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Noise Suppression on the Tunable Laser for Precise Cavity Length Displacement Measurement
Radek Šmíd1, Martin Čížek2, Břetislav Mikel3
1Institute of Scientific Instruments of Academy of Sciences of Czech Republic, v.v.i., Brno 61264, Czech Republic. smid@isibrno.cz.
Sensors (Basel, Switzerland)
|September 9, 2016
Summary
This study precisely measured Fabry-Perot cavity distances using a tunable laser diode. The technique achieved sub-nanometer resolution, enabling highly sensitive displacement measurements.
Area of Science:
- Optical metrology
- Precision engineering
- Laser physics
Background:
- Fabry-Perot cavities are crucial for precise measurements.
- Ultra-low expansion materials are used for stable optical components.
- High-resolution distance measurements are essential in various scientific fields.
Purpose of the Study:
- To measure the absolute distance within a Fabry-Perot cavity.
- To demonstrate sub-nanometer resolution in distance measurements.
- To achieve precise displacement measurement capabilities.
Main Methods:
- Utilized an ultra-wide tunable laser diode for distance measurement.
- Employed an unbalanced heterodyne fiber interferometer to stabilize a DFB laser.
- Suppressed laser frequency noise by up to 40 dB and reduced linewidth to below 300 kHz.
Main Results:
- Achieved a relative measurement resolution of 10^-9.
- Demonstrated a resolution of 0.3 nm for a 0.178 m long cavity.
- Enabled displacement measurements with a precision of 0.5 mm.
Conclusions:
- The developed method offers high-resolution absolute distance measurements.
- The technique is suitable for precise displacement sensing applications.
- Ultra-low expansion materials enhance the stability of optical cavities for metrology.
