Perspectives on Photonic Integration T. L. Koch Prof. of ECE and - PowerPoint PPT Presentation

Center for Optical Technologies Perspectives on Photonic Integration T. L. Koch Prof. of ECE and Physics Director Center for Optical Technologies Lehigh University Bethlehem, Pennsylvania, USA 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies OUTLINE: � Photonic Integration: - what it isn’t - what it is � Status, market-induced trends, challenges 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies The greatest story of Integration … • Sketch from Jack Kilby’s lab notebook of IC concept at TI • Use semiconductor for circuit elements • p-n junctions for capacitors • bulk semi for resistors, etc. • Demonstrated simple circuits like flip-flop, oscillators, etc., in Ge 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies Silicon Planar Processing … • Noyce at Fairchild simultaneously files IC concept in Si • Hoerni introduces planar process in Si • The race is on … 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies The Digital Revolution Ramps Up! • First commercial IC in 1961 • 2 logic gates ( 4 bipolar transistors, 4 resistors) • Rapid industry advances ensue: • Linear ckts, op amps, etc. • Digital logic gates 1966 TTL logic chip 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies Relentless Advance of IC Integration Moore’s Law (1965) • • Doubling in # of transistors every 18 months (60% CAGR) Example (close to true!): • - 1965 most complex digital chip had 64 transistors 2000 intro of Pentium IV - processor w/est. 42 million transistors DRAM tracking also - 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies * 10,000 3000 Optics Progress: Even Faster 1000 * than Moore’s Law! 300 10 YEAR IMPROVEMENT EXPERIMENTAL 100 Capacity (Gb/s) × 100 30 IC Density : 10 × 200 ! Fiber Capacity: 3 COMMERCIAL 1 Experimental Single Channel (ETDM) Multi-Channel (WDM) 0.3 Single Channel (OTDM) WDM + OTDM * WDM + Polarization Mux 0.1 Commercial Single Channel (ETDM) 0.03 Multi-Channel (WDM) 80 82 84 86 88 90 92 94 96 98 00 02 Year 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies Get a Grip! Capacity growth is not traceable to integration - Photonic Integration offers promise of cost, power, size reduction • however …. Massive, repetitive digital blocks in electronic IC’s are truly, • fundamentally, application enabling � Power of digital processing & especially software in volume markets are drivers for Moore’s Law 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies So Turn Back The Clock, reset our expectations … • 1964 early linear IC - Matched actives & passives on chip • 1965 first commercial fully integrated OP AMP These analog circuits would not have driven Moore’s Law & $B fabs … but they do target clear volume applications and are powerful and enabling in their reduced cost, size, and power! 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies Photonic Integrated Circuit Vision Exemplary PIC with large variety of guided-wave elements: WAVELENGTH INPUT FIBER AGILE LASER MODULATOR POLARIZATION CONTROLER SWITCHES DETECTOR WAVELENGTH AGILE LASER AMPLIFIER Fig. from S. K. Korotky FILTER OUTPUT COUPLER FIBER DETECTORS Monolithically interconnected optical and optoelectronic components fabricated on a common substrate 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies Why hasn’t this taken off? Monolithically Integrated Balanced Heterodyne Receiver PIC Koch, et al PTL 2, 1990 p. 577 2005 WOCC – Newark April 22, 2005

