Chirping of the waveguide grating router for free-spectral-range mode selection in the multi-frequency laser

The multi-frequency waveguide grating router laser (MFL)[1] consists of a waveguide grating router[24] integrated with semiconductor amplifiers. N ports at one end of the router terminate in optical amplifiers with cleaved mirror facets, and one port at the other end terminates in a partially reflecting mirror, or possibly an additional optical amplifier. Each of the N resonant cavities provides a different intracavity filter frequency due to the router. These intracavity filters are precisely spaced with respect to each other, resulting in an MFL output consisting of N precisely spaced laser frequencies.