HIGH BIT RATE OPTICAL FIBRE NETWORKS - optical fibre selection and implementation

Transcription

1 HIGH BIT RATE OPTICAL FIBRE NETWORKS - optical fibre selection and implementation prepared and delivered by ϕ 19th January 2000

2 PO Box MT65 LEEDS LS17 8YD UK Tel: +44 (0) Fax: +44 (0) Training Design and specification and IT cost management Project management Audits and arbitration 2000

3 Mike Gilmore Senior Partner, PO Box MT65 LEEDS LS17 8YD UK Tel: +44 (0) Fax: +44 (0) Training Design and specification and IT cost management Project management Audits and arbitration Standards UK Fibreoptic Industry Association, Technical Director BSI, Chairman, TCT7/-/1: IT PD1001: EMC and structured cabling BS 7718: CoP Installation of Fibre optic Europe CENELEC, Convenor, TC215 WG1: IT EN : ISDN Basic Access EN : ISDN Primary Rate EN 50173: Generic - Design pren 50174: Installation pren 50xxx: Testing of Installed International ISO/IEC, Member, JTC1 SC25 WG3: Generic ISO/IEC 11801: Generic - Design ISO/IEC : Administration ISO/IEC TR : Planning and Installation ISO/IEC TR : Testing optical cabling and via IEC SC46A WG2 IEC 61935: Testing copper cabling 2000

4 Agenda Session One Designing attenuation-limited networks Attenuation-limited LAN systems Break Session Two Designing bandwidth-limited networks Bandwidth-limited LAN systems Session Three Multi-Gigabit applications Practical implementation issues End 2000

5 Agenda Session One Designing attenuation-limited networks Attenuation-limited LAN systems optical fibre transmission multimode, singlemode optical fibre attenuation transmission wavelengths/windows optical fibre components optical fibre connecting hardware optical power budget optical loss budget Break 2000

6 Optical fibre construction Core Cladding Core and cladding have different optical properties Refractive index (R.I.) n x = c/v x c = speed of light in a vacuum v x = speed of light in material x Light is transmitted in the core when n core > n cladding 2000

7 Total internal reflection light lost from cladding R.I. = n 2 < n 1 R.I. = n 1 light travelling at critical angle θ c sin (θ c ) = n 2 / n 1 highest order mode zero order mode 2000

8 Acceptance angle: N.A. light lost from cladding R.I. = n 2 < n 1 R.I. = n 1 α θ c sin (θ c ) = n 2 / n 1 sin (α) = {n n 2 2 } 0.5 = NA (numerical aperture) Light injected into optical fibre = coupled power = f (core diameter 2 ) = f (NA 2 ) 2000

9 MMF: Multimode optical fibre n 2 n 1 θ c STEP(PED) INDEX (S.I.) MMF path lengths: maximum variation path times: maximum variation bandwidth: modal dispersion n 2 n 1 (r) GRADED INDEX (G.I.) MMF path lengths: significant variation path times: limited variation bandwidth: 1st order: modal dispersion 2nd order: chromatic dispersion Geometry options d/d NA 50/ /

10 SMF: Singlemode optical fibre nm NA = NA = Core diameter (microns) NA = 0.20 n 2 n 1 STEP(PED) INDEX (S.I.) SMF path lengths: no variation path times: no variation bandwidth: 1st order: chromatic dispersion 2nd order: pulse shape dispersion Geometry d/d NA 8-10/

11 Attenuation in optical fibre Attenuation = signal loss INTRINSIC ATTENUATION scattering due to variations in structure wavelength dependent material absorption impurities (necessary) impurities (unavoidable) wavelength dependent path length dependent EXTRINSIC ATTENUATION microbending deformation of the CCI CCI = core-cladding interface macrobending deformation of the optical fibre 2000

12 Attenuation coefficient Transmitted power linear transmission = P out /P in (%) logarithmic attenuation = -10 log 10 (P out /P in ) (db) P in = x P out = x/2 P out = x/4 Transmission (%) Attenuation (db) Length = L Length = 2L Length (km) L 2L Attenuation (db) Attenuation coefficient α = x dbkm

