JP2002310729A - Method and instrument for distribution type physical quantity measurement - Google Patents
Method and instrument for distribution type physical quantity measurementInfo
- Publication number
- JP2002310729A JP2002310729A JP2001110225A JP2001110225A JP2002310729A JP 2002310729 A JP2002310729 A JP 2002310729A JP 2001110225 A JP2001110225 A JP 2001110225A JP 2001110225 A JP2001110225 A JP 2001110225A JP 2002310729 A JP2002310729 A JP 2002310729A
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- Prior art keywords
- optical fiber
- wavelength
- sensing
- add
- light
- Prior art date
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Links
- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000005259 measurement Methods 0.000 title abstract description 14
- 239000013307 optical fiber Substances 0.000 claims abstract description 100
- 230000003287 optical effect Effects 0.000 claims description 12
- 230000005284 excitation Effects 0.000 claims description 10
- 238000000926 separation method Methods 0.000 claims description 10
- 238000000691 measurement method Methods 0.000 claims description 8
- 239000006185 dispersion Substances 0.000 claims description 5
- 238000005086 pumping Methods 0.000 claims description 4
- 230000005540 biological transmission Effects 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 5
- 238000012423 maintenance Methods 0.000 description 4
- 238000001069 Raman spectroscopy Methods 0.000 description 3
- 238000009529 body temperature measurement Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 102100038080 B-cell receptor CD22 Human genes 0.000 description 1
- 102100022626 Glutamate receptor ionotropic, NMDA 2D Human genes 0.000 description 1
- 101000884305 Homo sapiens B-cell receptor CD22 Proteins 0.000 description 1
- 101000972840 Homo sapiens Glutamate receptor ionotropic, NMDA 2D Proteins 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000009022 nonlinear effect Effects 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
- CCEKAJIANROZEO-UHFFFAOYSA-N sulfluramid Chemical group CCNS(=O)(=O)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F CCEKAJIANROZEO-UHFFFAOYSA-N 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
Landscapes
- Measuring Temperature Or Quantity Of Heat (AREA)
- Indication And Recording Devices For Special Purposes And Tariff Metering Devices (AREA)
- Optical Transform (AREA)
- Spectrometry And Color Measurement (AREA)
- Geophysics And Detection Of Objects (AREA)
- Light Guides In General And Applications Therefor (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、光ファイバを用い
た分布型の物理量センシングに係り、特に、２次元、３
次元の分布センシングが可能で、事故時の復旧が容易
で、信頼性が高く、構成が簡素な分布型物理量計測方法
及び計測装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to distributed physical quantity sensing using an optical fiber, and more particularly, to two-dimensional, three-dimensional physical quantity sensing.
The present invention relates to a distributed physical quantity measurement method and a measurement apparatus which can perform dimensional distribution sensing, facilitate recovery from an accident, have high reliability, and have a simple configuration.
【０００２】[0002]
【従来の技術】光ファイバを用いたセンシング方法の従
来技術には、以下のものがある。2. Description of the Related Art The prior art of a sensing method using an optical fiber includes the following.
【０００３】（１）ラマン散乱を用いた分布型温度計測 図３に示されるように、この方法では、トリガされたパ
ルス光をセンサ用光ファイバに入射させ、ラマン散乱に
よって発生するストークス光と反ストークス光との強度
比の温度依存性を利用して光ファイバ長手方向の温度分
布を計測する。この方法の文献として特公平１１−４４
５８４号がある。(1) Distributed Temperature Measurement Using Raman Scattering As shown in FIG. 3, in this method, a triggered pulse light is made incident on a sensor optical fiber, and the Stokes light generated by Raman scattering is reflected by the reflected light. The temperature distribution in the longitudinal direction of the optical fiber is measured using the temperature dependence of the intensity ratio with the Stokes light. As a literature on this method, Japanese Patent Publication No. 11-44
No. 584.
【０００４】（２）光ファイバブラッググレーティング
（以下、ＦＢＧと言う）を利用した分布型センサ 図４に示されるように、この方法では、ＦＢＧを長手方
向の複数箇所に形成した光ファイバに広波長帯域を有す
る光を入射し、その反射光をファブリペロットフィルタ
(Fabry-Perot Filter)に通して受光器(Detector)で受光
し、反射光の中心波長からの変位を検出する。これによ
り、光ファイバ長手方向の歪み分布、温度分布等の計測
が可能である。この方法の文献として「オプトニュー
ス」１９９６，Ｎｏ６，ＰＰ２９−３１がある。(2) Distributed sensor using optical fiber Bragg grating (hereinafter referred to as FBG) As shown in FIG. 4, in this method, an optical fiber in which FBGs are formed at a plurality of locations in the longitudinal direction has a wide wavelength range. Injects light with a band and reflects the reflected light to Fabry-Perot filter
(Fabry-Perot Filter) and received by a photo detector (Detector) to detect the displacement from the center wavelength of the reflected light. This makes it possible to measure the strain distribution, temperature distribution, and the like in the longitudinal direction of the optical fiber. As a reference of this method, there is “Opto News” 1996, No. 6, PP29-31.
