The speed and simplicity of the metal-semiconductor-metal (MSM) detector has made it a prime candidate for use in integrated optoelectronic circuits. While in most applications the optical input is coupled in through the top surface of the device, it is also possible to distribute the optical signal by means of transparent waveguides that are located below the absorbing detector layer. By controlling the degree of coupling between the waveguide and detector layers the detectors can be made to act as optical taps. The optical signal can thus be shared among a series of detectors as required in optoelectronic switching applications. We have made a series of simple ridge waveguides, each with a number of MSM structures designed for the characterization of absorption, responsivity and frequency response. A 4x4 optoelectronic switch was also fabricated and analyzed. We show that balancing the switch is accomplished by tailoring the absorption coefficient in the detector region so that all detectors absorb equal amounts of optical power. / Thesis / Master of Engineering (ME)

Metal-semiconductor-metal (MSM) photodetectors are becoming attractive devices for optoelectronic integrated circuits due to their high speed and simplicity. Optoelectronic matrix switches based on MSM detector arrays offer many advantages such as zero-bias off-state, low bias voltage, high speed and large bandwidth. While in many applications the optical input is coupled in through the top surface of the device, optical signals can also be distributed through transparent waveguides that are located below the absorbing detector layer. Such waveguide-coupled detectors will act as optical taps when the coupling between the waveguide and detector layers is well under control. In this thesis, a 4x4 MSM waveguide-coupled optoelectronic matrix switch was demonstrated and analyzed. The strength of the coupling between the waveguide and detector layers was predicted theoretically and confirmed experimentally. Franz-Keldysh effect in this device was also demonstrated. / Thesis / Master of Engineering (ME)