Reconfigurable 1x4 optical switch in InGaAsP multiple quantum wells

We report on an integrated 1x4 optical switch that operates using the principle of carrier-induced refractive index change in InGaAsP multiple quantum wells. The device is very simple, requiring only the currents applied to two electrodes for complete operational control. An area-selective zinc in-diffusion process is used to channel the current into the multiple quantum wells, thereby enhancing the efficiency of the carrier based effects. As a result, the electrical power consumption of the device is significantly reduced, allowing the switch to be operated uncooled and under d.c. current conditions. Our initial 1x4 switch exhibits a -8 dB crosstalk between channels. However, improvements on the switch design and better control during the device fabrication process will significantly enhance this value.