GaAs waveguide detector array for an IOC spectrum analyzer

Integrated optical circuits (IOC's) combining optical signal propagation with high-speed photoelectronic detection have a high potential for very fast analog or digital signal processing. A wideband, real-time spectrum analyzer using thermally grown oxides on a silicon substrate has been investigated by Anderson, Sun et al, which demonstrated the feasibility of a 3-channel time demultiplexing scheme. Data rates of 1 Mbps have been achieved using GaAs waveguide detectors, and frequency demultiplexing has also been investigated. Gallium Arsenide shows great promise as a semiconductor for use in IOC fabrication. A large variety of electronic and optical devices have been demonstrated in GaAs with the desirable attributes of high speed, low noise, and high efficiency. Lindley et al. have fabricated avalanche photodetectors with a large gain-bandwidth product (-50 GHz) and a signal-to-noise ratio of 30 dB. Stillman et al. have fabricated GaAs waveguides which operate with attenuation as low as 2 per cm at GaAs laser wavelengths. In addition, GaAs-AlGaAs double heterostructre lasers emitting at 9100 A have been integrated with high-purity GaAs waveguides.