JP2000009959A - Optical bus and signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical bus which is high in light utilization efficiency and is small in the fluctuation in signal light intensity at an exit position even if a relative positional relation between an incident position and exit position of signal light changes by providing the inside of an optical bus body with a signal light collimating means and a signal light diffusing means. SOLUTION: A convex cylindrical lens 3a disposed on one end face 4a side of the optical bus 1 converges the incident signal light from the end face 4a to the prescribed point in the optical bus body 4. A concave cylindrical lens 5 disposed near the prescribed point within the optical bus body 4 collimates the signal light propagating in the optical bus body 4 through the lens 3a. A light diffusing part 6 diffuses the signal light collimated by the lens 5 into the optical bus body 4. A convex cylindrical lens 3b disposed on another end face 4b side collimates the signal light which is diffused in the light diffusing part 6 and is emitted from another end face 4b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical bus for transmitting an optical signal and a signal processing device using the optical bus.

[0002]

2. Description of the Related Art With the development of very large scale integrated circuits (VLSI), circuit functions of circuit boards (daughter boards) used in data processing systems have been greatly increased. As the number of signal connections to each circuit board increases as circuit functions increase, a data bus board (motherboard) that connects each circuit board with a bus structure has a parallel architecture that requires a large number of connectors and connection lines. Has been adopted. Although the parallel bus has been improved by increasing the number of connection lines and miniaturization, the operating speed of the parallel bus has been improved. It may be limited by the operating speed of the bus. In addition, electromagnetic noise (EMI: Electro
The problem of magnetic interference is also a major constraint on improving the processing speed of the system.

In order to solve such a problem and improve the operation speed of the parallel bus, use of an in-system optical connection technique called optical interconnection has been studied. The outline of the optical interconnection technology is described in "Seiji Uchida, Academic Lecture Meeting of Circuit Packaging 15C01, pp. 146-64". 201-
202 ”and“ H. Tomimiuro et al. ,
“Packaging Technology for O
optical Interconnects ", IEEE
E Tokyo No. 33 pp. 81-86,19
94], various forms are proposed depending on the configuration of the system.

[0004] Among various types of optical interconnection techniques proposed in the past, Japanese Patent Application Laid-Open No. 2-41042 discloses an optical data transmission system using a high-speed, high-sensitivity light emitting / receiving device applied to a data bus. An example is disclosed in which light emitting / receiving devices are arranged on both front and back surfaces of each circuit board, and light emitting / receiving devices on adjacent circuit boards incorporated in the system frame are spatially optically coupled. A serial optical data bus for loop transmission between circuit boards has been proposed. In this method, an optical signal sent from a certain circuit board is subjected to optical / electrical conversion on an adjacent circuit board, and is further subjected to electrical / optical conversion on that circuit board. Each of the circuit boards is sequentially arranged in series, and is transmitted between all the circuit boards incorporated in the system frame while repeating optical / electrical conversion and electric / optical conversion on each circuit board.

For this reason, the signal transmission speed depends on and is limited by the light / electricity conversion speed and the electric / light conversion speed of the light receiving / light emitting device arranged on each circuit board.
In addition, since data transmission between each circuit board uses optical coupling via a free space by a light receiving / light emitting device arranged on each circuit board, it is arranged on both front and back sides of an adjacent circuit board. It is necessary that the optical alignment of the light emitting / receiving devices used is performed and that all circuit boards are optically coupled. Furthermore, since each circuit board is optically coupled via a free space, it is expected that interference (crosstalk) will occur between adjacent optical data transmission paths and data transmission failure will occur. In addition, it is expected that data transmission failure occurs due to scattering of an optical signal due to an environment in the system frame, for example, dust or the like. Furthermore, since each circuit board is arranged in series,
If one of the boards is removed, the connection will be interrupted at that point, and an extra circuit board will be required to compensate for the disconnection. That is, there is a problem that the circuit board cannot be freely inserted and removed, and the number of circuit boards is fixed.

