JP2012098196A - Bragg wavelength estimation method and apparatus therefor - Google Patents

Bragg wavelength estimation method and apparatus therefor Download PDF

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JP2012098196A
JP2012098196A JP2010247231A JP2010247231A JP2012098196A JP 2012098196 A JP2012098196 A JP 2012098196A JP 2010247231 A JP2010247231 A JP 2010247231A JP 2010247231 A JP2010247231 A JP 2010247231A JP 2012098196 A JP2012098196 A JP 2012098196A
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Tomio Nakajima
富男 中島
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IHI Inspection and Instrumentation Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To reduce an estimation error of a Bragg wavelength and to easily calibrate R value-wavelength characteristics.SOLUTION: A Bragg wavelength estimation apparatus includes an optical fiber 2 including an FBG sensor section 1, a wide-band light source 3, an optical circulator 4, an optical filter 5, a first optical/electric converter 6, a second optical/electric converter 7, a processing section 9 which calculates an R value of a non-dimensional quantity in accordance with a first output voltage (VT) and a second output voltage (VR), and a wavelength estimation section 10 which uses R value-Bragg wavelength characteristics acquired beforehand to estimate a Bragg wavelength of the FBG sensor. The processing section uses a product of a transmissivity (PTx) in a wavelength of the optical filter 5 and a first optical/electric conversion property (LET) normalized in a wavelength of the first optical/electric converter 6, and a product of a reflectance (PRx) in a wavelength of the optical filter 5 and a second optical/electric conversion property (LER) normalized in a wavelength of the second optical/electric converter 7 to determine R value-Bragg wavelength characteristics.

Description

本発明は、無次元のＲ値を用いるブラッグ波長推定方法及びその装置に関するものである。   The present invention relates to a Bragg wavelength estimation method using a dimensionless R value and an apparatus therefor.

近年、対象物のひずみ変化や温度変化を計測する手段には、FBG（Fiber Bragg Grating）センサ部を用いて計測するものがあり（例えば、特許文献１参照）、FBGセンサ部は、特定の波長の光信号であるブラッグ波長を反射するため、ブラッグ波長を推定することによりひずみ変化や温度変化を計測するようにしている。   In recent years, as a means for measuring strain change and temperature change of an object, there is one that uses an FBG (Fiber Bragg Grating) sensor unit (see, for example, Patent Document 1), and the FBG sensor unit has a specific wavelength. In order to reflect the Bragg wavelength, which is an optical signal, the strain change and temperature change are measured by estimating the Bragg wavelength.

具体的にブラッグ波長推定装置の一例を示すと、ブラッグ波長推定装置は、図９に示す如く、対象物（図示せず）にFBGセンサ部１を配置する光ファイバ２と、光ファイバ２へ光を連続的に出力する広帯域の広帯域光源３と、FBGセンサ部１のブラッグ波長で発生した反射光を分離する光サーキュレータ４と、入射光ポート５ａ及び透過光ポート５ｂ並びに反射光ポート５ｃの三つのポートを有して光サーキュレータ４からの反射光を入射光ポート５ａへ入射させる光学フィルタ５と、光学フィルタ５の透過光ポート５ｂから出力される透過光強度ＰＴを第一の出力電圧ＶＴに変換する第一の光電変換器６と、光学フィルタ５の反射光ポート５ｃから出力される反射光強度ＰＲを第二の出力電圧ＶＲに変換する第二の光電変換器７と、第一の出力電圧ＶＴと第二の出力電圧ＶＲを処理する処理部８とを備えている。また光ファイバ２のFBGセンサ部１は、光ファイバ２のコア部分に光軸方向に沿って一定の間隔で回折格子を形成しており、検査対象のひずみや温度変化により反射波長を変化させるようになっている。   Specifically, an example of the Bragg wavelength estimation device is shown in FIG. 9. The Bragg wavelength estimation device includes an optical fiber 2 in which the FBG sensor unit 1 is disposed on an object (not shown), and light to the optical fiber 2. The broadband light source 3 that continuously outputs the light, the optical circulator 4 that separates the reflected light generated at the Bragg wavelength of the FBG sensor unit 1, the incident light port 5a, the transmitted light port 5b, and the reflected light port 5c. An optical filter 5 having a port for allowing reflected light from the optical circulator 4 to enter the incident light port 5a, and the transmitted light intensity PT output from the transmitted light port 5b of the optical filter 5 is converted into a first output voltage VT. The first photoelectric converter 6, the second photoelectric converter 7 for converting the reflected light intensity PR output from the reflected light port 5c of the optical filter 5 into the second output voltage VR, and the first output. And a processing unit 8 for processing the pressure VT and the second output voltage VR. Further, the FBG sensor unit 1 of the optical fiber 2 has diffraction gratings formed at regular intervals along the optical axis direction in the core portion of the optical fiber 2 so that the reflection wavelength is changed by the strain or temperature change of the inspection object. It has become.

このようなブラッグ波長推定装置を用いてひずみ変化や温度変化を求める際には、FBGセンサ部１からの反射光を光サーキュレータ４を介して光学フィルタ５の入射光ポート５ａに入射させ、光学フィルタ５の透過光ポート５ｂから透過光強度ＰＴを出力し、且つ反射光ポート５ｃから反射光強度ＰＲを出力する。次に透過光強度ＰＴを第一の光電変換器６により第一の出力電圧ＶＴに変換し、且つ反射光強度ＰＲを第二の光電変換器７により第二の出力電圧ＶＲに変換し、処理部８に入力させる。続いて処理部８では、第一の出力電圧ＶＴと第二の出力電圧ＶＲとを用いてＲ＝（ＶＲ−ＶＴ）／（ＶＴ＋ＶＲ）により無次元量のＲ値を算出し、予め準備したＲ値−ブラッグ波長特性の曲線を用いてブラッグ波長を推定し、ひずみ変化や温度変化を計測するようにしている。   When the strain change or temperature change is obtained using such a Bragg wavelength estimation device, the reflected light from the FBG sensor unit 1 is incident on the incident light port 5a of the optical filter 5 via the optical circulator 4, and the optical filter 5 transmits the transmitted light intensity PT from the transmitted light port 5b, and outputs the reflected light intensity PR from the reflected light port 5c. Next, the transmitted light intensity PT is converted to the first output voltage VT by the first photoelectric converter 6, and the reflected light intensity PR is converted to the second output voltage VR by the second photoelectric converter 7. Input to unit 8. Subsequently, the processing unit 8 calculates a dimensionless R value by R = (VR−VT) / (VT + VR) using the first output voltage VT and the second output voltage VR, and prepares R in advance. A Bragg wavelength is estimated using a curve of value-Bragg wavelength characteristics, and a strain change and a temperature change are measured.

ここで予め準備したＲ値−ブラッグ波長特性の曲線は、光スペクトルアナライザを用いて測定したブラッグ波長と、出力電圧ＶＴ，ＶＲにより同じ処理で算出したＲ値とを用いて求められている。   The R value-Bragg wavelength characteristic curve prepared in advance here is obtained by using the Bragg wavelength measured using an optical spectrum analyzer and the R value calculated by the same processing using the output voltages VT and VR.

