JPS6334442B2 - - Google Patents

Info

Publication number
JPS6334442B2
JPS6334442B2 JP59011469A JP1146984A JPS6334442B2 JP S6334442 B2 JPS6334442 B2 JP S6334442B2 JP 59011469 A JP59011469 A JP 59011469A JP 1146984 A JP1146984 A JP 1146984A JP S6334442 B2 JPS6334442 B2 JP S6334442B2
Authority
JP
Japan
Prior art keywords
polarization
maintaining optical
optical fibers
optical fiber
principal
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
Application number
JP59011469A
Other languages
Japanese (ja)
Other versions
JPS60154212A (en
Inventor
Masataka Nakazawa
Noburu Shibata
Tsuneo Horiguchi
Masamitsu Tokuda
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Telegraph and Telephone Corp
Original Assignee
Nippon Telegraph and Telephone Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nippon Telegraph and Telephone Corp filed Critical Nippon Telegraph and Telephone Corp
Priority to JP59011469A priority Critical patent/JPS60154212A/en
Publication of JPS60154212A publication Critical patent/JPS60154212A/en
Publication of JPS6334442B2 publication Critical patent/JPS6334442B2/ja
Granted legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/105—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type having optical polarisation effects

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
  • Mechanical Coupling Of Light Guides (AREA)
  • Optical Couplings Of Light Guides (AREA)

Description

【発明の詳細な説明】 〔発明の属する技術分野〕 本発明は通信用光フアイバの接続方法に関す
る。特に、偏波保持光フアイバを接続するとき
に、その主軸を合わせるための方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a method for connecting optical fibers for communication. In particular, the present invention relates to a method for aligning the principal axes of polarization-maintaining optical fibers when connecting them.

〔従来技術の説明〕[Description of prior art]

光ヘテロダイン通信方式の開発が進展し、偏波
保持光フアイバの利用が注目されるようになつ
た。偏波保持光フアイバもその製造ピースは長さ
が限られるので、長距離伝送に使用するには、接
続を行うことが必要である。偏波保持光フアイバ
は、よく知られているように、伝送される光信号
の偏光方向は二つの主軸の方向に限られ、この二
つの偏光方向の光信号が光フアイバを伝播中に生
じるモード結合は極力抑制されなければならな
い。このため、偏波保持光フアイバの接続は、光
フアイバのコアを合わせる他に、主軸方向を正し
く合わせて行うことが必要である。 As the development of optical heterodyne communication systems progresses, the use of polarization-maintaining optical fibers has attracted attention. Polarization-maintaining optical fiber also has a limited length of manufactured pieces, so it is necessary to make connections in order to use it for long-distance transmission. As is well known, in polarization-maintaining optical fibers, the polarization directions of the transmitted optical signals are limited to two main axes, and the modes that occur when optical signals in these two polarization directions propagate through the optical fiber. Coupling must be suppressed as much as possible. For this reason, when connecting polarization-maintaining optical fibers, it is necessary not only to align the cores of the optical fibers, but also to properly align the directions of their principal axes.

すなわち二本の偏波保持光フアイバを接続する
には、その端部を互いに接近させ、コアを合わ
せ、ついでそのコア回りに回転を与えて主軸方向
を合わせてから接続を行うことになる。第１図は
その主軸を合わせるための従来例方法の説明図で
ある。二本の偏波保持光フアイバＡおよびＢを接
続するには、光源１および偏光子２を偏波保持光
フアイバＡの接続端と反対の端部に配置して、一
つの主軸に一致する光信号を入射させる。偏波保
持光フアイバＢの接続端と反対の端部では、得ら
れる出射光から入射側の主軸に対応する主軸方向
に一致する偏光方向の光信号を光検子５を介して
光検出器６で検出し、この電気出力を表示装置７
で観測する。このようにしておいて、接続端でコ
ア回りに両偏波保持光フアイバを回転させて、光
検出器６に得られるその主軸方向の偏光が最大に
なるように調節する。 That is, in order to connect two polarization-maintaining optical fibers, their ends should be brought close to each other, their cores aligned, and then the fibers should be rotated around the cores to align their principal axes before connection is made. FIG. 1 is an explanatory diagram of a conventional method for aligning the main axes. To connect two polarization-maintaining optical fibers A and B, a light source 1 and a polarizer 2 are placed at the end opposite to the connection end of polarization-maintaining optical fiber A, so that the light source 1 and the polarizer 2 Inject the signal. At the end of the polarization-maintaining optical fiber B opposite to the connecting end, an optical signal with a polarization direction corresponding to the main axis direction corresponding to the main axis on the incident side is transmitted from the obtained output light to a photodetector 6 via a photodetector 5. This electrical output is detected by the display device 7.
Observe with. In this manner, both polarization-maintaining optical fibers are rotated around the core at the connecting end to adjust the polarization in the principal axis direction obtained by the photodetector 6 to be maximum.

