JPS644612B2 - - Google Patents
Info
- Publication number
- JPS644612B2 JPS644612B2 JP13547081A JP13547081A JPS644612B2 JP S644612 B2 JPS644612 B2 JP S644612B2 JP 13547081 A JP13547081 A JP 13547081A JP 13547081 A JP13547081 A JP 13547081A JP S644612 B2 JPS644612 B2 JP S644612B2
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- optical
- pulse
- splice loss
- fiber
- 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.)
- Expired
Links
- 239000013307 optical fiber Substances 0.000 claims description 58
- 230000003287 optical effect Effects 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 4
- 239000000835 fiber Substances 0.000 description 5
- 238000007796 conventional method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000002834 transmittance Methods 0.000 description 3
- 230000002457 bidirectional effect Effects 0.000 description 1
- 238000005259 measurement 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
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
- Mechanical Coupling Of Light Guides (AREA)
- Light Guides In General And Applications Therefor (AREA)
Description
【発明の詳細な説明】
本発明は光フアイバの接続損失を測定する方法
に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring splice loss in optical fibers.
第１図は光フアイバの接続損失を測定する従来
の方法の一例を示す。第１図において、１は光源
で、２は光フアイバ、３は前記光フアイバに接続
された光フアイバ、４は前記二つの光フアイバの
接続点である。５は光パワーの検出器である。６
は接続点４の直前の光フアイバ２内の１点であ
る。従来は接続損失を測定するには、まずフアイ
バ３を通過した後の光パワーPjを光検出器５で測
定する。次に光フアイバ２を６の点で切断し、こ
の点での光パワーPiを検出器５で測定する。接続
損失をαとすると接続損失は
α＝10log10Pi／Pj（dB）
で算出される。ただし、この場合光フアイバ３の
長さが短く、その損失は無視し得る程度に小さい
と仮定している。 FIG. 1 shows an example of a conventional method for measuring splice loss of an optical fiber. In FIG. 1, 1 is a light source, 2 is an optical fiber, 3 is an optical fiber connected to the optical fiber, and 4 is a connection point between the two optical fibers. 5 is an optical power detector. 6
is a point in the optical fiber 2 immediately before the connection point 4. Conventionally, in order to measure splice loss, first the optical power P j after passing through the fiber 3 is measured with a photodetector 5 . Next, the optical fiber 2 is cut at a point 6, and the optical power P i at this point is measured by the detector 5. When the splice loss is α, the splice loss is calculated as α=10log 10 P i /P j (dB). However, in this case, it is assumed that the length of the optical fiber 3 is short and its loss is negligibly small.
一般に接続損失には方向性があるが、従来の方
法では、１回の測定で一方向の接続損失しか測定
できないという欠点があつた。 Generally, splice loss has directionality, but conventional methods have the disadvantage that splice loss can only be measured in one direction in one measurement.
本発明はこれらの欠点を除外するため、双方向
性を考慮した接続損失を測定できるように工夫し
たものである。以下図面により本発明を詳細に説
明する。 In order to eliminate these drawbacks, the present invention is devised so that connection loss can be measured in consideration of bidirectionality. The present invention will be explained in detail below with reference to the drawings.
第２図は本発明の一実施例図であつて、７はパ
ルス発振する光源、８はハーフミラー、２は光フ
アイバ、３は前記光フアイバに接続される光フア
イバ、９は光フアイバ２の終端、１０は光パルス
検出器、１１は光フアイバ２の終端と同様の切断
面をもつ光フアイバ３の終端である。 FIG. 2 is a diagram showing an embodiment of the present invention, in which 7 is a pulse-oscillating light source, 8 is a half mirror, 2 is an optical fiber, 3 is an optical fiber connected to the optical fiber, and 9 is the optical fiber 2. The terminal end 10 is an optical pulse detector, and 11 is the terminal end of the optical fiber 3 having a cut surface similar to the terminal end of the optical fiber 2.
第２図に示したP1〜P13はその点における光パ
ワーを示す。また、ハーフミラー８の反射率を
β、空気中から光フアイバへ、又は光フアイバか
ら空気中へ光が通過するときの光パワー透過率を
γ、光フアイバ２から光フアイバ３へ光が通過す
るときの透過率をt1、光フアイバ３から光フアイ
バ２へ光が通過するときの透過率をt2とする。 P 1 to P 13 shown in FIG. 2 indicate the optical power at that point. In addition, the reflectance of the half mirror 8 is β, the optical power transmittance when light passes from the air to the optical fiber or from the optical fiber to the air is γ, and the light passes from the optical fiber 2 to the optical fiber 3. The transmittance at this time is t 1 , and the transmittance when light passes from the optical fiber 3 to the optical fiber 2 is t 2 .