【０００５】以上は、１次元の分布型センシング方法で
あるが、２次元、３次元の分布型センシング方法として
次の公知例がある。The above is a one-dimensional distributed sensing method. There are the following known examples of two-dimensional and three-dimensional distributed sensing methods.
【０００６】（３）光ファイババンドルを用いた３次元
分布型センシング方法 図５に示されるように、この方法では、複数本の光ファ
イバ３３に光を入射し、これらの光を複数の測定点３２
で１本の光ファイバ３１に分岐（合成）し、１次元の分
布センサとして立体的な分布計測を行う。(3) Three-dimensional distributed sensing method using optical fiber bundles As shown in FIG. 5, in this method, light is incident on a plurality of optical fibers 33 and these lights are transmitted to a plurality of measurement points. 32
Branch (combine) into one optical fiber 31, and perform three-dimensional distribution measurement as a one-dimensional distribution sensor.
【０００７】[0007]
【発明が解決しようとする課題】上記従来技術には、次
のような問題点がある。The above prior art has the following problems.
【０００８】（１）ラマン散乱を用いた分布型温度計測 （ａ）散乱光を利用するために入射光パワーを上げる必
要がある。特に、光ファイバとの整合性を考慮し、１μ
ｍ前後の波長を利用すると散乱光はさらに微弱となる。
精度の高い計測を行うために、入射光パワーを上げる
と、光源に負担がかかり、信頼性に欠けることになる。
また、入射光パワーを補正するための回路が複雑とな
り、コスト高となる。(1) Distributed temperature measurement using Raman scattering (a) In order to use scattered light, it is necessary to increase the incident light power. In particular, considering the compatibility with the optical fiber, 1μ
When a wavelength of about m is used, the scattered light is further weakened.
Increasing the incident light power in order to perform highly accurate measurement imposes a burden on the light source, resulting in a lack of reliability.
Further, a circuit for correcting the incident light power becomes complicated, and the cost increases.
【０００９】（ｂ）センサ用光ファイバが１本の光ファ
イバで構成され、光を伝送する光ファイバ自体がセンサ
であることにより、光ファイバに事故（断線等）が発生
すると、光ファイバ全体を取り換えねばならず、保守が
困難であると共に事故からの復旧に時間がかかる。(B) Since the optical fiber for the sensor is composed of one optical fiber and the optical fiber for transmitting light itself is a sensor, if an accident (breakage or the like) occurs in the optical fiber, the entire optical fiber is replaced. It must be replaced, maintenance is difficult and it takes time to recover from the accident.
【００１０】（２）ＦＢＧを利用した分布型センサ この方法でも上記（１）の（ｂ）に共通した問題があ
る。そして、さらに （ａ）ＦＢＧを施した光ファイバで２〜３次元分布を測
定しようとすると、ＦＢＧ部分に外的歪みがかかり、こ
の外的歪みが時間的に変動し、測定しようとしている対
象とは異なる信号（雑音）が混入する可能性が大きい。
即ち、出力信号の信頼性が悪く、経年変化にも弱いこと
が予想される。(2) Distributed sensor using FBG This method also has a problem common to the above (1) (b). Further, (a) When trying to measure a two- or three-dimensional distribution with an optical fiber that has been subjected to FBG, external distortion is applied to the FBG portion, and this external distortion fluctuates over time. Is likely to be mixed with different signals (noise).
That is, it is expected that the reliability of the output signal is poor and the output signal is weak against aging.
【００１１】（ｂ）問題箇所の特定が困難である。(B) It is difficult to specify a problem part.
【００１２】（３）光ファイババンドルを用いた３次元
分布型センシング方法 （ａ）複数本の光ファイバに同時に光を入射するか、複
数の光源を必要とするため、前者では光源に負担がかか
り信頼性を欠き、後者ではコスト高になる。(3) Three-dimensional distributed sensing method using an optical fiber bundle (a) Light is incident on a plurality of optical fibers at the same time or a plurality of light sources are required. It lacks reliability and the latter is costly.
【００１３】そこで、本発明の目的は、上記課題を解決
し、２次元、３次元の分布センシングが可能で、事故時
の復旧が容易で、信頼性が高く、構成が簡素な分布型物
理量計測方法及び計測装置を提供することにある。[0013] Accordingly, an object of the present invention is to solve the above-mentioned problems, to enable two-dimensional and three-dimensional distributed sensing, to easily recover from an accident, to have high reliability, and to have a simple configuration of distributed physical quantity measurement. It is to provide a method and a measuring device.
