Trends in Optical Transceivers:

Transcription

1

2 Trends in Optical Transceivers: Light sources for premises networks Peter Ronco Corning Optical Fiber Asst. Product Line Manager Premises Fibers January 24, 2006

3 Outline: Introduction: Transceivers and their evolution within premises network Comparison of light sources for premises applications Light Emitting Diodes (LEDs) Fabry-Perot lasers DFB lasers VCSELs Manufacturing costs and the light source application space Transceivers and premises network system costs Optical fiber and light source compatibility Summary 3

4 Transceivers - Definition Transceivers combine transmitters with receivers in order to generate, encode and receive signals in a single package. These modules are installed at both ends of a system and vary by data rate, fiber type, application, operating λ, connector type and transmitter (light source). Trend smaller form factor? XENPAK GBIC XFP SFP QSFP 4

5 Small form factors reduce system footprint XFP component integration compared with a traditional 10G transponder XFP Transceiver 5 Footprint of 10G XFP transceiver is 10 times smaller than a traditional 10G XENPAK transponder Smaller XFP form factor requires less power

6 Transceiver- Packaging & Applications Packaging/ Form Factor Data Rate Protocol Light source λ and Fiber Type Reach XENPAK, XPAK, X2 10GbE, 10 G FC VCSEL DFB DFB 850MMF 1310 SMF 1550 SMF Up to550 m* up to 10 km Up to 40 km** GBIC 1 GbE, 1 & 2 G FC VCSEL FP or DFB 850 nm MMF 1310/1550 nm SMF up to 1100 m* up to 100 km XFP 10GbE/10 G FC OC-192 VCSEL DFB 850 nm/mmf 1310 nm/smf up to 550 m* up to 10 km SFP 1 GbE, 1, 2 & 4 G FC OC-3 to OC-48 VCSEL FP or DFB 850 nm MMF 1310/1550 nm SMF up to 1100 m* up to 100 km SFF 1 GbE, 1, 2 & 4 G FC OC-3 to OC-48 VCSEL FP or DFB 850 nm MMF 1310/1550 nm SMF up to 1100 m* up to 100 km 6 Link lengths with OM3+ fiber **With external electro absorption modulator GbE Gigabit Ethernet FC fiber channel, FP Fabry-Perot, DFB Distributed Feedback Laser

7 Data rates continue to rise Ethernet (Includes Copper) 16 Fibre Channel (Fiber only) Ports (MM) 10 Gbps 1 Gbps 100 Mbps Fiber Port's (MM) Gbps 2 Gbps 1 Gbps Sales of lower data rate ports decrease Sales of 1G, 4G and 10G ports continue to increase 7 Source: Yankee, Frost and Sullivan

8 10 Gb/s Light Source Port Types Port Type Light Source Fiber Type & System Reach Packaging / Form Factor SRshort reach LR long reach 850 nm VCSEL MMF 550 m* XFP, XENPAK, XPAK, X nm DFB SMF 10 km XENPAK XFP ER extended reach 1550 nm DFB SMF 40 km** XENPAK XFP LX nm DFB SMF 10 km MMF 300 m XENPAK, XPAK, X2 LRM 1310 nm FP MMF 220 m XENPAK 8 *Link lengths with OM3+ fiber ** 40 km for engineered link, 30km is defined distance SR short reach, LR long reach, ER Extended reach

9 Premises Light Sources - Operating Windows Historically popular transceivers for premises networks use either 850 nm or 1300 nm wavelength light sources 80 s 90 s 00 s 850nm 850 nm LEDs standardized at up to 10 Mb/s 850 nm VCSELs are standardized 1G (cost is a main factor) 850 nm VCSEL standard for 10 GbE 1300nm 1300 nm LEDs are standardized at 100 Mb/s nm appears to be the preferred wavelength for future 10 Gb/s premises network applications

10 Outline: Introduction: Transceivers and their evolution within premises network Comparison of light sources for premises applications Light Emitting Diodes (LEDs) Fabry-Perot lasers DFB lasers VCSELs Manufacturing costs and the light source application space Transceivers and premises network system costs Optical fiber and light source compatibility Summary 10

11 Light Sources for Communication Systems Basic requirements: High optical power output To extend reach and improve signal quality Fast response time (high modulation bandwidth) To facilitate high data rates Efficient fiber coupling (beam size and shape) To reduce packaging cost and increase power in fiber High reliability To yield long life times & to reduce operational cost 11

12 Laser Chip and Package electrode Chip with Bond Packaged Lasers with fiber pigtails 12

13 Comparison: Spectral Characteristics LED 60 nm λ Fabry-Perot Laser 4 nm Laser Diodes VCSEL < 0.5 nm ~ 3-10 db DFB laser 0.1 nm > 30dB Single longitudinal mode at λ B 13

14 Comparison: Maximum Data Rate & Modulation Bandwidth The modulation bandwidth of an LED or laser diode determines the maximum data rate. The modulation bandwidth of an LED is determined by carrier lifetime (2~5 ns). The maximum LED data rate is <1 Gbps. The modulation bandwidth of a laser diode is larger than an LED and is determined by laser power and photon lifetime in the cavity. Laser diodes can operate at 1 Gbps, 10 Gbps and beyond. Laser Diodes are necessary - for modern high data rate applications 14

