Open AccessTemperature-compensated multi-point refractive index sensing based on a cascaded Fabry-Perot cavity and FMCW interferometry
Author(s) -
Zongda Zhu,
Dexin Ba,
Lu Liu,
Liqiang Qiu,
Shunhu Yang,
Yongkang Dong
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.424995
Subject(s) - fabry–pérot interferometer , optics , interferometry , refractive index , multiplexing , sensitivity (control systems) , interference (communication) , materials science , free spectral range , fast fourier transform , optical power , physics , wavelength , laser , computer science , electronic engineering , telecommunications , channel (broadcasting) , algorithm , engineering
We proposed a novel temperature-compensated multi-point refractive index (RI) sensing system by the combination of the cascaded Fabry-Perot (FP) sensors and the frequency modulated continuous wave (FMCW) interferometry. The former is used for simultaneous sensing of RI and temperature, and the latter is used for multiplexing a series of the cascaded FP sensors to realize multi-point sensing. By means of Fourier transform-based algorithms, the interference spectra of each sub-FP sensors can be divided and demodulated independently. Experimentally, three cascaded FP sensors are multiplexed to verify multi-point RI and temperature sensing ability. RI sensitivity up to ∼1200 nm/RIU is obtained within RI range from 1.3330 to 1.3410, and temperature sensitivity up to ∼0.17 nm/°C is obtained within temperature range from 20 °C to 80 °C. The RI precision is as high as 10 -5 RIU and the temperature precision is as high as 0.05 °C. In addition, the prospective multiplexing number could reach about 4000 estimated by the minimum detectable light power. The proposed sensing system has potential advantages in the practical applications that require a large number sensing points.