A technique for transmitting data between circuit boards using free space is disclosed in Japanese Patent Application Laid-Open No. 61-196210. The technology disclosed herein includes a plate having two parallel surfaces, opposed to a light source, and includes a diffraction grating and a reflection element arranged on the surface of the plate. This is a method of optically coupling between circuit boards. However, in this method,
There is a problem that light emitted from one point can be transmitted to only one specific point, and that all circuit boards cannot be exhaustively connected like an electric bus. In addition, since free space is used, complicated optical systems are required,
Since alignment is difficult, it is expected that data transmission failure will occur due to crosstalk between adjacent optical data transmission lines due to the displacement of the optical element. Further, since connection information between circuit boards is determined by a diffraction grating and a reflection element arranged on the plate surface, the circuit board cannot be freely inserted and removed, and there is a problem that the expandability of the device is low.

[0007]

In order to solve these problems, it is conceivable to use an optical bus that diffuses, propagates, and emits the incident signal light. However, if such an optical bus is simply manufactured, When signal light is incident from one incident direction, the emission direction of the signal light emitted from the optical bus varies depending on the emission direction of the signal light. Further, when attention is paid to a certain emission position, the emission direction of the signal light emitted from the emission position varies depending on the incident position of the signal light. A light receiving element is arranged opposite to the emission position to receive the signal light emitted from the emission position. It is desirable that the light receiving element is provided with a condensing lens in order to improve light use efficiency. However, if the emission direction of the signal light varies as described above, the light condensing efficiency provided by the condensing lens provided in the light receiving element is reduced. Therefore, the amount of light received by the light receiving element varies. For this reason, it is necessary to detect light having a wide dynamic range. To configure a signal processing device using such an optical bus, it is necessary to design a circuit suitable for the wide dynamic range. However, there is a problem that it is difficult to design a circuit that conforms to the above, which tends to cause an increase in power consumption and cost.

Therefore, in order to solve these problems,
An optical bus including an optical path changing unit, a light diffusing unit, and a collimating unit as described below is conceivable. FIG. 6 is a schematic configuration diagram of an optical bus including an optical path changing unit, a light diffusing unit, and a collimating unit. As shown in FIG. 6, the optical bus 100 includes an optical diffusion unit 102 provided at a predetermined position inside an optical bus main body 101 and an incident signal light provided on one end face 101 a of the optical bus main body 101. It comprises an optical path changing means 103 for directing the light to the light diffusing means 102, and a collimating means 104 provided on the other end face 101b of the optical bus main body 101 for emitting the signal light diffused by the light diffusing means 102 as parallel light. ing. In the optical bus 100, the signal light is emitted at a fixed angle without depending on the relative positional relationship between the incident position and the emission position of the signal light, so that the light is condensed by the condenser lens provided in the light receiving element. Efficiency does not change, and fluctuations in signal light intensity due to signal light input / output positions can be suppressed. This optical bus 100
In order to obtain higher light use efficiency, the light diffusing means 1
As 02, it is necessary to use a light diffusion unit having a high transmittance and a diffusion characteristic of diffusing the signal light only within the light receiving range of the light receiving element that receives the emitted signal light.

However, since the light diffusion means having such a diffusion characteristic has directivity, the intensity distribution of the diffused light becomes non-uniform depending on the angle at which the signal light enters the light diffusion means. In the above-described optical bus 100, the angle of incidence on the light diffusion unit 102 changes depending on the incident position of the signal light. Therefore, when the light use efficiency is improved by using the light diffusion unit having the above-described diffusion characteristics, In this case, the signal light intensity at the emission position also varies due to the relative positional relationship between the incident position and the emission position. The present invention
In view of the above circumstances, an object of the present invention is to provide an optical bus with high light use efficiency and small fluctuation of signal light intensity at an emission position even when a relative positional relationship between an incident position and an emission position of signal light changes. And

[0010]

An optical bus according to the present invention, which achieves the above object, comprises: an optical bus main body for receiving signal light from one end face, propagating through the inside, and emitting signal light from the other end face; Via a converging means provided on the one end face side for converging the incident signal light to a predetermined point in the optical bus main body, and via the converging means provided near the predetermined point in the optical bus main body First collimating means for collimating the signal light propagating in the optical bus main body, and light diffusing means provided in the optical bus main body for diffusing the signal light collimated by the first collimating means And second collimating means provided on the other end face side for collimating the signal light diffused by the light diffusing means and emitted from the other end face.

