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Mems optical switches


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Published in: Technology, Business

Mems optical switches

  1. 1. MOHD NAZIR SHAKEEL Optical Switches
  2. 2. Introduction  In a MEMS optical switch, a micro-mirror is used to reflect a light beam.  The direction in which the light beam is reflected can be changed by rotating the mirror to different angles, allowing the input light to be connected to any output port.  This type of optical switch has been realized for the first time through the fusion of various techniques such as micro-machining techniques for fabricating the mirror, optical design techniques for achieving low-loss optical connections, and control techniques for positioning the mirror accurately.
  3. 3. What are the features?  Can switch optical signals without converting them into electrical signals.  Allows compact low-loss switches to be formed on any scale.  Switching can be performed in 10-30 msec.
  4. 4. What can it do?  Since this device can switch large numbers of optical signals simultaneously, it can be used as a trunk switch for handling large amounts of traffic, and as a switch in large urban communication networks.
  5. 5. Why optical switches  Explosive network traffic  Rapidly growing data rate and port count  Bottleneck due to conventional OEO switches (bandwidth, bit error rate and capacity mismatch)  Cost effective  Competition is in the high date rate range
  6. 6. Optical switches  What are the options (From Tellium Inc)
  7. 7. MEMS Optical Switches  What is MEMS  Micro-Electro-Mechanical System  What is MEMS optical switches  Steerable micro mirror array to direct optical light from input port to its destination port.  System-in-a-chip
  8. 8. 2D MEMS Switches  Mirrors have only 2 positions (cross or bar)  Crossbar configuration  N2 mirrors
  9. 9. 3D MEMS Switches  Mirrors can be tilted to any angles  N or 2N mirrors accomplishing non-block switching  Good scalability
  10. 10. How to fabricate  MEMS process
  11. 11. Actuating Mechanism (I)  Electrostatic mirrors are tilted by electrostatic force between opposite charged plates
  12. 12. Actuating Mechanism (II)  Electromagnetic attraction between electromagnets with different polarity
  13. 13. Actuating Mechanism (III)  Scratch Drive Actuators (SDAs) mecromachining scheme
  14. 14. Actuating Mechanism Comparison Actuating Mechanisms Advantages Disadvantages Electrostatic Well understood Good repeatability Nonlinearity in force- voltage relationship, High driving voltages. Electromagnetic Large force High linearity Low driving voltages Shielding magnetic devices Reliability to be proved Scratch Drive Actuator(SDA) No holdup voltage required Movement in small steps (10nm) (N/A)
  15. 15. Performance  Switching speed sub microsecond  Scalability 512 512  Insertion Loss 3-7 dB  Power dissipation less than electrical switch core
  16. 16. Challenges ? Controllability ? Reliability ? Manufacturability ? Serviceability ? Standardization
  17. 17. Conclusion  MEMS optical switches are currently dominant and promising in the future.  Open question to switch speed.  What is the ultimate requirement?  ALL-optical? Not yet.