JPS5830248A - Optical bus transmitting system - Google Patents

Abstract

PURPOSE:To improve the reliability of optical transmission, by equalizing the amount of light received at each photodetecting element by changing the amount of light dividing ratio at each light T-branch. CONSTITUTION:A channel 1a for transmitting light is composed of a light emitting element 31, a driving circuit 32, a photodetecting element 41, and an amplifying circuit 42. An optical fiber capable 4 connects the channel 1a with an IO controller 2a through a light variable T-branch 7 has a light variable T- coupler 7a. The amount of light dividing ratio of the branched light/transmitted light of the light T-branch 7 is variable, and the dividing ratio is changed by the IO controller 2a installed to the channel, so that the light receiving amount of each photodetecting element 41a is equalized.

Description

[Detailed Description of the Invention] The present invention is based on an optical bus transmission system consisting of a light emitting element, a light receiving element, an optical branch, and an optical 7-iper cable.In recent years, with the development of optical transmission technology, optical transmission has been put to practical use in a wide range of fields. There is one.

Optical transmission involves conversion of electrical signals and optical signals, but compared to electrical signal transmission, there are 1. It is expected to be applied to information processing systems because it has a large transfer capacity, is less susceptible to interference, and can be made into thinner cables. In order to widely apply it to information processing systems, it is necessary to establish an optical bus transmission method similar to the conventional bus transmission method using electric signals.

As an optical path transmission system, a method using an optical T-branch/T-coupler or an optical star branch/star coupler is known. 1st
The figure shows the conventional bus transmission method using electric signals, and the figure 2 shows the optical T.
An optical bus transmission system using branching and FIG. 3 shows an optical bus transmission system using optical star branching.

For example, channel 1 in an information processing device. IO controller (IOC) in la and multiple input/output devices 2.2
This is a bus transmission method or Hiroko bus transmission method provided between the A and A.

In the conventional bus transmission system shown in FIG. 1, the drive circuit (
The receiving circuit (RV) 22 provided in a plurality of l002 receives the electric signal of DV) 11 through an electric cable 3t- forming a transmission circuit, and conversely receives the electric signal of each DV21 provided in a plurality of l002 into a channel. RV installed in 1
12 is normally received.

Figure 2 shows an optical bus transmission system using an optical T-branch/optical block 2 for the electrical signal bus transmission system with the configuration shown in Figure 1, and Figure 3 uses an optical star branch/optical bus 1 plastic. This is an example of an optical bus transmission system.

Channel 1 in FiJ11 diagram in Figure 2 and Figure 3
A light emitting element 31 and its driving circuit 32 are provided in the optical transmission channel 1a on the DVIIO side, and a light receiving element 41 and its multiplication circuit 42 are provided on the RV12 side. In addition, in the optical transmission l002a, the light receiving element 41m and its amplifier circuit 4
2a is provided, and DV21) K light emitting element 31m and its drive circuit 32 & are provided. ◇4 is an optical fiber cable. As shown in the cross-sectional view, all of them are formed on the surface of a transparent body, for example, a glass plate, and are coated with a bar 7 mm 25 by vapor deposition of a good metal.
1 is arranged at 45° with respect to the optical axis, and a convex lens 52a,
b, c and optical connectors 53a, b, e are arranged, and the relationship between optical input and optical output is different, but the structure is common and can be used interchangeably.

In FIG. 4(a), incident light expanding and convex lenses 52a and 52b
At tC, the beam becomes parallel to the solar beam, and then the half-mirror 511C divides it into multi-branched light and transmitted light.In Figure 4), a portion of the light emitted by both people becomes composite light.The ratio is half-mirror. It becomes a constant value according to the characteristics of 51. Further, a similar part exists between the optical star branch 6 and the optical star coupler 6a, and 50 is a light-shielding container.