特開２０１０−４３８９２号公報JP 2010-43892 A

しかしながら、第一の出力電圧ＶＴ及び第二の出力電圧ＶＲから算出したＲ値を用いる場合には、光学フィルタ５の透過率ＰＴｘ及び反射率ＰＲｘからＲ＝（ＰＲｘ−ＰＴｘ）／（ＰＴｘ＋ＰＲｘ）で算出したＲ値−ブラッグ波長特性の曲線に対し、第一の光電変換器６、第二の光電変換器７の各個体差による偏差を生じるため、ブラッグ波長の推定に誤差を生じるという問題があった。ここで具体例を示すと、第一の出力電圧ＶＴ及び第二の出力電圧ＶＲから算出したＲ値と、透過率ＰＴｘ及び反射率ＰＲｘから算出したＲ値−ブラッグ波長特性の曲線では、図１０に示す如くＲ値の絶対値が０．６を超える領域で偏差を生じている。   However, when the R value calculated from the first output voltage VT and the second output voltage VR is used, R = (PRx−PTx) / (PTx + PRx) from the transmittance PTx and the reflectance PRx of the optical filter 5. There is a problem that an error occurs in the estimation of the Bragg wavelength because a deviation due to individual differences between the first photoelectric converter 6 and the second photoelectric converter 7 occurs in the calculated R value-Bragg wavelength characteristic curve. It was. As a specific example, an R value calculated from the first output voltage VT and the second output voltage VR and an R value-Bragg wavelength characteristic curve calculated from the transmittance PTx and the reflectance PRx are shown in FIG. As shown in FIG. 4, there is a deviation in a region where the absolute value of the R value exceeds 0.6.

また実際にブラッグ波長推定装置を用いる際には、ブラッグ波長の推定に伴う誤差を防止するように、装置構成や計測対象ごとに、第一の出力電圧ＶＴ，及び第二の出力電圧ＶＲからＲ値を算出してＲ値−ブラッグ波長特性の校正曲線を取得するため、手間と時間がかかるという問題があった。更に計測対象の測定前には、Ｒ値−波長特性の校正曲線を取得することができず、早急に準備することができないという問題があった。   Further, when the Bragg wavelength estimation device is actually used, the first output voltage VT and the second output voltage VR to R for each device configuration and measurement target so as to prevent errors associated with the Bragg wavelength estimation. Since the value is calculated and the calibration curve of the R value-Bragg wavelength characteristic is acquired, there is a problem that it takes time and effort. Further, before the measurement of the measurement object, there is a problem that the calibration curve of the R value-wavelength characteristic cannot be acquired, and it cannot be prepared immediately.

本発明は、上記従来の問題点に鑑みてなしたもので、ブラッグ波長の推定誤差を低減し、且つＲ値−波長特性を容易に校正することを目的とする。   The present invention has been made in view of the above-described conventional problems, and an object thereof is to reduce an estimation error of a Bragg wavelength and easily calibrate an R value-wavelength characteristic.

本発明のブラッグ波長推定方法は、広帯域光源から照射された連続光を光サーキュレータを介してFBGセンサ部に入射し、FBGセンサ部から反射した光を光サーキュレータにより分離し、入射光ポート及び透過光ポート並びに反射光ポートの三つのポートを有する光学フィルタに対して前記光サーキュレータからの光を入射光ポートへ入射し、前記透過光ポートから出力される透過光強度（ＰＴ）を第一の光電変換器により第一の出力電圧（ＶＴ）に変換し且つ前記反射光ポートから出力される反射光強度（ＰＲ）を第二の光電変換器により第二の出力電圧（ＶＲ）に変換し、前記第一の出力電圧（ＶＴ）及び第二の出力電圧（ＶＲ）を基礎にして無次元量のＲ値を算出し、予め取得したＲ値−ブラッグ波長特性を用いてFBGセンサ部のブラッグ波長を推定するブラッグ波長推定方法であって、
前記光学フィルタにおける透過率（ＰＴｘ）と、第一の光電変換器において正規化された第一の光電変換特性（ＬＥＴ）との積、及び
前記光学フィルタにおける反射率（ＰＲｘ）と、第二の光電変換器において正規化された第二の光電変換特性（ＬＥＲ）との積を用いて
Ｒ値−ブラッグ波長特性を求めるものである。 In the Bragg wavelength estimation method of the present invention, continuous light emitted from a broadband light source is incident on an FBG sensor unit via an optical circulator, and light reflected from the FBG sensor unit is separated by an optical circulator, and an incident light port and transmitted light are separated. The light from the optical circulator is incident on an incident light port with respect to an optical filter having three ports, a port and a reflected light port, and the transmitted light intensity (PT) output from the transmitted light port is converted into a first photoelectric conversion. The reflected light intensity (PR) output from the reflected light port is converted to the second output voltage (VR) by the second photoelectric converter, and converted to the first output voltage (VT) by the converter. A dimensionless R value is calculated based on the first output voltage (VT) and the second output voltage (VR), and the Bragg wave of the FBG sensor unit is obtained using the R value-Bragg wavelength characteristic acquired in advance. A Bragg wavelength estimation method for estimating,
The product of the transmittance (PTx) in the optical filter and the first photoelectric conversion characteristic (LET) normalized in the first photoelectric converter, and the reflectance (PRx) in the optical filter, The R value-Bragg wavelength characteristic is obtained using a product of the second photoelectric conversion characteristic (LER) normalized in the photoelectric converter.

本発明のブラッグ波長推定方法において、第一の光電変換器について光学フィルタの透過光強度（ＰＴ）に対する第一の出力電圧（ＶＴ）の変換比（ＶＴ／ＰＴ）を求め、且つ第二の光電変換器について光学フィルタの反射光強度（ＰＲ）に対する第二の出力電圧（ＶＲ）の変換比（ＶＲ／ＰＲ）を求め、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性と、第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性との和を２で除した特性を分母とし、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性を分子として、
第一の光電変換器において正規化された第一の光電変換特性（ＬＥＴ）を求めることが好ましい。 In the Bragg wavelength estimation method of the present invention, the conversion ratio (VT / PT) of the first output voltage (VT) to the transmitted light intensity (PT) of the optical filter is obtained for the first photoelectric converter, and the second photoelectric converter Obtain the conversion ratio (VR / PR) of the second output voltage (VR) to the reflected light intensity (PR) of the optical filter for the converter,
The sum of the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter and the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter is divided by 2. With the characteristic as the denominator,
Using the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter as a molecule,
It is preferable to obtain the first photoelectric conversion characteristic (LET) normalized in the first photoelectric converter.

本発明のブラッグ波長推定方法において、第一の光電変換器について光学フィルタの透過光強度（ＰＴ）に対する第一の出力電圧（ＶＴ）の変換比（ＶＴ／ＰＴ）を求め、且つ第二の光電変換器について光学フィルタの反射光強度（ＰＲ）に対する第二の出力電圧（ＶＲ）の変換比（ＶＲ／ＰＲ）を求め、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性と、第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性との和を２で除した特性を分母とし、
第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性を分子として、
第二の光電変換器において正規化された第二の光電変換特性（ＬＥＲ）を求めることが好ましい。 In the Bragg wavelength estimation method of the present invention, the conversion ratio (VT / PT) of the first output voltage (VT) to the transmitted light intensity (PT) of the optical filter is obtained for the first photoelectric converter, and the second photoelectric converter Obtain the conversion ratio (VR / PR) of the second output voltage (VR) to the reflected light intensity (PR) of the optical filter for the converter,
The sum of the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter and the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter is divided by 2. With the characteristic as the denominator,
Using the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter as a molecule,
It is preferable to obtain the second photoelectric conversion characteristic (LER) normalized in the second photoelectric converter.

