JPS612104A - Optical fiber cable - Google Patents

Optical fiber cable

Info

Publication number
JPS612104A
JPS612104A JP59122732A JP12273284A JPS612104A JP S612104 A JPS612104 A JP S612104A JP 59122732 A JP59122732 A JP 59122732A JP 12273284 A JP12273284 A JP 12273284A JP S612104 A JPS612104 A JP S612104A
Authority
JP
Japan
Prior art keywords
optical fiber
monitoring
signal transmission
cutting
parallel
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.)
Pending
Application number
JP59122732A
Other languages
Japanese (ja)
Inventor
Kazuo Suzuki
一雄 鈴木
Shinichi Tsuchida
土田　伸一
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.)
Fujitsu Ltd
Original Assignee
Fujitsu Ltd
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 Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP59122732A priority Critical patent/JPS612104A/en
Publication of JPS612104A publication Critical patent/JPS612104A/en
Pending legal-status Critical Current

Links

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
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/4429—Means specially adapted for strengthening or protecting the cables
    • G02B6/443—Protective covering
    • G02B6/4431—Protective covering with provision in the protective covering, e.g. weak line, for gaining access to one or more fibres, e.g. for branching or tapping
    • 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
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4439—Auxiliary devices
    • G02B6/4469—Security aspects

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
  • Testing Of Optical Devices Or Fibers (AREA)
  • Light Guides In General And Applications Therefor (AREA)

Abstract

PURPOSE:To prevent surely cutting and wire tapping by providing plural parallel optical fibers for monitoring in parallel with an optical fiber for signal transmission and spiral optical fibers for monitoring within the same covering. CONSTITUTION:The plural parallel optical fibers 3 for monitoring in parallel with the optical fiber 1 for signal transmission and the spirally wound plural spiral optical fibers 4 for monitoring are embedded in the covering material 2 around the fiber 1. An optical signal for monitoring which attains a specified level at the receiving end is passed through the fibers 3, 4. Cutting of either of the fibers 3, 4 or both thereof is always required to make radio tapping. The cutting is detected from the decrease in the photodetection level as a result of such cutting. The cutting and wire tapping of the optical fiber are thus surely prevented.

Description

【発明の詳細な説明】 ｔａ）　　発明の技術分野 本発明は光ファイバケーブルに係り、特に盗聴防止用の
光ファイバケーブルに関する。DETAILED DESCRIPTION OF THE INVENTION ta) Technical Field of the Invention The present invention relates to an optical fiber cable, and more particularly to an optical fiber cable for preventing eavesdropping.

（ｂ）　　技術の背景 近年光ファイバケーブルの普及は目覚ましく、重要回線
にも利用されるようになってきた。従って、とくに重要
回線については盗聴にたいする完全な防止手段の開発が
望まれている。(b) Background of the technology In recent years, optical fiber cables have become widespread and are now being used for important lines. Therefore, it is desired to develop a complete means to prevent eavesdropping, especially for important lines.

（Ｃ１従来技術と問題点 従来、このような光ファイバケーブルの盗聴を防止する
手段として、信号伝送用光ファイバの周囲に複数本の監
視用光ファイバを平行に埋設したものが提案されていた
が、光ファイバケーブルの長手方向にケーブル外皮を切
裂けば、監視用光ファイバを切断することなく信号伝送
用光ファイバを摘出して漏光をキャッチできるので、盗
聴を完全に防止できないという欠点があった。(C1 Prior Art and Problems Conventionally, as a means to prevent such eavesdropping on optical fiber cables, it has been proposed to bury multiple monitoring optical fibers in parallel around the signal transmission optical fiber. However, by cutting the cable jacket in the longitudinal direction of the optical fiber cable, the signal transmission optical fiber can be extracted and light leakage can be detected without cutting the monitoring optical fiber, but this method had the disadvantage that eavesdropping could not be completely prevented. .

