Integrated electro-optically tunable narrow-linewidth III-V laser

Abstract: We demonstrate an integrated electro-optically tunable narrow-linewidth III-V laser with an output power of 738.8 {\mu}W and an intrinsic linewidth of 45.55 kHz at the C band. The laser cavity is constructed using a fiber Bragg grating (FBG) and a tunable Sagnac loop reflector (TSLR) fabricated on thin film lithium niobate (TFLN). The combination of the FBG and the electro-optically tunable TSLR offers the advantages of single spatial mode, single-frequency, narrow-linewidth, and wide wavelength tunability for the electrically pumped hybrid integrated laser, which features a frequency tuning range of 20 GHz and a tuning efficiency of 0.8 GHz/V.