本発明のブラッグ波長推定装置は、FBGセンサ部を含む光ファイバと、
前記FBGセンサ部のブラッグ波長を含む連続光を照射する広帯域光源と、
該広帯域光源と、FBGセンサ部を含む光ファイバとの間に配置され、広帯域光源から照射された光を透過してFBGセンサ部に入射させ且つFBGセンサ部から反射した光を分離する光サーキュレータと、
入射光及び透過光並びに反射光の三つのポートを有して光サーキュレータにより分離された光を入射光ポートへ入射させる光学フィルタと、
該光学フィルタの透過光ポートから出力される透過光強度（ＰＴ）を第一の出力電圧（ＶＴ）に変換する第一の光電変換器と、
前記光学フィルタの反射光ポートから出力される反射光強度（ＰＲ）を第二の出力電圧（ＶＲ）に変換する第二の光電変換器と、
前記第一の出力電圧（ＶＴ）及び第二の出力電圧（ＶＲ）を基礎にして無次元量のＲ値を算出する処理部と、
予め取得したＲ値−ブラッグ波長特性を用いてFBGセンサのブラッグ波長を推定する波長推定部とを備えるブラッグ波長推定装置であって、
前記処理部は、
前記光学フィルタにおける透過率（ＰＴｘ）と、第一の光電変換器において正規化された第一の光電変換特性（ＬＥＴ）との積、及び
前記光学フィルタにおける反射率（ＰＲｘ）と、第二の光電変換器において正規化された第二の光電変換特性（ＬＥＲ）との積を用いて
Ｒ値−ブラッグ波長特性を求めるように構成されたものである。 The Bragg wavelength estimation device of the present invention, an optical fiber including an FBG sensor unit,
A broadband light source that emits continuous light including the Bragg wavelength of the FBG sensor unit;
An optical circulator disposed between the broadband light source and an optical fiber including the FBG sensor unit, which transmits the light irradiated from the broadband light source and enters the FBG sensor unit and separates the light reflected from the FBG sensor unit; ,
An optical filter that has three ports of incident light, transmitted light, and reflected light, and that makes the light separated by the optical circulator enter the incident light port;
A first photoelectric converter that converts transmitted light intensity (PT) output from a transmitted light port of the optical filter into a first output voltage (VT);
A second photoelectric converter that converts reflected light intensity (PR) output from the reflected light port of the optical filter into a second output voltage (VR);
A processing unit that calculates a dimensionless R value based on the first output voltage (VT) and the second output voltage (VR);
A Bragg wavelength estimation device including a wavelength estimation unit that estimates a Bragg wavelength of an FBG sensor using an R value-Bragg wavelength characteristic acquired in advance;
The processor is
The product of the transmittance (PTx) in the optical filter and the first photoelectric conversion characteristic (LET) normalized in the first photoelectric converter, and the reflectance (PRx) in the optical filter, The R value-Bragg wavelength characteristic is obtained using the product of the second photoelectric conversion characteristic (LER) normalized in the photoelectric converter.

本発明のブラッグ波長推定装置において、前記処理部は、
第一の光電変換器について光学フィルタの透過光強度（ＰＴ）に対する第一の出力電圧（ＶＴ）の変換比（ＶＴ／ＰＴ）を求め、且つ第二の光電変換器について光学フィルタの反射光強度（ＰＲ）に対する第二の出力電圧（ＶＲ）の変換比（ＶＲ／ＰＲ）を求め、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性と、第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性との和を２で除した特性を分母とし、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性を分子として、
第一の光電変換器において正規化された第一の光電変換特性（ＬＥＴ）を求めるように構成されたことが好ましい。 In the Bragg wavelength estimation apparatus of the present invention, the processing unit includes:
For the first photoelectric converter, the conversion ratio (VT / PT) of the first output voltage (VT) to the transmitted light intensity (PT) of the optical filter is obtained, and the reflected light intensity of the optical filter for the second photoelectric converter The conversion ratio (VR / PR) of the second output voltage (VR) with respect to (PR) is obtained,
The sum of the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter and the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter is divided by 2. With the characteristic as the denominator,
Using the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter as a molecule,
It is preferable that the first photoelectric conversion characteristic (LET) normalized in the first photoelectric converter is obtained.

本発明のブラッグ波長推定装置において、前記処理部は、
第一の光電変換器について光学フィルタの透過光強度（ＰＴ）に対する第一の出力電圧（ＶＴ）の変換比（ＶＴ／ＰＴ）を求め、且つ第二の光電変換器について光学フィルタの反射光強度（ＰＲ）に対する第二の出力電圧（ＶＲ）の変換比（ＶＲ／ＰＲ）を求め、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性と、第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性との和を２で除した特性を分母とし、
第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性を分子として、
第二の光電変換器において正規化された第二の光電変換特性（ＬＥＲ）を求めるように構成されたことが好ましい。 In the Bragg wavelength estimation apparatus of the present invention, the processing unit includes:
For the first photoelectric converter, the conversion ratio (VT / PT) of the first output voltage (VT) to the transmitted light intensity (PT) of the optical filter is obtained, and the reflected light intensity of the optical filter for the second photoelectric converter The conversion ratio (VR / PR) of the second output voltage (VR) with respect to (PR) is obtained,
The sum of the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter and the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter is divided by 2. With the characteristic as the denominator,
Using the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter as a molecule,
It is preferable that the second photoelectric conversion characteristic (LER) normalized in the second photoelectric converter is obtained.

本発明によれば、光学フィルタの波長における透過率（ＰＴｘ）と、第一の光電変換器において正規化された第一の光電変換特性（ＬＥＴ）との積、及び光学フィルタの波長における反射率（ＰＲｘ）と、第二の光電変換器において正規化された第二の光電変換特性（ＬＥＲ）との積を用い、補正したＲ値−ブラッグ波長特性を求めるので、当該Ｒ値−ブラッグ波長特性の曲線と、第一の出力電圧（ＶＴ）及び第二の出力電圧（ＶＲ）によるＲ値とを適切に比較し、ブラッグ波長の推定誤差を低減することができる。またFBGセンサ部を含む装置構成や計測対象に対して校正を行うことなく、光学フィルタの透過率（ＰＴｘ）、反射率（ＰＲｘ）、第一の光電変換器において正規化された第一の光電変換特性（ＬＥＴ）、第二の光電変換器において正規化された第二の光電変換特性（ＬＥＲ）を求めて代用するので、手間と時間を抑制して簡素化を図ることができる。更に、計測対象の測定前であっても、補正したＲ値−波長特性を容易に取得し、早急に準備することができるという優れた効果を奏し得る。   According to the present invention, the product of the transmittance (PTx) at the wavelength of the optical filter and the first photoelectric conversion characteristic (LET) normalized by the first photoelectric converter, and the reflectance at the wavelength of the optical filter. The corrected R value-Bragg wavelength characteristic is obtained by using the product of (PRx) and the second photoelectric conversion characteristic (LER) normalized in the second photoelectric converter. And the R value by the first output voltage (VT) and the second output voltage (VR) are appropriately compared, and the Bragg wavelength estimation error can be reduced. In addition, the optical filter transmittance (PTx), reflectance (PRx), and the first photoelectric normalized in the first photoelectric converter without calibration of the apparatus configuration including the FBG sensor unit and the measurement target Since the conversion characteristic (LET) and the second photoelectric conversion characteristic (LER) normalized in the second photoelectric converter are obtained and substituted, it is possible to simplify the operation by reducing labor and time. Furthermore, even before the measurement of the measurement target, it is possible to obtain an excellent effect that the corrected R value-wavelength characteristic can be easily acquired and prepared quickly.

