[OPTICAL REVIEW Vol. 8, No. 4 (2001) 294-300]
Design Criterion for Micro-Machine Scanner Optical Switch Based on Beam Steering Angle Error Analysis
R&D Department, Optical Components Division, Oki Electric Industry, Co., Ltd., 550-1 Higashiasakawa, Hachioji, Tokyo, 193-8550 Japan
(Received January 30, 2001; Accepted April 26, 2001)
The micro-machine scanner optical switch is gaining attention for its ability to switch over 100 ports. A beam steering error for devices using tilted mirrors or a moving lens is analyzed and schemes to overcome the limit are reported. The channel number is limited by the achievable beam steering error. A device with several hundred ports is possible with the beam steering error under 1%. Optimized focal length or fiber mode divergence angle is beneficial for increasing the channel number. To minimize the thermal expansion effect, large focal length is required indicating need for a compensation scheme to attain larger channel number. A new type of scanning optics is proposed to overcome the limit set by the beam steering error, and a new switch network described can further expand the channel number.
Key words : optical switch, optical cross-connect, scanner, angle error, micro-machine, micro electro-mechanical system, micro-mirror, moving-lens