128-channel polarization-insensitive frequency-selection-switch using high-silica waveguides on Si

A 128-channel polarization-insensitive frequency-selection-switch (FS-SW) with 10-GHz frequency spacing is discussed. The FS-SW was fabricated on Si using low-loss GeO/sub 2/-doped high-silica waveguides, and its frequency-insensitive operation was attained by the laser trimming adjustment of a-Si film which controls waveguide birefringence. The fiber-to-fiber loss of the transmitted channel was 6.7 dB in the pigtailed FS-SW and the total crosstalk level was less than -13 dB. By using this FS-SW, a 100-channel optical frequency division multiplexing (FDM) transmission-distribution experiment at 622 M b/s over a 50-km fiber length was achieved.<
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