この方法は原理に忠実な方法であるが、出射光
を検出するために検光子５の軸方向を合わせる手
数が必要であること、出射光の最大値となる点の
感度が悪く精密な主軸方向の検出ができないこ
と、入射端と出射端が別であることなどの欠点が
ある。 Although this method is faithful to the principle, it requires a lot of effort to align the axial direction of the analyzer 5 in order to detect the emitted light, and the sensitivity of the point where the emitted light has the maximum value is poor, and the precise principal axis direction There are disadvantages such as the inability to detect and the fact that the input end and output end are separate.

これを改良するものとして、第２図に示す方法
が知られている。この方法は、接続しようとする
二本の偏波保持光フアイバＡおよびＢの一端に設
けた光源１から、光フアイバＡの主軸方向に一致
する偏光方向のパルス状の光信号を入射する。光
フアイバＢの他端では、この出射光を光検出器６
で検出し、その電気出力を表示装置７で時間軸上
で観測する。 As a method for improving this, a method shown in FIG. 2 is known. In this method, a pulsed optical signal having a polarization direction that coincides with the principal axis direction of optical fiber A is input from a light source 1 provided at one end of two polarization-maintaining optical fibers A and B to be connected. At the other end of the optical fiber B, this emitted light is detected by a photodetector 6.
, and its electrical output is observed on the time axis on the display device 7.

この方法では、入射端から一つの光パルス信号
を入射すると、接続点でモード結合があるとき、
すなわち主軸方向が一致していないときには、出
射端では二つのモードの出射光が観測される。こ
の二つのモードの光信号は群伝播時間に差Δtが
あるので、出射端の表示装置７には例えば第３図
１のように二つのパルス信号が観測される。この
状態で接続端をコアの回りに回転させて、第３図
２さらに第３図３のように調節すると、接続点で
モード結合の最も小さくなる位置を知ることがで
きる。 In this method, when one optical pulse signal is input from the input end, when there is mode coupling at the connection point,
That is, when the principal axis directions do not match, two modes of emitted light are observed at the output end. Since there is a difference Δt in group propagation time between the optical signals of these two modes, two pulse signals are observed on the display device 7 at the output end, as shown in FIG. 3, for example. In this state, by rotating the connecting end around the core and adjusting it as shown in FIG. 3 2 and then as shown in FIG. 3 3, it is possible to know the position where the mode coupling is the smallest at the connecting point.

この方法は出射端に検光子が不要であること、
二つのパルスが一つになるように調節すればよい
ので感度がよいなどの利点があるが、入射端と出
射端とは別である。したがつて、ケーブルピース
が製造工場に巻き取られている状態のときにはよ
いが、ケーブルが布設された後では、入射端と出
射端とは遠方になつてしまい測定の能率がいちじ
るしく悪くなる。 This method does not require an analyzer at the output end;
It has advantages such as good sensitivity because it is only necessary to adjust the two pulses into one, but the input end and the output end are separate. Therefore, this is fine when the cable piece is being wound up at the manufacturing factory, but after the cable is installed, the input end and the output end are far apart, and the efficiency of measurement is significantly reduced.

〔発明の目的〕[Purpose of the invention]

本発明はこれを改良するもので、入射端と出射
端とが同一端にあり、しかも測定感度が高く調節
の容易な接続方法を提供することを目的とする。 The present invention is an improvement on this, and aims to provide a connection method in which the input end and the output end are located at the same end, and which has high measurement sensitivity and is easy to adjust.

