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Article
Publication date: 23 February 2018

Yage Zhan, Ziyang Shen, Zeyu Sun, Qiao Yu, Hong Liu and Yong Kong

The purpose of this paper is to theoretically analyze and experimentally demonstrate the investigation of and present a kind of sensing system for monitoring simultaneous…

Abstract

Purpose

The purpose of this paper is to theoretically analyze and experimentally demonstrate the investigation of and present a kind of sensing system for monitoring simultaneous temperature and strain measurements based on highly nonlinear fiber (HNLF) and single mode fiber (SMF).

Design/methodology/approach

First, the stimulated Brillouin scattering (SBS) characteristics of the HNLF have been studied, including the Brillouin gain bandwidth, Brillouin gain center frequency and SBS threshold. Second, based on the Brillouin gain center frequency, the Brillouin frequency shift coefficients of strain and temperature in HNLF have been studied. Third, the sensing and signal interrogation scheme for simultaneous monitoring of temperature and strain with high resolution has been presented.

Findings

It is found that the HNLF has a wider Brillouin gain bandwidth. The SBS threshold of HNLF is 78 mW, which is much larger than 7.9 mW of SMF. Also, the Brillouin frequency shift coefficients of strain and temperature in HNLF are 0.0308 and 0.413 MHz/°C, respectively.

Originality/value

The larger threshold of SBS is useful to avoid SBS under certain situations that Spontaneous Brillouin Scattering is necessary and should be applied. The technique is based on the fact that the Brillouin frequency shift coefficients of strain and temperature in HNLF are different from those in SMF. Therefore, the two-parameter monitoring can be achieved by producing SBS and obtaining the back-scattering Brillouin signal light simultaneously in HNLF and SMF.

Details

Sensor Review, vol. 39 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 14 June 2013

Yage Zhan, Kan Gu, Hua Wu and Jun Luo

The on‐line concentration and temperature measurement of solutions is of great interest as a means of quality production control in many industrial processes, such as in…

Abstract

Purpose

The on‐line concentration and temperature measurement of solutions is of great interest as a means of quality production control in many industrial processes, such as in food service industry, pharmaceuticals industry, chemical industry and environmental engineering, especially for harmful solutions or solutions that cannot be reached by the operator. This paper seeks to address these issues.

Design/methodology/approach

A high resolution all‐fiber multi‐parameter sensor system has been studied theoretically and experimentally. The sensor system can be used for on‐line monitoring of concentration and temperature simultaneously and dynamically. A combined long period fiber grating (CLPG) is used as the sensor head based on its resonance wavelength shifts being almost linearly with concentration and temperature, and also based on that the two applied resonance peaks have different concentration‐wavelength coefficients and different temperature‐wavelength coefficients. Two wavelength‐matched fiber Bragg gratings (FBGs) are used to convert resonance peak wavelengths of the CLPG into corresponding intensities for interrogation.

Findings

When the concentration and the temperature all fluctuate dynamically during experiments, a concentration resolution of 0.03 g/L has been achieved in the range of 0∼200 g/L, and a temperature resolution of 0.02C has been realized in the range of −20∼60C.

Originality/value

On‐line monitoring of concentration and temperature for solutions is a means of quality production control in biological, chemical and other many industrial processes, such as in food service industry, pharmaceuticals industry, chemical industry, and also in environmental engineering, especially for harmful solutions or solutions that cannot be reached by the operator. Optical fiber sensors have numerous advantages over traditional sensors, such as immunity to electromagnetic interference, higher stability and sensitivity, more easiness of multiplex, being competent for application in harsh environments, “smart structures” and on‐site measurements. Long period optical fiber grating sensor is the most appropriate sensor for multi‐parameter monitoring in the fields mentioned above, which has all the advantages of optical fiber sensor. Besides, optical fiber grating sensors can be used for monitoring more accurately because its signal is coded by wavelength. The all‐fiber sensor system is suitable for remote monitoring of many solutions, such as the solutions of NaCl, glucose, alcohol, and hydrocarbon.

Details

Sensor Review, vol. 33 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 21 September 2015

Yage Zhan, Qiao Yu, Kun Wang, Fu Yang and Borui Zhang

The purpose of this paper is to theoretically analyze and experimentally demonstrate the investigation on and optimization of a distributed optical fiber sensor based on…

Abstract

Purpose

The purpose of this paper is to theoretically analyze and experimentally demonstrate the investigation on and optimization of a distributed optical fiber sensor based on phase-sensitive optical time domain reflectometer (F-OTDR) for disturbance detection.

Design/methodology/approach

The F-OTDR system is investigated and optimized in two aspects: the hardware parameter and the interrogation scheme.

Findings

Based on the optimized hardware and the new interrogation scheme, the performances of the F-OTDR system have been improved greatly, compared with conventional F-OTDR system. A location accuracy of 2 m and a signal-to-noise ratio (SNR) of 16 dB have been achieved under a spatial resolution of 8 m. On the other hand, four disturbances at four different locations have been detected and located simultaneously, which is the most effective detection system with the maximum detection capability reported to date, to the best of the authors’ knowledge.

Originality/value

Four disturbances at four different locations have been detected and located simultaneously, which is the most effective detection system with the maximum detection capability reported to date, to the best of the authors’ knowledge. With same hardware conditions, more existing disturbances can be detected by using the new interrogation scheme, which is helpful to reduce the miss report of disturbance.

Details

Sensor Review, vol. 35 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

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