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

fYear

2014

fDate

14-16 Nov. 2014

Firstpage

137

Lastpage

142

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;

fLanguage

English

Publisher

ieee

Conference_Titel

Advanced Infocomm Technology (ICAIT), 2014 IEEE 7th International Conference on

Conference_Location

Fuzhou

Print_ISBN

978-1-4799-5454-4

Type

conf

DOI

10.1109/ICAIT.2014.7019544

Filename

7019544