まず第２図ａにおいて、光フアイバ２の終端か
らの光パルスのパワーP7を、光パルス検出器１
０で測定すると、
P7＝P1γ2（１−γ）β ……(1)
と表わされる。次に第２図ｂのように、光フアイ
バ２に光フアイバ３を接続する。１１は光フアイ
バ３の終端であつて、光フアイバ２の終端面と同
様の切断面となつている。光フアイバ３の終端１
１から反射された光パルスのパワーP13を光パル
ス検出器１０で測定する。このときP13は次式で
表わされる。 First, in FIG. 2a, the power P7 of the optical pulse from the end of the optical fiber 2 is measured by the optical pulse detector 1.
When measured at 0, it is expressed as P 7 =P 1 γ 2 (1−γ) β (1). Next, as shown in FIG. 2b, the optical fiber 3 is connected to the optical fiber 2. 11 is the terminal end of the optical fiber 3, and has a cut surface similar to the terminal end surface of the optical fiber 2. Termination 1 of optical fiber 3
The power P 13 of the optical pulse reflected from the optical pulse detector 10 is measured by the optical pulse detector 10 . At this time, P 13 is expressed by the following formula.
P13＝P1γ2（１−γ）t1t2β ……(2) したがつて P13／P7＝t1t2 ……(3) の関係が得られる。 P 13 =P 1 γ 2 (1−γ) t 1 t 2 β ...(2) Therefore, the following relationship is obtained: P 13 /P 7 =t 1 t 2 ...(3).
第３図は時間的に分離された光パルスの一例を
示す図で、第３図ａはフアイバ２の入射端と終端
からの反射パルスS1，S2を示しており、第３図ｂ
はフアイバ２とフアイバ３を接続した際の入射
端、接続点、フアイバ３の終端からの反射パルス
S1，S2，S3を示している。L1は光フアイバ２の
長さ、L2は光フアイバ３の長さ、ｃは光速、ｎ
は光フアイバの屈折率である。第３図に示すよう
に反射パルス、S2とS3の間の時間は、2nL2／ｃ
である。この時間を考慮して反射パルスS2とS3を
測定する。 FIG. 3 is a diagram showing an example of temporally separated optical pulses, and FIG. 3a shows reflected pulses S 1 and S 2 from the input end and the terminal end of the fiber 2, and FIG.
is the reflected pulse from the input end, connection point, and end of fiber 3 when fiber 2 and fiber 3 are connected.
S 1 , S 2 , and S 3 are shown. L 1 is the length of optical fiber 2, L 2 is the length of optical fiber 3, c is the speed of light, n
is the refractive index of the optical fiber. As shown in Figure 3, the time between the reflected pulses, S 2 and S 3 , is 2nL 2 /c
It is. Reflection pulses S 2 and S 3 are measured taking this time into consideration.
したがつて第２図ｂに示す光フアイバ２と光フ
アイバ３の接続点の双方向平均の接続損失をα1と
すると、α1は次式で与えられる。 Therefore, if α 1 is the bidirectional average connection loss at the connection point between optical fiber 2 and optical fiber 3 shown in FIG. 2b, α 1 is given by the following equation.
α1＝−10／２log10P13／P7 ……(4)
よつてP7、P13を測定することにより、(4)式か
ら接続損失α1を求めることができる。 α 1 =−10/2log 10 P 13 /P 7 (4) Therefore, by measuring P 7 and P 13 , the splice loss α 1 can be determined from equation (4).
以上説明したように、本発明による光フアイバ
接続損失の測定方法は、接続点を含む光フアイバ
に光パルスを入射し、接続前後に光フアイバの終
端面からの反射パルスのパワーを測定することに
よつて、方向性を考慮した接続損失を測定するこ
とができる。また、接続される２本の光フアイバ
のうちの１本を基準光フアイバとすれば、他の光
フアイバと基準光フアイバとのコア径、楕円率、
偏心率等の違いを総合的に評価することもでき
る。 As explained above, the method for measuring optical fiber splice loss according to the present invention involves injecting an optical pulse into an optical fiber including a splicing point, and measuring the power of the reflected pulse from the end face of the optical fiber before and after splicing. Therefore, it is possible to measure splice loss taking directionality into consideration. Also, if one of the two optical fibers to be connected is used as a reference optical fiber, the core diameter, ellipticity,
It is also possible to comprehensively evaluate differences in eccentricity, etc.