Comparing the optical bus transmission method using the optical TO board 5/optical coupler 5 & in Fig. 2 and the optical bus transmission method using the optical star branch 6/optical star coupler 6a shown in Fig. 3 in and \, the optical fiber cable The total length of the optical T branch 5/optical T coupler 5a is shorter, and it is also superior in terms of the cost of the optical 7-IPA cable and the difficulty of installing the optical 7-IPA cable, so it can be said that it is preferable to PL. However, optical T branch/optical T
The optical path transmission system using Kagura has the disadvantage that it is difficult to distribute the power level of received light evenly due to the distribution of light. For example, when using the optical T-branch 5, the branched light of the optical T-branch /
When the division ratio of transmitted light is large, the amount of light received by the light receiving element 41m at the near end 10C2a is large, and the amount of light received by the light receiving element 41m at the far end 10C2a is small, and when the division ratio is small, the amount of light received at the far end is large. The amount of light received at the near end becomes smaller.

For example, in the configuration shown in Fig. 2, if there are 5 l0C2a #1 to #5 and the insertion loss of the optical T-branch 5 and the loss of the fiber cable 4 can be ignored, the division ratio of branched light/transmitted light of the optical T-branch is 1. /3: For 2/3, use #1 110C2
1/3 of the amount of light received = -4,8db) If -6,5db
, -8,3db, -10,1db and -7,Od
b, the division ratio is 1/10: 9/10 (in case of D, the amount of light received at 1002m for #l is 1/10 = -10d
-10,5dbt -10,9db, -1
1.4db and -1.8db.

In this way, according to the division ratio of the optical T-branch, 10 of #1 to 5 are
There are cases where there is a difference in the amount of light received at 0.2m.

The sign 114p rate of the signal is greatly affected by the amount of light received, so we have explained the example of optical T-branching using half T-branch, but in the case of nine T-branching using other means, there will be a difference in the amount of light received by 4IOC2&. It is obvious that the conventional optical transmission path method using optical T-branches 5 causes variations in the code error rate in multiple 1002m, lowering the reliability of the optical transmission system as a whole, and reducing the maximum light that can be connected. It has the disadvantage that the number of T minutes is also limited.

An object of the present invention is to provide a means for compensating for this drawback. Therefore, the present invention provides a light emitting element, a plurality of light receiving elements, and a light T corresponding to the plurality of light receiving elements.
In an optical bus transmission system consisting of optical 7-way fiber cables that connect the optical T-branches to each of the above-mentioned elements and the optical T-branches,
For each branch, the light intensity division ratio of branched light/transmitted light is variable,
Information on the amount of light received by each light-receiving element and split light at each optical T-branch/
There is no means for transmitting the light intensity division ratio information of the transmitted light from the light receiving element side to the light emitting element side.
This method is characterized in that the amount of light received by a plurality of light receiving elements is made equal by changing the light amount division ratio of divided light/transmitted light for classification to the light emitting element side.

The following [IIK will specifically explain one embodiment of the present invention] Figures (a) and (b) show the functions of variable branching light/transmitted light used in the optical bus transmission system in one embodiment of the present invention. FIG. 3 is a structural diagram of the optical variable T-branch 7 provided. The optical variable T-branch 7 is the fifth
As shown in Fig. 4(a), the conventional optical T-branch 5 has a variable half splitter 54 instead of the half 9-51, and the other configuration is as shown in Fig. 4(a).
) (b) and the same convex lens 52a.

b, @ and light; nectar 53a, b@c.

Variable half mirror 54 is 11! As shown in the perspective view of FIG. A shaft 54b is attached to a variable half mirror plate 54a whose film thickness is sequentially and continuously changed.
is provided, and the variable bar 2-plate 54 is provided with the rotation of the shaft 54b.
It is configured so that the incident light can be continuously branched for 100 seconds by rotating it. 50a is a light-transmitting container. The variable optical T-coupler 7a has the same structure as that shown in FIG. The input and output are reversed.

FIG. 6 shows an optical bus transmission system according to an embodiment of the present invention: a plurality of optical T branches 5/5/5 used in the conventional optical bus transmission system shown in FIG. Optical T coupler 5 & multiple 9Ts with variable branching/transmission light function
The branch 77 light T-cube is the same except that the fIlk was changed to 77a.

and \, the amount of light received by each l002a in the optical bus transmission system using a plurality of optical T-branches 7 in the iris 6 diagram is adjusted to be equal in frame according to the following procedure.