本発明の実施の形態例を示すブロック図である。It is a block diagram which shows the example of embodiment of this invention. 一例の光電変換器の場合におけるＶＴ，ＶＲ、Ｒ値−ブラッグ波長特性を示すデータである。It is data which shows VT, VR, R value-Bragg wavelength characteristic in the case of an example photoelectric converter. 他例の光電変換器の場合におけるＶＴ，ＶＲ、Ｒ値−ブラッグ波長特性を示すデータである。It is the data which shows the VT, VR, R value-Bragg wavelength characteristic in the case of the photoelectric converter of another example. 光学フィルタの透過率特性及び反射率特性から求めたＲ値−ブラッグ波長特性を示すデータである。It is data which shows R value-Bragg wavelength characteristic calculated | required from the transmittance | permeability characteristic and reflectance characteristic of an optical filter. 一例の光電変換器の場合において正規化された光電変換特性を示すデータである。It is the data which shows the photoelectric conversion characteristic normalized in the case of the photoelectric converter of an example. 他例の光電変換器の場合において正規化された光電変換特性を示すデータである。It is the data which shows the photoelectric conversion characteristic normalized in the case of the photoelectric converter of another example. 正規化された光電変換特性をＶＴ，ＶＲに反映した場合、ＶＴ，ＶＲによるＲ値が、フィルタ特性によるＲ値−ブラッグ波長特性に一致する結果を示すデータである。When the normalized photoelectric conversion characteristics are reflected in VT and VR, the R value by VT and VR is data indicating a result of matching the R value by the filter characteristics and the Bragg wavelength characteristic. 正規化された光電変換特性をフィルタ特性に反映した場合、フィルタ特性によるＲ値−ブラッグ波長特性が、ＶＴ，ＶＲによるＲ値に一致する結果を示すデータである。When the normalized photoelectric conversion characteristic is reflected in the filter characteristic, the R value-Bragg wavelength characteristic based on the filter characteristic is data indicating a result of matching with the R value based on VT and VR. 従来のブラッグ波長推定装置を示すブロック図である。It is a block diagram which shows the conventional Bragg wavelength estimation apparatus. 光電変換器のＶＴ，ＶＲから求めたＲ値と、光学フィルタ特性によるＲ値−ブラッグ波長特性との誤差を示すグラフである。It is a graph which shows the error of R value calculated | required from VT and VR of the photoelectric converter, and R value-Bragg wavelength characteristic by an optical filter characteristic.

以下、本発明の、ブラッグ波長推定方法及び装置を実施する形態例を図１〜図８を参照して説明する。なお、図中、図９と同一の符号を付した部分は同一物を表わしている。   DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the Bragg wavelength estimation method and apparatus according to the present invention will be described below with reference to FIGS. In the figure, the same reference numerals as those in FIG. 9 denote the same parts.

実施の形態例は、従来例と同様に、FBGセンサ部１の光ファイバ２、広帯域光源３、光サーキュレータ４、光学フィルタ５、第一の光電変換器６、第二の光電変換器７を備えており、第一の光電変換器６と第二の光電変換器７には処理部９が接続され、更に処理部９には波長推定部１０が接続されている。ここで光学フィルタ５は、入射光ポート５ａ及び透過光ポート５ｂ並びに反射光ポート５ｃの三つを有するものであって、光サーキュレータ４により分離された光を入射光ポート５ａへ入射させ、且つ透過光を透過光ポート５ｂから出力すると共に反射光を反射光ポート５ｃから出力するものである。また光学フィルタ５は、透過光及び反射光を生じるならば特に種類や構成は制限されるものではない。また処理部と波長推定部は一つの装置で構成しても良い。   The embodiment includes an optical fiber 2, a broadband light source 3, an optical circulator 4, an optical filter 5, a first photoelectric converter 6, and a second photoelectric converter 7, as in the conventional example. A processing unit 9 is connected to the first photoelectric converter 6 and the second photoelectric converter 7, and a wavelength estimation unit 10 is further connected to the processing unit 9. Here, the optical filter 5 has an incident light port 5a, a transmitted light port 5b, and a reflected light port 5c. The light separated by the optical circulator 4 is incident on the incident light port 5a and transmitted. Light is output from the transmitted light port 5b and reflected light is output from the reflected light port 5c. The type and configuration of the optical filter 5 are not particularly limited as long as the optical filter 5 generates transmitted light and reflected light. Further, the processing unit and the wavelength estimation unit may be configured by a single device.

処理部９では、所定のプログラムや関数処理により、第一の光電変換器６からの第一の出力電圧ＶＴ，第二の光電変換器７からの第二の出力電圧ＶＲを用いてＲ＝（ＶＲ−ＶＴ）／（ＶＴ＋ＶＲ）により無次元のＲ値を算出するようになっている。   The processing unit 9 uses the first output voltage VT from the first photoelectric converter 6 and the second output voltage VR from the second photoelectric converter 7 by a predetermined program or function process, and R = ( A dimensionless R value is calculated by (VR−VT) / (VT + VR).

また処理部９では、準備段階として、光学フィルタ５の波長における透過率ＰＴｘと、第一の光電変換器６において正規化された第一の光電変換特性ＬＥＴとの積、及び光学フィルタ５の波長における反射率ＰＲｘと、第二の光電変換器７において正規化された第二の光電変換特性ＬＥＲとの積を用いて、光学フィルタ５によるＲ値−ブラッグ波長特性が求められている。なお光学フィルタ５によるＲ値−ブラッグ波長特性は、他の機器で求めた後、入力されても良い。   In the processing unit 9, as a preparation stage, the product of the transmittance PTx at the wavelength of the optical filter 5 and the first photoelectric conversion characteristic LET normalized by the first photoelectric converter 6, and the wavelength of the optical filter 5. The R value-Bragg wavelength characteristic by the optical filter 5 is obtained by using the product of the reflectance PRx at λ and the second photoelectric conversion characteristic LER normalized by the second photoelectric converter 7. The R value-Bragg wavelength characteristic by the optical filter 5 may be input after it is obtained by another device.

ここで、以下、準備段階として、第一の光電変換器６の波長において正規化された第一の光電変換特性ＬＥＴと、第二の光電変換器７の波長において正規化された第二の光電変換特性ＬＥＲとを求める工程を説明する。   Here, hereinafter, as a preparation stage, the first photoelectric conversion characteristic LET normalized at the wavelength of the first photoelectric converter 6 and the second photoelectric element normalized at the wavelength of the second photoelectric converter 7 are used. A process for obtaining the conversion characteristic LER will be described.

処理部９では、光学フィルタ５を透過した透過率ＰＴｘの透過光強度ＰＴ、または光学フィルタ５を反射した反射率ＰＲｘの反射光強度ＰＲ、第一の出力電圧ＶＴ、第二の出力電圧ＶＲから、第一の光電変換器６の変換比をＶＴ／ＰＴとして求め、第二の光電変換器７の変換比をＶＲ／ＰＲとして求める。   In the processing unit 9, from the transmitted light intensity PT of the transmittance PTx that has passed through the optical filter 5, or the reflected light intensity PR of the reflectance PRx that has reflected from the optical filter 5, the first output voltage VT, and the second output voltage VR. The conversion ratio of the first photoelectric converter 6 is obtained as VT / PT, and the conversion ratio of the second photoelectric converter 7 is obtained as VR / PR.

