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External Modulation Laser Module Assembly for Improving Measurement Performance of Homodyne Interferometry
Tao Zhang1,2, Tao Sun3, Jiean Li1
1Center of Ultra-Precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150001, China.
Sensors (Basel, Switzerland)
|October 7, 2020
Summary
An external modulation laser module assembly (EMLMA) suppresses nonlinear errors in interferometry. This advanced light source improves measurement resolution from 7 to 2 nm, enhancing system performance without optical changes.
Area of Science:
- Optics and Photonics
- Metrology
- Signal Processing
Background:
- Interferometry systems are susceptible to nonlinear errors and noise from spurious reflections.
- Stray and background light can degrade measurement accuracy and resolution.
Purpose of the Study:
- To propose an external modulation laser module assembly (EMLMA) for suppressing nonlinear errors in interferometry.
- To enhance the measurement performance and stability of interferometric systems.
Main Methods:
- The EMLMA utilizes radio frequency phase modulation and a specific modulation amplitude switching mode.
- Amplitude modulation shifts the signal of interest to a high-frequency bandwidth to reduce noise.
Main Results:
- Measurement error and stability of the interferometry system were significantly improved.
- Spurious reflection-induced offset decreased, and measurement resolution improved from 7 nm to 2 nm.
Conclusions:
- The EMLMA effectively suppresses nonlinear errors and noise in interferometry.
- It offers a plug-and-play solution to enhance existing interferometric systems without structural modification.
