Photonic-crystal microresonator-based LiDAR engine

TL;DR

This paper demonstrates a tunable photonic-crystal microresonator laser for LiDAR, showing a trade-off between frequency sweep range and noise, with experimental proof-of-concept ranging.

Contribution

It introduces a design-controlled SIL laser based on PhC microresonators, enabling tunable FMCW LiDAR with CMOS compatibility and improved performance.

Findings

Stronger SIL feedback increases sweep range but affects phase noise and linewidth.

Achieved 224 THz/s linear chirp over 3 GHz using CMOS microheater tuning.

Measured 10 m fiber length with sub-3 mm standard deviation in ranging.

Abstract

Self-injection-locked (SIL) narrow-linewidth lasers based on high-Q microresonators are promising sources for frequency-modulated continuous-wave (FMCW) LiDAR, but the SIL mechanism as well as its key characteristics such as the frequency sweep range and the noise performance are often determined by uncontrolled backscattering in the resonator. Here, we investigate a tunable SIL laser based on a corrugated photonic-crystal (PhC) microresonator in which the feedback strength is set by design. Numerical and experimental results show that stronger SIL feedback expands the sweep range accessible through resonator modulation while also impacting the phase-noise and linewidth during sweeping, revealing a trade-off between frequency tunability and noise performance. Using CMOS-compatible microheater tuning (sub-1 V driving voltage), we demonstrate linearized up- and down-chirps with 224 THz/s over approximately 3 GHz and, in a proof-of-concept ranging experiment, measure a 10 m fiber length with a standard deviation below 3 mm. These results establish PhC microresonators with engineered SIL feedback as robust, compact, CMOS-compatible LiDAR engines.