Auto-correction method for improving temperature stability in a long-range Raman fiber temperature sensor

et al. 2019

IEEE Photonics J.

Self Cite

In recent years, optic-fiber sensors have been required to simultaneously measure the structure's crack and environmental temperature in the infrastructure monitoring system. We proposed and experimentally demonstrated a distributed optic-fiber sensor based on the Raman loop configuration and fiber loss characteristic for detecting the temperature and structure's crack. Among them, the Raman loop configuration with reference fiber is proposed to detect the temperature profile along the sensing fiber. It can eliminate the influence of external physical perturbation on the temperature measurement results, and do not require pre-calibration process before measurement. The temperature experimental results show that the temperature accuracy and spatial resolution can reach up to 0.28°C and 1.2 m with the response time of 1.04 s. In addition, the information of crack is extracted by using the loss characteristics of Stokes, which is based on optical time domain reflectometry. The experiment results indicate that the fiber loss coefficient keeps a good linear variation between the crack ranges of 1.6 mm and 5.6 mm. The studies achieve the temperature and crack measurement only by one fiber.

“…Among them, the anti-Stokes light is sensitive to temperature. The R-DTS can use it as a signal channel and the Stokes light as a reference channel [10], [11].…”

Section: Loop Configuration With Reference Fiber For Temperature Measmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Temperature and Crack Measurement Using Distributed Optic-Fiber Sensor Based on Raman Loop Configuration and Fiber Loss

et al. 2019

IEEE Photonics J.

Self Cite

“…In 1985, the RDTS was first reported by Dakin et al [7]. Over the past thirty years, a number of advanced techniques for improving the temperature measurement accuracy of RDTS systems have been proposed by researchers, which includes optical pulse coding techniques [8,9,10], a differential attenuation correction system [11], Rayleigh noise cancellation technology [12] a and constant temperature control system [13]. The optical pulse coding techniques improve the signal-to-noise (SNR) as well as the input optical power of RDTS systems.…”

Section: Introductionmentioning

confidence: 99%

Raman Distributed Temperature Sensor with Optical Dynamic Difference Compensation and Visual Localization Technology for Tunnel Fire Detection

Yan

et al. 2019

Sensors

Self Cite

The field of tunnel fire detection requires a Raman distributed temperature sensor (RDTS) with high-accuracy and visual localization. A novel temperature demodulation method to improve the temperature measurement accuracy of the RDTS systems is presented. This method is based on the optical dynamic difference compensation algorithm, which can eliminate the optical power fluctuation. In addition, the visual localization technology is presented by using the longitudinal lining model (LLM) of a three-dimensional (3D) temperature display, which enhances the engineering application of RDTS in tunnel fire detection. Experimental results indicate that the temperature measurement accuracy is optimized from 7.0 °C to 1.9 °C at the sensing distance of 18.27 km by using the presented method. We provide a solution for temperature field monitoring as well as fire visual localization of the tunnel through RDTS systems.

“…Over the past 30 years, to achieve long-distance and high-accuracy measurements of RDTS systems, several advanced techniques have been introduced, including optical pulse coding techniques [9,10], Rayleigh noise cancellation technology [11], and a multistage constant temperature controller [12]. Optical pulse coding techniques improve the signal-to-noise ratio (SNR) of RDTS systems, resulting in a nearly 10-fold resolution improvement.…”

Section: Introductionmentioning

confidence: 99%

RDTS-Based Two-Dimensional Temperature Monitoring with High Positioning Accuracy Using Grid Distribution

Jin

2019

Sensors

A novel two-dimensional (2D) positioning method based on Raman distributed temperature sensing (RDTS) has been reported to dramatically improve positioning accuracy. Using a well-designed 2D distribution of optical fiber and corresponding algorithms, the heat source can be accurately located without crosstalk; however, there is a tradeoff between sensing distance and positioning accuracy. In our experiments, an RDTS system with a spatial resolution of 0.8 m along a 3 km multimode fiber (MMF) is used with specific 2D routing rules and corresponding algorithms. A positioning accuracy of about 0.1 m is obtained without hardware modification, which could be improved through the dense arrangement of fiber; however, this would sacrifice the sensing length. This solution can be used for both flat surfaces and curved surfaces such as pipes or tank surfaces. This scheme can also be extended to three-dimensional positioning using a delicate routing design of sensing fiber.