Open AccessHigh sensitivity temperature measurement via mask-free hybrid polymer long period fiber grating
Author(s) -
Bjorn Paulson,
Haemyeong Jung,
Ji-Hyun Hwang,
Seongjin Hong,
Sang-Hwa Lee,
Jun Ki Kim,
Kyunghwan Oh
Publication year - 2018
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.016125
Subject(s) - materials science , optics , long period fiber grating , attenuation , coupled mode theory , optoelectronics , photodiode , optical fiber , attenuation coefficient , fiber optic sensor , band rejection , grating , optical power , refractive index , plastic optical fiber , laser , telecommunications , physics , computer science , antenna (radio)
Long-period fiber gratings (LPFGs) are useful for environmental sensing under conditions of high corrosiveness and electromagnetic interference. Most LPFGs are fabricated by coherent or high-power UV illumination of an optical fiber under an amplitude mask, resulting in narrow and environmentally-dependent band rejection. We present a hybrid LPFG waveguide fabricated without an amplitude mask through polymer self-assembly under low-power incoherent UV illumination, which demonstrates high-temperature sensitivity in its transmission spectrum compared to LPFG sensors based purely on silica waveguides. A sensitivity of 1.5 nm °C -1 is obtained experimentally for attenuation near 1180 nm, and a sensitivity of 4.5 nm °C -1 with a low random error was obtained with a composite of attenuation bands. Finite element method simulations and coupling mode theory reveal this to be due to a thermo-optic coefficient one order of magnitude greater than that of fused silica. The device has potential for a simple and inexpensive transmission intensity based temperature sensor consisting of an infrared light source, the LPFG, a bandpass filter, and a photodiode.