Simulations of a sub-kilohertz linewidth laser in monolithic indium phosphide

Narrow-linewidth lasers play a crucial role in various applications, including sensing, coherent communication, and quantum communication. Semiconductor lasers achieving narrow linewidths employ long external cavities to extend photon lifetime within the resonator. For monolithically integrated (active-passive) platforms the loss of the passive waveguides puts a limit on this approach, however. To our knowledge, the state-of-the-art linewidth for such monolithic lasers stands at 10 kHz