A crosspoint switch with gain

A compact crosspoint switch is an important element for future photonic switching systems. There are a number of advantages of using a twin-guide laser amplifier as opposed to conventional lithium niobate or semiconductor directional couplers for the crosspoint switch. Firstly, the amplifier has gain and can compensate for the switch insertion loss. Secondly, it has been predicted for the travelling-wave configuration that the switch can be controlled either electrically or optically, via the intensity of the input signal. The authors have recently reported the first demonstration of these switching properties for a Fabry-Perot twin-ridge amplifier. Here, they discuss how the crosstalk and sensitivity to wavelength is reduced by coating all the facets with a low-reflectivity (LR) coating, examine the polarization dependence and compare the results with theory