US Patent 9103991 Multi-pole optical signal switch

An optical switch having multiple input and output ports directs any number of WDM signals, each arriving at a respective input port, to any one of the output ports. The optical switch includes an array of LC pixels, each positioned to receive a WDM signal transmitted through one of the ports, and an array of reflective elements, each associated with one of the LC pixels. The LC pixels are controlled to cause a WDM signal incident thereon to attain an attenuation state while an output of the WDM signal is being switched by an associated reflective element, such that when an output for a WDM signal is switched from a first port to a second port, the switching can be performed in a hitless manner.