Abstract

Coherent optical techniques have great potential in multichannel systems as a result of the frequency selectivity and the very high receiver sensitivities that can be achieved. Among the different types of optical receivers available for coherent detection, the dual-detector balanced optical receiver [l] has emerged as the most preferred one. Such a receiver, which has two photodetectors in a balanced mixer configuration, has been shown to be useful in suppressing local oscillator (LO) excess intensity noise and requires less local oscillator power than a conventional single-detector receiver. Monolithic integration of different constituents of the balanced receiver has been demonstrated by several laboratories, including a 3 dB directional coupler with integrated balanced detectors [2], a tunable DFB laser with coupler and detectors [3], a tunable DBR laser with tunable coupler and waveguide detectors [4], and balanced twin p-i-n photodetectors [5].

© 1991 Optical Society of America