Absolute distance measurement with a gain-switched dual optical frequency comb

Area of Science:

• Optics and Photonics
• Metrology
• Instrumentation

Background:

• Accurate distance measurement is crucial for numerous modern societal and industrial applications.
• Traditional methods often face limitations such as periodic ambiguity or restricted measurement ranges.
• Advancements in optical metrology are essential for enhancing precision and expanding capabilities.

Purpose of the Study:

• To propose and demonstrate a novel absolute distance measurement method.
• To overcome the limitations of periodic ambiguity in distance sensing.
• To achieve high accuracy for arbitrary distances using a compact system.

Main Methods:

• Utilizing mode-resolved spectral interferometry.
• Employing a gain-switched dual optical frequency comb.
• Tuning the repetition frequency of the dual comb between 1.1 GHz and 1.4 GHz.

Main Results:

• Demonstrated an absolute distance measurement for displacements up to 2.5 meters.
• Achieved a measurement accuracy of 12 µm, validated against a He-Ne laser interferometer.
• The system successfully broke the constraint of periodic ambiguity inherent in some measurement techniques.

Conclusions:

• The proposed gain-switched dual comb method provides a robust solution for absolute distance measurement.
• The compact and simplified system offers significant advantages for industrial implementation.
• This technique paves the way for enhanced precision in metrology and related fields.