CROSSTALK REDUCTION IN A 10-GHZ SPACING ARRAYED-WAVE-GUIDE GRATING BYPHASE-ERROR COMPENSATION

The crosstalk in arrayed-waveguide grating multiplexers with a channel spacing of 10 GHz is reduced by compensating for the phase errors aft er fabrication. We used the thermooptic effect realized with a thin-fi lm heater and the photoelastic effect obtained with amorphous silicon film, respectively, for dynamic and static phase-error compensation. T hese two methods were applied to confirm the principle and to realize a stable, stand-alone device, respectively. We have achieved a crossta lk of less than -35 dB for the TE polarization mode in a 16 x 16, 10 G Hz-spacing arrayed-waveguide grating by using these two phase-error co mpensation techniques. Static phase-error compensation results in a st able multiplexer which features a low crosstalk of less than -30 dB fo r one of the two polarization modes of all the channels without any ex ternal control equipment.