Paper

Ultrafast tunable lasers using lithium niobate integrated photonics

Rui Ning Wang, Seidler, Paul, Kippenberg, Tobias J, Huang, Guanhao, Riedhauser, Annina, Popoff, Youri, Drechsler, Ute, Moehl, Charles, Caimi, Daniele, Lihachev, Grigory, Riemensberger, Johann, Churaev, Mikhail, Anat Siddharth, Hoenl, Simon, Liu, Junqiu, Snigirev, Viacheslav

2022

Overview

Recent advances in the processing of thin-film LNOI have enabled low-loss photonic integrated circuits, modulators with improved half-wave voltage, electro-optic frequency combs and novel on-chip electro-optic devices, with applications ranging from 5G telecommunication and microwave photonics to microwave-to-optical quantum interfaces. Lithium niobate integrated photonic circuits could equally be the basis of integrated narrow-linewidth frequency-agile lasers. Pioneering work on polished lithium niobate crystal resonators has led to the development of electrically tunable narrow-linewidth lasers. Here we report low-noise frequency-agile lasers based on lithium niobate integrated photonics and demonstrate their use for coherent laser ranging. This is achieved through heterogeneous integration of ultra-low-loss silicon nitride photonic circuits with thin-film lithium niobate via direct wafer bonding. This platform features low propagation loss of 8.5 dB/m enabling narrow-linewidth lasing (intrinsic linewidth of 3 kHz) by self-injection locking to a III-V semiconductor laser diode. The hybrid mode of the resonator allows electro-optical laser frequency tuning at a speed of 12 PHz/s with high linearity, low hysteresis and while retaining narrow linewidth. Using this hybrid integrated laser, we perform a proof-of-concept FMCW LiDAR ranging experiment, with a resolution of 15 cm. By fully leveraging the high electro-optic coefficient of lithium niobate, with further improvements in photonic integrated circuits design, these devices can operate with CMOS-compatible voltages, or achieve mm-scale distance resolution. Endowing low loss silicon nitride integrated photonics with lithium niobate, gives a platform with wide transparency window, that can be used to realize ultrafast tunable lasers from the visible to the mid-infrared, with applications from OCT and LiDAR to environmental sensing.

• Publisher: Cornell University Library, arXiv.org
• Subject: Circuit design / CMOS / Frequency locking / Group III-V semiconductors / Hybrid modes / Integrated circuits / Lasers / Lidar / Lithium niobates / Microwave photonics / Modulators / Optics / Photonics / Resonators / Semiconductor lasers / Silicon nitride / Tunable lasers