Dual-mode self-injection locking in a laser diode-coupled-cavity system.

Area of Science:

• Photonics and Laser Physics
• Optical Engineering
• Nonlinear Optics

Background:

• Self-injection locking in laser systems is crucial for stabilized narrow-linewidth lasers and soliton microcombs.
• Coupled cavities enhance optical frequency comb generation, improving efficiency and bandwidth.

Purpose of the Study:

• To develop a methodology for investigating self-injection locking in laser diode-coupled-cavity systems with Rayleigh backscattering.
• To analyze critical coupling conditions and locking ranges in these systems.

Main Methods:

• Derived rate equations to model the coupled-cavity system.
• Obtained analytical expressions for effective detuning and critical coupling coefficient.
• Performed analytical and numerical simulations to analyze locking behavior.

Main Results:

• Demonstrated dual-mode locking behavior in self-injection locking systems with coupled cavities inducing mode splitting.
• Explained resonance splitting via phase-balancing effects and identified loss compensation through coupling strength tuning.
• Derived an analytical expression for the critical coupling coefficient.

Conclusions:

• The proposed methodology provides a theoretical foundation for stabilized multi-frequency narrow-linewidth laser sources.
• This work supports the realization of high-efficiency, broadband soliton microcombs using coupled-cavity systems.