（ｄｌ　　発明の目的 本発明は上記従来の欠点に鑑み、信号伝送用光ファイバ
の摘出が、監視用光ファイバの破損無しに成し得ない構
造にすることにより、盗聴に伴う光ファイバケーブルの
破損、被覆部分の切断を監視可能な光ファイバケーブル
の提供を目的とする。(dl Purpose of the Invention In view of the above-mentioned drawbacks of the conventional art, the present invention provides a structure in which the signal transmission optical fiber cannot be removed without damaging the monitoring optical fiber. The purpose of the present invention is to provide an optical fiber cable that can monitor cutting of the coated portion.

（ｅｌ　　発明の構成 そしてこの目的は、信号伝送用光ファイバの周囲に被覆
を施してなる光ファイバケーブルにおいて、前記被覆内
に前記信号伝送用光ファイバと平行する複数の監視用平
行光ファイバと、螺旋状に巻かれた監視用螺旋光ファイ
バとを埋設して成ることを特徴とする本発明の光ファイ
バケーブルを提供することにより達成される。(el) The structure and object of the invention is to provide an optical fiber cable in which a signal transmission optical fiber is coated around the signal transmission optical fiber, and a plurality of monitoring parallel optical fibers that are parallel to the signal transmission optical fiber within the coating; This is achieved by providing the optical fiber cable of the present invention, which is characterized in that it is embedded with a spirally wound monitoring spiral optical fiber.

（ｆ）　　発明の実施例 以下本発明の実施例を図面によって詳述する。(f) Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

第１図は本発明による光ファイバケーブルの側面図、第
２図は第１図の断面図を示す。FIG. 1 shows a side view of an optical fiber cable according to the invention, and FIG. 2 shows a sectional view of FIG. 1.

図において、信号伝送用の光ファイノＸ１の周囲は合成
樹脂等にてなる被覆材２にて被覆されており、この被覆
材２には光ファイバ１と平行する複数の監視用平行光フ
ァイバ３と、螺旋状に巻かれた別の複数の監視用螺旋光
ファイバ４とが埋設された構造になっている。In the figure, the periphery of an optical fiber X1 for signal transmission is covered with a covering material 2 made of synthetic resin, etc., and this covering material 2 includes a plurality of parallel optical fibers 3 for monitoring parallel to the optical fiber 1. , and another plurality of spirally wound monitoring spiral optical fibers 4 are buried therein.

信号伝送用光ファイバ１には、本来の目的である情報光
信号を通し、複数の監視用平行光ファイバ３と監視用螺
旋光ファイバ４にはそれぞれ受信端が一定レベルとなる
安定な監視用光信号を通ず。The optical fiber 1 for signal transmission passes the information optical signal, which is the original purpose, and the parallel optical fibers 3 for monitoring and the spiral optical fiber 4 for monitoring each carry stable monitoring light whose receiving end is at a constant level. Pass the signal.

受信側では監視用平行光ファイバ３と監視用螺旋光ファ
イバ４のそれぞれの受光レベルを常時監視し、受光レベ
ルの低下を検出することにより監視用の光ファイバが切
断され、信号伝送用光ファイバ１の情報光信号が盗聴さ
れ始めたことを知ることができる。On the receiving side, the light reception level of each of the monitoring parallel optical fiber 3 and the monitoring spiral optical fiber 4 is constantly monitored, and when a decrease in the light reception level is detected, the monitoring optical fiber is cut, and the signal transmission optical fiber 1 is cut. It is possible to know that the information optical signals of

