Monolithic semiconductor active waveguide optical switch

We have utilized a semiconductor optical amplifier (SOA) as an optical gain/absorption switch and have demonstrated an array of such switches in the form of a monolithic 4 X 4 optical crossbar switch. This device is completely nonblocking and can be operated in either a point-to-point or broadcast mode, simultaneously linking any combination of four input/output ports on one side with any combination of ports on the other. It is housed in a standard hybrid flatpack, with external control leads and eight connectorized optical fibers. The device consists of ridge waveguides, etched-facet turning mirrors, and etched T-branches laid out into an all- optical-path network. It is fabricated from a single GaAs quantum well/AlGaAs GRINSCH epitaxial structure on an N+ GaAs substrate. Because the paths are optical, they transmit signals in either direction -- i.e., the device can operate in a duplex (bidirectional) mode. We have demonstrated switching functionality, simultaneous routing of two digital FM video signals, and routing of pseudo-random NRZ data.