13 Transmission wavelengths/windows Attenuation coefficient MMF: 1st Window: nm 2nd window: nm SMF: 2nd window: nm 3rd window: nm 2nd Window 3rd Window 1st Window Blue Red Wavelength (nm) VISIBLE LIGHT INFRA-RED - OPTICAL FIBRE 2000

14 MM optical fibre Optical fibre geometry (standardized) 50/ /125 Core diameter (µm) 50 ± ± 3 Cladding diameter (µm) 125 ± ± 3 NA 0.20 ± ± Attenuation (db) 850nm 1300nm Optical fibre performance parameters (options) Attenuation coefficient dbkm -1 max. Modal bandwidth MHz.km min. 850nm 1300nm 850nm 1300nm???? Modal Bandwidth (MHz) Channel length (m) Channel length (m) 2000

15 MMF performance options Attenuation coefficient dbkm -1 max. Modal bandwidth MHz.km min. 850nm 1300nm 850nm 1300nm 50/125 and 62.5/ / ISO/IEC and EN (1995) ANSI/TIA/EIA 568A (1995) 50/ ISO/IEC and EN (2001) 62.5/ ISO/IEC and EN (2001) 50/ /125 Attenuation coefficient dbkm -1 max. 850nm 1300nm / nm Modal bandwidth MHz.km min. 1300nm 850nm nm /125 and 62.5/ /

16 Connecting hardware DEMOUNTABLE CONNECTOR Adaptor MECHANICAL SPLICE I.M.M. FUSION SPLICE weld Plug Plug Capillary Sleeve P in P out P in P out P in P out P reflected P reflected P reflected Attenuation Insertion loss (db) = -10 log 10 (P out /P in ) Reflection Return loss (db) = -10 log 10 (P reflected /P in ) Modal bandwidth and delay no effect 2000

17 Connecting hardware options SPLICES ISO/IEC and EN (1995/2001) Insertion loss (max.) Singlemode/multimode 100% < 0.30 db Return loss Singlemode Multimode - - DEMOUNTABLE CONNECTING HARDWARE: INTEROPERABILITY STANDARDS TO in ISO/IEC and EN (1995) ST (BFOC2,5): MMF SC-D (duplex ): MMF IEC IEC TO in ISO/IEC and EN (2001) Insertion loss (max.) Singlemode/multimode 100% < 0.75 db Singlemode 26dB Return loss Multimode 20dB SC-D (duplex ): MMF IEC % < 0.5 db, 100% < 0.75 db 35dB 20dB DEMOUNTABLE CONNECTING HARDWARE: ALTERNATIVE INTERFACE STANDARDS Interoperability not guaranteed by standards F-SMA, CF-03, CF-04, BAM, LSA, FC, D, OF-2, OCCA-PC, OCCA-BU, CF-08, SC, DS, F-05, MU, MPO SFF types in preparation: LC, SG (Volition), MT-RJ 2000

18 Optical power budget (OPB) - I P TX (dbm) = 10 log 10 P TX (mw) P RX (dbm) = 10 log 10 P RX (mw) Input power P TX milliwatts (mw) 1W = 1000mW 1mW = 1000µW dbm referenced to 1mW 1mW = 0 dbm 0.5mW = -3 dbm 0.1mW = -10 dbm 0.05mW = -13 dbm Received power P RX milliwatts (mw) 1W = 1000mW 1mW = 1000µW dbm referenced to 1mW 2000

19 Optical power budget (OPB) - II Best of breed Low temperature (LEDs) Early life (LEDs) P TX dbm (max) Minimum OPB (db) Too much received signal P RX dbm (max) Absolute power (dbm) P TX dbm (min) Worst of breed High temperature (LEDs) End of life (LEDs) Maximum OPB (db) Too little received signal P RX dbm (min) 2000

