JPH02140640A - Backscattering light measuring instrument - Google Patents
Backscattering light measuring instrumentInfo
- Publication number
- JPH02140640A JPH02140640A JP29413688A JP29413688A JPH02140640A JP H02140640 A JPH02140640 A JP H02140640A JP 29413688 A JP29413688 A JP 29413688A JP 29413688 A JP29413688 A JP 29413688A JP H02140640 A JPH02140640 A JP H02140640A
- Authority
- JP
- Japan
- Prior art keywords
- light
- measured
- optical
- path length
- optical waveguide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 claims abstract description 55
- 238000005259 measurement Methods 0.000 claims abstract description 6
- 239000000835 fiber Substances 0.000 abstract description 9
- 238000010586 diagram Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000002789 length control Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
- G01M11/31—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter and a light receiver being disposed at the same side of a fibre or waveguide end-face, e.g. reflectometers
- G01M11/3172—Reflectometers detecting the back-scattered light in the frequency-domain, e.g. OFDR, FMCW, heterodyne detection
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
Abstract
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は光導波路の障害点の探索に利用する。[Detailed description of the invention] [Industrial application field] The present invention is used to search for failure points in optical waveguides.
特に、光導波路内で生じる後方散乱光を高精度で測定す
る装置に関する。In particular, the present invention relates to a device that measures backscattered light generated within an optical waveguide with high precision.
本発明は、先導波路内で生じた後方散乱光に参照光を干
渉させることにより後方散乱光を測定する装置において
、参照光の光路に複数の反射鏡を配置して反射光路長を
制御することにより、長尺の光導波路について測定可能
とするものである。The present invention provides an apparatus for measuring backscattered light by interfering a reference light with backscattered light generated in a leading waveguide, in which a plurality of reflecting mirrors are arranged in the optical path of the reference light to control the length of the reflected optical path. This makes it possible to measure long optical waveguides.
第４図は従来例後方散乱光測定装置の構成を示す。 FIG. 4 shows the configuration of a conventional backscattered light measuring device.
光源１からの出射光は、ファイバ形光結合器２により二
つに分割される。分割された一方は、全反射鏡４により
反射され、これが参照光として利用される。分割された
他方は、被測定光導波路３に入射する。被測定先導波路
３内で生じた後方散乱光は、再びファイバ形光結合器２
に入射し、先の参照光と合波される。この合波光はレン
ズ５により平行ビームとなり、ビームスプリッタ６およ
びプリズム７．８により構成されるマイケルソン干渉計
に入射する。The light emitted from the light source 1 is split into two by a fiber type optical coupler 2. One of the divided beams is reflected by a total reflection mirror 4, and is used as a reference beam. The other divided part enters the optical waveguide 3 to be measured. The backscattered light generated within the guided waveguide 3 to be measured is returned to the fiber type optical coupler 2.
and is combined with the previous reference light. This combined light is turned into a parallel beam by a lens 5, and enters a Michelson interferometer constituted by a beam splitter 6 and a prism 7.8.
マイケルソン干渉計の入射光は、その一部がビームスプ
リッタ６を透過し、プリズム８で反射する。ビームスプ
リッタ６で反射された光は、プリズム７で反射し、プリ
ズム８で反射された光と合波され、光検出器９に入射す
る。Part of the incident light of the Michelson interferometer passes through the beam splitter 6 and is reflected by the prism 8. The light reflected by the beam splitter 6 is reflected by the prism 7 , is combined with the light reflected by the prism 8 , and enters the photodetector 9 .
プリズム７は移動台１０上をビーム方向に長さｌにわた
り移動することができる。また、ファイバ形光結合器２
から全反射鏡４への光路長と、被測定光導波路３への光
路長とは等しく設定されている。したがって、プリズム
７側のアームの長さがプリズム８側のアームの長さより
ｒだけ長ければ、被測定先導波路３．の入射端からｒ／
ｎ（ｎは被測定光導波路３の屈折率）の位置で生じた後
方散乱光を測定できる。The prism 7 can be moved over a length l on the moving table 10 in the beam direction. In addition, fiber type optical coupler 2
The optical path length from the to the total reflection mirror 4 and the optical path length to the optical waveguide 3 to be measured are set to be equal. Therefore, if the length of the arm on the prism 7 side is longer than the length of the arm on the prism 8 side by r, then the leading waveguide to be measured 3. r/ from the incident end of
Backscattered light generated at a position n (n is the refractive index of the optical waveguide 3 to be measured) can be measured.
