Optical power monitoring Data logging of all error’d events Error tracking and acknowledgment 43

Design Examples – Single Link -7 d. Bm @ 1310 nm SDI @ 270 Mb/s SD EO -32 d. Bm 40 Km’s -7 d. Bm @ 1310 nm HDSDI @ 1. 485 Gb/s HD EO Loss Budget SD SD OE -23 d. Bm 40 Km’s HD OE SDI @ 270 Mb/s HDSDI @ 1. 485 Gb/s Dispersion HD HD FP DFB SD HD HD FP DFP TX Power (d. Bm) -7 -7 0 FP Line width (nm) 4 4 0. 2 RX Sens (d. Bm) -32 -23 Dispersion (ps/nm. km) 2 2 2 Available Budget 25 16 23 Distance (km) 40 40 40 Distance (Km) 40 40 40 Dispersion (ps) 320 16 Fiber Loss (0. 35 d. B/km@1310) 14 14 14 32 0 RX Jitter Tolerance (UI) 0. 4 Connectors 4 4 4 RX Jitter Tolerance (ps) 1480 270 Connector Loss 1 1 1 Headroom (ps) -50 254 Total Loss 15 15 15 116 0 Headroom 10 1 8 44

Post House Facility Link – New Location #2 Location #1 SDI @ 270 Mb/s 1310 HDSDI @ 1. 485 Gb/s O to E E to O SDI @ 270 Mb/s HDSDI @ 1. 485 Gb/s Analog Video Mux + EO Demux+OE Analog Video Analog Audio OE+Demux EO + Mux Analog Audio Demux+OE Analog Video EO + Mux Analog Audio Analog Video Mux + EO Analog Audio OE+Demux GBE 10/100 Mb/s Ethernet RS 422 AES E to O CWDM D 16 CWDM M 16 2 Km’s Gbe 10/100 Mb/s Ethernet RS 422 Mux +EO Demux +OE Mux + EO GBE AES 45

RF Typical Over. Satellite fiber optics -Applications Application With SNMP Monitoring L-Band Downlink (950 Mhz – 2250 Mhz) Vertical Horizontal LNB Power LB EO LB OE Ethernet / SNMP BPX-RF DA 8 -RF Router BPX-RF Remote SNMP Monitoring & Control Ethernet / SNMP Satellite Receiver Satellite Receiver HPA C or Ku Up Conv IF OE IF EO DA-RF Video Mod BPX-RF IF Uplink (70/140 Mhz) 46

Large Video MAN – Fully protected KABC Circle seven KRCA KNBC 2. 3 7. 3 KVEA 2. 9 2. 3 5. 75 LA Zoo 2. 3 Extra KABC Prospect RSE 25 mi KCBS Fox TV Gaming Fox Sports KSCI Ent. . Tonight 7. 25 1. 1 1. 5 1. 1 9 Net Australia 2. 7 2. 1 4 mi CBS VYVX Fiber Dodger Stadium 11 mi 1. 5 0 2. 5 Intelsat RSH RSK 0. 5 5. 5 mi 8 mi 0. 5 8 mi 9. 8 mi 5. 5 mi 0. 5 KTTV CNN 1. 1 KTLA One Wilshire 6. 2 7. 5 E! 0. 8 NCTC Pac TV 7. 25 KMEX 0. 7 Japan Telecom 0. 75 Globesat Direct TV 10. 5 13. 5 mi 10. 5 BT 47

Single Fiber Technology 48

4 Gbps CWDM Link n SANET, AMREJ – cheapest solution n Gigabit Ethernet, Low cost switches as repeaters (Cisco 3550) CWDM 49

Modular x. WDM System Passive Optical Modules CWDM ch 1 CWDM ch 2 CWDM ch 3. . 8 ch. Mux Demux CWDM line Power 1 CWDM ch 8 A/D West Passive Optical ch 1 ch 2. . A/D East Power 2 ch 1 ch 2 A/D West ch 1. . ch 4 . . A/D East ch 1. . Ch 4 . . 2 ch. Add Drop Mux 4 ch. Add Drop Mux Line West Line Interf. Active Optical Line East Line West Line East Options: • 8 channels Mux/Demux • 2 channels Add/Drop • 4 channels Add/Drop 50

Modular x. WDM System Line Interface Modules Standard Duplex Internal Line Power 1 Standard Simplex Passive Optical Internal Line Interf. Protected West Power 2 Active Optical Protected East External West Internal West External East Internal East Options: • Standard Line Interface (duplex) • Standard Line Interface (simplex) • Protected Line Interface • Add/Drop Line Interface 51

Modular x. WDM System Configurable Channels (CWDM Lambdas) Wavelength color code • 1470 nm gray • 1490 nm violet • 1510 nm blue Power 1 Power 2 Passive Optical • 1530 nm green • 1550 nm yellow • 1570 nm orange • 1590 nm red • 1610 nm brown Line Interf. Active Optical 52

Modular x. WDM System Configurable Channels (Local Interface) Fiber Wavel. MM Speed Power 1 850 nm 1. 25 Gbps SM 1300 nm 2, 48 Gbps Power 2 Passive Optical Line Interf. Active Optical 53

Optical drop/insert mux 54

Multicast Drop and continue – optical splitter pipes n IPTV multicast n Broadband Video – put them all on the one wave-length n 55

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GMPLS: Technologies for Dynamic Optical Networks n n n GMPLS standards are still evolving for optical networks Growing interest for dynamic lightpath configurations Meriton’s path management includes a number of GMPLS concepts n n n Meriton will implement GMPLS in step with customer’s key requirements for mesh networking n n n OSPF routing on NEs (used for management network today) GMPLS LMP for auto network discovery, lightpath testing, and cable miswiring Pre-provisioned shared protection (enabled by GMPLS signaling) Dynamic (best-effort) signaled protection Operator signaled lightpaths (S-LPs) Client on-demand wavelengths (O-UNI signaling) Participation in initiatives such as Internet 2 HOPI, CANARIE UCLP, etc. , is critical 67