JPS5991745A - Coupler for optical communication - Google Patents

Abstract

PURPOSE:To attain the switching without hit of a transmission signal and less in the insertion loss by providing a bypass circuit between branches of two directional couplers and inserting a photoelectric and electrooptic converters between other branches. CONSTITUTION:Bidirectional transmission is attained between optical transmission lines L1 and L2 via a bypass including a delay circuit DL between branches #1 of directional couplers CP1, CP2. When an amplifier is inserted between the photoelectric converters O/E1, O/E2 and the electrooptic converters E/O1, E/O2 in the branches #2, #3, a signal from the transmission lines L1, L2 is amplified and transmitted to the transmission lines L2, L1 for attaining the bidirectional transmission. Since the coupling between branches is blocked, no oscillation of detour due to amplification takes place. The bidirectional transmission is kept in the bypass of the branch #1 at a failure of the branches #2, #3, and since no switching is operated, no hit of the optical transmission is produced and since the optical transmission loss of the couplers CP1, CP2 is low, the insertion loss is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical communication coupling device that is inserted into an optical transmission line of a bidirectional time division multiplex communication system and performs signal relaying or coupling.

When inserting a terminal device, etc. that receives signals into an optical transmission path, optical communication is essentially a power transmission, and signal branching due to high impedance loads is impossible. Some kind of coupling device is required, but if the coupling device is turned off or a failure occurs, signal transmission between other terminal devices may be blocked.

For this purpose, it has become common practice to provide a bypass path into the coupling device.

FIGS. 1 and 2 show a coupling it with a bypass path.
This is a block diagram showing a conventional example of
An optical switch Sl, 82 is inserted between one optical transmission line L1 and the other transmission line L2, and is normally connected to a photoelectric converter 0/E such as a light receiving transistor and a lightning converter E101 such as a light emitting diode. The transmission line -L H + L z is connected, but in response to the occurrence of these failures, the optical switch S□ is switched to the bypass route.

It is said that it will switch S2.

Note that a signal processing circuit SP is inserted between the photoelectric converter 0/E and the electro-optic converter E10, and performs signal relay amplification, signal transmission/reception, etc.

In addition, in FIG. 2, an optical splitter DV and an optical coupler cp are inserted between the optical transmission lines L1 and L1, and a photoelectric converter 0/E1 signal processing circuit is connected to one of the paths branched by these. sp, an electro-optical converter E10 is inserted, and the other path is set as a bypass path Lb.

However, in FIG. 1, the switching operation of the optical switches s1 and S2 causes an instantaneous interruption phenomenon force S in optical transmission, and to prevent this, the switching system must be duplicated, which complicates the configuration. At the same time, the optical switches S, , S, are expensive, and have disadvantages such as relatively large insertion loss for optical transmission.

On the other hand, in Fig. 2, it is generally applied only to unidirectional communication, and when applied to bidirectional communication, the configuration becomes complicated and expensive, and there are disadvantages such as increased insertion loss for optical transmission. .

The present invention has been made in view of the conventional drawbacks, and a first object is to provide a first and &
If two directional optical couplers are used and these first branches are connected to form a bypass path, the optical converter and the electro-optical converter □ can be connected between the second and third branches. insert,
This paper proposes a binding method for Mitsutoshihaku that is suitable for Nakago Masume 9, etc.

However, the second purpose is to use first and second directional optical couplers having multiple branches, connect these first branches to form a bypass path, and 2. 3rd
A photoelectric converter and an electro-optical converter are inserted between the branch branches of the optical fiber, and a signal processing circuit that performs various types of signal processing is inserted between these, making the coupling suitable for electrical processing of transmission signals. It provides equipment.

Furthermore, the third purpose is to use first and second directional optical couplers that connect a plurality of branches, connect these branches of force l to form a bypass path, and
2. Insert a photoelectric converter and an electro-optical converter between the third branches, and insert a coupling circuit between them for branching and mixing signals, branching signals from the optical transmission line and
Hikaritsu (optical communications), which has made great strides in inserting signals into optical transmission lines.
It provides an April payment system.

The present invention will be described in detail below with reference to Figure 3 showing an embodiment.

Figure 3 is a block diagram corresponding to the ν1 invention.