20 Optical loss budget (OLB) Cable 1 Cable 2 Cable 3 A B L 1 L 2 L 3 Channel Optical loss budget: limits of calculated channel attenuation In the example: OLB min = L 1 *α (Cable 1) + L 2 *α (Cable 2) + L 3 *α (Cable 3) + loss A + loss B (db) using min. values OLB max = L 1 *α (Cable 1) + L 2 *α (Cable 2) + L 3 *α (Cable 3) + loss A + loss B (db) using max. values In general: OLB min = Σα (Cable i) x L i + Σconnectors/splices (db) OLB max = Σα (Cable i) x L i + Σconnectors/splices (db) using minimum values using maximum values 2000

21 Designing attenuation-limited systems APPLICATION FUNCTION SIGNAL CLARITY in window used PROTOCOL FUNCTION Attenuation Dispersion Delay Coupling Length Length Connectivity DESIGN RULES OLB max < OPB max OLB min > OPB min observe delay limits 2000

22 Agenda Session One Designing attenuation-limited networks Attenuation-limited LAN systems Break attenuation-limited LAN standards MMF Light injection devices coupling losses OPB-based cabling design channel length equations 2000

23 Attenuation-limited LAN standards 850 nm 1300 nm ISO/IEC : FOIRL ISO/IEC : 10BASE-FL/FB ISO/IEC TR : 4 & 16 Mb/s Token Ring IEEE : Demand priority ISO/IEC : FDDI PMD ISO/IEC : 100BASE-FX IEEE : Demand priority 52 Mb/s 50/125 Max. length (m) OPB max. (db) 62.5/125 Max. length (m) OPB max. (db) Mb/s Calculated values using 1.5dB of connecting hardware losses 62.5/125 seems to offer advantages OPB (db)

24 MMF light injection devices VISIBLE LIGHT Blue Red INFRA-RED - OPTICAL FIBRE 1st Window 2nd Window Bit rate Wavelength (nm) Cost < 40000Mb/s < 2000Mb/s < 500Mb/s Multimode LASER standard VCSEL CD Singlemode LASER Multimode LASER Multimode LED < 100Mb/s Multimode LED 2000

25 Coupling losses LED or optical fibre LASER COUPLING LOSSES From LED LASER SMF 0 db 0 db 0 db 0 db 0 db -4.7 db -4.7dB 0 db 0 db 0 db ~-26 db ~-26 db ~-22 db 0 db 0 db To SMF 2000

26 OPB-based cabling design BD BD FD FD FD BD BD FD FD FD BD BD FD FD FD FD FD FD CD CD BD BD CAMPUS CABLING BUILDING CABLING Maximum channel length = (OPB - total connection loss)/cable attenuation 2000

27 Channel length equations 850 nm 1300 nm ISO/IEC : FOIRL ISO/IEC : 10BASE-FL/FB ISO/IEC TR : 4 & 16 Mb/s Token Ring IEEE : Demand priority ISO/IEC : FDDI PMD ISO/IEC : 100BASE-FX IEEE : Demand priority 52 Mb/s 155 Mb/s 50/ /125 CAP Channel length (m) CAP x - 85y x - 85y x - 85y x - 85y x - 200y x - 200y x - 200y x - 200y 2000 Channel length (m) x - 85y x - 85y x - 85y x - 85y x - 200y x - 200y x - 200y x - 200y x - 200y x - 200y x = no. of mated 0.5dB y = no. of 0.3dB 2000

28 Agenda Session One Designing attenuation-limited networks Session Two Designing bandwidth-limited networks modal bandwidth bandwidth-limited technology Attenuation-limited LAN systems Break Bandwidth-limited LAN systems 2000

29 Modal bandwidth Gb/s 500 Mb/s Gb/s 500 Mb/s Modal Bandwidth (MHz) MHz.km MMF Channel length (m) Modal Bandwidth (MHz) MHz.km MMF Channel length (m) Attenuation coefficient dbkm -1 max. Modal bandwidth MHz.km min. 850nm 1300nm 850nm 1300nm 50/125 and 62.5/ / ISO/IEC and EN (1995) ANSI/TIA/EIA 568A (1995) 50/ ISO/IEC and EN (2001) 62.5/ ISO/IEC and EN (2001) 2000