〔発明の特徴〕[Features of the invention]

本発明は、二本の偏波保持光フアイバのそれぞ
れの端部を相互に接近させるステツプと、その端
部のコア位置を合わせるステツプと、その端部の
主軸方向を合わせるステツプと、その端部を相互
に接続するステツプとを含む偏波保持光フアイバ
の接続方法において、上記主軸方向を合わせるス
テツプは、上記二本の偏波保持光フアイバのうち
の一本の偏波保持光フアイバの接続する端部の反
対側の端部からこの一本の偏波保持光フアイバの
一つの主軸方向に光パルスを入射させ、この光パ
ルスにより上記二本の偏波保持光フアイバ内で発
生する後方散乱光を上記反対側の端部で二つの主
軸の少なくとも一つについて時間軸上で観測し、
接続しようとする点以遠で発生する後方散乱光に
ついて、上記一つの主軸方向の光パワーが最大に
なり、もしくは上記一つの主軸とは別の主軸方向
の光パワーが最小になるように調節する方法を含
むことを特徴とする。 The present invention comprises a step of bringing the respective ends of two polarization-maintaining optical fibers close to each other, a step of adjusting the core position of the ends, a step of adjusting the main axis direction of the ends, and a step of bringing the respective ends of the two polarization-maintaining optical fibers closer to each other. In the method for connecting polarization-maintaining optical fibers, the step of aligning the main axis direction connects one polarization-maintaining optical fiber of the two polarization-maintaining optical fibers. A light pulse is input in the direction of one of the principal axes of this one polarization-maintaining optical fiber from the opposite end, and this light pulse generates backscattered light within the two polarization-maintaining optical fibers. is observed on the time axis for at least one of the two principal axes at the opposite end,
A method of adjusting backscattered light generated beyond the point to be connected so that the optical power in the direction of the one principal axis is maximized, or the optical power in the direction of a principal axis other than the one principal axis is minimized. It is characterized by including.

〔実施例による説明〕[Explanation based on examples]

第４図は本発明実施例方法の説明図である。光
源１は光パルス信号を発生し、この光パルス信号
は、偏光子２をビームスプリツタ８を介して、接
続される二本の偏波保持光フアイバのうちの一本
の偏波保持光フアイバＡの一端に入力される。こ
の光パルス信号はこの偏波保持光フアイバの中を
伝播し、後方散乱光を発生する。この後方散乱光
は、この偏波保持光フアイバの中を逆方向に伝播
して、上記一端に現れ、ビームスプリツタ８によ
り、検光子５を介して光検出器６に入力する。光
検出器６の電気出力は、低雑音増幅器９により増
幅され、平均処理回路１０で信号雑音比が改善さ
れて、表示装置７に表示される。この表示装置７
では、偏波保持光フアイバの一端に現れた後方散
乱光の強度（対数表示、dB）が時間軸上に表示
される。 FIG. 4 is an explanatory diagram of a method according to an embodiment of the present invention. A light source 1 generates an optical pulse signal, and this optical pulse signal is transmitted to a polarizer 2 via a beam splitter 8 to one of two polarization-maintaining optical fibers to be connected. It is input to one end of A. This optical pulse signal propagates through this polarization maintaining optical fiber and generates backscattered light. This backscattered light propagates in the opposite direction in this polarization-maintaining optical fiber, appears at the above-mentioned one end, and is input to a photodetector 6 via an analyzer 5 by a beam splitter 8. The electrical output of the photodetector 6 is amplified by a low-noise amplifier 9, the signal-to-noise ratio is improved by an averaging circuit 10, and the resulting signal is displayed on a display device 7. This display device 7
, the intensity (in logarithmic representation, dB) of the backscattered light appearing at one end of the polarization-maintaining optical fiber is displayed on the time axis.

接続しようとする二本の偏波保持光フアイバＡ
およびＢはその接続しようとする点を接近させ、
コア合わせを行いこの接続しようとする点を光信
号が通過する状態とする。 Two polarization maintaining optical fibers A to be connected
and B bring the points to be connected closer together,
The cores are aligned and the optical signal passes through the point to be connected.

