Optical spectrum control circuit using an arrayed-waveguide grating and tunable phase shifters

We proposed and fabricated an optical spectrum control circuit using an arrayed-waveguide grating (AWG) and an array of channel waveguides with tunable phase shifters. We found that the spectral phase and amplitude of a modulated optical signal could be arbitrarily controlled if the number of channel waveguides was set to be more than twice the number of waveguides in the AWG. As a first demonstration, we successfully obtained a flat band-pass filter function with the fabricated device by controlling the tunable phase shifters to control the interference between the light propagating through them.