30 Bandwidth-limited technology Historic applications have channel lengths defined by OPB OPB > calculated bandwidth for distances supported New applications use data rates for which bandwidth requirements define channel lengths longer lengths cannot be guaranteed even if low attenuation channels are used Modal bandwidths have rarely been specified by users/installers Modal bandwidth difficult/impossible to measure on-site bandwidth-limited applications are installed with higher risk Higher data rates utilise LASER technologies CD LASERS, VCSELs and standard LASERs reductions in OPBs due to restricted power input/channel lengths Optical fibre modal bandwidth measured using LED launch conditions LASER sources should provide improved bandwidth some problems found with RI profiles OPTICAL FIBRE SELECTION AND CONFIGURATION IMPACTED 2000

31 Designing bandwidth-limited systems APPLICATION FUNCTION SIGNAL CLARITY in window used PROTOCOL FUNCTION Attenuation Dispersion Delay Coupling Length Connectivity Modal bandwidth DESIGN RULES OLB max < OPB max OLB min > OPB min observe delay limits observe fibre specific length limits Length 2000

32 Agenda Session One Designing attenuation-limited networks Session Two Designing bandwidth-limited networks Attenuation-limited LAN systems Break Bandwidth-limited LAN systems bandwidth-limited LAN standards channel length equations resilient networks 2000

33 Bandwidth-limited LAN standards 850 nm 1300 nm 50/ /500MHz.km OPB max. 62.5/ /500MHz.km OPB max. Max. length Max. length (m) (db) (m) (db) (db) 155 Mb/s CD 14165: 266 Mb/s CD 14165: 531 Mb/s 622 Mb/s IEEE 802.3: 1000BASE-SX: Gigabit Ethernet CD 14165: 1062 Mb/s CD 14165: 133 Mb/s CD 14165: 266 Mb/s 622 Mb/s IEEE 802.3: 1000BASE-LX: Gigabit Ethernet > Assuming no connecting hardware loss OPB /125 seems to offer advantages 2000

34 OF Application Grading G1 G2 G3 G4 G5 G6 MMF Token Ring 100BASE-FX FDDI ATM52 (1300) ATM155 ( BASE-FL 10BASE-FB ATM155 (850) 1000BASE-LX ATM622 (1300)* 1000BASE-SX ATM622 (850) SMF FDDI ATM52 (1310) ATM155 (1310) 1000BASE-LX ATM622 (1310) G7 G4 G5 G6 G4 G5 G6 G3 G3 G2 G1 G2 G1 G Channel length (m) 62.5/125 50/125 SMF KEY FEATURES lengths shown assume 1.5dB connecting hardware loss G2 applications limited on 50/125 G5 applications limited on 62.5/125 not all applications supported on singlemode 2000

35 Channel length equations 850 nm 1300 nm 155 Mb/s CD 14165: 266 Mb/s CD 14165: 531 Mb/s 622 Mb/s IEEE 802.3: 1000BASE-SX: Gigabit Ethernet CD 14165: 1062 Mb/s CD 14165: 133 Mb/s CD 14165: 266 Mb/s 622 Mb/s IEEE 802.3: 1000BASE-LX: Gigabit Ethernet 50/ /500MHz.km CAP Channel length (m) CAP x - 85y x - 85y x - 85y x - 85y x - 85y x - 85y x - 85y x - 85y x - 200y x - 200y x - 200y / /500MHz.km Channel length (m) x - 85y x - 85y x - 85y x - 85y x - 200y x - 200y x - 200y x - 200y x - 200y x = no. of mated 0.5dB y = no. of 0.3dB 2000

36 Bandwidth-based cabling design BD BD FD FD FD BD BD FD FD FD BD BD FD FD FD FD FD FD CD CD BD BD CAMPUS CABLING BUILDING CABLING Maximum channel length = (OPB - total connection loss)/cable attenuation 2000

