Photonic-integrated wavelength selective switch for S+C+L applications

We propose a novel modular photonic integrated Wavelength Selective Switch (WSS) based on a reconfigurable optical multiplexer architecture, capable to operate over the S+C+L bands and scalable. The densely integrated solution takes advantage of an input stage with grating assisted contra-directional couplers to separate channels in the three considered communication bands, followed by a cascade of two-stage ladder ring resonators, to separating each transmitted channel. A final switching stage routes the signal to the desired output fiber, with a cascade of thermally controlled Mach-Zehnder interferometers. The transmission penalty of the proposed solution has been evaluated in a coherent transmission scenario.