US Patent 9285538 Reducing temperature drift of an arrayed waveguide grating

A wavelength selective device including an arrayed waveguide grating is disclosed. The wavelength selective device includes a MEMS mirror, which couples light from an input port to an elongate aperture of an input star coupler or slab of the arrayed waveguide grating. A controller tilts the MEMS mirror in response to a sensed temperature change of the arrayed waveguide grating, thereby lessening a sensitivity of the arrayed waveguide grating to the temperature change. The MEMS mirror can also be tilted to shift wavelengths of the wavelength channels of the arrayed waveguide grating by pre-defined amounts upon receiving a corresponding remote command.