High-power and narrow-linewidth laser on thin-film lithium niobate enabled by photonic wire bonding
Cornelis A. A. Franken, Rebecca Cheng, Keith Powell, Georgios Kyriazidis, Victoria Rosborough, Juergen Musolf, Maximilian Shah, David R. Barton, Gage Hills, Leif Johansson, Klaus J. Boller, Marko Lončar
Abstract
Thin-film lithium niobate (TFLN) has emerged as a promising platform for the realization of high-performance chip-scale optical systems, spanning a range of applications from optical communications to microwave photonics. Such applications rely on the integration of multiple components onto a single platform. However, while many of these components have already been demonstrated on the TFLN platform, to date, a major bottleneck of the platform is the existence of a tunable, high-power, and narrow-linewidth on-chip laser. Here, we address this problem using photonic wire bonding to integrate optical amplifiers with a TFLN feedback circuit. We demonstrate an extended cavity diode laser with an excellent side mode suppression ratio exceeding 60 dB and a wide wavelength tunability over 43 nm. At higher currents, the laser produces a high maximum on-chip power of 76.2 mW while maintaining 51 dB side mode suppression. The laser frequency stability over short timescales shows an ultra-narrow intrinsic linewidth of 550 Hz. Long-term recordings indicate a high passive stability of the photonic wire bonded laser with 58 hours of mode-hop-free operation, with a trend in the frequency drift of only 4.4 MHz/h. This work verifies photonic wire bonding as a viable integration solution for high performance on-chip lasers, opening the path to system level upscaling and Watt-level output powers.