A 4-CHANNEL RIDGE-WAVE-GUIDE QUANTUM-WELL WAVELENGTH DIVISION DEMULTIPLEXING DETECTOR AND ITS OPTIMIZATION

We present a four-channel wavelength division demultiplexing detector using the principle of quantum confined Stark effect. This device is b ased on a ridge waveguide GaAs-AlGaAs single quantum well graded index separate confinement heterostructure. Four detectors are fabricated s equentially along the wave guide and their band gaps are tuned to prog ressively smaller values by applying progressively larger reverse bias voltages. Thus each detector responds preferably to one of the four i nput wavelengths. For transverse electric polarization, better than - 10 dB crosstalk was achieved with a 14 nm wavelength separation. When operated as a three-channel device, better than - 15 dB crosstalk was achieved with a 18 nm wavelength separation. For transverse magnetic p olarization, better than - 10 dB crosstalk was achieved with a 16 nm w avelength separation. We also present a theoretical study that leads t o the optimization of the device.