According to another aspect of the present invention, there is provided a signal processing apparatus comprising: a base; a signal light emitting end for emitting signal light; a circuit for generating a signal to be carried by the signal light emitted from the signal light emitting end; A plurality of circuit boards mounted with at least one of a signal light incident end for receiving signal light and a circuit for performing signal processing based on a signal carried by the signal light incident from the signal light incident end,

An optical bus main body for receiving signal light from one end face and propagating through the inside to emit signal light from the other end face; and an optical bus main body provided on the one end face side for receiving the incident signal light. And a first collimator provided near the predetermined point inside the optical bus main body and configured to collimate the signal light propagating through the optical bus main body via the converging means. Means, light diffusion means provided inside the optical bus main body for diffusing the signal light collimated by the first collimating means, and light diffusion means provided on the other end face side, which is provided on the other end face side. An optical bus having second collimating means for collimating the signal light emitted from the other end face, and the signal light emitting end or the signal light incident end mounted on the circuit board being mounted on the circuit board; Wherein the the condition being optical bus optically coupled with a plurality of base fixing portion for fixing on said substrate.

[0013]

Embodiments of the present invention will be described below. FIG. 1 is a plan view showing a first embodiment of the optical bus of the present invention. As shown in FIG.
The optical bus main body 4, the convex cylindrical lenses 3a and 3b provided on both end surfaces 4a and 4b of the optical bus main body 4, the concave cylindrical lens 5 provided inside the optical bus main body 4, and the concave And a light diffusing portion 6 provided adjacent to the cylindrical lens 5 of FIG.

The optical bus body 4 receives signal light from one end face 4a, propagates through the inside, and emits signal light from the other end face 4b. The convex cylindrical lens 3 a provided on the end face 4 a converges the incident signal light to a predetermined point in the optical bus main body 4. A concave cylindrical lens 5 provided near a predetermined point inside the optical bus main body 4 collimates the signal light propagating in the optical bus main body 4 via the cylindrical lens 3a. The light diffusion unit 6 diffuses the signal light collimated by the concave cylindrical lens 5 into the optical bus main body 4. The convex cylindrical lens 3b provided on the other end surface 4b side collimates the signal light diffused by the light diffusion unit 6 and emitted from the other end surface 4b.

The convex cylindrical lens 3a in the present embodiment corresponds to the converging means in the present invention, and the concave cylindrical lens 5 corresponds to the first collimating means in the present invention. The light diffusing section 6 corresponds to the light diffusing means according to the present invention, and the convex cylindrical lens 3b corresponds to the second collimating means according to the present invention. Here, the convex cylindrical lens 3a, the concave cylindrical lens 5, and the convex cylindrical lens 3b are located on the same optical axis 10 and have the convex cylindrical lens 3a.
a and the concave cylindrical lens 5 have the same focal point. In addition, the focal point of the convex cylindrical lens 3 b is arranged so as to be located in the light diffusion section 6.

FIG. 2 is a schematic diagram showing how signal light propagates in the optical bus according to the first embodiment of the present invention. FIG.
In the case where the signal light 7a parallel to the optical axis 10 is incident on the incident position A with respect to the convex cylindrical lens 3a provided on the one end face 4a side of the optical bus 1,
The state of propagation of the signal light when the signal light 7b parallel to 0 is incident on the incident position B is shown. As shown in FIG. 2, the signal lights 7a and 7b incident on the incident positions A and B are
Each beam is converged by the convex cylindrical lens 3a and is incident on the concave cylindrical lens 5. Since the convex cylindrical lens 3a and the concave cylindrical lens 5 are arranged so that the optical axis and the focal position are equal, the signal lights 7a and 7b pass through the concave cylindrical lens 5 and are parallel to the optical axis 10. The light is emitted as light and enters the light diffusion unit 6.