次に、第一の光電変換器６における変換比ＶＴ／ＰＴの波長ごとの特性と、第二の光電変換器７における変換比ＶＲ／ＰＲの波長ごとの特性との和を２で除した特性（（ＶＴ／ＰＴ）＋（ＶＲ／ＰＲ））／２を分母とし、第一の光電変換器６における変換比ＶＴ／ＰＴの波長ごとの特性を分子とし、第一の光電変換器６において正規化された第一の光電変換特性ＬＥＴを求める。なお、第一の光電変換器６において正規化された第一の光電変換特性ＬＥＴを数式で示すと［式１］になる。
[式１]

Figure 2012098196
ここで、第一の光電変換器６において正規化された第一の光電変換特性ＬＥＴは、変換比ＶＴ／ＰＴの物理量の単位を無次元化したものである。 Next, a characteristic obtained by dividing the sum of the characteristics for each wavelength of the conversion ratio VT / PT in the first photoelectric converter 6 and the characteristics for each wavelength of the conversion ratio VR / PR in the second photoelectric converter 7 by 2. ((VT / PT) + (VR / PR)) / 2 is used as the denominator, and the characteristics for each wavelength of the conversion ratio VT / PT in the first photoelectric converter 6 are used as numerators. The first photoelectric conversion characteristic LET is obtained. The first photoelectric conversion characteristic LET normalized in the first photoelectric converter 6 is expressed by [Expression 1].
[Formula 1]
Figure 2012098196
Here, the first photoelectric conversion characteristic LET normalized in the first photoelectric converter 6 is obtained by making the unit of the physical quantity of the conversion ratio VT / PT dimensionless.

一方、第一の光電変換器６における変換比ＶＴ／ＰＴの波長ごとの特性と、第二の光電変換器７における変換比ＶＲ／ＰＲの波長ごとの特性との和を２で除した特性（（ＶＴ／ＰＴ）＋（ＶＲ／ＰＲ））／２を分母とし、第二の光電変換器７における変換比ＶＲ／ＰＲの波長ごとの特性を分子とし、第二の光電変換器７において正規化された第二の光電変換特性ＬＥＲを求める。なお、第二の光電変換器７において正規化された第二の光電変換特性ＬＥＲを数式で示すと［式２］になる。
[式２]

Figure 2012098196
ここで、第二の光電変換器７において正規化された第二の光電変換特性ＬＥＲは、変換比ＶＲ／ＰＲの物理量の単位を無次元化したものである。 On the other hand, a characteristic obtained by dividing the sum of the characteristic for each wavelength of the conversion ratio VT / PT in the first photoelectric converter 6 and the characteristic for each wavelength of the conversion ratio VR / PR in the second photoelectric converter 7 ( (VT / PT) + (VR / PR)) / 2 is used as the denominator, the characteristics of the conversion ratio VR / PR in the second photoelectric converter 7 for each wavelength are normalized, and the second photoelectric converter 7 is normalized. The obtained second photoelectric conversion characteristic LER is obtained. The second photoelectric conversion characteristic LER normalized in the second photoelectric converter 7 is expressed by [Expression 2].
[Formula 2]
Figure 2012098196
Here, the second photoelectric conversion characteristic LER normalized in the second photoelectric converter 7 is obtained by making the unit of the physical quantity of the conversion ratio VR / PR dimensionless.

そして処理部９では、第一の光電変換器６において正規化された第一の光電変換特性ＬＥＴと、第二の光電変換器７において正規化された第二の光電変換特性ＬＥＲとが入力記録されており、第一の光電変換器６において正規化された第一の光電変換特性ＬＥＴと、光学フィルタ５の波長における透過率ＰＴｘとの積、及び第二の光電変換器７において正規化された第二の光電変換特性ＬＥＲと、光学フィルタ５の波長における反射率ＰＲｘとの積により、Ｒ＝（ＬＥＲとＰＲｘの積−ＬＥＴとＰＴｘの積）／（ＬＥＴとＰＴｘの積＋ＬＥＲとＰＲｘの積）を介してＲ値とブラッグ波長を求め、補正したＲ値−ブラッグ波長特性の曲線が得られるようになっている。   In the processing unit 9, the first photoelectric conversion characteristic LET normalized in the first photoelectric converter 6 and the second photoelectric conversion characteristic LER normalized in the second photoelectric converter 7 are input recorded. The product of the first photoelectric conversion characteristic LET normalized in the first photoelectric converter 6 and the transmittance PTx at the wavelength of the optical filter 5 and the second photoelectric converter 7 are normalized. R = (product of LER and PRx−product of LET and PTx) / (product of LET and PTx + the product of LER and PRx) by the product of the second photoelectric conversion characteristic LER and the reflectance PRx at the wavelength of the optical filter 5 The R value and the Bragg wavelength are obtained through the product, and a corrected R value-Bragg wavelength characteristic curve is obtained.

波長推定部１０では、第一の出力電圧ＶＴ、第二の出力電圧ＶＲにより算出したＲ値を、第一の光電変換特性ＬＥＴ、第二の光電変換特性ＬＥＲ、透過率ＰＴｘ、反射率ＰＲｘにより算出したＲ値−ブラッグ波長特性の曲線と対比し、ブラッグ波長を推定するようになっている。   In the wavelength estimator 10, the R value calculated from the first output voltage VT and the second output voltage VR is determined by the first photoelectric conversion characteristic LET, the second photoelectric conversion characteristic LER, the transmittance PTx, and the reflectance PRx. The Bragg wavelength is estimated by comparing with the calculated R value-Bragg wavelength characteristic curve.

［試験１］
以下、一例の光電変換器の場合、及び他例の光電変換器におけるＶＴ，ＶＲ、光電変換器によるＲ値−ブラッグ波長特性、光学フィルタによるＲ値−ブラッグ波長特性について算出し、その結果を示す。図２では一例の光電変換器のＶＴ，ＶＲ、光電変換器によるＲ値−ブラッグ波長特性を示し、図３では他例の光電変換器のＶＴ，ＶＲ、光電変換器によるＲ値−ブラッグ波長特性を示し、図４では光学フィルタによるＲ値−ブラッグ波長特性を示している。ここで図４では光学フィルタから３回のデータを取得したが、取得ごとの偏差は生じなかった。また図２のＲ値−ブラッグ波長特性、図３のＲ値−ブラッグ波長特性を図４に入れた場合には、図９の如く両者に偏差があることを示すものになる。 [Test 1]
Hereinafter, in the case of an example photoelectric converter and in other examples of the photoelectric converter, VT, VR, R value-Bragg wavelength characteristic by the photoelectric converter, R value-Bragg wavelength characteristic by the optical filter are calculated, and the results are shown. . FIG. 2 shows VT, VR and R value-Bragg wavelength characteristics of an example photoelectric converter, and FIG. 3 shows VT, VR of another example of the photoelectric converter and R value-Bragg wavelength characteristic of the photoelectric converter. FIG. 4 shows the R value-Bragg wavelength characteristic by the optical filter. Here, in FIG. 4, data was acquired three times from the optical filter, but no deviation occurred at each acquisition. When the R value-Bragg wavelength characteristic of FIG. 2 and the R value-Bragg wavelength characteristic of FIG. 3 are entered in FIG. 4, it indicates that there is a deviation as shown in FIG.

