Upcoming Technology & Standards in Fiber Optics. Rohit Agrawal Application Engineer

Transcription

1 Upcoming Technology & Standards in Fiber Optics Rohit Agrawal Application Engineer

2 Optical Wave Guide Optical Fiber: composed of at least two optically different materials Buffer coating cladding core Core: center optical layer of the fiber where the light is transmitted Cladding: outside optical layer that traps the light in the core and guides it alone Buffer coating: hard plastic coating that protects the glass from moisture or physical damage

3 Light Transmission Fundamentals Electrical Pulse IN Light Pulse Light Pulse Electrical Pulse OUT Electrical to Light Conversion Light to Electrical Conversion LED Light Source Photo- Detector Electrical Pulse In = Electrical Pulse Out Electrical /Optical Conversion on Each End

4 Basic Properties of Light Reflection Refraction Refraction is the bending of the path of a light due to its change in speed as it passes across the boundary separating two media Refractive Index = velocity of light in a vacuum velocity of light in a medium n(vacuum) = 1 n(air) = n(water) = 1.33 n(fiber) 1.46 Cladding (n 2 ) Core (n 1 ) n 1 >n 2

5 Light Transmission: Fundamentals In Fiber Light Propagation: Total internal reflection is required for light to travel through an optical fiber Cladding Reflection Total Internal Reflection Core Refraction Cladding Light will always change speed and direction when it moves from one substance (IOR) to another. The index of refraction for both core and cladding plus the angle of incidence determines whether reflection or refraction occurs

6 Light Transmission: Spectrum Wavelength is a characteristic of light that is emitted from the light source and is measured in nanometers (nm) Single-mode

7 Light Transmission: Attenuation The loss of light intensity as it propagates along the fiber Measured in db/km Wavelength dependent Lower attenuation typically extends reach for applications Power in Power out db = 10 log (Power out / Power in) 7

8 Light Transmission: Intrinsic Loss Absorption Fiber Scattering 8

9 Light Transmission: Extrinsic Loss Microbend Macrobend Cladding Core 9

10 Macro bending Rule of Thumb The rule of thumb for minimum bend radius is: 30mm for bare, single mode fiber 10 times the cable s outside diameter (O.D.) for un armored Cable 15 times the cable s O.D. for armored cable

11 Macro bending During Installation Even when best practices are employed, mistakes can occur that result in kinked and bent cables beyond recommended minimum bend radius >5 db Pinched Fiber A common practice today is to store slack in a tie-wrapped loop When a jumper is re-positioned, a tight loop can result high db loss Bit Error Rate > Link Unaffected

12 Marco bending Bend Optimized Fiber Technology Multimode optical fiber has many modes of light traveling through the fiber. As each of these modes moves closer to the edge of the core, it is more likely to escape, especially if the fiber is bent. As the bend radius is decreased, the amount of light that leaks out of the core increases. Core Dissipation of energy Cladding

13 Marco bending Bend Optimized Fiber Technology Bend-optimized multimode fiber is capable of confining almost all the energy of the different modes, even in the most challenging bending scenarios. Fiber utilizes a specially engineered optical trench to trap the energy in the many modes which propagate within the fiber core. The energy is confined inside the fiber

14 Marco bending Bend Optimized Fiber Technology Bend Insensitive Multimode Fiber Improved bend performance Fiber is backward compatible Current Std: IEC Bend Radius 37.5 mm Number of Turns 100 Max 850 nm 0.5 db ClearCurve 850 nm 0.05 db Current Std: ITU - G Bend Radius 15 mm Number of Turns 2 Max 850 nm 1 db ClearCurve 850 nm 0.1 db International Electro technical Commission 90% better bend attenuation than current IEC standard International Telecommunications Union 90% better bend attenuation than current ITU standard

15 Marco bending Clear Curve Fiber Test Standard 50 µm fibre The problem Moderate loss with moderate bends Bend insensitive 50 μm fibre Increased loss with tighter bends 3 db difference! The solution

16 Fiber Standard Description IEC SMF Type ITU Spec. TIA Spec Standard Singlemode Fiber B1.1 G.652A OS1 Cutoff Shifted Fiber B1.2 G.654 Low Water Peak Fiber B1.3 G.652D OS2 Dispersion Shifted Fiber B2 G.653 Non Zero Dispersion Shifted Fiber B4 G.655 Bend Insensitive Fiber G.657 Multi Mode Fiber OM1, OM2, OM3, OM4 G.651 OM1, OM2, OM3, OM4

17 Fiber Standard OM μm TB/LT OM2 50 μm TB/LT OM3 50 μm TB/LT OM4 50 μm TB/LT OS2 8 μm LT 250 µm Optical Fiber Type 62.5 μm 50 μm 50 μm 50 μm Single-mode ISO/IEC Nomenclature Maximum Attenuation (db/km) OM1 OM2 OM3 OM4 OS2 3.4/ / / / /0.4/0.3 Minimum Over Filled Launch (OFL) Bandwidth (MHz km) 200/ / / /500 -/-/- Minimum Effective Modal Bandwidth (EMB) (MHz km) 220/- 950/- 2000/- 4700/-/- -/-/- Serial 1 Gig Distance (m) 300/ / / / /-/- Serial 10 Gig Distance (m) 33/- 150/- 300/- 550/ /-/40000