【００１４】[0014]
【課題を解決するための手段】上記目的を達成するため
に本発明の方法は、広帯域波長の光を発する励起光源
と、光の波長毎にセンシングゾーンを割り当てる光ファ
イバとを用いた分布型物理量計測方法において、前記セ
ンシングゾーンにＦＢＧを施したセンシング光ファイバ
を用い、このセンシング光ファイバの一端を開放して反
射型とし、反対端をアドアンドドロップ機能を有するア
ドアンドドロップフィルタに接続し、各センシングゾー
ンの数に相当する数のアドアンドドロップフィルタを幹
線用光ファイバで多段に接続し、初段の幹線用光ファイ
バに波長無依存スプリッタを接続し、前記励起光源から
の広帯域波長励起光を初段及びその後段の幹線用光ファ
イバに導き、各センシング光ファイバで反射されて初段
の幹線用光ファイバから戻ってくる信号光を波長分離フ
ィルタに導くようにしたものである。In order to achieve the above object, a method according to the present invention is directed to a distributed physical quantity using an excitation light source for emitting light of a wide wavelength band and an optical fiber for allocating a sensing zone for each wavelength of light. In the measurement method, using a sensing optical fiber having an FBG applied to the sensing zone, one end of the sensing optical fiber is opened to be a reflection type, and the other end is connected to an add-and-drop filter having an add-and-drop function. A number of add-and-drop filters corresponding to the number of sensing zones are connected in multiple stages with a mainline optical fiber, a wavelength-independent splitter is connected to the first-stage mainline optical fiber, and a broadband wavelength pumping light from the pumping light source is connected to the first-stage. And the main optical fiber for the first stage, which is guided to the optical fiber for the main line of the subsequent stage and reflected by each sensing optical fiber, The signal light returned et is obtained so as to guide the wavelength separation filter.
【００１５】前記アドアンドドロップフィルタは、幹線
用光ファイバを伝達してくる励起光から一つの波長の励
起光を当該段のセンシング光ファイバに分岐し、残りの
波長の励起光を次段の幹線用光ファイバに入射させても
よい。The add-and-drop filter branches the pump light of one wavelength from the pump light transmitted through the main optical fiber to the sensing optical fiber of the corresponding stage, and converts the pump light of the remaining wavelength into the main line of the next stage. May be incident on the optical fiber for use.
【００１６】前記幹線用光ファイバが、波長多重による
送信電力増大による非線形光学効果を十分抑制できるよ
う、一定の分散値を有する光ファイバであってもよい。The optical fiber for the trunk line may be an optical fiber having a constant dispersion value so that a nonlinear optical effect due to an increase in transmission power due to wavelength multiplexing can be sufficiently suppressed.
【００１７】前記ＦＢＧの中心波長が前記アドアンドド
ロップフィルタの選択波長であってもよい。[0017] The center wavelength of the FBG may be a selected wavelength of the add-and-drop filter.
【００１８】前記励起光がスーパコンデニアム光であっ
てもよい。[0018] The excitation light may be super-condensium light.
【００１９】また、本発明の装置は、広帯域波長の光を
発する励起光源に波長無依存スプリッタを介して初段の
幹線用光ファイバを接続し、その初段の幹線用光ファイ
バにアドアンドドロップフィルタを接続し、そのアドア
ンドドロップフィルタの選択波長出力側にその選択波長
を中心波長とするＦＢＧを施した反射型のセンシング光
ファイバを接続し、前記アドアンドドロップフィルタの
非選択波長出力側には、後段の幹線用光ファイバを介し
て選択波長の異なるアドアンドドロップフィルタを順次
接続し、各アドアンドドロップフィルタの選択波長出力
側に、それぞれの選択波長を中心波長とするＦＢＧを施
した反射型のセンシング光ファイバを接続し、前記波長
無依存スプリッタにより各センシング光ファイバで反射
されて初段の幹線用光ファイバから戻ってくる信号光を
波長分離フィルタに導くようにしたものである。Further, in the apparatus of the present invention, a first-stage trunk optical fiber is connected to a pump light source that emits light of a broadband wavelength via a wavelength-independent splitter, and an add-and-drop filter is connected to the first-stage trunk fiber. Connected to the selected wavelength output side of the add-and-drop filter, and connected to a reflection-type sensing optical fiber provided with FBG having the selected wavelength as the center wavelength, and to the non-selected wavelength output side of the add-and-drop filter, Add-and-drop filters having different selected wavelengths are sequentially connected via the optical fiber for the trunk line at the subsequent stage, and a reflection-type FBG having the selected wavelength as the center wavelength is applied to the selected wavelength output side of each add-and-drop filter. Connect the sensing optical fiber, and the main line of the first stage is reflected by each sensing optical fiber by the wavelength-independent splitter. The signal light returning from the optical fiber is obtained by the guided to the wavelength separation filter.
