VCSEL Technology and Digital

Transcription

1 VCSEL Technology and Digital Applications Marco Ghisoni Zarlink Semiconductor AB

2 Outline Introduction Today's Digital Applications Mass market Parallel optical modules Future VCSEL Developments higher speed long wavelength Conclusion & Acknowledgements

3 VCSEL - design Vertical cavity surface emitting laser Standard VCSEL based on GaAs active region, emits at 850nm Very complex epitaxial growth over 200 layers, control to single atomic layer Functionality included in the growth, lasing region, mirrors, electrical regions Oxidisation of specific layer provides electrical and optical confinement oxide p-mirror Oxidised current confining layer Active region n-mirror

4 VCSEL - characteristics The VCSEL is to photonics as CMOS is to electronics Low threshold (< 1 ma) Dynamic single-mode (longitudinal) Transversal single or multi mode High laser-fiber coupling efficiency to MMF High efficiency (> 50%) 2-D Arrays Large temperature range High reliability Compatible with low power electronics Low cost wafer-scale chip production On-wafer testing and screening

5 VCSEL - characteristics Power [mw] Low threshold and temperature C Current [ma] Uniformity (12-channel array) Current [ma] 2.5Gbps operation (filtered) Optical power [mw]

6 Outline Introduction Today's Digital Applications Mass market Parallel optical modules Future VCSEL Developments higher speed long wavelength Conclusion & Acknowledgements

7 Digital Application - mass market As stated in the introduction VCSELs offer a low-cost high-speed emitter technology Cost reduction is in both chip-cost and packaging-cost Mass-market VCSEL application In recent years the use of optical interconnection for data communication primarily for connecting optical networking equipment in LANs and for SANs has grown Standards for such interconnections have developed: Gigabit Ethernet (1.25Gbps) Fibre Channel (1.06Gbps)

8 Digital Application - mass market Standardised low-cost transceiver modules based on VCSEL technology have been developed 850nm MMF up to 275/550m with 62.5/50µm core Two standard packages small-form factor (SFF) small-form factor pluggable (SFP) Current developments are on 2xGbE and 2xFC speed modules, i.e. up to 2.5 Gbps VCSEL based modules are a mass-market commodity < $ 50 per transceiver module (in volume) Market size >> 1 million units per annum

9 Digital Application - POM An industry drive is to increase total data throughput Parallel Optical Modules offer a cost-effective solution Typical POM Characteristics Based on parallel multi-mode fibre-ribbon each fibre carrying a separate data channel 12-channels in parallel Bit-rates per channel, e.g. 2.5Gbps Total throughput > 30Gbps over 300m VCSEL technology make POMs possible VCSEL are perfect for any array based solutions low drive currents, results in low power consumption

10 Digital Application - POM market Terabit switches/routers proprietary intra-system backplane LAN, SAN applications OC-192VSR Infiniband General point to multi-point communication applications Inter- and Intra-board applications Optical Backplane using Parallel Optics Switch I/O Chassis Chassis I/O Chassis <300 m

11 Outline Introduction Todays Digital Applications Mass market Parallel optical modules Future VCSEL Developments higher speed long wavelength Conclusion & Acknowledgements

12 Developments - 10Gbps VCSELs have been developed for higher speed operation In market terms the next milestone is 10Gbps operation for standards such as 10 Gigabit Ethernet Figure below 850nm VCSEL 10Gbps eye diagram

13 Developments nm VCSELs 850-nm VCLs - Technology of choice for short-distance data communication over multimode fibre 1300-nm VCLs - Target is the application space for longer distance communication over singlemode fiber (in competition with low-cost FPs and uncooled DFBs) From Compound Semiconductor, March 2000

14 Developments nm VCSELs Recent breakthroughs on GaAs-based VCSELs for 1300nm 1.0 T = C Threshold current [ma] Power [mw] Current [ma] 10-90C Current [ma] Power [mw] Threshold current [ma] InGaAsN QW λ > 1280nm InGaAs QW λ > 1270nm Temperature [ C] Temperature [ C] Companies sampling transceiver modules based on 1300nm VCSELs (e.g. Infineon, Picolight)

15 Outline Introduction Today's Digital Applications Mass market Parallel optical modules Future VCSEL Developments higher speed long wavelength Conclusion & Acknowledgements

16 Conclusion The VCSEL provides a low-cost, high-speed emitter The availability of such an emitter has allowed the rapid development of a MMF based short distance digital optical interconnection market (e.g. GbE) By utilising the ease of array manufacture the VCSEL is the basis for a parallel optical module market The development of 1300nm VCSELs opens the door for an even greater penetration into the large SMF market VCSELs will be the dominant laser for digital communication applications

17 Acknowledgements Mattias Hammar and co-workers Royal Institute of Technology, Stockholm Anders Larsson and co-workers Chalmers University of Technology, Gothenburg Andrew Joel and co-workers IQE Europe Ltd., Cardiff Part of this work funded by the European IST GIFT program