Watt level continuous-wave laser in silicon photonics

High power sources are desired in integrated photonics to utilize their full potential for various applications such as in telecom, medical, and remote sensing. However, the signal power from the integrated photonic sources has been quite limited. One of the main reasons for this is the usage of small optical mode area waveguides, which, although they help in keeping the footprint small and increasing the gain efficiency, limit the energy storage and extraction capability of the signal from an integrated device, thus limiting the output power. By increasing the optical mode area, one allows the photons to interact with a significantly larger number of gain ions, allowing large energy storage and power extraction. In light of this, we show a high-power continuous wave laser based on a recently demonstrated large-mode-area gain waveguide, which requires no external amplifier. The maximum power generated from the distributed Bragg reflector laser is close to 1.35 W with a slope efficiency of more than 50%, and it operates around the long wavelength window (∼1.85 μm) relevant for medical, space, and defense applications. The power level demonstrated here enables silicon photonics based continuous wave light sources comparable to their benchtop counterparts and brings them significantly closer to mass production and deployment for desired applications.