いま、偏波保持光フアイバＡおよびＢの二つの
主軸をＸ、Ｙとし、偏光子２をＸ軸に合わせ、検
光子５をＹ軸に合わせると、偏波保持光フアイバ
Ａの中では主軸ＸとＹとの間にはほとんどモード
結合がないから、光検出器６に検出される後方散
乱光はきわめて小さい。接続点の軸合わせが十分
に行なわれていない状態では、光パルス信号が接
続点を通過すると、主軸Ｘを伝播していた光パル
ス信号のエネルギーの一部が主軸Ｙに結合するの
で、接続点より遠方では主軸Ｙのモードで後方散
乱光が発生し光検出器６に検出される。 Now, let the two principal axes of polarization-maintaining optical fibers A and B be X and Y, and if the polarizer 2 is aligned with the X-axis and the analyzer 5 is aligned with the Y-axis, then in polarization-maintaining optical fiber A, the principal axis Since there is almost no mode coupling between Y and Y, the backscattered light detected by the photodetector 6 is extremely small. If the axis of the connection point is not sufficiently aligned, when the optical pulse signal passes through the connection point, part of the energy of the optical pulse signal that was propagating along the main axis X will be coupled to the main axis Y. At a farther distance, backscattered light is generated in the mode of the principal axis Y and is detected by the photodetector 6.

この状態で、接続しようとする点で両偏波保持
光フアイバの端部をコアの回りに相互に回転さ
せ、両偏波保持光フアイバＡおよびＢの主軸Ｘが
近づくと、偏波保持光フアイバＢの主軸Ｘ方向に
結合する光エネルギーは小さくなるから、主軸Ｙ
方向に偏光する接続点以遠の後方散乱光は小さく
なる。したがつて、端部をコアの回りに相互に回
転させて、主軸Ｙ方向に偏光する接続点以遠の後
方散乱光を最小に調節すると、そのときの状態が
モード結合の最も小さい状態であつて、その状態
で接続を実行すればよい。 In this state, the ends of both polarization-maintaining optical fibers are mutually rotated around the core at the point to be connected, and when the principal axes X of both polarization-maintaining optical fibers A and B approach, the polarization-maintaining optical fibers are connected. Since the light energy coupled in the direction of the principal axis X of B becomes smaller, the principal axis Y
Backscattered light from the connection point that is polarized in the direction becomes smaller. Therefore, if the ends are mutually rotated around the core and the backscattered light beyond the connection point polarized in the principal axis Y direction is adjusted to the minimum, the state at that time is the state with the smallest mode coupling. , just connect in that state.

いま、検光子５を主軸Ｙに一致させるとした
が、この検光子５の偏光方向を主軸Ｘに一致させ
る場合には、入射光の偏光方向が主軸Ｘの方向で
あるから、主軸Ｘに一致する偏光方向の後方散乱
光は比較的高いレベルで発生しているので、光検
出器６には比較的高いレベルの出力が得られる。
このときには、接続点以遠で発生する後方散乱光
について、その値が最大になるように、接続する
端部をコア回りに回転させて調節すればよい。 Now, we have assumed that the analyzer 5 is aligned with the principal axis Y, but when the polarization direction of the analyzer 5 is made to be aligned with the principal axis X, since the polarization direction of the incident light is in the direction of the principal axis Since the backscattered light in the polarization direction is generated at a relatively high level, the photodetector 6 can obtain an output at a relatively high level.
At this time, the end to be connected may be adjusted by rotating around the core so that the value of backscattered light generated beyond the connection point is maximized.

