Silicon photonics based 1 × 2 wavelength selective switch using fold-back arrayed-waveguide gratings.

We report on a novel design of a wavelength selective switch (WSS) using silicon photonics technology. It comprises of 1 x 4 interleavers, arrayed-waveguide gratings (AWGs) connected to fold-back waveguides, and 1 x 2 optical Mach-Zehnder interferometer switches. In the proposed WSS, fold-back waveguides enable the AWGs to be used for both demultiplexing and multiplexing. Therefore the WSS has less waveguide crossings than a conventional configuration. Moreover, a 20-channel, 200-GHz spacing, 1 x 2 fold-back type WSS was fabricated on 5 mm x 10 mm SOI chip using CMOS technology.