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1. MOHD NAZIR SHAKEEL Optical Switches
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. 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. 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. 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. Optical switches What are the options (From Tellium
Inc)
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. 2D MEMS Switches Mirrors have only 2 positions (cross or
bar) Crossbar configuration N2 mirrors
9. 3D MEMS Switches Mirrors can be tilted to any angles N or 2N
mirrors accomplishing non-block switching Good scalability
10. How to fabricate MEMS process
11. Actuating Mechanism (I) Electrostatic mirrors are tilted by
electrostatic force between opposite charged plates
12. Actuating Mechanism (II) Electromagnetic attraction between
electromagnets with different polarity
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. Performance Switching speed sub microsecond Scalability 512
512 Insertion Loss 3-7 dB Power dissipation less than electrical
switch core
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.