Fiber Bragg Grating (FBG) Sensors in a High-Scattering Optical Fiber Doped with MgO Nanoparticles for Polarization-Dependent Temperature Sensing

Abstract

The characterization of Fiber Bragg Grating (FBG) sensors on a high-scattering fiber, having the core doped with MgO nanoparticles for polarization-dependent temperature sensing is reported. The fiber has a scattering level 37.2 dB higher than a single-mode fiber. FBGs have been inscribed by mean of a near-infrared femtosecond laser and a phase mask, with Bragg wavelength around 1552 nm. The characterization shows a thermal sensitivity of 11.45 pm/°C. A polarization-selective thermal behavior has been obtained, with sensitivity of 11.53 pm/°C for the perpendicular polarization (S) and 11.08 pm/°C for the parallel polarization (P), thus having 4.0% different sensitivity between the two polarizations. The results show the inscription of high-reflectivity FBGs onto a fiber core doped with nanoparticles, with the possibility of having reflectors into a fiber with tailored Rayleigh scattering properties.

Performance Analysis of Scattering-Level Multiplexing (SLMux) in Distributed Fiber-Optic Backscatter Reflectometry Physical Sensors

“…The scattering gain recorded with the M01 preform, which appears as the most interesting method for SLMux, has a range of 5.7 dB (37.2-42.9 dB), while the two-way loss achieves a minimum of 22.1 dB/m and a maximum of 30.8 dB/m. This fiber has been used by Beisenova et al and Molardi et al [18,19,30], and the data are in agreement with Table 2, with some fluctuations also due to the random nature of nanoparticle distribution. Conversely, fibers drawn from the G22 fiber, achieve a higher gain (47.5-49.3 dB), but losses fall with a 10× higher rate, up to almost 300 dB/m [30].…”

“…This fiber has been used by Beisenova et al and Molardi et al [18,19,30], and the data are in agreement with Table 2, with some fluctuations also due to the random nature of nanoparticle distribution. Conversely, fibers drawn from the G22 fiber, achieve a higher gain (47.5-49.3 dB), but losses fall with a 10× higher rate, up to almost 300 dB/m [30]. In the middle between the two preforms, the R04 fiber pattern achieves a gain of 40.0 dB and losses of 134.0 dB/m.…”

“…random nature of nanoparticle distribution. Conversely, fibers drawn from the G22 fiber, achieve a higher gain (47.5-49.3 dB), but losses fall with a 10× higher rate, up to almost 300 dB/m [30]. In the middle between the two preforms, the R04 fiber pattern achieves a gain of 40.0 dB and losses of 134.0 dB/m.…”

“…As shown in by Yan et al and Molardi et al, it is possible to efficiently inscribe FBGs on the MgO-NP fiber [24,30]. The effect of FBGs is to increase the overall reflectivity over the Rayleigh scattering floor, by adding the Bragg grating spectrum on top of the Rayleigh scattering.…”

Fiber Bragg grating sensors for monitoring of physical parameters: a comprehensive review

“…108 At high temperature, it is difficult to record results using bare FBG due to low thermal coefficient of silica. Research has been conducted to improve sensitivity at high temperature using coating on FBG, 109 doping of certain material in silica, [110][111][112] formation of stable, 113 or using polymer optical fiber. In polymer optical fiber as proposed in Ref.…”