37 Optical fibre selection <1Gb/s Max. OLB (db) Optical fibre choices 850 nm 1300 nm < 200 metres < 500 metres Either 50/125 1 or 62.5/ /125 1 SMF > 1Gb/s < 1500 metres < 2000 metres / / / /125 3 SMF > 200Mb/s 1 50/125: 3.5/1.5dBkm -1, 500/500MHz.km /125: 3.5/1.5dBkm -1, 200/500MHz.km preferred /125: 3.5/1.5dBkm -1, 200/500MHz.km adequate 2000

38 Agenda Sessi Attenuation-limited LAN systems Break 10 Gb/s Ethernet objectives proposals optical fibre developments Bandwidth-limited LAN systems Session Three Multi-Gigabit applications Practical implementation issues End 2000

39 10 Gb/s Ethernet: 802.3ae (03/02) OBJECTIVES switched operation only star topology support link aggregation support 10GB/s Ethernet and GB/s SONET 2000 m, m and m over SMF 100 m over existing MMF 300 m over new optical 850nm PROPOSALS legacy MMF 850nm VCSELs: ~ 65 m 850nm 4 x parallel optics: 300 m 850nm PAM-5 coding: >100 m 1300nm FP LASERs: > 100 m 1300nm 4 x WWDM: 300 m enhanced MMF 850nm VCSELs: 300 m legacy SMF 1300nm LASERs: 300 m to m 1550nm LASERs: m 2000

40 Optical fibre developments PROPOSALS UNDERWAY 50/125µm: 3.5/1.5dBkm -1, 2200/500MHz.km Bandwidth measurement made using LASER launch conditions 2000

41 Agenda Session One Session Two Session Three channel configuration SFF connections testing the link testing the channel maintenance Multi-Gigabit applications Practical implementation issues End 2000

42 Channel configuration Reduce loss to a minimum for a given length do not use unnecessary connections CC CC PP PP Consider splicing of pre-manufactured tails remember: 1 mated connection = 142 metres (@ 850 nm in MMF) = 333 metres (@ 1300 nm in MMF) 1 splice = 85 metres (@ 850 nm in MMF) = 200 metres (@ 1300 nm in MMF) Lower overall loss than field terminations Adopt cleaning procedures to minimise contamination losses 2000

43 SFF connections Differ dramatically from conventional connectors performance cost size duplex nature plug/socket configuration rather than plug/adaptor/plug good for the inexpert user bad for testing bad for cleaning ANSI/TIA/EIA 568B.3 (2000?) proposal exists to remove specific selection of connector currently SC-D this allows the use of SFF options let the market decide Considerable range of options no definition of SFF some undergoing IEC interface standardiazation LC, MT-RJ and SG (Volition) interface standards do not guarantee interoperability all items are proprietary joint set consistency is required 2000

44 Testing the link - conventional CONVENTIONAL METHOD Source (S) and Meter (M) correct transmission window wavelength correction (850 nm) fitted with correct adaptors stable calibrated Test leads BS 7718 (IEC ) Measurement error up to 0.75dB hides localised faults small incremental losses stress-induced cause of breaks later No evidence of test S S Loss M P 1 P 2 M CUT = CUT result - reference result = P 2 - P 1 This test configuration is suitable for patch panel - patch panel installations on both multimode and single mode. Refer to BS 7718 or IEC and -2 for alternative configurations 2000

45 Testing the link - SFF S/M S/M S/M S/M P 1 P 1 CUT P 2 P 2 CUT Courtesy of Innovation Loss = CUT result - reference result = P 2 - P

46 Testing the installation - OTDR OTDR Joint Loss (db) link length Optical Time Domain Reflectometer operating in correct transmission window calibrated Test (launch) lead in accordance with BS7718 (IEC ) 2000

47 Testing the channel - SFF S/M P 1 S/M S/M P 1 Channel under test P 2 S/M P 2 Channel loss = CUT result - reference result = P 2 - P

48 Maintenance CLEANLINESS IS NEXT TO GODLINESS WORKING GIGABIT NETWORKS SFF connectors are proprietary adopt cleaning regime recommended 2000

49 End full colour copy of this presentation including explanatory notes /gendocs/gsf.pdf the next MELTING POT seminars are on 23rd March th March