(1) Initially, the light amount division ratio of each optical T-branch 7 is set to the minimum. (Increase the amount of transmitted light.) Q) At that point, measure the amount of light received by the table light receiving element 41m.

If the amount of received light does not reach the minimum level that allows optical transmission, the light amount division ratio of the optical T-branch 7 corresponding to that light receiving element 41m is increased to the minimum level that allows optical transmission.

(3) Each l002a transmits the light amount division ratio of each optical T-branch 7 and the received light amount information of the light receiving element 41a to the channel 1a.
to be transmitted. In the example shown in the diagram, light is transmitted to the light receiving element 41 of the channel 11 by the light emitting element 31m provided in each l0C2aK through the optical fiber coupler 4 and the optical T coupler 7a.

(4) Optical T-branch 7 from each l002m in channel 1 &
The loss in the optical fiber cable 4 and the optical T-branch 7 is calculated from the light intensity division ratio, the information on the amount of light received by the light receiving element 41a, and the information on the amount of light emitted by the light emitting element 31 of channel 1a. Based on these values, calculate the light intensity division ratio of each optical T-branch 7 so that the amount of light received by all light-receiving elements 41m is equal.0(5) Light intensity division of nine T-branches 7 calculated for each l002aK Transmit 11t of hate. For this information transmission, the light emitting element 31 of channel 1m uses the optical bus transmission system to send the information to each light receiving element 41a.

(6) In each l002a, the light intensity division ratio of the corresponding optical T-branch 7 is changed and set according to the light intensity division ratio information from channel 1 &.

As described above, it is possible to equalize the amount of light received by each light receiving element 41a, which satisfies the name IOC2m. In the case of an information processing system, these procedures may be incorporated into a function for automatically diagnosing each input/output device when the system is changed or, if necessary, when the information processing system is powered on.

The above has explained the operation by the optical T branch 7 from channel 1a to each l0C2a, but from each l002a to channel 1a.
Needless to say, it is possible to equalize the amount of light received in the optical transmission to the channel based on the information on the amount of light received in the channel and the light amount combination ratio in the T coupler. Also, if you do not use a half mirror and use a T coupler with no coupling loss, the amount of light received in the channel will be almost equal.
If necessary, the light emission amount t141 of the light emitting element of each IOC can be adjusted.In accordance with an embodiment of the present invention, the light intensity division ratio of each party T branch is changed by 1F to adjust the light reception amount of each light receiving element. By making them equal, a highly reliable optical bus transmission system can be obtained.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional bus transmission system using electrical signals, Figure 2 is a block diagram of a conventional optical bus transmission system using optical T-branches/optical T-coupler, and Figure 3 is a block diagram of a conventional optical bus transmission system. A block diagram of an optical bus transmission system using branching/optical stackers, Figures 4 (a) and (b) show the conventional optical bus transmission system.
A cross-sectional view of the structure of the branching/optical T-cube 2, Fig. 5 (a) ■) is a diagram showing the structure of the variable T limb, and Fig. 6 is a block diagram of the optical bus transmission system in a simple embodiment of the present invention. It is. 1.1a is the channel, 2,2a is the tunnel 2.3
is a transmission cable, 4 is an optical fiber cable, and 5F! , an optical T-branch, 5a is an optical T-cube, 2 is an optical star branch, 6& is an optical star coupler, 7 is an optical variable T-branch, and 7at; is an optical variable T-branch. 72 Otsuguchi

Claims (1)

[Claims] In an optical bus transmission system consisting of one light-emitting element, a plurality of light-receiving elements, an optical T-branch corresponding to the plurality of light-receiving elements, and an optical fiber cable connecting each of the elements to an optical T-branch, each of the optical T-branches A means for making the light intensity division ratio of the branched light/transmitted light variable and transmitting the received light quantity information of each light receiving element and the light quantity division ratio information of the branched light/transmitted light in each party T branch from the light receiving element side to the light emitting element side. If you are not prepared for this, you can change the light amount division ratio of the branched light/transmitted light of each optical T branch from the light emitting element side to the light receiving element side.
An optical bus transmission method that equalizes the amount of light received by several light receiving elements.