しかし、機械的な精度の問題から、移動台によりプリズ
ムを移動させることのできる長さｌは通常は２０ｃｍが
限度である。このため、被測定光導波路のβ／ｎより先
の位置については後方散乱光を測定できない欠点があっ
た。However, due to problems with mechanical accuracy, the length l over which the prism can be moved by the moving table is usually limited to 20 cm. Therefore, there is a drawback that backscattered light cannot be measured at a position beyond β/n of the optical waveguide to be measured.
本発明は、以上の問題点を解決し、測定可能な長さの限
界を取り除いて長尺の先導波路についても後方散乱光を
測定できる装置を提供することを目的とする。SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide an apparatus that can measure backscattered light even for a long leading waveguide by removing the limit on the measurable length.
本発明の後方散乱光測定装置は、後方散乱光と参照光と
の光路長差を変化させるため、一以上の反射手段と、こ
の一以上の反射手段のそれぞれの反射方向を入射方向ま
たは次の反射手段の方向のいずれかに制御して反射光路
長を段階的に制御する角度制御手段とを含むことを特徴
とする。In order to change the optical path length difference between the backscattered light and the reference light, the backscattered light measuring device of the present invention includes one or more reflecting means, and the reflection direction of each of the one or more reflecting means is changed from the incident direction to the next direction. It is characterized by including an angle control means for controlling the reflection means in any direction to control the reflected optical path length stepwise.
後方散乱光と参照光との光路長差を変化させることによ
り、被測定光導波路内の異なる点で生じる後方散乱光を
測定できる。反射光路長を段階的に制御すると、被測定
光導波路内の測定範囲が段階に変化する。したがって、
反射手段を多数設けることにより、測定可能な範囲を大
幅に拡大できる。By changing the optical path length difference between the backscattered light and the reference light, backscattered light generated at different points within the optical waveguide to be measured can be measured. When the reflected optical path length is controlled stepwise, the measurement range within the optical waveguide to be measured changes stepwise. therefore,
By providing a large number of reflecting means, the measurable range can be greatly expanded.
第１図は本発明実施例後方散乱光測定装置のブロック構
成図である。FIG. 1 is a block diagram of a backscattered light measuring device according to an embodiment of the present invention.
この装置は、光源１を備え、この光源１の出射光を被測
定光導波路３に入射する入射手段および出射光から参照
光を分岐する光分岐手段としてファイバ形光結合器２を
備え、この参照光を被測定光導波路３の入射端に現れる
後方散乱光に合波する光合波手段としてビームスプリッ
タ６およびプリズム７．８を備え、後方散乱光と参照光
の光路長差を変化させる光路長差制御手段として移動台
１０を備え、ビームスプリッタ６の出力光により被測定
先導波路３からの後方散乱光の強度分布を求める信号処
理手段として光検出器９および信号処理部１５を備える
。This device includes a light source 1, a fiber-type optical coupler 2 as an input means for inputting light emitted from the light source 1 into an optical waveguide 3 to be measured, and an optical branching means for branching a reference light from the emitted light. A beam splitter 6 and a prism 7.8 are provided as optical combining means for combining light with backscattered light appearing at the input end of the optical waveguide 3 to be measured, and an optical path length difference that changes the optical path length difference between the backscattered light and the reference light. A movable table 10 is provided as a control means, and a photodetector 9 and a signal processing section 15 are provided as signal processing means for determining the intensity distribution of backscattered light from the guided waveguide 3 to be measured using the output light of the beam splitter 6.