つぎにこの状況を定量的に検討すると、光フア
イバＡのｘ軸方向の入射パワーをＰとし、各光フ
アイバの伝送損失は等しくαdB／Kmとする。また
誘電率ゆらぎの非対角要素によつて発生するモー
ド結合係数をｈ、光フアイバＡの長さをＺとす
る。このとき光フアイバＡの出力としてはｘ軸方
向およびｙ軸方向のパワーをそれぞれPx、Pyと
すると、 Px（Ｚ）≒Pexp（−αZ） …（１−１） Py（Ｚ）≒Phz exp（−αZ） …（１−２） となる。後方散乱光の発生係数を光フアイバＡ，
ＢについてSA、SBとし、光パルス幅内での後方
へのモード結合量CAとすると、光フアイバＡの
各主軸方向の後方散乱光のパワーPBSXおよびPBSY
は PBSX（Ｚ）＝SAPexp（−2αZ） …（２−１） PBSY（Ｚ）＝2SAhZPexp（−2αZ） ＋CAPexp（−2αZ） …（２−２） となる。ここで、第５図に示すように、接続点で
角度θだけ主軸の回転があり、光フアイバＢの主
軸をx′、y′と表わすと、光フアイバＢ、入射端近
傍のx′軸方向およびy′軸方向への伝搬パワーPx′、
Py′は、 Px′＝Px cos2θ＋Py sin2θ …（３−１） Px′＝Px sin2θ＋Py cos2θ …（３−２） となる。光フアイバＢからの後方散乱光のパワー
PBSX′およびPBSY′は、 PBSX′＝SBPx′＋CBPy′ …（４−１） PBSY′＝SBPy′＋CBPx′ …（４−２） となる。ただし、CBは後方へのモード結合係数
である。後方散乱光は再びθの変換を受けて光フ
アイバＡに戻つてくるので、ｘ軸方向およびｙ軸
方向での光フアイバＢからの信号（接続点の近傍
は、 PBSX（Ｚ＝Ｚ＋ΔZ）＝PBSX′cos2θ ＋PBSY′sin2θ …（５−１） PBSY（Ｚ＝Ｚ＋ΔZ）＝PBSX′sin2θ ＋PBSY′cos2θ …（５−１） となる。ここで我々はPBSY（Ｚ）について注目し
ているので式(3)、(4)、(5)を用い、さらにモード結
合方程式を解くことにより、 PBSY（Ｚ）＝〔１／２（SB＋CB）−２−2P｛cos2
θ−sin2θ／２｝2 ・（１−4hZ）（SB−CB）〕・exp（−2αZ）…
(6) を得る。ここで、θ＝０の場合、すなわち主軸が
一致している場合には、PBSY（Ｚ＝０）はSB≫CB
であることを考慮して、 PBSY＝CBPexp（−2αZ） ＋2SBhZPexp（−2αZ） …(7) となる。しかし、θ≠０のときには、π／４まで
PBSYは単調増加関数となる。すなわち、式(6)をθ
で偏微分とすると、 δPBSY／δθ＝δ／δθ〔Ｐ／２（SB＋CB）−2P｛
cos2θ−sin2θ／２｝・（１−4hZ）（SB−CB）〕 ＝Ｐ／２（１−4hZ）（SB−CB）exp（−2αZ）・
sin4θ＞０…(8) となる。すなわち、hZは10-2〜10-3であるため １−4hZ＞０ となり、また消光比が10〜30dBの光フアイバに
おいてはレイリー散乱の係数SBの方が後方モード
結合係数CBに比べて102程度大きい。したがつて
SB≫CBであることから式(8)は ０θπ／４ の範囲で単調増加となり、PBSYはθの変化ととも
に増加することがわかる。したがつて、θ＝０の
ときPBSYが最小となり、θの正負を問わず主軸の
不一致とともにPBSYは増加する。したがつてPBSY
が最小になるように接続点で光フアイバＢを回転
させればよい。 Next, considering this situation quantitatively, it is assumed that the incident power in the x-axis direction of the optical fiber A is P, and the transmission loss of each optical fiber is equal to αdB/Km. Further, let h be the mode coupling coefficient generated by off-diagonal elements of dielectric constant fluctuation, and let Z be the length of the optical fiber A. At this time, as the output of optical fiber A, if the power in the x-axis direction and the y-axis direction is Px and Py, respectively, Px (Z) ≒ Pexp (-αZ) ... (1-1) Py (Z) ≒ Phz exp ( −αZ) …(1-2) The generation coefficient of backscattered light is expressed as optical fiber A,
Assuming that B is S A and S B , and the amount of backward mode coupling within the optical pulse width is C A , the power of back scattered light in each principal axis direction of optical fiber A is P BSX and P BSY
