Photonic-crystal microresonator-based LiDAR engine

Area of Science:

• Photonics
• Laser Technology
• Optical Engineering

Background:

• Self-injection-locked (SIL) lasers with high-Q microresonators are key for frequency-modulated continuous-wave (FMCW) LiDAR.
• Uncontrolled backscattering often limits SIL laser performance, affecting sweep range and noise.

Purpose of the Study:

• To investigate a tunable SIL laser using a corrugated photonic-crystal (PhC) microresonator with designed feedback strength.
• To analyze the impact of feedback strength on sweep range, phase noise, and linewidth.

Main Methods:

• Utilized numerical simulations and experimental validation.
• Employed CMOS-compatible microheater tuning with low driving voltage (<1 V).
• Demonstrated linearized up- and down-chirps and performed fiber length ranging experiments.

Main Results:

• Stronger SIL feedback expands the accessible frequency sweep range.
• A trade-off exists between frequency tunability and noise performance (phase noise, linewidth).
• Achieved 224 THz/s sweep rates over ~3 GHz and measured 10 m fiber length with <3 mm standard deviation.

Conclusions:

• PhC microresonators with engineered SIL feedback offer a robust, compact, and CMOS-compatible solution for LiDAR engines.
• The designed feedback mechanism allows for controlled tuning of laser characteristics.
• This approach paves the way for advanced FMCW LiDAR systems.