Reducing temperature drift of an arrayed waveguide grating

A wavelength selective device comprising:

• an input port for inputting an optical beam;
• a splitter for splitting a portion of the optical beam to create a first split portion of the optical beam;
• a reflector, optically coupled to the input port, for varying an angle of a second split portion of the optical beam;
• a focusing element, optically coupled to the reflector, for focusing the second split portion of the optical beam into a focal spot displaceable by varying the angle of the second split portion of the optical beam;
• an arrayed waveguide grating comprising an input slab, having an elongate aperture for receiving the focal spot, and a plurality of output waveguides for outputting wavelength sub-beams of the second split portion of the optical beam,
• wherein the input slab is disposed so that, when the angle of the second split portion of the optical beam is varied, the focal spot is displaced along the elongate aperture;
• a temperature sensor, thermally coupled to the arrayed waveguide grating, for sensing a change of temperature of the arrayed waveguide grating;
• and
• a controller, electrically coupled to the temperature sensor and the reflector, for receiving the first split portion of the optical beam and varying the angle of the second split portion of the optical beam upon sensing the change of temperature of the arrayed waveguide grating, so as to lessen a wavelength drift of the wavelength sub-beams induced by the change of temperature of the arrayed waveguide grating,
• wherein the first split portion of the optical beam is used to power the controller.