【００２０】[0020]
【発明の実施の形態】以下、本発明の一実施形態を添付
図面に基づいて詳述する。An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.
【００２１】図１に示されるように、本発明に係る分布
型物理量計測装置は、広帯域波長の光を発する励起光源
と、その励起光を伝送する幹線用光ファイバを長手方向
に区画して光の波長毎にセンシングゾーンを割り当てる
光ファイバとを用いた分布型物理量計測装置であって、
広帯域波長の光を発する励起光源４０１に波長無依存ス
プリッタ（波長無依存２×１光スプリッタ）４０２を介
して初段の幹線用光ファイバ４００を接続し、その初段
の幹線用光ファイバ４００にアドアンドドロップ(Add a
nd Drop)機能を有する波長選択フィルタであるアドアン
ドドロップフィルタ４１１を接続し、そのアドアンドド
ロップフィルタ４１１の選択波長出力側にその選択波長
λ1 を中心波長とするＦＢＧ（ＦＢＧ1 ）を施し一端を
開放した反射型のセンシング光ファイバ４２０の反対端
を接続することにより、波長λ1を初段のセンシングゾ
ーンに割当て、前記アドアンドドロップフィルタ４１１
の非選択波長出力側には、後段の幹線用光ファイバ４０
０を介して選択波長の異なるアドアンドドロップフィル
タ４１２，…，４１Ｎ−１，４１Ｎを順次接続し、各ア
ドアンドドロップフィルタの選択波長出力側に、それぞ
れの選択波長を中心波長とするＦＢＧ（ＦＢＧ2 〜ＦＢ
ＧN ）を施した反射型のセンシング光ファイバ４２２，
…，４２Ｎ−１，４２Ｎを接続することにより、各波長
を各段のセンシングゾーンに割当て、前記波長無依存ス
プリッタ４０２により各センシング光ファイバ４２１〜
４２Ｎで反射されて初段の幹線用光ファイバ４００から
戻ってくる信号光をＡＷＧ(Arrayd Waveguide Grating)
からなる波長分離フィルタ４０４に導くようにしたもの
である。As shown in FIG. 1, the distributed physical quantity measuring apparatus according to the present invention comprises an excitation light source that emits light of a broadband wavelength, and a main optical fiber that transmits the excitation light, divided in the longitudinal direction. A distributed physical quantity measurement device using an optical fiber that allocates a sensing zone for each wavelength of
A first-stage trunk optical fiber 400 is connected to a pump light source 401 that emits light of a broadband wavelength via a wavelength-independent splitter (wavelength-independent 2 × 1 optical splitter) 402, and is added to the first-stage trunk optical fiber 400. Drop (Add a
An add-and-drop filter 411, which is a wavelength selection filter having an nd drop function, is connected to the selected wavelength output side of the add-and-drop filter 411, and an FBG (FBG 1 ) having the selected wavelength λ 1 as a center wavelength is applied. The wavelength λ 1 is assigned to the first-stage sensing zone by connecting the opposite end of the reflection-type sensing optical fiber 420 having the open end, and the add-and-drop filter 411 is connected.
The non-selected wavelength output side has a main optical fiber 40
, 41N-1, 41N of different selection wavelengths are sequentially connected via the FBG0, and the selected wavelength output side of each add-and-drop filter is connected to an FBG (FBG) having the selected wavelength as a center wavelength. 2 to FB
G N ) reflection type sensing optical fiber 422,
, 42N-1, 42N are connected to assign each wavelength to the sensing zone of each stage, and the sensing optical fibers 421 to 421 are connected by the wavelength-independent splitter 402.
AWG (Arrayed Waveguide Grating) converts the signal light reflected by 42N and returned from the first-stage main optical fiber 400 to AWG (Arrayed Waveguide Grating).
