Wavelength Add/Drop Switching Using Tilting Micromirrors

We describe a wavelength add/drop switch which routes individual signals in and out of a wavelength-multiplexed data stream without interrupting the remaining channels. The switch uses free-space optical wavelength multiplexing and a column of micromechanical tilt-mirrors to switch 16 channels at 200 GHz spacing from 1531-1556 nm. The electrostatically-actuated tilt mirrors use an 80 V peak-to-peak 300 KHz sinusoidal drive signal to switch between +/-10 degrees with a 20 microsecond response. The total fiber-to-fiber insertion loss for the packaged switch is 5 dB for the passed signals and 8 dB for added and dropped signals, with 0.2 dB polarization dependence. Switching contrast was 30 dB or more for all 16 channels and all input and output states. We demonstrate operation by switching 622 Mb/s data on 8 wavelength channels between the two input and output ports with negligible eye closure.