JPH1141177A - Parallel optical transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the variation of transmission delay as the whole parallel optical transmission device by reducing the variation of the sum of each transmission delay by the electric wiring of an optical transmitting module, the electric wiring of the optical receiving module, and table fibers for each channel. SOLUTION: This device is constituted of an optical transmitting module 101, optical receiving module 102, and tape fibers 103a-103d. The length of each tape fiber 103a-103d is set so that a difference between the maximum value and the minimum value among all the channels of the sum of transmission delay by each electric wiring of the optical transmitting and receiving modules 101 and 102 and the tape fibers 103a-103d of a transmitted signal can not be larger than a difference between the maximum value and the minimum value of the sum of transmission delay by the electric wiring of the optical transmitting and receiving modules 101 and 102, or a difference between the maximum value and the minimum value of the sum of transmission delay by the tape fibers 103a-103d. Thus, skew as a whole can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel optical transmission device used for an optical interconnection system.

[0002] The optical interconnection technology is a wiring technology for high-speed, high-density packaging in communication devices and the like. The optical transmission device used in the optical interconnection system is composed of an optical transmission module, an optical reception module, and an optical fiber. The input electric signal is converted into an optical signal by the optical transmission module, and transmitted through the optical fiber as a transmission line. Then, the light is received by the optical receiving module, converted into an electric signal, and output. The parallel optical transmission device is obtained by increasing the transmission speed and the mounting density by increasing the number of channels of the optical transmission device. Usually, a tape fiber is used for a multi-core optical fiber which is a transmission path of the parallel optical transmission device.

On the other hand, skew is a problem in parallel transmission. The skew is a variation in transmission delay of a signal between channels, and is quantitatively defined by a difference between a maximum delay value and a minimum delay value of all channels of transmission delay. The transmission speed and transmission distance of a parallel transmission system are often limited by the skew of all channels rather than the transmission speed and transmission distance of each channel. Therefore, skew management is an important issue in a parallel transmission system, and it is desirable to reduce it as much as possible.

[0004] The total transmission delay of each channel is obtained by accumulating delays generated in various processes for each channel from when a signal is input to the optical transmission module to when it is output from the optical reception module. . Therefore, the dispersion of the transmission delay is caused by the dispersion between channels of the delay occurring in each process of transmission. For example, what is called fiber skew is a difference in transmission delay of an optical signal between tape channels as a transmission path between channels. Also,
In the optical transmission module and the optical reception module of the parallel optical transmission device, the pads of the narrow pitch IC and the wide pitch input / output terminals are connected by electric wiring, but the structure is efficiently realized on a small substrate. Therefore, the wiring length of the electric wiring differs for each channel, and a difference in transmission delay of electric signals often occurs.

In the conventional parallel optical transmission apparatus, in order to reduce the skew, a method of reducing a variation in delay generated in each of these transmission processes, for example, a method of using a tape fiber having a small fiber skew is used. I was

However, the above-mentioned parallel optical transmission apparatus has the following problems. That is, even if the dispersion of delays occurring in the individual steps of transmission is reduced, the dispersion of the total transmission delay in which those delays are accumulated is a result of the superposition of the dispersion of delays occurring in the individual steps of transmission.
In general, it is larger than the variation in delay that occurs in each process of transmission. This problem will be described below with reference to the drawings.

FIG. 3 shows a parallel optical transmission apparatus 300 having 40 channels and a transmission distance of 100 m. This parallel optical transmission device 300
It comprises an optical transmission module 301, an optical reception module 302, and tape fibers 303a, 303b, 303c, 303d. FIG. 4 is a diagram showing an example of a variation in transmission delay due to electric wiring for each channel of the optical transmitting module 301 or the optical receiving module 302. As can be seen from this figure, the transmission delay is different between each channel, and the skew of each is about 125 ps (difference between the maximum value and the minimum value in FIG. 4). If this is doubled, the optical transmission module 301
The value of the electric wiring skew of both the optical receiving module 302 and the optical receiving module 302 is obtained, which is about 250 ps.

[0008] Tape fibers 303a, 303b, 303c and 303d
Is a GI-50 / 12 with 10 channels with low fiber skew
5 For tape fiber. FIG. 5 is a diagram showing an example of variation in transmission delay per unit distance of each channel of the tape fiber. From this figure, it can be seen that the fiber skew per unit distance is about 1.5 ps / m. Tape fibers 303a, 303b, 303c and 303d have a length of 10
Since it is 0.00m, the fiber skew is about 150ps.

