CN102680022A - Single fiber Bragg grating sensor for simultaneously measuring temperature and stress - Google Patents

Abstract

The invention provides a single fiber Bragg grating sensor for simultaneously measuring temperature and stress, which is applicable to the field of fiber sensing. The single fiber Bragg grating sensor is characterized by being manufactured by using a phase masking method as a fiber Bragg grating, and being divided into two parts with an equal length; a left half part (1) of the fiber Bragg grating is packaged in a polymer substrate (2); and a right half part (3) of the fiber Bragg grating is plated with a layer of metal protection film (4) by using a combined chemical-plating and electric-plating method. A metal plating method comprises the following steps of: cleaning dirt on the surfaces of the bare fiber Bragg grating and a tail fiber by ethyl alcohol; absorbing a layer of readily oxidizable matters on the surface of the bare fiber Bragg grating; generating a thin metal layer on the surface of the bare fiber Bragg grating; carrying out chemical-plating on the bare fiber Bragg grating; and carrying out electrical-plating the bare fiber Bragg grating. The sensor is easy to manufacture; the temperature and stress sensing sensitivity of the sensor is improved; and the sensor can be used for simultaneously measuring the temperature and the stress by only using the single fiber Bragg grating.

Description

The simultaneously-measured single fibre grating sensor of a kind of temperature stress

Technical field

The present invention relates to the simultaneously-measured single fibre grating sensor of a kind of temperature stress, be applicable to fields such as optical fiber communication, Fibre Optical Sensor.

Background technology

Fiber Bragg Grating FBG has become the sensing element of very promising strain, temperature and other parameter measurement.Optical fiber Bragg raster is in the sensing measurement of reality; The cross sensitivity problem that has stress and temperature; Promptly in one-shot measurement, be difficult to the foveal reflex wavelength shift of stress and the caused optical fiber Bragg raster of temperature variation is differentiated out, must take some measure to distinguish or compensate.In order to overcome this limitation, a lot of new technologies and method have been proposed.For example dual wavelength stratum grating mixes Bragg grating, the fiber grating of two kinds of materials; Two diameter fiber gratings; The band polarization waves stratum's fiber grating of filtration, the fiber grating that combines with EDFAs, fiber grating Fabry---pool sieve chamber method; The long-period gratings method, the fiber grating for preparing under the different condition.These methods can solve the problem of temperature and pressure cross sensitivity; But most scheme needs two gratings; Or need the grating or the special complicated technology of needs of special construction, use the optical fibre device that surpasses will increase system cost, and can make the preparation of detector become complicated.The long-period gratings method is utilized in multiple response bandwidth in the macrocyclic grating and realizes the synchro measure to temperature and strain.In fact, because the spectral bandwidth scope is big, be difficult to accurately measure the minor shifts of wavelength for long-period gratings.For this reason, if can adopt single Bragg grating to realize the separation sensing of temperature and pressure, will be very valuable in practical application.

Summary of the invention

Technical matters to be solved by this invention provide a kind of can be to the simultaneously-measured single fibre grating sensor of temperature stress.

Technical scheme of the present invention:

The simultaneously-measured single fibre grating sensor of a kind of temperature stress; This fiber-optic grating sensor is the Fiber Bragg Grating FBG of being processed by the phase mask method; It evenly is divided into two parts of equal in length; The left-half of Fiber Bragg Grating FBG is encapsulated in a kind of polymeric substrates, and the right half part of Fiber Bragg Grating FBG plates the layer of metal diaphragm through electroless plating and the method for electroplating combination.The right half part of Fiber Bragg Grating FBG adopts electroless plating to combine plating with electroplating, and the steps include:

Step 1 is used the alcohol wash clean with the dirt on bare fibre Bragg grating and tail optical fiber surface;

Step 2 is at bare fibre Bragg grating surface adsorption one deck readily oxidizable substance;

Step 3 generates one deck thin metal layer on bare fibre Bragg grating surface;

Step 4 is carried out electroless plating to the bare fibre Bragg grating;

Step 5 is electroplated the bare fibre Bragg grating.

Beneficial effect of the present invention:

The present invention proposes the simultaneously-measured single fibre grating sensor of temperature stress, and is simple in structure, makes easily; The temperature and the stress sensing sensitivity of sensor have been improved; In actual Application in Sensing, measure when only needing single fiber grating just can realize temperature, stress.