is P BSX (Z) = S A Pexp (-2αZ) ... (2-1) P BSY (Z) = 2S A hZPexp (-2αZ) + C A Pexp (-2αZ) ... (2-2). Here, as shown in Fig. 5, there is a rotation of the principal axis by an angle θ at the connection point, and if the principal axes of optical fiber B are expressed as x' and y', optical fiber B is in the x'-axis direction near the input end. and the propagation power Px′ in the y′-axis direction,
Py' becomes Px'=Px cos 2 θ+Py sin 2 θ...(3-1) Px'=Px sin 2 θ+Py cos 2 θ...(3-2). Power of backscattered light from optical fiber B
P BSX ′ and P BSY ′ are as follows: P BSX ′=S B Px′+C B Py′ (4-1) P BSY ′=S B Py′+C B Px′ (4-2). However, C B is the backward mode coupling coefficient. The backscattered light returns to optical fiber A after being transformed by θ again, so the signals from optical fiber B in the x-axis and y-axis directions (near the connection point are: P BSX (Z=Z+ΔZ)= P BSX ′cos 2 θ +P BSY ′sin 2 θ …(5-1) P BSY (Z=Z+ΔZ)=P BSX ′sin 2 θ +P BSY ′cos 2 θ …(5-1) Here, we Since we are focusing on P BSY (Z), by using equations (3), (4), and (5) and further solving the mode coupling equation, P BSY (Z) = [1/2 (S B + C B ) −2−2P {cos 2
 θ−sin 2 θ/2} 2・(1−4hZ)(S B −C B )〕・exp(−2αZ)…
(6) is obtained. Here, when θ=0, that is, when the principal axes coincide, P BSY (Z=0) is S B ≫C B
Considering that, P BSY = C B Pexp (−2αZ) + 2S B hZPexp (−2αZ) …(7). However, when θ≠0, up to π/4
P BSY is a monotonically increasing function. In other words, equation (6) is changed to θ
If we take the partial differential as δP BSY /δθ=δ/δθ [P/2(S B +C B )−2P{
cos 2 θ−sin 2 θ/2}・(1−4hZ)(S B −C B )] =P/2(1−4hZ)(S B −C B )exp(−2αZ)・
sin4θ>0…(8). That is, since hZ is 10 -2 to 10 -3, 1-4hZ > 0, and in an optical fiber with an extinction ratio of 10 to 30 dB, the Rayleigh scattering coefficient S B is higher than the backward mode coupling coefficient C B. It's about 102 times bigger. Therefore
Since S B ≫C B , equation (8) increases monotonically in the range of 0θπ/4, and it can be seen that P BSY increases as θ changes. Therefore, P BSY is minimum when θ=0, and P BSY increases as the principal axes mismatch regardless of whether θ is positive or negative. Therefore P BSY
What is necessary is to rotate the optical fiber B at the connection point so that the distance is minimized.

