Enhanced pressure and thermal sensitivity of polymer optical fiber Bragg grating sensors. (October 2020)

• Record Type: Journal Article
• Authors: Woyessa, Getinet; Pedersen, Jens K.M.; Nielsen, Kristian; Bang, Ole
• Is Part Of: Optics & laser technology. Volume 130(2020)
• Publication Date: 2020-10
• Subjects: Polymer waveguide -- Fiber Bragg grating -- Fiber optic sensors -- Sensitivity; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2020.106357
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: POF grating pressure and temperature sensitivities are enhanced by pre-straining. The pressure sensitivity of POF grating is improved by a factor of five. The temperature sensitivity of POF grating is boosted by more than a factor of ten. The sensitivity enhancement is stable above a certain threshold of pre-strain. Pre-straining enable well-conditioned simultaneous measurements with dual gratings. Abstract: One of the features of reliable polymer optical fiber (POF) Bragg grating sensors is high sensitivity. Towards this, we have investigated a method to enhance the intrinsic pressure and thermal sensitivity of fiber Bragg grating (FBG) sensors inscribed in POFs. By pre-straining the FBG we demonstrated that: (1) the pressure induced mechanical contraction of the fiber can be suppressed, resulting in an increase in the pressure sensitivity of the grating by a factor of 5; and (2) the temperature induced strain can be suppressed, resulting in an increase in the thermal response by more than a factor of 10. The pressure sensitivity enhancement was found to be independent of the amount of pre-strain for levels ranging from 0.07 to 0.33%. The enhancement of the temperature sensitivity was also found to be independent of the amount of pre-strain, but only for temperatures up to when the thermal expansion cancels the pre-strain.