Title :
Relative humidity sensor based on optical fiber gratings and polyvinyl alcohol
Author :
Jingyi Yang ; Xinyong Dong ; Kai Ni ; Chi Chiu Chan ; Shum, Perry Ping
Author_Institution :
Inst. of Optoelectron. Technol., China Jiliang Univ., Hangzhou, China
Abstract :
A relative humidity (RH) sensor operating in reflection mode is proposed and experimentally demonstrated by using a polyvinyl alcohol (PVA)-coated tilted-fiber Bragg grating (TFBG) cascaded by a reflection-band-matched chirped-fiber Bragg grating (CFBG). The sensing principle is based on the RH-dependent refractive index (RI) of the PVA coating which modulated the transmission of the TFBG. The CFBG is properly designed to reflect a broadband of light spectrally suited at the cladding mode resonance region of the TFBG, thus the reflected optical signal passes through and the intensity is modulated by the TFBG twice so that the sensitivity improves significantly. RH measurement with sensitivity of ~1.7402 μW/% RH in the range from 20% to 90% is realized.
Keywords :
Bragg gratings; fibre optic sensors; humidity sensors; intensity modulation; optical design techniques; optical films; optical modulation; optical polymers; polymer films; refractive index; CFBG; PVA coating; RH sensor; RH-dependent refractive index; TFBG; cladding mode resonance region; intensity modulation; optical fiber gratings; polyvinyl alcohol; reflected optical signal; reflection-band-matched chirped-fiber Bragg grating; relative humidity sensor; sensitivity; tilted-fiber Bragg grating; Fiber gratings; Optical fiber sensors; Optical fibers; Optical reflection; Relative humidity sensor; chirped-fiber Bragg grating; polyvinyl alcohol; tilted-fiber Bragg grating;
Conference_Titel :
Advanced Infocomm Technology (ICAIT), 2014 IEEE 7th International Conference on
Conference_Location :
Fuzhou
Print_ISBN :
978-1-4799-5454-4
DOI :
10.1109/ICAIT.2014.7019544