The optical transmission module 30 of the parallel optical transmission device 300
Transmission delay due to electrical wiring in 1 and the optical receiving module 302
Transmission delay due to electrical wiring of the tape fibers 303a and 30
3b, 303c and 303d overlap with the transmission delay,
The variation in delay between the channels is as shown in FIG. From this figure, the skew is about 300 ps, which is larger than the individual value of the electric wiring skew or the fiber skew.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object of the present invention is to provide a parallel optical transmission device with reduced skew as a whole.

[0011]

In order to achieve the above object, a parallel optical transmission apparatus according to the present invention achieves the above-mentioned object by transmitting a signal transmitted by an optical wiring of an optical transmission module and by transmitting an electric signal of an optical receiving module. The difference between the maximum value and the minimum value of the sum of the delay and the transmission delay due to the tape fiber among all the channels is the transmission delay due to the electric wiring of the optical transmission module and the transmission delay due to the electric wiring of the optical receiving module. The difference between the maximum value and the minimum value of the sum of all the channels or the difference between the maximum value and the minimum value of the all channels of the transmission delay caused by the tape fiber is not larger than the difference. The length of each of the tape fibers is set.

Further, another parallel optical transmission device of the present invention provides a transmission delay of a signal transmitted by an electric wiring of an optical transmission module, a transmission delay by an electric wiring of an optical reception module, and a sum of a transmission delay by a tape fiber. The difference between the maximum value and the minimum value of all the channels is the maximum of the sum of the transmission delay due to the electric wiring of the optical transmission module and the transmission delay due to the electric wiring of the optical receiving module. The length and individual length of each tape fiber so that the difference between the value and the minimum value or the difference between the maximum value and the minimum value of the transmission delay due to the tape fiber among all the channels is smaller. The transmission delay value of each channel in the tape fiber is set.

In such a parallel optical transmission apparatus of the present invention, variations in transmission delay due to electrical wiring of the optical transmission module, variations in transmission delay due to electrical wiring of the optical receiving module, and variations in transmission delay due to tape fiber are reduced. Even if they exist, parallel optical transmission is achieved by reducing the variation in the sum of the transmission delay due to the electrical wiring of the optical transmission module, the transmission delay due to the electrical wiring of the optical receiving module, and the transmission delay due to the tape fiber for each channel. Variations in transmission delay of the entire device can be reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment] FIG. 1 is a diagram for explaining a first embodiment of the present invention. 100 is 40 channels, transmission distance is 10
This is a parallel optical transmission device of 0 m. This parallel optical transmission device 100
Is composed of an optical transmission module 101, an optical reception module 102, and tape fibers 103a, 103b, 103c, and 103d. The transmission delay due to the electric wiring of each channel of the optical transmission module 101 or the optical reception module 102 is shown in FIG.
The skew of each is about 125ps. Optical transmitting module 101 and optical receiving module 102
The value of the electric wiring skew of both is about 25
0ps.

[0016] Tape fibers 103a, 103b, 103c and 103d
Is a 10 channel GI-50 / 125 tape fiber.
The variation of the transmission delay per unit distance of each channel of the tape fiber is as shown in FIG. 5, and the fiber skew per unit distance is about 1.5 ps / m. The length of these tape fibers is
103d is adjusted to 100.02 m, 103b and 103c are adjusted to 100.00 m in length, and the fiber skew is about 150 ps each.

The optical transmission module 10 of the parallel optical transmission device 100
The transmission delay due to the electrical wiring of 1 and the optical receiving module 102
Transmission delay due to the electrical wiring of the
3b, 103c and 103d,
The variation in delay between the channels is as shown in FIG. From this figure, it can be seen that the skew is about 250 ps, which is not larger than the electric wiring skew, and the skew as a whole is reduced as compared with the conventional example shown in FIG.

Embodiment 2 FIG. 2 is a view for explaining a second embodiment of the present invention. 200 is 40 channels, transmission distance is 10
This is a parallel optical transmission device of 0 m. This parallel optical transmission device 200
Comprises an optical transmitting module 201, an optical receiving module 202, and tape fibers 203a, 203b, 203c, and 203d. The transmission delay due to the electric wiring of each channel of the optical transmission module 201 or the optical reception module 202 is shown in FIG.
The skew of each is about 125ps. Optical transmitting module 201 and optical receiving module 202
The value of the electric wiring skew of both is about 25
0ps.