The first directional optical coupler cp□ to which the common branch +0 is connected to one optical transmission line, and the other optical transmission line L! A second directional optical coupler cp, which is connected to a common branch 4=00, is provided, and each first branch Φ1 is interconnected through a delay element DL of an optical fiber host. , thereby forming a bidirectional bypass path.

Further, the second branch≠2 of the directional optical coupler cp is connected to the input of the first photoelectric converter 0/E□, and the second branch ≠2 of the directional optical coupler cp
The third branch of p□-#3 is the first electro-optical converter E10
The second branch ≠2 of the directional optical coupler cp, which is connected to the output of the photoelectric converter 0/E1,
Electro-optical converter E10. connected to the output of the coupler cp
, is connected to the input of the second photoelectric converter 0/E, which corresponds to the third branch branch ÷3 of the electro-optical converter E10.

Note that while the directional optical couplers cp, , cp2 also function as branching devices, coupling between the branches is prevented.

Therefore, bidirectional transmission is performed between the optical transmission lines Ll and L via the bypass path including the delay element DL, and the photoelectric converters 0/Et, 0/Ex and the electro-optical converters E'/O□, If you insert an amplifier etc. between the Elo2 and the optical transmission lines ■ and □, the signals from the optical transmission lines
1 and electro-optical converter E10. 4a from the optical transmission line L2.
The signal is amplified and transmitted to the optical transmission line L□ via the optical % converter 0/E and the electro-optical converter E101.

However, since coupling between the branches is prevented, even if amplification is performed between the branches, oscillations etc. will not occur due to recirculation, but if the paths of branches +2 and +3 are disturbed Even if the optical transmission path 8,
Bidirectional transmission between L1 is maintained, there is no switching operation, so there is no momentary interruption of optical transmission, and the optical transmission loss of the directional optical couplers CPs and CP2 is relatively low, so there is no insertion loss. or decrease.

Fig. 4) is a block diagram corresponding to the second invention, and Fig. 3 is similar to Fig. 3, but photoelectric conversion? 807 tons.

A first signal processing circuit SP and a second signal processing circuit SP2 are inserted between the output of 0/E2 and the electro-optical converters E101 and E10□, respectively.
/EI, 0/E2 is received, υ, waveform-shaped, postcoded, etc., and the waveform-shaped signal or encoded signal is sent to the electro-optical converter E10. , Elo.

In addition, in Fig. 4, a bypass path is constructed via the delay element ])L, and even if a failure occurs in the path between branch branches +2 and +3, , bidirectional transmission between the optical transmission lines LH1Lx is maintained.

FIG. 5 is a block diagram corresponding to the third invention, and FIGS. 3 and 4 are the same. 5. Photoelectric converter 0
/El, 0/Efi output and electro-optical converter E10□, E
A first coupling circuit CC having OR gates G1 and G2, a circle and a second coupling circuit CC between the inputs of 10□
2 is inserted into each one, and B C1 city conversion city V El, 0
The signal from /E2 is branched and applied to the terminal device TE via OR gate G3, while photoelectric converter 0/&.

The signal from the external terminal device TE75, etc. is mixed with the signal from the terminal device TE75, etc. by the OR gates G1 and G2, and then sent to the electro-optical converter E10. ．． Giving to Elo.

Therefore, the signal from the optical transmission line L1 is transmitted to the photoelectric converter 0/
The signal from the 11 transmission line L2 is transmitted to the optical transmission line L2 via the path of E8, OR gate GI, and electro-optical converter E10□, while the signal from the 11 transmission line L2 is photoelectrically converted N O/! 2.OR gate G□
, through the path of the electro-optical converter E101, and are transmitted to the optical transmission line L1, and the signals from the optical transmission lines L1, L27'' are given to the terminal device TE, while the signal from the terminal device TE is transmitted to the optical transmission line L1. The optical transmission line L1 is transmitted to the optical transmission line L and Ls.
, Lr1, and at the same time, signals are transmitted and received by the terminal device TE using the optical transmission lines LX and L2.

In addition, in FIG. 5, 11 bypass lines are also formed via the delay element DL, and even if a failure occurs in the branch +2 or the power path, the bidirectional optical transmission lines L1 and L2 can be maintained. Transmission is to be maintained.