15 Overall Comparison: LED, FP, DFB & VCSEL sources Source Type Spectral Content Bandwidth Applications Operating λ [nm] Launch Power Most Suitable Fiber LED Wide continuum Low, determined by career lifetime Low Data rates (<1 Gb/s) mw (-10 dbm) MMF Fabry- Perot Wide with narrow modes High determined by power and cavity <2.5 Gb/s Wide spectrum impairs signal in dispersive fiber mw (8.8 dbm) MMF and SMF DFB Single mode (>30 db side mode suppression) High determined by power and cavity 2.5 Gb/s Narrow spectrum enables longer distances mw (17.8 dbm) SMF VCSEL Narrow, no sidebands High determined by power and cavity 1 GbE and 10 GbE 850 (1310*) 0.5 mw (-3 dbm) MMF 850 & 1310 SMF 1310 * Developed recently, expensive and have limited availability 15

16 VCSEL - Characteristics Currently used in short-haul data networks in the near infrared (850 nm) Advantages Can be produced in high volume and at low cost High fiber coupling efficiency due to circular output beam spot Direct modulation from 1 10 Gb/s Disadvantages Technology not mature for long wavelengths i.e. for 1300 nm and 1550 nm Output power is not suitable for longer distances 16

17 Future VCSELs 1300 & 1550 nm long wavelength development Issues Longer wavelength high reliability devices are more difficult to fabricate Need a longer vertical cavity & highly reflective mirrors for longer λs to achieve lasing Increased heat dissipation requirements are an issue especially at higher ambient temperatures Alignment and packaging of 1300 and 1550 nm devices more difficult due to tighter tolerances Difficulty in manufacture results in higher cost per device $$$ 17

18 Outline: Introduction: Transceivers and their evolution within premises network Comparison of light sources for premises applications Light Emitting Diodes (LEDs) Fabry-Perot lasers DFB lasers VCSELs Manufacturing costs and the light source application space Transceivers and premises network system costs Optical fiber and light source compatibility Summary 18

19 A Semiconductor Wafer in Manufacture 19

20 FP and DFB Laser Manufacturing Process Wafer Lay down Wafer cutting Laser test x N Optical Alignment & Packaging +V? x N 20 N die = N lasers FP & DFB devices tested in series = higher manufacture costs -V N devices N tests M fails N-M passes N-M Packages Non-symmetric output beam complicates alignment

21 VCSEL Devices Tested in Parallel * 21 * DBR: Distributed Bragg Reflector All VCSEL chips on same wafer can be tested simultaneously Circular output beam simplifies coupling during packaging process

22 VCSEL Manufacturing Process Wafer Lay down Laser test x 1 Wafer cutting Optical Alignment & Packaging +V??? x V N devices 1 test M fails N-M passes N -M die = N M lasers Some VCSEL parameters are tested in parallel = lower manufacture costs N-M Packages Circular output beam eases alignment

23 Manufacturing Process Determines Device Cost Relative Laser Cost Manufacturing cost drivers DFB $$$$$ Serial Testing Non Circular output beam DFB grating required FP $$$ Serial Testing Non Circular output beam 1300 VCSEL $$$ Parallel Testing Circular output beam Difficult alignment, cavity & mirror fabrication Low volume VCSEL $ Parallel Testing Circular output beam Ease of alignment & fabrication

24 Outline: Introduction: Transceivers and their evolution within premises network Comparison of light sources for premises applications Light Emitting Diodes (LEDs) Fabry-Perot lasers DFB lasers VCSELs Manufacturing costs and the light source application space Transceivers and premises network system costs Optical fiber and light source compatibility Summary 24

25 Premises Network Costs Both capital expenditures and operating expenses need to be considered Capital investment is dictated by component costs Hardware Cable Transceivers Switch Electronics Operating costs are largely driven by Space requirements Power consumption Cooling costs 25

26 Capital Expenditure Assumptions: Equipment costs shown, installation and operation not included 300 m cable: 12 OM3 fibers at 850 nm, 12 standard MMF at 1300 nm, 12 single mode fibers at 1300 nm Operate at 1 Gb/s for 10 years, upgrade to 10 Gb/s list prices Transceivers 24% Fiber Optic Cable 1% Jumpers, Connectors < 1% Patch Panel, Rack < 1% Capital expenditure is dominated by the cost of the switch electronics Transceivers are also a large component of the system cost Switch Electronics 74% 26

27 VCSELs Reduce Capital Costs for High Data Rate Premises Networks Low cost 850nm VCSELs enable the use of low cost transceivers (XENPAK, X2, XFP) OM3 MMF enables the use of low cost 850nm VCSELs SR LX4 LR Hardware Cable Transceivers MMF 850 nm MMF 1300 nm Single-Mode 1300 nm OM3 fiber + VCSEL technology enables the use of low cost transceivers, reducing overall initial capital expenditures 27

28 Transceiver cost determines application segment Relative Laser Cost Price Sensitive Market? DFB $$$$$ Long Haul FP $$$ Metro Access 1300 VCSEL $$$ LANs 28 $ 850 VCSEL Premises Low cost 850 VCSELs dominate the price sensitive Premises market

29 10Gb/s Operating Costs Optical vs. Copper Fiber ~2W Power Consumption Copper ~8W Cooling Requirements Transceiver Size $ Data Center Area $$$$ 29

30 Summary To support higher data rates, premises light sources have migrated from LEDs to lasers There are 3 main laser types: DFBs, Fabry Perots & VCSELs 850nm VCSELs and XFPs in particular offer the lowest total cost solution and so are the dominant lasers for transceivers for the price sensitive premises market 1310nm VCSELs have a higher device cost and are more suited to Metro/Access/LAN applications Laser optimised MMF must be installed to take advantage of cost benefits of 850 nm VCSELs 30

31