Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course O-MEMS Fiber Switches Olav Solgaard Stanford University Motivation Fiber switch concepts  2x2 switch  Matrix switch  3-D switch  Scaling  Experimental demonstrations  Challenges  Optical quality, large switches, reliability, speed, fiber alignment, packaging…….  Network impact  Packet switching? Conclusions

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Beam Steering Optical Switch  Analog mirrors  2N scaling  Lucent, C-speed, Xros(NT),.....

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Fresnel Zone Lens Fresnel Zone plate on polysilicon plate, which is rotated out of the plane on microhinges. The fact that the lens is an amplitude grating limits its diffraction efficiency. Lin, Lee, Pister, Wu, UCLA, 1994.

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course 2 x 2 fiber-optic switch  Compact design  One-mask fabrication using DRIE on SOI  Integration of fibers, lenses, and micromirrors  2 by 1 operation  By-pass switch  AT&T, JDSU In 1 In 2 Out 2 Out 1

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course 1 x 2 Matrix Switch

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course 2x2 switch – DRIE of SOI manipulator comb drives Fiber grooves or channels Springs Bryant Hichwa etal, OCLI/JDS Uniphase, “A Unique Latching 2x2 MEMS Fiber Optics Switch”, Optical MEMS 2000, Kauai, August th, 2000.

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course DRIE etched vertical micromirror  Pro:  Simple fabrication (one masking step)  Simple packaging  Con:  Scaling  Large device count  Immature fabrication processes (reliability) C. Marxer, N.F. de Rooij, Jrnl of Lightwave Tech., Vol. 17, No. 1, Jan 1999

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course NxN Matrix OXC  Simple 1 by 2 cross-points  Digital mirrors  N 2 scaling  Large motion  Reliability??  OMM, Onix, AT&T, Agilent.....

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Waveguide Cross Connects Champagne Switch (Agilent) Vertical Directional Coupler S. Yu, M. Owen, R. Varrazza, R.V. Plenty, I.H. White, “High speed optical packet routing demonstration of a vertical coupler cross point switch array”, Proceedings of the Conference on Lasers and Electro-optics(CLEO), San Francisco, May 7-12, 2000, pp

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course AGILENT’s NxN OXC based on InkJet Technology

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Micromachined tilt-up mirrors TORSIONAL HINGE 100  m COMB DRIVE TORSIONAL HINGES 100  m COMB DRIVES Fast-mirror designSlow-mirror design For 15 degrees optical deflection: Fast mirror: 36.1 V rms at 4.6 kHz Slow mirror: 60 V pp below resonance

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Coupling chip

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Diode-laser display CCD camera Laser-diode array Scanning micromirror

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Video Display System Based on Microscanners (TV on a chip) Computer controls the laser diode and both scanning mirrors The laser beam hits the fast scanning mirror,... is imaged onto the slow scanning mirror, …and the image is projected onto the screen Surface micromachined, flip-up scanning mirror 1f 2f

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Single-chip scanner layout 633nm HeNe Laser Mirror Curvature Compensation Optics Output Optics Camera Spatial Filter Acousto-Optic Modulator Fast mirror Output mirror Slow mirror Single-Chip Raster- Scanner Mechanical Shutter

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Micromachined raster-scanner

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Two-chip scanner images a d e c f b g h Resolution: 62 by 66 pixels, optical scanning angles 5.3 and 5.7 degrees Acousto-optic modulator switches the laser light off during mirror wobble.

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Large Arrays Texas Instrument’s DMD NASA's Next Generation Space Telescope (2008) with 4M micromirrors by Sandia NL Lucent’s Optical X-Connect

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course System on a chip Laser-to-fiber coupling Micropositioners of mirrors and gratings High-resolution raster scanner

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Grating Light Valve

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course UNIQUE FUNCTIONALITY Silicon Dioxide Silicon Nitride Silicon Substrate 25 to 100 µm Top electrode Diffractive micro optics Adaptive micro optics Configurable holograms Photonic Crystals Applications:  1-D and 2-D spatial light modulators (Projection displays - Silicon Light Machines)  Displacement sensors (AFM arrays - C. Quate)  IR sensors  Sensor integration, free-space communication  Diffractive lenses and holograms (Fresnel zone plates - M. Wu, UCLA)  Spectroscopy

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Grating Light Modulator Silicon Dioxide Silicon Nitride Silicon Substrate Individual ribbons are from 1 to 2 µm wide and from 25 to 100 µm long. Top electrode Substrate electrode Beams up, reflection Beams down, diffraction Cross section

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course High-contrast GLM Dark StateBright State sin  on  sin  off 

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course High Speed Switching Light Output 20 nsec Switching Speed time down up GLV devices switch in as little as 20 nsec (~1,000 times faster than TI DMD)

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Grating Light Valve Technology GLV Basic Projection System Advantages: Traditional light source and projection system Disadvantages: 2-D Addressing Large Array =>Low yield

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course SEMs of Grating Light Valve 1-D Grating Light Valve with Silicon nitride ribbons. The detailed picture shows the termination of the ribbons and the addressing lines. Courtesy Silicon Light Machines.

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course GLV Device Reliability Ribbon material is Silicon Nitride — a stable ceramic material Device operates at small fraction of material’s tensile breaking stress Ratio of [ribbon length]:[max deflection] is about 800:1 No contact between ribbon and substrate Negligible change in natural frequency after equivalent of 10,000 hours of television use Courtesy of Silicon Light Machines

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course GLV Pixel Fundamental Contrast >2000:1 contrast at the GLV device Courtesy of Silicon Light Machines

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course The Scanned GLV Architecture Relative to Scanned Beam (CRT) 1,000X lower channel bandwidth Natural gamma, smoothly blended images Variable aspect ratios without light loss Relative to 2-D Panel 2,000X fewer pixels, smaller silicon die size Retains high optical MTF No “screen door” effect Courtesy of Silicon Light Machines

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course GLM Characteristics Small ( /4) required deflection  High Speed  Good heat dissipation => high power-handling capability  1-D implementation & simple structure => High Yield  CMOS “compatible” => Inexpensive, flexible fabrication  “On-chip” interferometer  Good reliability

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course MEMS Phased Arrays Linear array of piston-motion mirrors for beam steering. Each micromirror is 110  m long and 27  m wide. D.M. Burns and V.M. Bright 1997.

Optical MEMS in communication and sensing Copyright O. Solgaard, All federal and state copyrights reserved for all original material presented in this course Variable Blaze Grating Variable Blaze grating with torsional hinges for tilting of each element in the array. Burns, Bright, and Gustavson 1997.