Tape fibers 203a, 203b, 203c and 203d
Is a 10 channel GI-50 / 125 tape fiber.
Among them, the dispersion of the transmission delay per unit distance of each channel of the tape fibers 203b and 203c is as shown in FIG. 5, and the fiber skew per unit distance is about 1.5p.
s / m. On the other hand, the transmission delay value per unit distance of each channel of the tape fibers 203a and 203d is adjusted so as to be distributed linearly as shown in FIG. 8, and the fiber skew per unit distance is about 2.5 ps /. m. The length of these tape fibers is adjusted to 100.02 m for tape fibers 203a and 203d, and to 100.00 m for 203b and 203c.
And 203c are about 150 ps, and the tape fibers 203a and 203d are about
250ps.

The optical transmission module 20 of the parallel optical transmission device 200
The transmission delay due to the electrical wiring of 1 and the optical receiving module 202
Transmission delay due to the electrical wiring of the tape fiber 203a, 20
3b, superimposing the transmission delay by 203c and 203d,
The variation in delay between the channels is as shown in FIG. From this figure, the skew is about 150 ps, which is smaller than the electric wiring skew or the fiber skew, and the skew as a whole is reduced as compared with the conventional example shown in FIG. 6 and the first embodiment shown in FIG. You can see that there is.

In the above description, the limited embodiments of the present invention have been described. However, it is needless to say that the present invention is not limited to these embodiments. For example, the tape fiber may be divided in the length direction and connected by an optical fiber connector. Needless to say, the number of channels is not limited to 40.

[0022]

According to the present invention, in the parallel optical transmission device, the dispersion of the sum of the transmission delay due to the electric wiring of the optical transmission module, the transmission delay due to the electric wiring of the optical receiving module, and the transmission delay due to the tape fiber is reduced. The skew of the entire parallel optical transmission device can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first embodiment of a parallel optical transmission device according to the present invention.

FIG. 2 is a diagram illustrating a parallel optical transmission apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a conventional parallel optical transmission device.

FIG. 4 is a diagram illustrating an example of a variation in transmission delay due to electric wiring for each channel of an optical transmission module or an optical reception module.

FIG. 5 is a diagram illustrating an example of a variation in transmission delay per unit distance of each channel of a 10-fiber tape fiber.

FIG. 6 is a diagram illustrating an example of a variation in delay between channels in a conventional parallel optical transmission device.

FIG. 7 is a diagram illustrating an example of variation in delay between channels in the first embodiment of the parallel optical transmission device according to the present invention.

FIG. 8 is a diagram showing an example of a variation in transmission delay per unit distance of each channel of a 10-fiber tape fiber used in a second embodiment of the parallel optical transmission device according to the present invention.

FIG. 9 is a diagram showing an example of a variation in delay between channels in the second embodiment of the parallel optical transmission device according to the present invention.

[Explanation of symbols]

 100, 200, 300 Parallel optical transmission device 101, 201, 301 Optical transmission module 102, 202, 302 Optical receiving module 103, 203, 303 Tape fiber

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04B 10/18

Claims (2)

[Claims] An optical transmission module having a built-in electric wiring,
In a parallel optical transmission device that includes an optical receiving module and a tape fiber with a built-in electric wiring and transmits a multi-channel signal, a transmission delay of the signal to be transmitted due to the electric wiring of the optical transmitting module, The difference between the maximum value and the minimum value of the sum of the transmission delay caused by the electric wiring and the transmission delay caused by the tape fiber among all the channels is the transmission delay caused by the electric wiring of the optical transmission module and the electric delay of the optical reception module. From the difference between the maximum value and the minimum value of the sum of the transmission delays due to the wiring among all the channels, or the difference between the maximum value and the minimum value among the all the channels of the transmission delay due to the tape fiber. A parallel optical transmission device wherein the lengths of the individual tape fibers are set so as not to increase. 2. An optical transmission module having a built-in electric wiring.
In a parallel optical transmission device that includes an optical receiving module and a tape fiber with a built-in electric wiring and transmits a multi-channel signal, a transmission delay of the signal to be transmitted due to the electric wiring of the optical transmitting module, The difference between the maximum value and the minimum value of the sum of the transmission delay caused by the electric wiring and the transmission delay caused by the tape fiber among all the channels is the transmission delay caused by the electric wiring of the optical transmission module and the electric delay of the optical reception module. From the difference between the maximum value and the minimum value of the sum of the transmission delays due to the wiring among all the channels, or the difference between the maximum value and the minimum value among the all the channels of the transmission delay due to the tape fiber. To reduce the length of each of the tape fibers and the value of the transmission delay of each channel in each tape fiber, Parallel optical transmission apparatus characterized by was boss.