次に、一例の光電変換器の場合、及び他例の光電変換器の場合における、正規化された光電変換特性ＬＥＴ，ＬＥＲ等を示す。図５では一例の光電変換器の場合における正規化された光電変換特性ＬＥＴ，ＬＥＲを示し、図６では他例の光電変換器の場合における正規化された光電変換特性ＬＥＴ，ＬＥＲを示し、図７では正規化された光電変換特性ＬＥＴ，ＬＥＲをＶＴ，ＶＲに反映した場合、ＶＴ，ＶＲによるＲ値が補正されることを示している。ここで図７では、一例の光電変換器及び他例の光電変換器の出力電圧ＶＴを、正規化された光電変換特性ＬＥＴで除して補正し、且つ一例の光電変換器及び他例の光電変換器の出力電圧ＶＲを、正規化された光電変換特性ＬＥＲで除して補正した場合に、補正後のＲ値が、光学フィルタのＲ値−ブラッグ波長特性に一致することを示している。なお図７中、白抜きの丸は、一例の光電変換器による補正前のＲ値を示し、黒印の丸は、一例の光電変換器による補正後のＲ値を示し、白抜きの三角は、他例の光電変換器による補正前のＲ値を示し、黒印の三角は、他例の光電変換器による補正後のＲ値を示し、更に直線は光学フィルタの透過率及び反射率によるＲ値−ブラッグ波長特性の曲線を示している。   Next, normalized photoelectric conversion characteristics LET, LER, etc. in the case of the photoelectric converter of one example and the case of the photoelectric converter of another example are shown. FIG. 5 shows normalized photoelectric conversion characteristics LET and LER in the case of an example photoelectric converter, and FIG. 6 shows normalized photoelectric conversion characteristics LET and LER in the case of another example photoelectric converter. 7 indicates that when the normalized photoelectric conversion characteristics LET and LER are reflected in VT and VR, the R value by VT and VR is corrected. Here, in FIG. 7, the output voltage VT of the photoelectric converter of the example and the photoelectric converter of the other example is corrected by dividing by the normalized photoelectric conversion characteristic LET, and the photoelectric converter of the example and the photoelectric converter of the other example are corrected. It shows that when the output voltage VR of the converter is corrected by dividing it by the normalized photoelectric conversion characteristic LER, the corrected R value matches the R value-Bragg wavelength characteristic of the optical filter. In FIG. 7, a white circle indicates an R value before correction by an example photoelectric converter, a black circle indicates an R value after correction by an example photoelectric converter, and a white triangle indicates The R value before correction by the photoelectric converter of the other example is shown, the black triangle indicates the R value after correction by the photoelectric converter of the other example, and the straight line is R by the transmittance and reflectance of the optical filter. The curve of a value-Bragg wavelength characteristic is shown.

一方で図７の結果は、ブラッグ波長が既知の場合に得られる結果であり、実際の計測では、光電変換器の出力電圧ＶＴ，ＶＲのみしか得ることができない。このため、光電変換器の出力電圧ＶＴ，ＶＲを、正規化された光電変換特性ＬＥＴ，ＬＥＲで除して補することの代わりに、光学フィルタの透過率ＰＴｘ及び反射率ＰＲｘに、正規化された光電変換特性ＬＥＴ，ＬＥＲを積算して補正し、光学フィルタの透過率ＰＴｘ及び反射率ＰＲｘによるＲ値−ブラッグ波長特性を求め、図８に示す如く当該Ｒ値−ブラッグ波長特性が、出力電圧ＶＴ，ＶＲによるＲ値に一致するようにしている。なお図８中、白抜きの丸は、一例の光電変換器による補正前のＲ値を示し、直線は、光学フィルタの透過率及び反射率による補正前のＲ値−ブラッグ波長特性の曲線を示し、破線は、光学フィルタの透過率及び反射率による補正後のＲ値−ブラッグ波長特性の曲線を示している。   On the other hand, the result of FIG. 7 is a result obtained when the Bragg wavelength is known. In actual measurement, only the output voltages VT and VR of the photoelectric converter can be obtained. For this reason, the output voltages VT and VR of the photoelectric converter are normalized to the transmittance PTx and the reflectance PRx of the optical filter instead of compensating by dividing by the normalized photoelectric conversion characteristics LET and LER. The photoelectric conversion characteristics LET and LER are integrated and corrected to obtain an R value-Bragg wavelength characteristic based on the transmittance PTx and the reflectance PRx of the optical filter, and the R value-Bragg wavelength characteristic is output voltage as shown in FIG. It is made to correspond to the R value by VT and VR. In FIG. 8, a white circle indicates an R value before correction by an example of a photoelectric converter, and a straight line indicates a curve of R value before correction by the transmittance and reflectance of an optical filter-Bragg wavelength characteristic curve. The broken line indicates a curve of the R value-Bragg wavelength characteristic after correction based on the transmittance and reflectance of the optical filter.

このように、実施の形態例によれば、光学フィルタ５の波長における透過率ＰＴｘと、第一の光電変換器６の波長において正規化された第一の光電変換特性ＬＥＴとの積、及び光学フィルタ５における反射率ＰＲｘと、第二の光電変換器７において正規化された第二の光電変換特性ＬＥＲとの積を用い、補正したＲ値−ブラッグ波長特性を求めるので、当該Ｒ値−ブラッグ波長特性の曲線と、第一の出力電圧ＶＴ及び第二の出力電圧ＶＲによるＲ値とを適切に比較し、ブラッグ波長の推定誤差を低減することができる。またFBGセンサ部１を含む装置構成や計測対象に対して校正を行うことなく、光学フィルタの透過率ＰＴｘ、反射率ＰＲｘ、第一の光電変換器６において正規化された第一の光電変換特性ＬＥＴ、第二の光電変換器７において正規化された第二の光電変換特性ＬＥＲを求めて代用するので、手間と時間を抑制して簡素化を図ることができる。更に、計測対象の測定前であっても、補正したＲ値−波長特性を容易に取得し、早急に準備することができる。   Thus, according to the embodiment, the product of the transmittance PTx at the wavelength of the optical filter 5 and the first photoelectric conversion characteristic LET normalized at the wavelength of the first photoelectric converter 6, and the optical Since the corrected R value-Bragg wavelength characteristic is obtained using the product of the reflectance PRx in the filter 5 and the second photoelectric conversion characteristic LER normalized in the second photoelectric converter 7, the R value-Bragg It is possible to appropriately compare the curve of the wavelength characteristic with the R value based on the first output voltage VT and the second output voltage VR, and to reduce the estimation error of the Bragg wavelength. Further, the optical filter transmittance PTx, the reflectance PRx, and the first photoelectric conversion characteristic normalized by the first photoelectric converter 6 without calibrating the apparatus configuration including the FBG sensor unit 1 and the measurement target. Since the LET and the second photoelectric conversion characteristic LER normalized in the second photoelectric converter 7 are obtained and substituted, it is possible to simplify the operation by reducing labor and time. Furthermore, even before measurement of the measurement target, the corrected R value-wavelength characteristic can be easily obtained and prepared quickly.

実施の形態例において、第一の光電変換器６について光学フィルタ５の透過光強度ＰＴに対する第一の出力電圧ＶＴの変換比ＶＴ／ＰＴを求め、且つ第二の光電変換器７について光学フィルタ５の反射光強度ＰＲに対する第二の出力電圧ＶＲの変換比ＶＲ／ＰＲを求め、第一の光電変換器６における当該変換比ＶＴ／ＰＴの波長ごとの特性と、第二の光電変換器７における当該変換比ＶＲ／ＰＲの波長ごとの特性との和を２で除した特性を分母とし、第一の光電変換器６における当該変換比ＶＴ／ＰＴの波長ごとの特性を分子として、第一の光電変換器６の波長において正規化された第一の光電変換特性ＬＥＴを求めるので、補正したＲ値−ブラッグ波長特性を容易且つ好適に求めることができる。   In the embodiment, the conversion ratio VT / PT of the first output voltage VT with respect to the transmitted light intensity PT of the optical filter 5 is obtained for the first photoelectric converter 6, and the optical filter 5 for the second photoelectric converter 7. The conversion ratio VR / PR of the second output voltage VR with respect to the reflected light intensity PR of the first photoelectric converter 6 is obtained, and the characteristics for each wavelength of the conversion ratio VT / PT in the first photoelectric converter 6 and the second photoelectric converter 7 The characteristic obtained by dividing the sum of the conversion ratio VR / PR and the characteristics for each wavelength by 2 is used as the denominator, and the characteristics for each wavelength of the conversion ratio VT / PT in the first photoelectric converter 6 is used as the numerator. Since the first photoelectric conversion characteristic LET normalized at the wavelength of the photoelectric converter 6 is obtained, the corrected R value-Bragg wavelength characteristic can be obtained easily and suitably.