ここで本実施例の特徴とするところは、光路長制御手段
にさらに、一以上の反射手段として全反射鏡４．１２．
１３．１４を備え、この一以上の全反射鏡４．１２．１
３．１４のそれぞれの反射方向を入射方向または次の反
射手段の方向のいずれかに制御して反射光路長を段階的
に制御する角度制御手段として角度制御部１６．１７．
１８．１９を備えたことにある。Here, the feature of this embodiment is that the optical path length control means further includes a total reflection mirror 4.12 as one or more reflection means.
13.14, the one or more total reflection mirrors 4.12.1
Angle control section 16.17.3.14 serves as an angle control means for controlling the reflection direction of each of 16.14 to either the incident direction or the direction of the next reflecting means to control the reflected optical path length stepwise.
18.19.
ファイバ形光結合器２の参照光出射端と全反射鏡４との
間、およびファイバ形光結合器２の合波光出射端とビー
ムスプリッタ６０間には、それぞれ対物レンズ１１およ
びレンズ５が配置される。An objective lens 11 and a lens 5 are arranged between the reference light output end of the fiber type optical coupler 2 and the total reflection mirror 4, and between the combined light output end of the fiber type optical coupler 2 and the beam splitter 60, respectively. Ru.
プリズム７の位置および全反射鏡４．１２．１３．１４
の角度は、信号処理部１５から移動台１０および角度制
御部１６．１７．１８．１９を制御することにより設定
される。Position of prism 7 and total reflection mirror 4.12.13.14
The angle is set by the signal processing unit 15 controlling the movable table 10 and the angle control units 16, 17, 18, and 19.
第２図はそれぞれの全反射鏡４．１２．１３．１４によ
り得られる測定範囲を示す。FIG. 2 shows the measurement range obtained by each total reflection mirror 4.12.13.14.
光源１からの出射光は、ファイバ形光結合器２により二
つに分割され、その一方は、対物レンズ１１により平行
ビームとなり、全反射鏡４．１２．１３または１４で反
射され、同じ経路をたどって再びファイバ形光結合器２
に入射する。The light emitted from the light source 1 is split into two by the fiber optic coupler 2, one of which is converted into a parallel beam by the objective lens 11, reflected by the total reflection mirror 4, 12, 13 or 14, and sent along the same path. Follow the fiber optic coupler 2 again.
incident on .
全反射鏡４の位置は、参照光がこの全反射鏡４で反射さ
れたときに、その光路長が被測定先導波路３の入射端に
おける反射光の光路長と等しくなるように設定される。The position of the total reflection mirror 4 is set so that when the reference light is reflected by the total reflection mirror 4, its optical path length is equal to the optical path length of the reflected light at the input end of the leading waveguide 3 to be measured.
したがって、ビームスプリッタ６およびプリズム７．８
によって構成されるマイケルソン干渉計の両アームの光
路長が一致したときに得られる信号は、被測定先導波路
３の入射端における反射を示す。また、移動台１０の最
大可動位置β（＝２０Ｃｍ）において得られる信号は、
被測定光導波路３の屈折率をｎとして、その入射端から
ｌ ／ ｎの位置における後方散乱光の強度を示す。Therefore, beam splitter 6 and prism 7.8
The signal obtained when the optical path lengths of both arms of the Michelson interferometer configured by the above coincide with each other indicates reflection at the input end of the leading waveguide 3 to be measured. Furthermore, the signal obtained at the maximum movable position β (=20Cm) of the moving table 10 is
Assuming that the refractive index of the optical waveguide 3 to be measured is n, the intensity of backscattered light at a position l/n from the input end is shown.
