Noise Suppression on the Tunable Laser for Precise Cavity Length Displacement Measurement

0463114 - ÚPT 2017 RIV CH eng J - Journal Article
Šmíd, Radek - Čížek, Martin - Mikel, Břetislav - Hrabina, Jan - Lazar, Josef - Číp, Ondřej
Noise Suppression on the Tunable Laser for Precise Cavity Length Displacement Measurement.
Sensors. Roč. 16, č. 9 (2016), 1428:1-11. E-ISSN 1424-8220
R&D Projects: GA ČR(CZ) GPP102/12/P962; GA ČR GB14-36681G; GA MŠMT(CZ) LO1212; GA MŠMT ED0017/01/01
Institutional support: RVO:68081731
Keywords : Fabry-Perot cavity * unbalance Michelson interferometer * noise suppression * heterodyne interferometry * displacement measurement
Subject RIV: BH - Optics, Masers, Lasers
Impact factor: 2.677, year: 2016

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.
Permanent Link: http://hdl.handle.net/11104/0262391