Temperature Sensing Using Frequency Beating Technique From Single-Longitudinal Mode Fiber Laser

Abstract

In this paper, a high-resolution fiber temperature sensor is proposed and demonstrated using the frequency beating technique. The sensor uses a constant wavelength (CW) at 1539.96 nm as the reference signal for the frequency beating technique. The sensor signal is provided by a fiber Bragg grating (FBG) tuned single-longitudinal mode (SLM) fiber laser, which consists of a 0.5-m long highly doped Zirconium-Erbium doped with an erbium concentration of 3000 ppm as the gain medium. The signal of the SLM, which is generated by the FBG in response to external temperature changes, is mixed with the CW signal using a 3-dB fused coupler into a 6-GHz photodetector to generate frequency beating. The typical response of the system is about 1.3 GHz/°C, with nominal temperature measurement resolutions of 0.0023°C being achieved, taking into account the resolution bandwidth of 3 MHz of the radio frequency spectrum analyzer.Index Terms-Dual-wavelength pulse, erbium-doped fiber, frequency generation, saturable absorber.

A Switchable Erbium Doped Fiber Ring Laser System for Temperature Sensors Multiplexing

“…Figure 5b shows the beat frequency dependence with the temperature, measured by using a time averaging technique. High sensitivity of 1.55 GHz/°C with a linearity of 0.9993 was obtained, being these values are better than the obtained in [10] , that were 1.30 GHz/°C with a linearity of 0.9662 or in [9] 1.47 GHz/°C with a linearity of 0.9935. Considering that all of the FBGs and PSFBGs were written in the same fiber and with the same process, all of them have the same behavior with the temperature (1.55 GHz/°C) resulting in an absolute equation for the measured temperature:…”

“…The limitation of this system was the measured range due to the direct dependence of this range with the BW of the detector. In [10] was used a commercial tunable laser source (TLS) for beating its emission with the EDFRL signal. This system presented the same problem in the measurement range and increased the final cost because of the addition of a TLS.…”

“…Figure 6 shows the theoretical range of an application where different reference temperatures are employed to improve the dynamic range. This is an important advantage in comparison with other sensors systems [9,10] wherein the temperature range is limited by the BW of the detector. The transient switching response of the sensors was also studied.…”

Stable dual-wavelength erbium-doped fiber laser using novel fabricated side-polished arc-shaped fiber with deposited ZnO nanoparticles

“…The proposed laser would have significant real-world applications, particularly for applications that require narrowly spaced wavelengths, such as sensor and reference signals sources [30,31] or multi-wavelength sources [32] , and also in the generation of new laser sources that exploit various non-linear optical phenomena, such as four-wave mixing [33] . The arc-polished fiber also provides a new platform on which various materials, such as ZnO nanoparticles, can be deposited, allowing for the exploration of new applications, such as the generation of passively pulsed outputs or even the exploitation of various nonlinear phenomenon such as Brillouin scattering.…”

Fiber optic strain measurements using distributed sensor system under static pressure conditions

“…FBG 0.0023°C (Ahmad et al, 2012) 10 n (Liu et al, 2012) FBG ( Merzbacher et al, 1996;Maaskant et al, 1997;Liu et al, 2012) 1 5000 6000 ( Earles et al, 2011) 6000…”