This is led to a wavelength separation filter 404 consisting of:
【００２２】本発明では、単一ファイバ方式の問題を解
決するために、一連の幹線用光ファイバ４００の長手方
向に配置されたセンシングゾーンの数に相当する数のア
ドアンドドロップフィルタ（光アドアンドドロップ回路
とも言う）４１１〜４１Ｎを幹線用光ファイバ４００に
多段に挿入し、各段にてドロップ波長の光をセンシング
光ファイバ４２１〜４２Ｎに入射させてＦＢＧからの反
射光をアドアンドドロップフィルタ４１１〜４１Ｎのア
ド機能を用いて幹線用光ファイバ４００の前段方向に伝
搬する波として戻す。このようにして各アドアンドドロ
ップフィルタ４１１〜４１Ｎで異なる波長の光をその波
長をブラッグ中心波長とするＦＢＧにドロップし、各Ｆ
ＢＧからの反射光を幹線用光ファイバ４００にアドして
戻し、光源側（前段方向）に伝搬させる。各ＦＢＧから
の波長の異なる光は、初段の幹線用光ファイバ４００と
励起光源４０１との間に設けた波長無依存スプリッタ４
０２を介し波長分離フィルタ４０４により分波し、この
分波された光を図示しない分析装置で受光して信号を解
析する。分析装置では、各ＦＢＧで受けた波長変化をス
ペクトル分析法や振幅変化計測法などにより計測し、そ
の計測結果から各センシングゾーンにおける物理量を求
める。尚、波長分離フィルタ４０４に入射される光を光
増幅するために、エルビウム添加光ファイバ増幅器（Ｅ
ＤＦＡ）４０３を設けてもよい。In the present invention, in order to solve the problem of the single fiber system, a number of add-and-drop filters (optical add-and-drop filters) corresponding to the number of sensing zones arranged in the longitudinal direction of the series of main optical fibers 400 are used. 411-41N are inserted into the main optical fiber 400 in multiple stages, and light of the drop wavelength is made incident on the sensing optical fibers 421-42N at each stage, and reflected light from the FBG is added and dropped by the add-and-drop filter 411. Using the add function of .about.41N, the signal is returned as a wave propagating in the direction preceding the main optical fiber 400. In this way, light of different wavelengths is dropped by each of the add-and-drop filters 411 to 41N to the FBG having that wavelength as the Bragg center wavelength, and
The reflected light from the BG is added back to the main optical fiber 400 and propagated to the light source side (front direction). Light of different wavelengths from each FBG is supplied to a wavelength-independent splitter 4 provided between the first-stage trunk optical fiber 400 and the pump light source 401.
The signal is then separated by a wavelength separation filter 404 via an optical filter 02, and the separated light is received by an analyzer (not shown) to analyze a signal. In the analyzer, the wavelength change received by each FBG is measured by a spectrum analysis method, an amplitude change measurement method, or the like, and a physical quantity in each sensing zone is obtained from the measurement result. In order to optically amplify the light incident on the wavelength separation filter 404, an erbium-doped optical fiber amplifier (E
DFA) 403 may be provided.
【００２３】この構成において、幹線用光ファイバ４０
０は、高パワーの光が送信されても非線形効果による影
響を受けがたい、ある分散値を有する光ファイバである
ことが望ましく、低損失性を考慮するなら、波長は１．
５５μｍ帯で選択し、分散スロープは小さくしても、ゼ
ロ分散点を避けて使用することが望ましい。また、アド
アンドドロップフィルタ４１１〜４１Ｎは、次に述べる
ように、ＡＷＧを２個接続した３端子を有する１×２光
導波路形回路でもよい。また、励起光はスーパコンデニ
アム光であってもよい。In this configuration, the trunk optical fiber 40
0 is desirably an optical fiber having a certain dispersion value that is hardly affected by nonlinear effects even when high-power light is transmitted, and the wavelength is 1.
It is desirable to select a wavelength in the 55 μm band and avoid the zero dispersion point, even if the dispersion slope is small. Further, as described below, the add-and-drop filters 411 to 41N may be 1 × 2 optical waveguide circuits having three terminals to which two AWGs are connected. Also, the excitation light may be super-condensed light.
【００２４】次に、アドアンドドロップフィルタ（光ア
ドアンドドロップ回路）について説明する。図２に示さ
れるように、アドアンドドロップフィルタは、２つのＡ
ＷＧフィルタ５０１，５０２をガラス導波路５１上に形
成し、一方のＡＷＧフィルタ５０１を分波器とし、他方
のＡＷＧフィルタ５０２を合波器とし、ＡＷＧフィルタ
５０１で分波した１つの波長の光をドロップ信号として
出力できるよう構成したものである。即ち、複数の波長
λ1 〜λN を含む広帯域波長の励起光が入力される入力
側には分波器であるＡＷＧフィルタ５０１の入力端を使
用し、ＡＷＧフィルタ５０１の複数の出力端のうち１つ
の所望の波長λi の出力端を選択波長出力側に使用し、
残りの出力端を合波器であるＡＷＧフィルタ５０２の各
入力端に接続し、ＡＷＧフィルタ５０２の出力端を非選
択波長出力側に使用する。これにより、前述のアド機能
及びドロップ機能、即ち、アドアンドドロップ機能が実
現される。Next, an add-and-drop filter (optical add-and-drop circuit) will be described. As shown in FIG. 2, the add-and-drop filter has two A
The WG filters 501 and 502 are formed on the glass waveguide 51, one AWG filter 501 is used as a demultiplexer, and the other AWG filter 502 is used as a multiplexer, and light of one wavelength demultiplexed by the AWG filter 501 is output. It is configured so that it can be output as a drop signal. That is, the input end of the AWG filter 501, which is a demultiplexer, is used on the input side to which the excitation light of a wide band wavelength including a plurality of wavelengths λ 1 to λ N is input, and among the plurality of output ends of the AWG filter 501, Using the output end of one desired wavelength λ i on the selected wavelength output side,
The remaining output terminals are connected to the respective input terminals of the AWG filter 502, which is a multiplexer, and the output terminal of the AWG filter 502 is used for the non-selected wavelength output side. As a result, the above-described add function and drop function, that is, the add-and-drop function is realized.