第１図は従来の光フアイバ接続損失の測定方法
の説明図、第２図は本発明による光フアイバ接続
損失の測定方法の一実施例図、第３図は時間的に
分離された光パルスの一例を示す図である。
１……光源、２……光フアイバ、３……光フア
イバ２に接続される光フアイバ、４……光フアイ
バ２と光フアイバ３の接続点、５……光パワー検
出器、６……接続点４の直前の光フアイバ２内の
一点、７……パルス発振器、８……ハーフミラ
ー、９……光フアイバ２の終端、１０……光パル
ス検出器、１１……光フアイバ２の終端と同様の
切断面を持つ光フアイバ３の終端。
FIG. 1 is an explanatory diagram of a conventional method for measuring optical fiber splice loss, FIG. 2 is an illustration of an embodiment of the method for measuring optical fiber splice loss according to the present invention, and FIG. 3 is an illustration of temporally separated optical pulses. It is a figure showing an example. DESCRIPTION OF SYMBOLS 1... Light source, 2... Optical fiber, 3... Optical fiber connected to optical fiber 2, 4... Connection point between optical fiber 2 and optical fiber 3, 5... Optical power detector, 6... Connection One point in the optical fiber 2 immediately before the point 4, 7...pulse oscillator, 8...half mirror, 9...the end of the optical fiber 2, 10...the optical pulse detector, 11...the end of the optical fiber 2 Terminal end of optical fiber 3 with similar cut surface.
Claims (1)
て、該光フアイバの終端からの反射パルスの光パ
ワーP7を光パルス検出器で測定し、次に該光フ
アイバを他の光フアイバに接続し、再び光パルス
をこの接続した光フアイバに入射し、この接続し
た二つの光フアイバの長さをそれぞれL1、L2と
し、ｃを光速、ｎを光フアイバの屈折率とし、前
記光パワーP7を測定してから2nL2／ｃなる時間
を経過した時点で、前記接続した光フアイバの終
端からの反射パルスの光パワーP13を測定して、
光フアイバ接続損失α1をα1＝−10／２log10P13／P7な
る 式より求めることを特徴とする光フアイバ接続損
失の測定方法。[Claims] 1. A light pulse is input into an optical fiber to be connected, and the optical power P 7 of the reflected pulse from the end of the optical fiber is measured with an optical pulse detector, and then the optical fiber is connected to another optical fiber. The optical pulse is again input to the optical fiber, and the lengths of the two optical fibers are L 1 and L 2 respectively, c is the speed of light, and n is the refractive index of the optical fiber. Then, at a time point of 2nL 2 /c after measuring the optical power P 7 , measure the optical power P 13 of the reflected pulse from the end of the connected optical fiber,
A method for measuring optical fiber splice loss, characterized in that optical fiber splice loss α 1 is determined from the formula α 1 =−10/2log 10 P 13 /P 7 .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13547081A JPS5782740A (en) | 1981-08-31 | 1981-08-31 | Measuring method for connection loss of optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13547081A JPS5782740A (en) | 1981-08-31 | 1981-08-31 | Measuring method for connection loss of optical fiber |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15713377A Division JPS5488153A (en) | 1977-12-26 | 1977-12-26 | Measuring method of optical fiber connection loss |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5782740A JPS5782740A (en) | 1982-05-24 |
| JPS644612B2 true JPS644612B2 (en) | 1989-01-26 |
Family
ID=15152458
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13547081A Granted JPS5782740A (en) | 1981-08-31 | 1981-08-31 | Measuring method for connection loss of optical fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5782740A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5960410A (en) * | 1982-09-30 | 1984-04-06 | Tohoku Electric Power Co Inc | Welding method of optical fiber |
| US4671629A (en) * | 1984-04-26 | 1987-06-09 | Buehler Ltd. | Microscope for examining the surface finish of fiber optic ends |
| IT1199897B (en) * | 1985-07-22 | 1989-01-05 | Cselt Centro Studi Lab Telecom | METHOD AND DEVICE FOR THE MEASUREMENT OF COUPLING LOSSES BETWEEN SINGLE-MODE OPTICAL FIBERS |
| JPH0810284B2 (en) * | 1987-11-20 | 1996-01-31 | 日本電信電話株式会社 | Method and device for aligning optical axis of optical waveguide |
-
1981
- 1981-08-31 JP JP13547081A patent/JPS5782740A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5782740A (en) | 1982-05-24 |
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