ORMOCER Coated Fiber-Optic Bragg Grating Sensors at Cryogenic Temperatures

Abstract

ORMOCER coated Fiber-Bragg-Gratings (FBGs) were investigated at cryogenic temperatures. Below T = 40 K the Bragg wavelength of uncoated FBG is nearly independent on temperature. ORMOCER coated FBG are temperature dependent over the whole temperature range investigated from 10 to 300 K. For 50-300 K, the ORMOCER coating contributes to an additional linear temperature shift of the Bragg wavelength of 2.4 pm/K. Below 40 K the temperature dependence decreases to 1.0 pm/K. ORMOCER coated FBGs can be used as sensor at cryogenic temperatures. Index Terms-FiberBragg grating (FBG) sensor, functional coating, temperature sensor.

MilliKelvin resolution in cryogenic temperature distributed fibre sensing based on coherent Rayleigh scattering

“…The response is experimentally analysed at cryogenic temperatures where high sensitivity is required. The thermal sensitivity of the sensing system is over the 77 K to 300 K range, for a standard acrylate-coated single-mode fibre and a specially coated fibre with inorganic-organic hybrid materials (ORMOCERs) 7 . In our measurements the effect of the coating is not at all as expected, since it is not crucial in term of sensitivity, but has a clear impact on the thermo-mechanical memory of the fibre.…”

Cryogenic Temperature Measurement Using Rayleigh Backscattering Spectra Shift by OFDR

“…C RYOGENIC temperature measurements are becoming more and more important in many fields, such as the energy industry, transportation, medical technology [1], aerospace [2] and so on. Due to the many advantages of an optical fiber sensor, such as intrinsic electrical isolation, immunity to electromagnetic interference, high sensitivity and accuracy, compactness, and wide bandwidth and multiplexing capabilities [1], it is becoming an attractive means for the measurement of the temperature distribution in harsh environments.…”

“…Due to the many advantages of an optical fiber sensor, such as intrinsic electrical isolation, immunity to electromagnetic interference, high sensitivity and accuracy, compactness, and wide bandwidth and multiplexing capabilities [1], it is becoming an attractive means for the measurement of the temperature distribution in harsh environments.…”

“…There are several types of optical fiber sensors available for extracting distributed temperature information, including the Raman optical time domain reflectometry (OTDR), the Brillouin OTDR [3] and the well-known fiber Bragg gratings (FBGs) [1]. In method of the Raman OTDR and Brillouin OTDR, the sensing media is optical fiber and they can achieve truly distributed measurement, namely every point on fiber Manuscript can sense.…”

“…aerospace applications) that require a better sensing spatial resolution. FBGs have been extended to the applications of cryogenic temperature measurements [1], [2], [5], [6], which can achieve high temperature sensitivity but they are not distributed measurements, actually, they are only sensing available on the FBG points, not every point on fiber. FBGs are often limited by the number of gratings that can be multiplexed in a single fiber.…”