第１図と第２図とから分かるように、監視用平行光ファ
イバ３と監視用螺旋光ファイバ４とは信号伝送用光ファ
イバ１に対して縦横に配置されているので、信号伝送用
光ファイバｌの情報光信号を盗聴しようとすれば、監視
用平行光ファイバ３と監視用螺旋光ファイバ４とのどち
らかを、或いは両方を必ず切断しなければならない。そ
の切断により前述のように信号伝送用光ファイバ１の情
報光信号が盗聴され始めたことを知ることができる。As can be seen from FIGS. 1 and 2, the monitoring parallel optical fiber 3 and the monitoring spiral optical fiber 4 are arranged vertically and horizontally with respect to the signal transmission optical fiber 1. In order to eavesdrop on the information optical signal of 1, either or both of the monitoring parallel optical fiber 3 and the monitoring spiral optical fiber 4 must be cut. By the disconnection, it can be known that the information optical signal of the signal transmission optical fiber 1 has begun to be tapped, as described above.

なお、図において信号伝送用光ファイバ１は１本の場合
について説明したが、本発明は多芯ケーブルの場合にも
適用可能なことはいうまでもない。In addition, although the case where the number of signal transmission optical fibers 1 is one is explained in the figure, it goes without saying that the present invention is also applicable to the case of a multi-core cable.

（ｇｌ　　発明の効果 以上詳細に説明したように本発明の光ファイバケーブル
の構造によれば、信号伝送用光ファイバの露出に際して
必ず監視用光ファイバの切断を伴うので、確実に盗聴を
防止することが可能となる。(gl Effects of the Invention As explained in detail above, according to the structure of the optical fiber cable of the present invention, the monitoring optical fiber is always cut when the signal transmission optical fiber is exposed, so wiretapping can be reliably prevented. becomes possible.

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

第１図は本発明による光ファイバケーブルの側面図、第
２図は第１図の断面図を示す。 図において、１は信号伝送用の光ファイバ、２は被覆材
、３は監視用平行光ファ・イバ、４は監視用螺旋光ファ
イバを示す。 第１図 第２図FIG. 1 shows a side view of an optical fiber cable according to the invention, and FIG. 2 shows a sectional view of FIG. 1. In the figure, 1 is an optical fiber for signal transmission, 2 is a coating material, 3 is a parallel optical fiber for monitoring, and 4 is a spiral optical fiber for monitoring. Figure 1 Figure 2

Claims (1)

【特許請求の範囲】[Claims] 信号伝送用光ファイバの周囲に被覆を施してなる光ファ
イバケーブルにおいて、前記被覆内に前記信号伝送用光
ファイバと平行する複数の監視用平行光ファイバと、螺
旋状に巻かれた監視用螺旋光ファイバとを埋設して成る
ことを特徴とする光ファイバケーブル。An optical fiber cable comprising a signal transmission optical fiber coated around the signal transmission optical fiber, the coating including a plurality of monitoring parallel optical fibers parallel to the signal transmission optical fiber, and a monitoring spiral light wound in a spiral. An optical fiber cable characterized by being formed by burying a fiber.
JP59122732A 1984-06-13 1984-06-13 Optical fiber cable Pending JPS612104A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP59122732A JPS612104A (en) 1984-06-13 1984-06-13 Optical fiber cable

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP59122732A JPS612104A (en) 1984-06-13 1984-06-13 Optical fiber cable

Publications (1)

Publication Number Publication Date
JPS612104A true JPS612104A (en) 1986-01-08

Family

ID=14843212

Family Applications (1)

Application Number Title Priority Date Filing Date
JP59122732A Pending JPS612104A (en) 1984-06-13 1984-06-13 Optical fiber cable

Country Status (1)

Country Link
JP (1) JPS612104A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1591816A1 (en) * 2004-04-28 2005-11-02 Corning Incorporated Cables and cable installations
JP2014106380A (en) * 2012-11-28 2014-06-09 Fujikura Ltd Optical fiber cable, and manufacturing method and manufacturing device thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1591816A1 (en) * 2004-04-28 2005-11-02 Corning Incorporated Cables and cable installations
JP2014106380A (en) * 2012-11-28 2014-06-09 Fujikura Ltd Optical fiber cable, and manufacturing method and manufacturing device thereof

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