As described above, the signal light beams 7a and 7b are transmitted to the light diffusing portion 6 by the action of the convex cylindrical lens 3a and the concave cylindrical lens 5 even if the incident positions A and B with respect to the optical bus 1 are different from each other. Are incident at the same incident angle, so that the intensity distribution of the signal light beams 8a and 8b diffused from the light diffusion unit 6 is uniform even when the light diffusion unit 6 has directivity. The signal light beams 8a and 8b diffused by the light diffusing unit 6 are emitted as signal light beams 9a and 9b via a convex cylindrical lens 3b provided on the other end surface 4b side of the optical bus 1, but the convex cylindrical lens Since the focal position of 3b is located in the light diffusion section 6, the convex cylindrical lens 3b emits signal lights 9a and 9b substantially parallel to the optical axis 10.

As described above, the convex cylindrical lens 3
a acts as a converging means for converging the incident signal lights 7a and 7b to a predetermined point in the optical bus main body 4, and the concave cylindrical lens 5 collimates the signal light propagating in the optical bus main body 4 for the first. Act as collimating means for
The convex cylindrical lens 3b functions as second collimating means for collimating the signal lights 9a and 9b diffused by the diffusing means and emitted from the other end face 4b. Alternatively, the convex cylindrical lens 3a and the concave cylindrical lens 5 are configured so that the signal light beams 7a and 7b respectively incident from different incident positions A and B are incident on the light diffusion unit 6 at the same incident angle. It can be described as acting as an optical path conversion means for converting the optical path of the signal light.

As described above, the signal light beams 7a and 7b have the same incident angle to the light diffusion unit 6 even though the incident positions A and B with respect to the optical bus 1 are different from each other. Emission positions C-C ', D- of signal light from bus 1
Since the emission angles of the signal lights 9a and 9b can be equalized without depending on D ', even if the light use efficiency is improved by using a light diffusion section or a condenser lens having directivity, the signal light 9a, 9b is improved. And the intensity distribution of the signal light on the emission side can be kept uniform without being affected by the fluctuation of the incident position.

As a converging means for converging incident light to a predetermined point in the optical bus main body 4, a linear Fresnel lens, a plano-convex lens, a biconvex lens, a Fresnel lens, or the like is used in addition to the above-mentioned convex cylindrical lens 3a. be able to. As the first collimating means for collimating the signal light propagating in the optical bus main body via the converging means, in addition to the concave cylindrical lens 5 described above, a convex cylindrical lens or a 周期 cycle A long distributed index lens or the like can be used. In addition to the convex cylindrical lens 3b, a linear Fresnel lens, a plano-convex lens, a biconvex lens, a Fresnel lens, or the like is used as the second collimating means for collimating the signal light emitted from the other end surface 4b of the optical bus main body 4. Can be used.

In this embodiment, the optical bus main body 4 and the convex cylindrical lens 3a or the optical bus main body 4 and the convex cylindrical lens 3b are formed as separate members, respectively. Of the optical bus main body 4 and the convex cylindrical lens 3a, or
The optical bus body 4 and the convex cylindrical lens 3b may be formed integrally with each other. Similarly, the optical bus main body 4 and the concave cylindrical lens 5 may be integrally formed. Although the optical bus 1 in which the optical bus main body 4 has only one layer is shown in the above embodiment, the optical bus main body 4 as described above may be used as a laminated structure by stacking a plurality of layers.

FIG. 3 is a plan view showing a second embodiment of the optical bus of the present invention. As shown in FIG.
Reference numeral 1 denotes an optical bus main body 14 and a convex cylindrical lens 13 as in the first embodiment shown in FIG.
a, and a convex cylindrical lens 13b, but differs from the first embodiment in the following points. That is, instead of the concave cylindrical lens 5 which is the first collimating means in the first embodiment, a circular gap 15 filled with a substance having a refractive index lower than the refractive index of the optical bus body 14 is used. The first collimating means is provided, and the light diffusing portion 16 is built in the circular gap 15. Since the circular gap 15 is filled with a substance having a refractive index lower than the refractive index of the optical bus body 14, the same collimating action as that of the concave cylindrical lens 5 in the first embodiment is performed. Can be made. Here, the optical axes of the convex cylindrical lens 13 a and the convex cylindrical lens 13 b are both set on the same optical axis 10, and the optical axis 10 passes through the center of the circular gap 15. The diffusion part 16 is disposed at the center of the circular gap 15. Also, the convex cylindrical lens 13
The focal positions of a and the convex cylindrical lens 13b are configured to coincide with the focal positions of the concave lens formed by the circular gap 15.