However, in FIGS. 3 to 5, the delay element DL is
When the signals from the branches +1 to ≠3 are combined in the directional optical couplers CP1 and C20 by applying a delay time equal to the delay time of the signal living between the branches ≠2 and = #r3, the combined signal This is to prevent the waveform distortion that occurs in the composite signal.If the transmission speed of the transmission signal is low, the waveform distortion that occurs in the composite signal can be ignored.
11-1 can also directly control each other.

In addition, a large number of branch branches are provided, photoelectric converters and electro-optical converters are inserted between these, and relay amplifiers, signal processing circuits, coupling circuits, etc. are individually installed between the photoelectric converters and the τ optical converters. The present invention is flexible in various forms, such as the same effect when inserted, or an optical π2 converter or an electro-optical converter, an amplifier, a waveform shaping circuit, etc. may be integrated.

As is clear from the above description, according to the present invention, there is provided a coupling liquid which does not cause the instantaneous M[ of the transmission signal due to switching and has a bypass path with less large swing loss.

This will replace the remarkable effects in optical communications such as the data/way system.

[Brief explanation of drawings]

Figures 1 and o: z are block diagrams showing conventional examples;
3.1 is a block diagram of an embodiment corresponding to the first invention, and 4.
The figure is a block diagram of an embodiment corresponding to the second invention, and FIG. 5 is a block diagram of an actual female 1i corresponding to the third invention. Ll, L2...O optical transmission line, cp□, C20...
Directional optical coupler, NaO・Fist・・Common branch, +1-43・・
・・Branch branch, 0/E0.0/E2・Fist・・Photoelectric converter,
E10□, Elo,...Electronic converter, SPI,
SF3...Signal processing circuit, C own, CC2...Fist coupling circuit. Patent applicant: Masaki Yamakawa (and 1 other person), Ne9el Co., Ltd. agent

Claims (3)

[Claims] (1) The common branch is connected to one optical transmission line and has a first branch, the second branch is connected to the input of the tenth photoelectric converter, and the third branch is connected to the first optical transmission line. a first directional optical coupler connected to the output of the converter, a common branch connected to the other optical transmission line, and a first branch in the first directional optical coupler; branch and the second branch corresponds to the first photoelectric converter.
A third branch is connected to the output of the electro-optical converter of the first ? b. A coupling device for optical communication, comprising an optical converter and a second directional optical coupler connected to the input of a corresponding 20th photoelectric converter. (2) The common branch is connected to one optical transmission line and has a first branch, the second branch is connected to the input of the first photoelectric converter, and the third branch is connected to the first branch. The first directional optical coupler is connected to the field of the optical converter, and the common branch is connected to the other optical transmission line, and the first branch branch is connected to the other optical transmission line.
a first branch in the directional optical coupler, a second branch connected to the output of a second electro-optical converter corresponding to the photoelectric converter of the snore 1, and a third branch; a second directional optical coupler connected to the input of a second photoelectric converter corresponding to the first electro-optical converter; a first signal processing circuit inserted between the input of the first photoelectric converter and the second photoelectric converter, and receiving a signal from the first photoelectric converter and transmitting a signal to the second photoelectric converter; a second signal inserted between the output of the electro-optical converter and the input of the first electro-optical converter for receiving a signal from the second electro-optical converter and transmitting a signal to the first electro-optical converter; A coupling device for optical communication characterized by comprising a processing circuit. (3) The common branch is connected to one optical transmission line and has a first branch, the second branch is connected to the input of the first photoelectric converter, and the third branch is connected to the first branch. a first directional optical coupler connected to the output of the electro-optical converter, a common branch connected to the other optical transmission line and a first branch connected to the first directional optical coupler in the first directional optical coupler; The second branch is connected to the output of the second electro-optical converter corresponding to the first photo-electric converter, and the third branch is connected to the output of the second electro-optical converter corresponding to the first photo-electric converter. a second directional optical coupler connected to the input of a 20th photoelectric converter corresponding to P, and between the output of the first photoelectric converter and the input of the power 2 electro-optical converter; a first coupling circuit that is inserted and branches a signal from the tenth photoelectric converter, mixes the signal with an external signal, and supplies the mixed signal to the second electro-optical converter; and one of the second photoelectric converters. The output of the first electric light 8! a second coupling circuit inserted between the input of the converter and the second photoelectric converter, which branches the signal from the second photoelectric converter, mixes the signal with the external signal, and supplies the mixed signal to the first electro-optical converter; A coupling device for optical communication, characterized by comprising: