Described herein are lasers comprising an output port to output an optical signal, a plurality of waveguide segments forming an optical cavity length, and a resonant optical cavity comprising the optical cavity length, a gain medium included in the resonant optical cavity to amplify the optical signal, and a heating element disposed near at least two of the plurality of waveguide segments, the heating element controllable to adjust the phase of the optical signal by heating the waveguide segments. Described herein are optical devices comprising a first plurality of ports to output a plurality of optical signals, a second plurality of ports to receive the plurality of optical signals, and a plurality of coupling waveguides. The plurality of waveguide may comprise a pair of adjacent waveguides separated by a first distance, each of the pair of adjacent waveguides comprising a different width.