次に、全反射鏡４０反射方向を全反射鏡１２の方向とし
、全反射鏡１２が入射光を入射方向に反射するように設
定する。ここで、全反射鏡４と全反射鏡１２との間の光
路長をｌに設定しておく。このときには、マイケルソン
干渉計の両アームが一致したときに、被測定光導波路３
内のＩ！ ／ ｎの位置における後方散乱光を測定でき
る。また、移動台１０が最大可動位置βに移動したとき
には、ｆ！ ／ ｎ ＋１！ ／ ｎ ＝ ２ Ｘ ｌ
／ ｎの位置の後方散乱光を測定できる。移動台１０
がこの中間の位置にあるときには、それに対応して被測
定先導波路３内の！！／ｎないし２β／ｎの間の各点に
おける後方散乱光を測定できる。Next, the direction of reflection of the total reflection mirror 40 is the direction of the total reflection mirror 12, and the total reflection mirror 12 is set so as to reflect the incident light in the direction of incidence. Here, the optical path length between the total reflection mirror 4 and the total reflection mirror 12 is set to l. At this time, when both arms of the Michelson interferometer match, the optical waveguide to be measured 3
Inner I! / Backscattered light at the position n can be measured. Furthermore, when the movable table 10 moves to the maximum movable position β, f! / n +1! / n = 2 X l
/ Backscattered light at position n can be measured. Mobile platform 10
When is at this intermediate position, correspondingly ! in the leading waveguide 3 to be measured. ! Backscattered light at each point between /n and 2β/n can be measured.
以下同様にして、被測定先導波路３の測定可能範囲を増
加させることができる。In the same manner, the measurable range of the leading waveguide 3 to be measured can be increased.
全反射鏡４．１２．１３．１４による光路長変更の動作
を第３図に示す。FIG. 3 shows the operation of changing the optical path length by the total reflection mirror 4.12.13.14.
以上説明したように、本発明の後方散乱光測定装置は、
任意の長さの先導波路についてその内部で生じる後方孜
乱光を測定できる。本発明は、光集積回路その他におけ
る導波路長が長い回路について、障害点を高精度に探索
できる効果がある。As explained above, the backscattered light measuring device of the present invention includes:
It is possible to measure the back scattering light generated inside a leading waveguide of arbitrary length. INDUSTRIAL APPLICABILITY The present invention has the advantage of being able to search for fault points with high precision in optical integrated circuits and other circuits with long waveguide lengths.
第１図は本発明実施例後方散乱光測定装置の構成を示す
図。
第２図は測定範囲を示す図。
第３図は全反射鏡による光路長変更を示す図。
第４図は従来例後方散乱光測定装置の構成を示す図。
１・・・光源、２・・・ファイバ形光結合器、３・・・
被測定先導波路、４．１２．１３．１４・・・全反射鏡
、５・・・レンズ、６・・・ビームスプリッタ、７．８
・・・プリズム、９・・・光検出器、１０・・・移動台
、１１・・・対物レンズ、１５・・・信号処理部、１６
．１７．１８．１９・・・角度制御部。
特許出願人 日本電信電話株式会社
代理人 弁理士 井 出 直 孝
？Ｉ’１１ 回
間隔
測定範匠
菖 ２ ロ
（Ｑ）
光路長の変更
烹 ３ 回FIG. 1 is a diagram showing the configuration of a backscattered light measuring device according to an embodiment of the present invention. FIG. 2 is a diagram showing the measurement range. FIG. 3 is a diagram showing optical path length change using a total reflection mirror. FIG. 4 is a diagram showing the configuration of a conventional backscattered light measuring device. 1... Light source, 2... Fiber type optical coupler, 3...