実施の形態例において、第一の光電変換器６について光学フィルタ５の透過光強度ＰＴに対する第一の出力電圧ＶＴの変換比ＶＴ／ＰＴを求め、且つ第二の光電変換器７について光学フィルタ５の反射光強度ＰＲに対する第二の出力電圧ＶＲの変換比ＶＲ／ＰＲを求め、第一の光電変換器６における当該変換比ＶＴ／ＰＴの波長ごとの特性と、第二の光電変換器における当該変換比ＶＲ／ＰＲの波長ごとの特性との和を２で除した特性を分母とし、第二の光電変換器７における当該変換比ＶＲ／ＰＲの波長ごとの特性を分子として、第二の光電変換器７の波長において正規化された第二の光電変換特性ＬＥＲを求めるので、補正したＲ値−ブラッグ波長特性を容易且つ好適に求めることができる。   In the embodiment, the conversion ratio VT / PT of the first output voltage VT with respect to the transmitted light intensity PT of the optical filter 5 is obtained for the first photoelectric converter 6, and the optical filter 5 for the second photoelectric converter 7. The conversion ratio VR / PR of the second output voltage VR with respect to the reflected light intensity PR of the first photoelectric converter 6 is obtained, and the characteristics for each wavelength of the conversion ratio VT / PT in the first photoelectric converter 6 and the second photoelectric converter in the second photoelectric converter The characteristic obtained by dividing the sum of the conversion ratio VR / PR and the characteristic for each wavelength by 2 is used as the denominator, and the characteristic for each wavelength of the conversion ratio VR / PR in the second photoelectric converter 7 is used as the numerator. Since the second photoelectric conversion characteristic LER normalized at the wavelength of the converter 7 is obtained, the corrected R value-Bragg wavelength characteristic can be obtained easily and suitably.

なお、本発明のブラッグ波長推定方法及びその装置は、本発明の要旨を逸脱しない範囲内において種々変更を加え得ることは勿論である。   Of course, the Bragg wavelength estimation method and apparatus of the present invention can be variously modified without departing from the gist of the present invention.

１ FBGセンサ部
２ 光ファイバ
３ 広帯域光源
４ 光サーキュレータ
５ 光学フィルタ
５ａ 入射光ポート
５ｂ 透過光ポート
５ｃ 反射光ポート
６ 第一の光電変換器
７ 第二の光電変換器
９ 処理部
１０ 波長推定部
ＬＥＲ 第一の光電変換特性
ＬＥＴ 第二の光電変換特性
ＰＲ 反射光強度
ＰＲｘ 反射率
ＰＴ 透過光強度
ＰＴｘ 透過率
ＶＲ 第一の出力電圧
ＶＲ／ＰＲ 変換比
ＶＴ 第二の出力電圧
ＶＴ／ＰＴ 変換比 DESCRIPTION OF SYMBOLS 1 FBG sensor part 2 Optical fiber 3 Broadband light source 4 Optical circulator 5 Optical filter 5a Incident light port 5b Transmitted light port 5c Reflected light port 6 First photoelectric converter 7 Second photoelectric converter 9 Processing part 10 Wavelength estimation part LER First photoelectric conversion characteristic LET Second photoelectric conversion characteristic PR Reflected light intensity PRx Reflectivity PT Transmitted light intensity PTx Transmittance VR First output voltage VR / PR conversion ratio VT Second output voltage VT / PT conversion ratio

Claims (6)

