Multicore fiber sensor for high-temperature applications up to 1000°C

Abstract

A novel high temperature sensor based on customized multicore fiber (MCF) is proposed and experimentally demonstrated. The sensor consists of a short, few-centimeter-long segment of MCF spliced between two standard single-mode fibers. Due to interference effects, the transmission spectrum through this fiber chain features sharp and deep notches. Exposing the MCF segment to increasing temperatures of up to 1000°C results in a shift of the transmission notches toward longer wavelengths with a slope of approximately 29 pm/°C at lower temperatures and 52 pm/°C at higher temperatures, enabling temperature measurements with high sensitivity and accuracy. Due to its compact size and mechanical rigidity, the MCF sensor can be subjected to harsh environments. The fabrication of the MCF sensor is straightforward and reproducible, making it an inexpensive fiber device.

Hollow Core Fiber Based Interferometer for High-Temperature (1000 °C) Measurement

“…Further increases in the temperature to constant values of 900 °C and 1005 ℃, result in the blue shift increase with time becoming more significant, which indicates the sensor's stability deteriorates with the long term exposure to higher temperatures, above 800 °C. This problem can be solved by introducing an annealing process which helps to eliminate the residual stress and thermal memory existing in the fiber structure [11,30]. As shown in Fig.…”

“…Interferometer based temperature sensors, on the other hand, have the advantages of a relatively simple fabrication process, a much lower cost and can be fabricated for example by tapering or combining different optical fiber structures. Based on a variety of different fiber structure configurations, a number of interferometer based sensors have been proposed for high temperature sensing, such as those based on multimode fibers, thin core fibers, microcavities, microchannels, twin core, multi core fibers, and photonic crystal fibers (PCF) [11][12][13][14][15][16][17]. Multimode and thin core fiber based temperature sensors show poor spectral Q factors and hence the temperature measurement accuracy is relatively low.…”

“…In FPI based sensors there is a need to very precisely control the size of the microcavity in the order of micrometers, as small variations in the cavity length will result in significant changes to the actual spectrum achieved by comparison to the intended spectrum. Moreover, most of the air gap FPI based temperature sensors have a very limited temperature sensitivity (~1 pm/°C) [22][23][24] and contamination from dust and other pollutants is a significant issue for the long term stability of the sensor, due to a structure that is typically open to the environment [11]. Recently, functionalized HCF based interferometer structures has been reported for use as a biosensor, a magnetic field sensor, a humidity sensor and a displacement sensor [25][26][27][28].…”

Investigation of a novel temperature-sensing mechanism based on strain-induced optical path-length difference in a multicore optical fiber

“…For example, Antonio-Lopez et al [7] sandwiched a segment of 2-3 cm of seven-core fiber between two single mode fibers by splicing them to each other, thus constructing a Fabry-Perot type interferometer to measure temperatures of up to 1000…”

Supersensitive sensors based on multicore optical fibres

“…Our MCFs have a central core and two or six cores symmetrically or asymmetrically distributed around the central core [4][5][6]. All the cores have the same refractive index and are coupled optically.…”