【００２５】図１の分布型物理量計測装置の作用を説明
する。The operation of the distributed physical quantity measuring device shown in FIG. 1 will be described.
【００２６】励起光源４０１からの光は波長無依存スプ
リッタ４０２を介して幹線用光ファイバ４００に入射す
る。この光は、各センシングゾーンのアドアンドドロッ
プフィルタ４１１〜４１Ｎにおいて、それぞれに接続さ
れたセンシング光ファイバ４２１〜４２Ｎの各ＦＢＧの
ブラッグ波長λ1 〜λN の光が選択されて分岐される。
各センシングゾーンにおいて、ＦＢＧに歪みや温度が印
加されていると、ブラッグシフトΔλB1〜ΔλBNを受け
た光λ´1 〜λ´N がアドアンドドロップフィルタ４１
１〜４１Ｎを介して幹線用光ファイバ４００に戻され、
後方（前段方向）に伝搬する。この光は、波長無依存ス
プリッタ４０２で分岐され、光増幅器４０３で増幅され
た後、波長分離フィルタ４０４で分波され、図示しない
分析装置に出力される。The light from the excitation light source 401 is incident on the main optical fiber 400 via the wavelength-independent splitter 402. This light is divided at the add-and-drop filters 411 to 41N of the respective sensing zones by selecting the light of the Bragg wavelengths λ 1 to λ N of the respective FBGs of the connected sensing optical fibers 421 to 42N.
In each sensing zone, when strain or temperature is applied to the FBG, the light λ ′ 1 to λ ′ N that have received the Bragg shifts Δλ B1 to Δλ BN are added to the add-and-drop filter 41.
It is returned to the main optical fiber 400 through 1-41N,
Propagation backward (front direction). This light is split by a wavelength-independent splitter 402, amplified by an optical amplifier 403, demultiplexed by a wavelength separation filter 404, and output to an analyzer (not shown).
【００２７】以上の実施形態では、アドアンドドロップ
フィルタは、１つの波長の光をドロップするように構成
したが、複数波長の光をドロップするように構成しても
よく、このアドアンドドロップフィルタに複数のＦＢＧ
を形成したセンシング光ファイバを接続してもよい。こ
れにより、２次元、３次元の分布センシングが可能とな
る。In the above embodiment, the add-and-drop filter is configured to drop light of one wavelength. However, the add-and-drop filter may be configured to drop light of multiple wavelengths. Multiple FBGs
May be connected. This enables two-dimensional and three-dimensional distribution sensing.
【００２８】また、各センシングゾーンに設けるセンサ
は、ＦＢＧを用いたセンシング光ファイバに限らず、例
えば、光式のパッシブセンサを用いて電界センサ、電流
センサ、流速センサを構成してもよい。そして、光で計
測を行う複数の種類（物理量）のセンサを各センシング
ゾーンに設け、波長分波した光に各々の物理量の情報を
担持させ、図示しない分析装置において、センサ種類に
応じた信号処理を行うように構成するとよい。The sensors provided in each sensing zone are not limited to sensing optical fibers using FBGs. For example, electric field sensors, current sensors, and flow rate sensors may be formed using optical passive sensors. A plurality of types (physical quantities) of sensors that measure with light are provided in each sensing zone, and information of each physical quantity is carried by the wavelength-division light. It is good to be constituted to perform.
【００２９】本発明の分布型物理量計測装置は、火山周
辺や海溝に埋め込むことにより、その埋設地域における
歪みや温度などの物理量分布を計測し、地震予知、噴火
予知などに利用することが可能である。The distributed physical quantity measuring device of the present invention can be used for earthquake prediction, eruption prediction, and the like by measuring the physical quantity distribution such as strain and temperature in the buried area by embedding it in the vicinity of a volcano or a trench. is there.
【００３０】[0030]
【発明の効果】本発明は次の如き優れた効果を発揮す
る。The present invention exhibits the following excellent effects.