18 Relative Size Comparison 62.5 micron 50 micron 8.3 micron 125 micron NA = 0.29 NA = 0.20 NA = 0.13

19 Fiber Modes A mode is a defined path in which light travels Singlemode fibers have a single light path. Multimode fibers have multiple light paths (500+) µm or 62.5 µm Approximate No. of Modes nm 1300 nm 1550 nm 8.3 µm um 50 um SM

20 Bandwidth The rate at which information can be sent through a channel The greater the bandwidth, the more information that can be sent in a given amount of time System bandwidth is measured in MHz at one km. In general, when a system's bandwidth is 200 MHz km, it means that 200 million pulses of light per second will travel down 1 km (1000 meters) of fiber, and each pulse will be distinguishable by the receiver

21 Cabling Infrastructure for Advanced Data Center Designs Fiber Type and Performance Fiber Standards TIA-492AAAC OM3 detailed fiber standard was released in March 2002 TIA-492AAAD OM4 detailed fiber standard was released in August 2009 TIA-942 Rev A recommends OM4 400 Performance High-data-rates in conjunction with the desired application distances support OM3 and OM4 as the default choice fiber types.

22 Polarity Basic Concepts Transceivers alike on both ends of optical circuit Polarity is defined relative to keyway orientation Transmitter (Tx) on one end of optical circuit has to be connected to Receiver (Rx) on the other end Transmit Receive Transmit (Tx) Receive (Rx) Transmit Receive keyways

23 Duplex Administration A duplex lead is an X-over and this can be seen adjacent. If connecting two hardware interfaces TX goes to RX As all cords are X-over and one is used at either end of the fiber link it requires that link to have an X- over in order to maintain TX to RX The fiber link X-over is done in one of two ways Transmit Receive Keys Keys Swapping a duplex lead at one end is not one of them! Keys Up Transmit Receive

24 IEEE 802.3ba Ethernet 40G Data Center 40GBASE-SR4 (parallel optics) 100 m on OM3 10G on 4 fibers per direction 150 m on OM4 10G on 4 fibers per direction Metro, BB, WAN 40GBASE-LR4 (cwdm) 10 km on single-mode 4λ x 10G 1300 nm region 40GBASE-FR (Serial) 2 km on single-mode 1λ x 40G 1550 nm Server Access 40GBASE-CR4 7 m over copper 4 x 10G (twinax copper)

25 40G Ethernet Parallel Optics 12-fiber MTP Connector Interface QSFP Tx

26 IEEE 802.3ba Ethernet 100G Data Center 100GBASE-SR10 (parallel optics) 100 m on OM3 10G on 10 fibers per direction 150 m on OM4 10G on 10 fibers per direction Metro, BB, WAN 100GBASE-LR4 (dwdm) 10 km on single-mode 4λ x 25G 1300 nm Region 100GBASE-ER4 (dwdm) 40/30 km on single-mode 4λ x 25G 1300 nm dwdm Server Access 100GBASE-CR10 7 m over copper 10 x 10G (twinax copper)

27 100G Ethernet Parallel Optics CXP Transceiver technology =< 3 watts per port can only support 100GBase-SR10 CFP Transceiver technology supports both 100GBase-SR10 (MM) and 100GBase-LR4 (SM) Low density due to power and form factor Source: USConec Source: Molex

28 100G 4 Lane Solution A Call For Interest (CFI) was approved at the July IEEE plenary meeting. Next Generation 100 Gb/s Optical Ethernet Study Group working to develop guidance in accordance five criteria stated in PAR Intent of work in to reduce MMF and SMF cost/power while increasing line card density. Considering 4x25G PMDs for both SMF and MMF as an alternative to 10x10G PMD

29 Pre terminated 12 fiber Solution What are Plug & Play Systems? A tip-to-tip product set consisting of: 1. Factory-terminated cable, commonly known as a trunk, with a preinstalled protective pulling grip 2. Connector modules 3. Patch Cords Plug & Play Module MTP-terminated Trunk Cable Plug & Play Module Patch Cord DONE!!! Patch Cord

30 Method A 12f Connectivity

31 Method B 12f Connectivity

32 Method C 12f Connectivity

33 Method Universal 12f Connectivity T R

34 Polarity Management of 12f Connectivity Schemes Connectivity method Array connector cable type Array adapter type Array patch cord type A A:1-1 A One Type-A:1-1 One Type-B:1-1 B B:1-1 B Two Type-B:1-1 C C:1-1 A One Type-B:1-1 One Type-C:1-1 (Universal) B:1-1 A Two Type-B:1-1

35 Optical Connectivity 10G LC modules independently changed out for 40G and/or 100G MPO panels Duplex LC 10G ports Duplex LC 10G ports + 12-fiber MPO 40G ports 12-fiber MPO 40G ports and/or 24-fiber MPO 100G ports

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