広帯域光源から照射された連続光を光サーキュレータを介してFBGセンサ部に入射し、FBGセンサ部から反射した光を光サーキュレータにより分離し、入射光ポート及び透過光ポート並びに反射光ポートの三つのポートを有する光学フィルタに対して前記光サーキュレータからの光を入射光ポートへ入射し、前記透過光ポートから出力される透過光強度（ＰＴ）を第一の光電変換器により第一の出力電圧（ＶＴ）に変換し且つ前記反射光ポートから出力される反射光強度（ＰＲ）を第二の光電変換器により第二の出力電圧（ＶＲ）に変換し、前記第一の出力電圧（ＶＴ）及び第二の出力電圧（ＶＲ）を基礎にして無次元量のＲ値を算出し、予め取得したＲ値−ブラッグ波長特性を用いてFBGセンサ部のブラッグ波長を推定するブラッグ波長推定方法であって、
前記光学フィルタにおける透過率（ＰＴｘ）と、第一の光電変換器において正規化された第一の光電変換特性（ＬＥＴ）との積、及び
前記光学フィルタにおける反射率（ＰＲｘ）と、第二の光電変換器において正規化された第二の光電変換特性（ＬＥＲ）との積を用いて
Ｒ値−ブラッグ波長特性を求めることを特徴とするブラッグ波長推定方法。 The continuous light emitted from the broadband light source enters the FBG sensor unit via the optical circulator, and the light reflected from the FBG sensor unit is separated by the optical circulator. The light from the optical circulator is incident on the incident light port with respect to the optical filter having the transmission filter, and the transmitted light intensity (PT) output from the transmitted light port is converted to the first output voltage (VT) by the first photoelectric converter. ) And the reflected light intensity (PR) output from the reflected light port is converted to a second output voltage (VR) by the second photoelectric converter, and the first output voltage (VT) and the first output voltage (VT) Bragg wavelength estimation method for calculating a dimensionless R value based on the second output voltage (VR) and estimating the Bragg wavelength of the FBG sensor unit using the R value-Bragg wavelength characteristic acquired in advance There,
The product of the transmittance (PTx) in the optical filter and the first photoelectric conversion characteristic (LET) normalized in the first photoelectric converter, and the reflectance (PRx) in the optical filter, A Bragg wavelength estimation method, wherein an R value-Bragg wavelength characteristic is obtained using a product of a second photoelectric conversion characteristic (LER) normalized in a photoelectric converter. 第一の光電変換器について光学フィルタの透過光強度（ＰＴ）に対する第一の出力電圧（ＶＴ）の変換比（ＶＴ／ＰＴ）を求め、且つ第二の光電変換器について光学フィルタの反射光強度（ＰＲ）に対する第二の出力電圧（ＶＲ）の変換比（ＶＲ／ＰＲ）を求め、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性と、第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性との和を２で除した特性を分母とし、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性を分子として、
第一の光電変換器において正規化された第一の光電変換特性（ＬＥＴ）を求めることを特徴とする請求項１に記載のブラッグ波長推定方法。 For the first photoelectric converter, the conversion ratio (VT / PT) of the first output voltage (VT) to the transmitted light intensity (PT) of the optical filter is obtained, and the reflected light intensity of the optical filter for the second photoelectric converter The conversion ratio (VR / PR) of the second output voltage (VR) with respect to (PR) is obtained,
The sum of the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter and the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter is divided by 2. With the characteristic as the denominator,
Using the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter as a molecule,
The Bragg wavelength estimation method according to claim 1, wherein the first photoelectric conversion characteristic (LET) normalized in the first photoelectric converter is obtained. 第一の光電変換器について光学フィルタの透過光強度（ＰＴ）に対する第一の出力電圧（ＶＴ）の変換比（ＶＴ／ＰＴ）を求め、且つ第二の光電変換器について光学フィルタの反射光強度（ＰＲ）に対する第二の出力電圧（ＶＲ）の変換比（ＶＲ／ＰＲ）を求め、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性と、第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性との和を２で除した特性を分母とし、
第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性を分子として、
第二の光電変換器において正規化された第二の光電変換特性（ＬＥＲ）を求めることを特徴とする請求項１に記載のブラッグ波長推定方法。 For the first photoelectric converter, the conversion ratio (VT / PT) of the first output voltage (VT) to the transmitted light intensity (PT) of the optical filter is obtained, and the reflected light intensity of the optical filter for the second photoelectric converter The conversion ratio (VR / PR) of the second output voltage (VR) with respect to (PR) is obtained,
The sum of the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter and the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter is divided by 2. With the characteristic as the denominator,
Using the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter as a molecule,
The Bragg wavelength estimation method according to claim 1, wherein a second photoelectric conversion characteristic (LER) normalized in the second photoelectric converter is obtained. FBGセンサ部を含む光ファイバと、
前記FBGセンサ部のブラッグ波長を含む連続光を照射する広帯域光源と、
該広帯域光源と、FBGセンサ部を含む光ファイバとの間に配置され、広帯域光源から照射された光を透過してFBGセンサ部に入射させ且つFBGセンサ部から反射した光を分離する光サーキュレータと、
入射光及び透過光並びに反射光の三つのポートを有して光サーキュレータにより分離された光を入射光ポートへ入射させる光学フィルタと、
該光学フィルタの透過光ポートから出力される透過光強度（ＰＴ）を第一の出力電圧（ＶＴ）に変換する第一の光電変換器と、
前記光学フィルタの反射光ポートから出力される反射光強度（ＰＲ）を第二の出力電圧（ＶＲ）に変換する第二の光電変換器と、
前記第一の出力電圧（ＶＴ）及び第二の出力電圧（ＶＲ）を基礎にして無次元量のＲ値を算出する処理部と、
予め取得したＲ値−ブラッグ波長特性を用いてFBGセンサのブラッグ波長を推定する波長推定部とを備えるブラッグ波長推定装置であって、
前記処理部は、
前記光学フィルタにおける透過率（ＰＴｘ）と、第一の光電変換器において正規化された第一の光電変換特性（ＬＥＴ）との積、及び
前記光学フィルタにおける反射率（ＰＲｘ）と、第二の光電変換器において正規化された第二の光電変換特性（ＬＥＲ）との積を用いて
Ｒ値−ブラッグ波長特性を求めるように構成されたことを特徴とするブラッグ波長推定装置。 An optical fiber including an FBG sensor, and
A broadband light source that emits continuous light including the Bragg wavelength of the FBG sensor unit;
An optical circulator disposed between the broadband light source and an optical fiber including the FBG sensor unit, which transmits the light irradiated from the broadband light source and enters the FBG sensor unit and separates the light reflected from the FBG sensor unit; ,
An optical filter that has three ports of incident light, transmitted light, and reflected light, and that makes the light separated by the optical circulator enter the incident light port;
A first photoelectric converter that converts transmitted light intensity (PT) output from a transmitted light port of the optical filter into a first output voltage (VT);
A second photoelectric converter that converts reflected light intensity (PR) output from the reflected light port of the optical filter into a second output voltage (VR);
A processing unit that calculates a dimensionless R value based on the first output voltage (VT) and the second output voltage (VR);
A Bragg wavelength estimation device including a wavelength estimation unit that estimates a Bragg wavelength of an FBG sensor using an R value-Bragg wavelength characteristic acquired in advance;
The processor is
The product of the transmittance (PTx) in the optical filter and the first photoelectric conversion characteristic (LET) normalized in the first photoelectric converter, and the reflectance (PRx) in the optical filter, A Bragg wavelength estimation apparatus configured to obtain an R value-Bragg wavelength characteristic by using a product of a second photoelectric conversion characteristic (LER) normalized in the photoelectric converter. 前記処理部は、
第一の光電変換器について光学フィルタの透過光強度（ＰＴ）に対する第一の出力電圧（ＶＴ）の変換比（ＶＴ／ＰＴ）を求め、且つ第二の光電変換器について光学フィルタの反射光強度（ＰＲ）に対する第二の出力電圧（ＶＲ）の変換比（ＶＲ／ＰＲ）を求め、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性と、第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性との和を２で除した特性を分母とし、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性を分子として、
第一の光電変換器において正規化された第一の光電変換特性（ＬＥＴ）を求めるように構成されたことを特徴とする請求項４に記載のブラッグ波長推定装置。 The processor is
For the first photoelectric converter, the conversion ratio (VT / PT) of the first output voltage (VT) to the transmitted light intensity (PT) of the optical filter is obtained, and the reflected light intensity of the optical filter for the second photoelectric converter The conversion ratio (VR / PR) of the second output voltage (VR) with respect to (PR) is obtained,
The sum of the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter and the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter is divided by 2. With the characteristic as the denominator,
Using the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter as a molecule,
The Bragg wavelength estimation apparatus according to claim 4, wherein the Bragg wavelength estimation apparatus is configured to obtain a first photoelectric conversion characteristic (LET) normalized in the first photoelectric converter. 前記処理部は、
第一の光電変換器について光学フィルタの透過光強度（ＰＴ）に対する第一の出力電圧（ＶＴ）の変換比（ＶＴ／ＰＴ）を求め、且つ第二の光電変換器について光学フィルタの反射光強度（ＰＲ）に対する第二の出力電圧（ＶＲ）の変換比（ＶＲ／ＰＲ）を求め、
第一の光電変換器における当該変換比（ＶＴ／ＰＴ）の波長ごとの特性と、第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性との和を２で除した特性を分母とし、
第二の光電変換器における当該変換比（ＶＲ／ＰＲ）の波長ごとの特性を分子として、
第二の光電変換器において正規化された第二の光電変換特性（ＬＥＲ）を求めるように構成されたことを特徴とする請求項４に記載のブラッグ波長推定装置。 The processor is
For the first photoelectric converter, the conversion ratio (VT / PT) of the first output voltage (VT) to the transmitted light intensity (PT) of the optical filter is obtained, and the reflected light intensity of the optical filter for the second photoelectric converter The conversion ratio (VR / PR) of the second output voltage (VR) with respect to (PR) is obtained,
The sum of the characteristics for each wavelength of the conversion ratio (VT / PT) in the first photoelectric converter and the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter is divided by 2. With the characteristic as the denominator,
Using the characteristics for each wavelength of the conversion ratio (VR / PR) in the second photoelectric converter as a molecule,
The Bragg wavelength estimation device according to claim 4, wherein the second photoelectric conversion characteristic (LER) normalized in the second photoelectric converter is obtained.
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Publication number Priority date Publication date Assignee Title
CN103148880A (en) * 2013-03-01 2013-06-12 黑龙江大学 Color-filter-based multi-channel fiber bragg grating demodulator
JP2015021814A (en) * 2013-07-18 2015-02-02 株式会社Ｉｈｉ検査計測 Impact detection method and device

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CN103148880A (en) * 2013-03-01 2013-06-12 黑龙江大学 Color-filter-based multi-channel fiber bragg grating demodulator
JP2015021814A (en) * 2013-07-18 2015-02-02 株式会社Ｉｈｉ検査計測 Impact detection method and device

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