【００３１】（１）従来技術で用いていた散乱光ではな
く、センシング光ファイバからの反射光を受光している
ので、光源のパワーを大きくしなくても正確な計測が可
能になり、光源の信頼性を損ねることなくシステム全体
の信頼性を向上させることができる。(1) Since the reflected light from the sensing optical fiber is received instead of the scattered light used in the prior art, accurate measurement can be performed without increasing the power of the light source. The reliability of the entire system can be improved without impairing the reliability.
【００３２】（２）幹線用光ファイバから複数のセンシ
ング光ファイバを分岐した構成であるため、一部のセン
シング光ファイバに事故が発生しても、その事故箇所だ
けセンシング光ファイバを取り換えれば復旧することに
なり、保守が容易である。(2) Since a plurality of sensing optical fibers are branched from the trunk optical fiber, even if an accident occurs in some of the sensing optical fibers, it can be restored by replacing the sensing optical fiber only at the point of the accident. Maintenance is easy.
【００３３】（３）センシングゾーンを波長で区別でき
るので、区間標定が容易である。(3) Since the sensing zones can be distinguished by wavelength, section location is easy.
【００３４】（４）センシングゾーンには様々な光応用
センサを設置できるので、多様性、拡張性を有し、基本
ライン（幹線用光ファイバ及びアドアンドドロップフィ
ルタ）を布設しておけば、様々な光応用センサを設置
し、波長分離フィルタの先に適宜な分析装置を設置すれ
ば、様々な物理量の計測が可能である。(4) Since various optical sensors can be installed in the sensing zone, it has versatility and expandability, and if a basic line (optical fiber for trunk line and add-and-drop filter) is laid, various sensors can be installed. If various optical applied sensors are installed and an appropriate analyzer is installed in front of the wavelength separation filter, various physical quantities can be measured.
【００３５】（５）構成が簡素であり、しかも、上述の
ように信頼性が高く、保守が容易であることから、トー
タルコスト、保守コストの低減を図ることができる。(5) Since the configuration is simple, and the reliability is high and the maintenance is easy as described above, the total cost and the maintenance cost can be reduced.
【図１】本発明の一実施形態を示す分布型物理量計測装
置の構成図である。FIG. 1 is a configuration diagram of a distributed physical quantity measurement device according to an embodiment of the present invention.
【図２】本発明に用いるアドアンドドロップフィルタの
構成図である。FIG. 2 is a configuration diagram of an add-and-drop filter used in the present invention.
【図３】従来の分布型物理量計測装置の構成図である。FIG. 3 is a configuration diagram of a conventional distributed physical quantity measurement device.
【図４】従来の分布型物理量計測装置の構成図である。FIG. 4 is a configuration diagram of a conventional distributed physical quantity measurement device.
【図５】従来の分布型物理量計測装置の構成図である。FIG. 5 is a configuration diagram of a conventional distributed physical quantity measurement device.
４００ 幹線用光ファイバ ４０１ 励起光源 ４０２ 波長無依存スプリッタ ４０３ 光増幅器 ４０４ 波長分離フィルタ ４１１〜４１Ｎ アドアンドドロップフィルタ ４２１〜４２Ｎ センシング光ファイバ Reference Signs List 400 Optical fiber for trunk line 401 Excitation light source 402 Wavelength-independent splitter 403 Optical amplifier 404 Wavelength separation filter 411-41N Add-and-drop filter 421-42N Sensing optical fiber
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） // Ｇ０１Ｖ 1/00 Ｇ０１Ｄ 3/04 Ｚ Ｆターム(参考） 2F056 VF02 VF11 2F075 AA10 2F103 BA10 BA41 BA43 BA49 CA07 EB05 EB11 EC09 EC10 ED01 ED37 2G020 AA03 BA20 CA03 CB42 CC02 CD03 CD12 CD22 2H038 AA07 CA31 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI theme coat ゛ (reference) // G01V 1/00 G01D 3/04 Z F term (reference) 2F056 VF02 VF11 2F075 AA10 2F103 BA10 BA41 BA43 BA49 CA07 EB05 EB11 EC09 EC10 ED01 ED37 2G020 AA03 BA20 CA03 CB42 CC02 CD03 CD12 CD22 2H038 AA07 CA31
Claims (6)
の波長毎にセンシングゾーンを割り当てる光ファイバと
を用いた分布型物理量計測方法において、前記センシン
グゾーンに光ファイバブラッググレーティング（以下、
ＦＢＧと言う）を施した光ファイバ（以下、センシング
光ファイバという）を用い、このセンシング光ファイバ
の一端を開放して反射型とし、反対端をアドアンドドロ
ップ機能を有する波長選択フィルタ（以下、アドアンド
ドロップフィルタという）に接続し、各センシングゾー
ンの数に相当する数のアドアンドドロップフィルタを幹
線用光ファイバで多段に接続し、初段の幹線用光ファイ
バに波長無依存スプリッタを接続し、前記励起光源から
の広帯域波長励起光を初段及びその後段の幹線用光ファ
イバに導き、各センシング光ファイバで反射されて初段
の幹線用光ファイバから戻ってくる信号光を波長分離フ
ィルタに導くようにしたことを特徴とする分布型物理量
計測方法。In a distributed physical quantity measurement method using an excitation light source that emits light of a broadband wavelength and an optical fiber that allocates a sensing zone for each wavelength of light, an optical fiber Bragg grating (hereinafter, referred to as “the optical fiber Bragg grating”) is provided in the sensing zone.
