1. Noise Suppression on the Tunable Laser for Precise Cavity Length Displacement Measurement
- Author
-
Jan Hrabina, Ondřej Číp, Radek Šmíd, Břetislav Mikel, Martin Čížek, and Josef Lazar
- Subjects
Heterodyne ,heterodyne interferometry ,displacement measurement ,unbalance Michelson interferometer ,lcsh:Chemical technology ,Fabry-Perot cavity ,01 natural sciences ,Biochemistry ,Displacement (vector) ,Article ,Analytical Chemistry ,law.invention ,010309 optics ,Laser linewidth ,symbols.namesake ,Optics ,law ,0103 physical sciences ,lcsh:TP1-1185 ,noise suppression ,Electrical and Electronic Engineering ,010306 general physics ,Instrumentation ,Diode ,Physics ,Distributed feedback laser ,business.industry ,Laser ,Atomic and Molecular Physics, and Optics ,Fourier transform ,symbols ,business ,Tunable laser - Abstract
The absolute distance between the mirrors of a Fabry-Perot cavity with a spacer from an ultra low expansion material was measured by an ultra wide tunable laser diode. The DFB laser diode working at 1542 nm with 1.5 MHz linewidth and 2 nm tuning range has been suppressed with an unbalanced heterodyne fiber interferometer. The frequency noise of laser has been suppressed by 40 dB across the Fourier frequency range 30–300 Hz and by 20 dB up to 4 kHz and the linewidth of the laser below 300 kHz. The relative resolution of the measurement was 10 − 9 that corresponds to 0.3 nm (sub-nm) for 0.178 m long cavity with ability of displacement measurement of 0.5 mm.
- Published
- 2016