Leading wavepath to be measured, 4.12.13.14... Total reflection mirror, 5... Lens, 6... Beam splitter, 7.8
... Prism, 9... Photodetector, 10... Moving table, 11... Objective lens, 15... Signal processing section, 16
．． 17.18.19... Angle control section. Patent applicant: Nippon Telegraph and Telephone Corporation Representative: Patent attorney Naotaka Ide? I'11 Interval measurement interval 2 B (Q) Optical path length change 3 times
Claims (1)
と、 前記出射光から参照光を分岐する光分岐手段と、この参
照光を前記被測定光導波路の入射端に現れる後方散乱光
に合波する光合波手段と、 前記後方散乱光と前記参照光の光路長差を変化させる光
路長差制御手段と、 前記光合波手段の出力光から前記被測定光導波路の長手
方向における後方散乱光の強度分布を求める信号処理手
段と を備えた後方散乱光測定装置において、 前記光路長差制御手段は、一以上の反射手段と、この一
以上の反射手段のそれぞれの反射方向を入射方向または
次の反射手段の方向のいずれかに制御して反射光路長を
段階的に制御する角度制御手段とを含む ことを特徴とする後方散乱光測定装置。[Scope of Claims] 1. A light source, an input means for inputting light emitted from the light source into the optical waveguide to be measured, an optical branching means for branching a reference light from the emitted light, and a light branching means for branching the reference light from the output light to the optical waveguide to be measured. an optical multiplexing means for combining backscattered light appearing at an input end of a wave path; an optical path length difference control means for changing an optical path length difference between the backscattered light and the reference light; In a backscattered light measuring device comprising a signal processing means for determining the intensity distribution of backscattered light in the longitudinal direction of a measurement optical waveguide, the optical path length difference control means includes one or more reflecting means and the one or more reflecting means. A backscattered light measuring device comprising: an angle control means for controlling the reflection direction of each of the above to either the incident direction or the direction of the next reflecting means to control the reflected optical path length stepwise.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29413688A JP2726882B2 (en) | 1988-11-21 | 1988-11-21 | Backscattered light measurement device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29413688A JP2726882B2 (en) | 1988-11-21 | 1988-11-21 | Backscattered light measurement device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02140640A true JPH02140640A (en) | 1990-05-30 |
| JP2726882B2 JP2726882B2 (en) | 1998-03-11 |
Family
ID=17803773
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29413688A Expired - Fee Related JP2726882B2 (en) | 1988-11-21 | 1988-11-21 | Backscattered light measurement device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2726882B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5268739A (en) * | 1990-12-04 | 1993-12-07 | Cise S.P.A. | Laser apparatus for measuring the velocity of a fluid |
| EP0669525A2 (en) * | 1994-02-25 | 1995-08-30 | France Telecom | Interferometrical system for detecting and localising reflective defects of light guide structures |
| US5500733A (en) * | 1992-07-27 | 1996-03-19 | France Telecom | Interferometric system for the detection and location of reflecting faults of light-guiding structures |
| WO1998043069A1 (en) * | 1997-03-26 | 1998-10-01 | Kowa Company, Ltd. | Optical measuring instrument |
| WO1998043068A1 (en) * | 1997-03-26 | 1998-10-01 | Kowa Company, Ltd. | Optical measuring instrument |
-
1988
- 1988-11-21 JP JP29413688A patent/JP2726882B2/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5268739A (en) * | 1990-12-04 | 1993-12-07 | Cise S.P.A. | Laser apparatus for measuring the velocity of a fluid |
| US5500733A (en) * | 1992-07-27 | 1996-03-19 | France Telecom | Interferometric system for the detection and location of reflecting faults of light-guiding structures |
| EP0669525A2 (en) * | 1994-02-25 | 1995-08-30 | France Telecom | Interferometrical system for detecting and localising reflective defects of light guide structures |
| FR2716722A1 (en) * | 1994-02-25 | 1995-09-01 | France Telecom | Interferometric system for detecting and locating defective reflective structures guiding light. |
| EP0669525A3 (en) * | 1994-02-25 | 1995-11-08 | France Telecom | Interferometrical system for detecting and localising reflective defects of light guide structures. |
| US5615011A (en) * | 1994-02-25 | 1997-03-25 | France Telecom | Interferometric system for the detection and location of reflector faults of light-guiding structures |
| WO1998043069A1 (en) * | 1997-03-26 | 1998-10-01 | Kowa Company, Ltd. | Optical measuring instrument |
| WO1998043068A1 (en) * | 1997-03-26 | 1998-10-01 | Kowa Company, Ltd. | Optical measuring instrument |
| US6198540B1 (en) | 1997-03-26 | 2001-03-06 | Kowa Company, Ltd. | Optical coherence tomography have plural reference beams of differing modulations |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2726882B2 (en) | 1998-03-11 |
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