Description of drawings

The simultaneously-measured single fibre grating sensor construction of a kind of temperature stress of Fig. 1 synoptic diagram.

Embodiment

Below in conjunction with accompanying drawing the present invention is further described.

The simultaneously-measured single fibre grating sensor of a kind of temperature stress; See Fig. 1; This this fiber-optic grating sensor is the Fiber Bragg Grating FBG of being processed by the phase mask method; It evenly is divided into two parts of equal in length, and the left-half 1 of Fiber Bragg Grating FBG is encapsulated in a kind of polymeric substrates 2, and the right half part 3 of Fiber Bragg Grating FBG plates layer of metal diaphragm 4 through electroless plating and the method for electroplating combination.The right half part 3 of Fiber Bragg Grating FBG adopts electroless plating to combine plating with electroplating, and the steps include:

Step 1 is used the alcohol wash clean with the dirt on bare fibre Bragg grating and tail optical fiber surface;

Step 2 is at bare fibre Bragg grating surface adsorption one deck readily oxidizable substance;

Step 3 generates one deck thin metal layer on bare fibre Bragg grating surface;

Step 4 is carried out electroless plating to the bare fibre Bragg grating;

Step 5 is electroplated the bare fibre Bragg grating.

Because the left-half 1 of Fiber Bragg Grating FBG is encapsulated in the polymeric substrates; The Young modulus of polymkeric substance is very little; So its pressure sensing sensitivity can be significantly improved; The right half part 3 of Fiber Bragg Grating FBG grating is by after the metal plated, and temperature control can significantly promote, the raising of this structure the temperature and the stress sensing sensitivity of sensor.

In actual Application in Sensing, when temperature and pressure changed simultaneously, the bragg wavelength of initial Fiber Bragg Grating FBG can separately become two wavelength reflection peaks, the drift of measuring these two wavelength reflection peaks, according to following formula:

$\left[\begin{array}{c}F\\ \mathrm{\&Delta;T}\end{array}\right]=\frac{1}{K_{\mathrm{\&epsiv;}1}{K}_{T2}-K_{\mathrm{\&epsiv;}2}{K}_{T1}}\left[\begin{array}{cc}{K}_{T2}& -K_{T1}\\ -K_{\mathrm{\&epsiv;}2}& K_{\mathrm{\&epsiv;}1}\end{array}\right]\left[\begin{array}{c}\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{B1}\\ \mathrm{\&Delta;}{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00001665754800011.png"\; state="\{\{state\}\}">B</figure-callout>}2}\end{array}\right]$

Can calculate the variation of temperature and pressure.K wherein _{ε 1}And K _T1Be the stress and the temperature control of the left-half 1 of Fiber Bragg Grating FBG, K _{ε 2}And K _T2Be the stress and the temperature control of the right half part 3 of Fiber Bragg Grating FBG, F is the stress that applies, and Δ T is a variation of temperature, Δ λ _B1Be the variation of the wavelength reflection peak of the left-half 1 of Fiber Bragg Grating FBG, Δ λ _B2Variation for the wavelength reflection peak of the right half part 3 of Fiber Bragg Grating FBG.

The described polymkeric substance of present embodiment is a gelatin, and the metal of plating is a nickel.

Device used in the present invention is commercially available device.

Claims (2)

1. simultaneously-measured single fibre grating sensor of temperature stress is characterized in that:

This fiber-optic grating sensor is the Fiber Bragg Grating FBG of being processed by the phase mask method; It evenly is divided into two parts of equal in length; The left-half of Fiber Bragg Grating FBG (1) is encapsulated in a kind of polymeric substrates (2), and the right half part of Fiber Bragg Grating FBG (3) plates layer of metal diaphragm (4) through electroless plating and the method for electroplating combination.

2. the simultaneously-measured single fibre grating sensor of a kind of temperature stress according to claim 1 is characterized in that:

The right half part of Fiber Bragg Grating FBG (3) adopts electroless plating to combine plating with electroplating, and the steps include:

Step 1 is used the alcohol wash clean with the dirt on bare fibre Bragg grating and tail optical fiber surface;

Step 2 is at bare fibre Bragg grating surface adsorption one deck readily oxidizable substance;

Step 3 generates one deck thin metal layer on bare fibre Bragg grating surface;

Step 4 is carried out electroless plating to the bare fibre Bragg grating;

Step 5 is electroplated the bare fibre Bragg grating.

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