An optical fiber (hereinafter referred to as a sensing optical fiber) to which an FBG is applied is used. One end of the sensing optical fiber is opened to be a reflection type, and the other end is provided with a wavelength selection filter (hereinafter referred to as an add-and-drop function) having an add-and-drop function. And a number of add-and-drop filters corresponding to the number of each sensing zone are connected in multiple stages by a trunk optical fiber, and a wavelength-independent splitter is connected to the first-stage trunk optical fiber. The broadband wavelength pumping light from the pumping light source is guided to the first and subsequent trunk optical fibers, and the signal light reflected from each sensing optical fiber and returned from the first trunk optical fiber is guided to the wavelength separation filter. A distributed physical quantity measurement method, characterized in that:
線用光ファイバを伝達してくる励起光から一つの波長の
励起光を当該段のセンシング光ファイバに分岐し、残り
の波長の励起光を次段の幹線用光ファイバに入射させる
ことを特徴とする請求項１記載の分布型物理量計測方
法。2. The add-and-drop filter according to claim 1, wherein the pump light of one wavelength is branched from the pump light transmitted through the main optical fiber to the sensing optical fiber of the corresponding stage, and the pump light of the remaining wavelength is transmitted to the next stage. 2. The distributed physical quantity measuring method according to claim 1, wherein the light is incident on the main optical fiber.
る送信電力増大による非線形光学効果を十分抑制できる
よう、一定の分散値を有する光ファイバであることを特
徴とする請求項１又は２記載の分布型物理量計測方法。3. The optical fiber according to claim 1, wherein the trunk optical fiber is an optical fiber having a constant dispersion value so as to sufficiently suppress a nonlinear optical effect due to an increase in transmission power due to wavelength multiplexing. Distributed physical quantity measurement method.
ドロップフィルタの選択波長であることを特徴とする請
求項１〜３いずれか記載の分布型物理量計測方法。4. The distributed physical quantity measurement method according to claim 1, wherein a center wavelength of the FBG is a selected wavelength of the add-and-drop filter.
ることを特徴とする請求項１〜４いずれか記載の分布型
物理量計測方法。5. The distributed physical quantity measurement method according to claim 1, wherein said excitation light is super-condensed light.
無依存スプリッタを介して初段の幹線用光ファイバを接
続し、その初段の幹線用光ファイバにアドアンドドロッ
プフィルタを接続し、そのアドアンドドロップフィルタ
の選択波長出力側にその選択波長を中心波長とするＦＢ
Ｇを施した反射型のセンシング光ファイバを接続し、前
記アドアンドドロップフィルタの非選択波長出力側に
は、後段の幹線用光ファイバを介して選択波長の異なる
アドアンドドロップフィルタを順次接続し、各アドアン
ドドロップフィルタの選択波長出力側に、それぞれの選
択波長を中心波長とするＦＢＧを施した反射型のセンシ
ング光ファイバを接続し、前記波長無依存スプリッタに
より各センシング光ファイバで反射されて初段の幹線用
光ファイバから戻ってくる信号光を波長分離フィルタに
導くようにしたことを特徴とする分布型物理量計測装
置。6. A first-stage trunk optical fiber is connected to a pump light source that emits light of a broadband wavelength via a wavelength-independent splitter, and an add-and-drop filter is connected to the first-stage trunk optical fiber. FB with the selected wavelength as the center wavelength on the selected wavelength output side of the drop filter
A reflection type sensing optical fiber provided with G is connected, and add-and-drop filters having different selected wavelengths are sequentially connected to a non-selection wavelength output side of the add-and-drop filter via a post-stage main-line optical fiber, A reflection type sensing optical fiber provided with an FBG having the selected wavelength as a center wavelength is connected to the selected wavelength output side of each add-and-drop filter, and the first stage is reflected by each sensing optical fiber by the wavelength-independent splitter. Wherein the signal light returned from the main optical fiber is guided to a wavelength separation filter.
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