Silicon monolithic wavelength selective switch utilizing arrayed waveguide gratings and Bragg grating filters

A monolithic wavelength selective switch (WSS) using a silicon waveguide was fabricated and its characteristics were measured. The crosstalk of the silicon arrayed-waveguide grating (AWG), which is a drawback of the silicon waveguide type WSS, is reduced by introducing a Bragg grating filter (BGF), which can realize a waveguide type WSS with both fast switching and low crosstalk performance. The extinction ratio of the BGF was approximately 20 dB with a 3-dB bandwidth of 0.6 nm. The AWG had an average loss of 9.5 dB with a large second peak crosstalk. Switching experiments showed that the total loss averaged 20.5 dB, the crosstalk averaged -13.9 dB, and that switching responses were 13 μs for both the rise and fall.