Scalable Optical Switches With Large Port Count Based on a Waveguide Grating Router and Passive Couplers

A wavelength-selective optical switch based on waveguide grating routers (WGRs), passive splitters, and combiners is described. Tunable lasers on the transmitter side are the only active switching elements. The WGR is operated on multiple free-spectral ranges (FSRs) to achieve increased port count and switching capacity. Switching times of less than 24 ns between wavelengths covering three FSRs are demonstrated experimentally.