Open Access Paper
28 March 2023 Wavelength scanning spectroscopic gas detection based on laser frequency comb enabled by phase-shifted fiber Bragg grating (PS-FBG)
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Proceedings Volume 12601, SPIE-CLP Conference on Advanced Photonics 2022; 126010S (2023) https://doi.org/10.1117/12.2667183
Event: SPIE-CLP Conference on Advanced Photonics 2022, 2022, Online Only
Abstract
A wavelength scanning scheme enabled by phase-shifted fiber Bragg grating (PS-FBG) is proposed for gas absorption spectroscopy based on optical frequency comb (OFC). The PS-FBG works as an ultra-narrow bandpass optical filter to generate the gas sensing laser probe. To obtain the gas absorption signal, the electronical frequency beating and lock-in amplification are successively performed with the continuous tuning of the PS-FBG by using a piezo transducer (PZT). The intermediate beat note is monitored in real time for lock-in frequency compensation against the repetition frequency drift of the OFC. A carbon monoxide (CO) sensing system in direct absorption spectroscopy (DAS) configuration is developed based on a free-running fiber laser frequency comb. A triangular-wave PZT driving signal of 5 Hz is used for periodical spectrum scanning. At an intermediate beat note of ~ 50 kHz, the DAS signal is obtained with a lock-in constant of 200 μs. The CO detection limit of 0.356% for an integration time of 0.4 s and the minimum detectable absorbance of ~ 0.0021 are achieved, which indicate a better sensitivity performance.
© (2023) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Zhiwei Liu, Guofeng Yan, Junqiu Long, and Yunjiang Rao "Wavelength scanning spectroscopic gas detection based on laser frequency comb enabled by phase-shifted fiber Bragg grating (PS-FBG)", Proc. SPIE 12601, SPIE-CLP Conference on Advanced Photonics 2022, 126010S (28 March 2023); https://doi.org/10.1117/12.2667183
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KEYWORDS
Spectroscopy

Carbon monoxide

Laser frequency

Repetition frequency

Wavelength tuning

Absorption spectroscopy

Fiber Bragg gratings

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