Stabilization of a whispering gallery mode self-injection locked laser based on phase difference control

Area of Science:

• Optics and Photonics
• Laser Physics
• Micro-optics

Background:

• Self-injection locking (SIL) is crucial for high-performance lasers.
• Whispering gallery mode (WGM) microresonators offer unique optical properties.
• Stabilizing SIL in microresonator-coupled lasers remains a challenge.

Purpose of the Study:

• To investigate feedback control of phase difference for stabilizing SIL.
• To analyze the relationship between phase difference and microresonator transmission.
• To achieve stable SIL in a semiconductor laser coupled to a WGM microresonator.

Main Methods:

• Implementing feedback control on the phase difference between the WGM microresonator and laser cavity.
• Analyzing the transmitted light intensity through the microresonator.
• Utilizing selected phase shift devices and a controller for precise phase management.

Main Results:

• Successfully maintained the phase difference at a set point.
• Achieved stable self-injection locking in a fiber-coupled semiconductor laser.
• Demonstrated a narrow laser linewidth of approximately 200 Hz.
• Obtained a minimum normalized output wavelength Allan deviation of 1×10^-10.

Conclusions:

• Feedback control of phase difference is an effective method for SIL stabilization.
• This technique provides a reliable solution for high-stability microresonator-based lasers.
• The achieved performance metrics are significant for applications requiring precise wavelength control.