FIG. 4 is a schematic diagram showing how signal light incident from one end face of the optical bus main body propagates to the other end face in the second embodiment. As shown in FIG. 4, the signal lights 17a and 17 incident on the one end face 14a of the optical bus main body 14 from different incident positions A and B, respectively.
b is converged by the convex cylindrical lens 13a, enters the circular gap 15 from the left side in the drawing, is collimated by the circular gap 15, and enters the light diffusion unit 16. That is, the signal light 17a, 1
7b enters the light diffusion unit 16 at an equal incident angle to each other without depending on the incident positions A and B on the optical bus 11. The signal lights 18a and 18b diffused by the light diffusion unit 16 enter the optical bus main body 14 from the right side of the circular gap 15 as viewed in the drawing and travel toward the other end surface 14b. The signal lights 18a and 18b diffused by the light diffusing unit 16 are collimated by the convex cylindrical lens 13b because the light diffusing unit 16 is located near the focal point of the convex cylindrical lens 13b, and the respective emission positions C to C '. ,
D-D 'are emitted as signal lights 19a and 19b parallel to the optical axis 10. In the case where the incident position of the signal light incident on the light diffusion unit 16 is the signal light near the center point of the circular gap 15, the optical path conversion is performed after the light is diffused by the light diffusion unit 16 and passes through the circular gap 15. Optical bus body 14 without receiving
And is collimated by the convex cylindrical lens 13b, and is emitted as signal light 19c parallel to the optical axis 10 from near the emission position E substantially near the optical axis 10.

In the present embodiment, when signal light is incident from the other end face 14b of the optical bus 11, the same transmission as described above is performed, except that the signal light is transmitted in the opposite direction to that described above. The parallel light is emitted from the convex cylindrical lens 13a on one end surface 14a side. That is, according to the optical bus of the present embodiment, bidirectional transmission can be performed using only one optical bus. Next, an embodiment of a signal processing device configured using the optical bus of the present invention will be described.

FIG. 5 is a schematic configuration diagram showing an embodiment of a signal processing device configured using the optical bus of the present invention. FIG. 5 shows a base 29, a plurality of circuit boards 31, an optical bus 21,
Processing device 20 including a plurality of base fixing portions 30
It is shown. Each circuit board 31 includes a plurality of signal light input / output units 22a and 22 having both functions of a signal light emitting end for emitting signal light and a signal light incident end for receiving signal light.
b and an electronic circuit 3 for performing a plurality of signal processing and signal generation
2 is mounted. These electronic circuits 32 generate a signal to be carried by the signal light emitted from the signal light input / output units 22a and 22b, and a signal light input / output unit 22a, 2
2b that performs signal processing based on the signal carried by the signal light incident from 2b. Each signal light input / output unit 22
a and 22b are provided with a light emitting element 27 responsible for emitting signal light to the optical bus 21 and each signal light input / output unit 22 from the optical bus 21.
a, a light receiving element 28 for injecting the signal light to the 22b. The optical bus 21 is formed between a plurality of stacked bodies in which an optical bus main body 24 having the same configuration as the optical bus 11 of the second embodiment described with reference to FIG. It is configured as a laminated structure sandwiching the light absorbing layer 26, and has the same configuration as the optical bus 11 of the second embodiment described with reference to FIG. 3 on both end surfaces of the optical bus 21 having the laminated structure. A converging means composed of a convex cylindrical lens 23a and a second collimating means composed of a convex cylindrical lens 23b are provided. Each optical bus main body 24 receives signal light from one end face, propagates inside, and emits signal light from the other end face. Like the optical bus 11 of the second embodiment, each optical bus body 24 has:
A first collimating means for collimating the signal light propagating in the optical bus main body 24 via the converging means, and a light diffusing means for diffusing the signal light collimated by the first collimating means are built-in. I have. The plurality of substrate fixing portions 30 are formed by combining the plurality of circuit boards 31 with the signal light input / output portions 22a and 22b having both functions of the signal light emitting end and the signal light incident end mounted on the circuit board 31. It is fixed on the base 29 in a state of being optically coupled to the optical bus 21.