Center for Optical The Value Proposition: Technologies The merits of integration Systems vendors require reductions in cost, size, power; improvements in performance CW DFB Laser Module 10 Gb/s LiNbO 3 Module When two or more elements are optically interconnected to form a functional subsystem: • we pay for two or more packages (packaging can be 50-80% of cost, even more compelling than IC’s!) • we get larger subsystems; devices constrained to use long optical paths • we lose power from fiber coupling efficiencies (lower SNR) • we incur instabilities or fluctuations from coupling – efficiency, phase, reflections … Can these be so dramatic as to be market enabling? 10 Gb/s Integrated Modulator Laser Module Using InP-based PIC - ultimately yes, but in the near term we have … The challenging work of implementing a replacement technology! 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies What needs to be integrated … Two kinds of replacement technology… • Replacing discrete optical solution & offering improvements in cost, size and/or power. • Replacing FUNCTIONALITY previously done with electronics using optical networking architectures and optical technologies 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies But there’s also some subtlety … Two kinds of replacement technology… • Replacing discrete optical solution & offering improvements in cost, size and/or power. • Replacing FUNCTIONALITY previously done with electronics using optical networking architectures and optical technologies 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies Optically Amplified WDM Transmission System Data In Data Out λ 1 λ 1 RCVR XMTR O λ 2 λ 2 O D XMTR RCVR M M OA OA OA OA • U • U • X • X • RCVR XMTR λ N λ N λ A ~ 80-120 km Amplified (Non-regenerated) Transmission Line Er-Doped Fiber Small-Signal λ 1 , λ 2 ... λ N λ 1 , λ 2 ... λ N 35 nm Gain Σ P l ~ N µ W Σ P l ~ N mW Saturated Pump Laser λ (0.98 mm) 1550 nm Erbium-Doped Fiber Amplifier Gain Spectra 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies Data In Data Out λ 1 λ 1 RCVR XMTR O λ 2 λ 2 O D XMTR RCVR M OA OA OA OA M • U • • U • X • X RCVR XMTR λ N λ N λ A ~ 80-120 km Integrated DFB Laser/EA Modulator by SAG EA Modulator Section p-InGaAs/InP Cap DFB Laser Section AR HR Fe:InP Blocking n-InP Substrate Selective-Area MOCVD Grown InGaAsP MQW-SCH Grating 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies Data In Data Out λ 1 λ 1 RCVR XMTR O λ 2 λ 2 O D XMTR RCVR M OA OA OA OA M • U • • U • X • X RCVR XMTR λ N λ N λ A ~ 80-120 km What about the receive demux side? Discrete solutions: Cascaded Thin-Film Filters 2005 WOCC – Newark April 22, 2005

Center for Optical Typical TFF Demux Configuration Technologies Ex: 100 GHz 16-Channel Band-Pass Band-Pass Input Separator Separator Port 29 27 30 28 32 25 31 26 22 24 21 23 35 33 36 34 What about 160-channel? 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies Data In Data Out λ 1 λ 1 RCVR XMTR O λ 2 λ 2 O D XMTR RCVR M OA OA OA OA M • U • • U • X • X RCVR XMTR λ N λ N λ A ~ 80-120 km Si/SiO 2 Waveguide Grating Router: Output Star Input Star Coupler Coupler � Readily scalable to large channel count � Wafer scale processing � Stable, inexpensive optical interconnections 2005 WOCC – Newark April 22, 2005

Today's technology for WDM integration: Today's technology for WDM integration: World's smallest integrated AWGs AWGs: 40 channels integrated : 40 channels integrated World's smallest integrated 4.6 mm 1 Chip (mag 5x) Component 4.8 mm 4 Module 3 9 arrayed waveguide gratings+ 40 Photodetectors on-chip loss: 4 dB responsivity: 0.4 A/W crosstalk: - 35 dB

Center for Optical Technologies Data In Data Out λ 1 λ 1 RCVR XMTR O λ 2 λ 2 O D XMTR RCVR M OA OA OA OA M • U • • U • X • X RCVR XMTR λ N λ N λ A ~ 80-120 km Receive Receive Packaged Module 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies But there’s also some subtlety … Two kinds of replacement technology… • Replacing discrete optical solution & offering improvements in cost, size and/or power. • Replacing FUNCTIONALITY previously done with electronics using optical networking architectures and optical technologies 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies RECONFIGURABLE ACTIVE WDM ADD/DROP Space Switch λ 1 High-Capacity Traffic λ 2 λ 1 , λ 2 , .….. λ n λ 1 , λ 2 , .….. λ n Nx1 1xN λ -DMUX λ -MUX λ n Traditional Single-Channel Add/Drop High-Speed High-Speed • Electronic Traffic Reduced cost dynamic x x Electronic provisioning at λ granularity Add/Drop Add/Drop MUX/DMUX without full OEO OEO Low-Speed Electronic Interfaces Add/Drop Local Traffic 2005 WOCC – Newark April 22, 2005

Center for Optical Technologies 8- λ 1 × 9 Wavelength Selective Cross-connect Doerr et al, Bell Labs 4 λ , 1x5 example 8.6 cm Features: � 64 switches, 80 shutter/VOA’s � Any λ to any port � All paths have double rejection in both space and wavelength � Smaller and fewer activated switches than classic split-and-combine