式（２−２）および(7)に着目すると、 SA＞SB、CA＞CB の場合の後方散乱光のパワーは第５図ａに、また SA＜SB、CA＜CB の場合の後方散乱光のパワーを第５図ｂに示す。
いずれの場合にも、光フアイバＢでの後方散乱光
のレベルが最小になるように調整すればよい。 Focusing on equations (2-2) and (7), the power of backscattered light when S A > S B and C A > C B is shown in Figure 5a, and when S A < S B and C A < The power of backscattered light in the case of C B is shown in Figure 5b.
In either case, adjustment may be made so that the level of backscattered light in optical fiber B is minimized.

ｘ軸方向の散乱光を測定して接続する場合に
は、こんどは逆にPBSXが最大になるように光フア
イバＢを回転すればよい。この場合は検光子５の
偏光方向はｘ軸方向に設定する。 When connecting by measuring the scattered light in the x-axis direction, the optical fiber B should be rotated so that P BSX is maximized. In this case, the polarization direction of the analyzer 5 is set to the x-axis direction.

〔発明の効果〕〔Effect of the invention〕

以上説明したように、本発明によれば、偏波保
持光フアイバの接続点で主軸合わせを行う場合
に、接続する光フアイバの一端のみで観測を行う
ことができる優れた利点がある。すなわち、ケー
ブルを布設した後に接続を行う場合に、送信側と
受信側が同一地点になるので、測定の効率がいち
じるしく向上する。また、表示を観測しながら、
最小もしくは最大を求める方法であるから、操作
が簡単であり、誤りが少なく、感度が高くなる利
点がある。さらに、接続箇所が３箇所以上になる
場合にも、各接続箇所を個別に識別して接続を行
うことができる利点がある。 As explained above, according to the present invention, when performing principal axis alignment at the connection point of polarization-maintaining optical fibers, there is an excellent advantage that observation can be performed at only one end of the optical fibers to be connected. That is, when the cable is installed and then connected, the transmitting and receiving sides are located at the same location, which significantly improves measurement efficiency. Also, while observing the display,
Since this is a method of finding the minimum or maximum, it has the advantages of easy operation, fewer errors, and higher sensitivity. Furthermore, even when there are three or more connection points, there is an advantage that each connection point can be individually identified and connected.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は従来例方法の説明図。第２図は従来例
方法の説明図。第３図は従来例方法の動作説明
図。第４図は本発明実施例方法の説明図。第５図
は本発明実施例方法の動作説明図。第６図は接続
点の偏光方向角度を説明するための図。 １……光源、２……偏光子、５……検光子、６
……光検出器、７……表示装置、８……ビームス
プリツタ、９……低雑音増幅器、１０……平均処
理回路。 FIG. 1 is an explanatory diagram of a conventional method. FIG. 2 is an explanatory diagram of a conventional method. FIG. 3 is an explanatory diagram of the operation of the conventional method. FIG. 4 is an explanatory diagram of a method according to an embodiment of the present invention. FIG. 5 is an explanatory diagram of the operation of the method according to the embodiment of the present invention. FIG. 6 is a diagram for explaining the polarization direction angle of the connection point. 1...Light source, 2...Polarizer, 5...Analyzer, 6
... photodetector, 7 ... display device, 8 ... beam splitter, 9 ... low noise amplifier, 10 ... average processing circuit.

Claims (1)

【特許請求の範囲】 １ 二本の偏波保持光フアイバのそれぞれの端部
を相互に接近させるステツプと、 その端部のコア位置を合わせるステツプと、 その端部の主軸方向を合わせるステツプと、 その端部を相互に接続するステツプと を含む偏波保持光フアイバの接続方法におい
て、 上記主軸方向を合わせるステツプは、 上記二本の偏波保持光フアイバのうちの一本の
偏波保持光フアイバの接続する端部の反対側の端
部からこの一本の偏波保持光フアイバの一つの主
軸方向に光パルスを入射させ、 この光パルスにより上記二本の偏波保持光フア
イバ内で発生する後方散乱光を上記反対側の端部
で二つの主軸の少なくとも一つについて時間軸上
で観測し、 接続しようとする点以遠で発生する後方散乱光
について、上記一つの主軸方向の光パワーが最大
になり、もしくは上記一つの主軸とは別の主軸方
向の光パワーが最小になるように調節する 方法を含むことを特徴とする偏波保持光フアイ
バの接続方法。[Claims] 1. A step of bringing the respective ends of two polarization-maintaining optical fibers closer to each other, a step of adjusting the core position of the ends, and a step of adjusting the main axis direction of the ends, In the method for connecting polarization-maintaining optical fibers, the step of aligning the main axis direction involves connecting one of the two polarization-maintaining optical fibers to each other. A light pulse is input in the direction of one of the principal axes of this one polarization-maintaining optical fiber from the end opposite to the end to which it connects, and this light pulse generates a signal in the two polarization-maintaining optical fibers. The backscattered light is observed on the time axis for at least one of the two principal axes at the opposite end, and the optical power in the direction of the one principal axis is maximum for the backscattered light generated beyond the point to be connected. 1. A method for connecting polarization-maintaining optical fibers, the method comprising adjusting the optical power in a direction other than the above-mentioned one principal axis to a minimum.
JP59011469A 1984-01-24 1984-01-24 Connecting method of polarization maintaining optical fiber Granted JPS60154212A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP59011469A JPS60154212A (en) 1984-01-24 1984-01-24 Connecting method of polarization maintaining optical fiber

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP59011469A JPS60154212A (en) 1984-01-24 1984-01-24 Connecting method of polarization maintaining optical fiber

Publications (2)

Publication Number Publication Date
JPS60154212A JPS60154212A (en) 1985-08-13
JPS6334442B2 true JPS6334442B2 (en) 1988-07-11

Family

ID=11778931

Family Applications (1)

Application Number Title Priority Date Filing Date
JP59011469A Granted JPS60154212A (en) 1984-01-24 1984-01-24 Connecting method of polarization maintaining optical fiber

Country Status (1)

Country Link
JP (1) JPS60154212A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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

Also Published As

Publication number Publication date
JPS60154212A (en) 1985-08-13

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