Locking noise in laser frequency stabilization to an optical fiber delay line

Area of Science:

• Laser physics and optical systems
• Precision measurement techniques
• Fiber optic sensing

Background:

• Laser frequency stabilization is crucial for applications like spectroscopy and metrology.
• The Pound-Drever-Hall method is a common technique for high-precision laser locking.
• Noise in the locking process, particularly white frequency noise, can limit stabilization accuracy.

Purpose of the Study:

• To investigate the source of white frequency noise in laser locking to an optical fiber delay line using the Pound-Drever-Hall method.
• To analyze the impact of frequency discriminator nonlinearity on locking performance.
• To demonstrate a method for reducing this noise floor and improving laser stabilization.

Main Methods:

• Experimental implementation of laser frequency stabilization using the Pound-Drever-Hall technique.
• Theoretical analysis focusing on the frequency discriminator nonlinearity.
• Systematic variation of the locking bandwidth to observe its effect on noise levels.

Main Results:

• Identified a white frequency noise floor limiting the initial laser locking performance.
• Established a correlation between frequency discriminator nonlinearity and the observed noise.
• Demonstrated a significant reduction in white frequency noise by increasing the locking bandwidth.

Conclusions:

• The nonlinearity of the frequency discriminator was a key factor contributing to the white frequency noise floor.
• Increasing the locking bandwidth effectively mitigates the impact of this nonlinearity.
• The study provides a pathway to achieve higher precision in laser frequency stabilization for optical fiber systems.