Laser linewidth measurement based on long and short delay fiber combination

Area of Science:

• Optics and Photonics
• Laser Physics
• Signal Processing

Background:

• Accurate laser linewidth measurement is crucial for various optical applications.
• Traditional methods can be affected by noise, limiting precision, especially for narrow linewidth lasers.
• 1/f noise is a significant challenge in spectrum broadening measurements.

Purpose of the Study:

• To develop a novel numerical method for accurate laser linewidth measurement.
• To overcome the limitations of existing techniques in handling noise.
• To enable precise characterization of narrow linewidth lasers.

Main Methods:

• A numerical calculation employing an iterative algorithm.
• Utilizing self-heterodyne spectrum of long delay fiber as an initial value.
• Demodulating the short delay self-heterodyne spectrum with the iterative algorithm.

Main Results:

• The proposed method accurately measures laser linewidth.
• Successfully eliminates the influence of 1/f noise on spectrum broadening.
• Demonstrates enhanced precision for narrow linewidth laser characterization.

Conclusions:

• The iterative algorithm offers a powerful approach for accurate laser linewidth measurement.
• This method provides a robust solution for overcoming noise-related limitations.
• It is particularly effective for the precise measurement of narrow linewidth lasers.