Research on Fiber-Optic Optical Coherence Ranging System Based on Laser Frequency Scanning Interferometry

Area of Science:

• Optics and Photonics
• Metrology
• Optical Engineering

Background:

• Absolute distance measurement is crucial in various scientific and industrial applications.
• Traditional methods face challenges with non-cooperative targets and angled measurements.
• Laser interferometry offers high precision but often requires specialized setups.

Purpose of the Study:

• To propose and validate a novel system for absolute distance measurement using laser frequency scanning interferometry (FSI).
• To develop an integrated fiber-optic probe for versatile and robust distance sensing.
• To demonstrate the system's capability for measuring distances to non-cooperative targets at various angles.

Main Methods:

• Utilized a digitally tunable laser and synchronized pulses for interference signal acquisition via an analog-to-digital converter (ADC).
• Implemented a three-spectrum line interpolation method with a Hanning window for frequency domain demodulation.
• Leveraged single-mode optical fiber for spatial filtering and diffuse reflection for target interaction.

Main Results:

• Achieved a maximum measurement distance of 73.51 mm.
• Demonstrated high precision with a standard deviation of less than 0.19 μm under optimal conditions.
• Confirmed good measurement repeatability even with an offset angle to the target.

Conclusions:

• The developed FSI system provides accurate and repeatable absolute distance measurements.
• The integrated fiber-optic probe enhances usability for non-cooperative targets and angled measurements.
• The portable prototype validates the system's practical applicability in metrology.