InP-based monolithic functional devices for WDM network

This paper describes some of our recent results on semiconductor optical amplifier (SOA)-based monolithic functional devices for WDM networks. A WDM channel selector, which can select an arbitrary channel from WDM channels, will be discussed first. A monolithically integrated 64-channel selector on IriP substrate is demonstrated using a novel configuration that allows it to handle a large number of WDM channels. It is composed of two AWGs, SOA gates, and a multimode-interference coupler. The two key concepts are the use of the cyclic function of an AWG and two-step selection. Based on this configuration, the 64-channel WDM channel selector is realized with only 16 optical gates. Zero insertion loss was achieved for almost all channels in the fabricated device. Small sensitivity penalties with a typical value of 1.3 dB and fast channel switching of less than 1 .5 ns were obtained using the fabricated device. An all-optical wavelength converter will be then discussed. We have proposed a Sagnac interferometer integrated with parallel-amplifier structure (SIPAS) for filter-free all-optical wavelength conversion. A Mach-Zehnder interferometer with a SOA in each arm is monolithically integrated with a Sagnac interferometer. Wavelength conversion experiment was performed for lO-Gbitls RZ signal. Clear eye opening and low power penalty of 0.9 dB were achieved using the fabricated SIPAS.