High-precision absolute distance measurement by cascaded synthetic wavelength interferometry using a single...

Area of Science:

• Optical Metrology
• Precision Measurement
• Laser Interferometry

Background:

• Accurate distance and velocity measurements are crucial for industrial applications.
• Traditional interferometry often faces limitations in non-ambiguity range (NAR) or precision.

Purpose of the Study:

• To demonstrate high-precision absolute distance measurement using cascaded synthetic wavelength interferometry (SWI).
• To achieve meter-scale NAR combined with micrometer precision.
• To validate the technique for both static and dynamic measurements.

Main Methods:

• Utilizing a single GHz-rate electro-optic frequency comb (EO comb).
• Filtering three discrete comb modes to create phase-linked continuous-wave (CW) lasers.
• Generating synthetic wavelengths by varying comb modes and switching the EO comb repetition rate.

Main Results:

• Achieved a maximum non-ambiguity range (NAR) of approximately 3.74 m.
• Demonstrated instrument precision of ±4 µm, validated against a commercial HeNe interferometer.
• Showcased velocity measurement with a residual error of < ±15 µm/s.

Conclusions:

• The developed SWI technique offers a simple, robust method for high-precision absolute distance and velocity measurement.
• The combination of micrometer precision and meter-scale NAR is suitable for industry-relevant problems.
• This approach advances optical metrology for demanding applications.