1. MEMS Wavelength Add/Drop Switch Joseph Ford, James Walker, Vladimir Aksyuk, David Bishop References:J. Ford, V. Aksyuk, D. Bishop and J. Walker, “Wavelength add/drop switching using tilting micromirrors” Journal of Lightwave Technology 17(5) p.904-911, 1999 (first presented as post-deadline paper PD2.3 at the 1997 LEOS Annual Meeting) See also US patents #6,204,946 and #6,307,657

2. Switching in Dense Wavelength-Multiplexed Ring Networks Cost: $750k for transponders alone (~ $40k/channel at OC-48) Demultiplex, detect, and regenerate all wavelengths - de MUX - MUX e - de MUX Electronic switch fabric with local I/O RT RT RT RT e - MUX Conclusion: “Run away!” Value: Sub-wavelength grooming flexibility and full 3R regeneration Head-on approach: demultiplex into electronic switch fabric

3. Combine wavelength multiplexing and switching into a transparent optical component Instead: MEMS wavelength-selective add/drop switching Cost:Integration means less flexibility (channel count and pitch) Value: Cuts network build-out expense (first installed cost) & overall insertion loss T R deMUX / switch / reMUX Dropped channels Added channels

4. MEMS = Micro-Electro-Mechanical Systems Surface Micromachining LIGA (electroforming) Deep Reactive Ion Etching Electrostatic attraction Electromagnetic force Electrostriction Resistive heating Photos courtesy Sandia National Labs … manufactured using technology created for VLSI electronics to build micron-scale devices “released” by selective etching …& electrically controlled by

5. MEMS digital tilt-mirror switch Device: Surface micromachined in “MUMPS” 3-layers of polysilicon structure, (silicon nitride sacrificial layers) 50nm Gold on 3nm Chrome mirror Switches: 30 x 50 micron mirrors +/- 5 o (+/- 10 o optical)

6. Free-space wavelength multiplexing Ford, Walker, Goossen & Neilson, European Conf. On Optical Commun.. 1999 Package performance 3.7 dB loss, 0.1 dB PDL (incl. optical circulator) 100 nm spectral range (5 mm active area) Custom achromatic lens (athermal lens & kovar mechanics) I/O Fiber (to circulator) Electrical I/O Lens and /4 f = 50mm Micromechanical Switch Array Grating in tip/tilt mount 600 lp/mm, 43 o blaze angle Gold-coated epoxy on Zerudur substrate

7. Digital MEMS mirror switching Voltage Time V rms In V2 DropInPass V1 Drive waveform 20 V rms from 300 KHz sine (to avoid electrostatic charging) Switch response 20 microseconds (digital envelope on 300 KHz sine) ~2 microseconds (optimized drive waveform)

8. Prototype free-space optics package 600 lp/mm grating MEMS Switch Array f = 25 mm lens /4 plate f = 50 mm lens Pupil division optics separates I/O beams Light is either back-reflected or separated 2x magnification onto device plane Total insertion loss: 4 dB Resolution 16 channels @ 200 GHz (1.6 nm) 19 alignment knobs!

9. DROP ADD In V2 Out InBack V1 OUT IN DROP ADD IN PASS 2x2 add/drop switch configuration Optical circulators create 4 distinct ports from two I/O fibers IN PASS InPass V1 In Add V2 Drop Pass

10. Add/drop switch performance Pass: 5 dB loss, 30 dB contrastAdd/Drop: 7 dB loss, 30 dB contrast

11. 2002 European Conference on Optical Communications, Paper 2.3.1 MEMS tilt-mirror add/drop switches now in development… although not at Lucent or their spinoff Agere! Network Photonics “CrossWave 1-D MEMS” Switch www.networkphotonics.com/whitepapers/index.html JDS Uniphase MWS 1x4 add/drop switch