Electric wires (not shown) are laid on the base 29, and the electric wires are
Are electrically connected to the respective electronic circuits 32 on the circuit board 31 mounted on the base fixing part 30 via the base. Circuit board 31
Is mounted on the base fixing portion 30, the circuit board 31
The light-emitting element 27 provided in the device performs an electrical / optical conversion of an electric signal processed and output by a certain electronic circuit 32, and converts the converted signal light from predetermined signal light input / output units 22 a and 22 b to the optical bus 21. Out. The signal light incident on the optical bus 21 is subjected to optical path conversion by a convex cylindrical lens 23 a and a circular gap (not shown) provided in the optical bus main body 24, and is provided at a predetermined point of the optical bus main body 24. Incident on the light diffusing portion (not shown) at the same angle. The signal light whose optical path has been converted is diffused by the above-mentioned light diffusion unit, and is converted into parallel light by convex cylindrical lenses 23b and 23a on the exit side opposite to the incident side.
b and 22a are emitted toward the light receiving element 28 provided. The signal light received by the light receiving element 28 is subjected to optical / electrical conversion, and the converted electric signal is input to a predetermined electronic circuit 32 to perform predetermined signal processing. This signal processing device 2
0 has the optical bus 21 having the above configuration, so that high light use efficiency can be obtained, so that the processing speed of the signal processing device can be increased and the power consumption can be reduced.

Further, in the signal processing device 20, even if the relative positional relationship between the incident position of the signal light and the emission position of the signal light changes, the fluctuation of the intensity of the signal light incident on the light receiving element 28 is suppressed. . Therefore, it is not necessary to detect light having a wide dynamic range, and the circuit design of the electronic circuit 32 is facilitated. Therefore, low power consumption and low cost of the signal processing device can be achieved. Further, the signal processing device 2
0, the light emitting element 27 and the light receiving element 28 mounted on the circuit board 31 are optically coupled to the optical bus 21 at the same time that the circuit board 31 is mounted on the base fixing portion 30. Therefore, there is an advantage that delicate positioning is not required.

[0028]

As described above, according to the optical bus of the present invention, by providing the converging means, the first collimating means, the light diffusing means, and the second collimating means,
It is possible to realize an optical bus with high light use efficiency and a small variation in signal light intensity at the emission position even if the relative positional relationship between the incident position and the emission position of the signal light changes. Further, according to the signal processing device of the present invention, by using the optical bus, it is possible to configure a signal processing device having a high optical transmission efficiency of the signal light and a small variation in the intensity of the output signal light. Higher signal processing speed, lower power consumption,
And cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of an optical bus of the present invention.

FIG. 2 is a schematic diagram illustrating a state of propagation of signal light in an optical bus according to the first embodiment of the present invention.

FIG. 3 is a plan view showing a second embodiment of the optical bus of the present invention.

FIG. 4 is a schematic diagram illustrating a state in which signal light incident from one end face of an optical bus main body propagates to the other end face in the second embodiment.

FIG. 5 is a schematic configuration diagram illustrating an embodiment of a signal processing device configured using the optical bus of the present invention.

FIG. 6 is a schematic configuration diagram of an optical bus including an optical path changing unit, a light diffusing unit, and a collimating unit.

[Description of Signs] 1 optical bus 3a, 3b cylindrical lens 4 optical bus main body 4a, 4b end face 5 cylindrical lens 6 light diffusing portion 7a, 7b, 8a, 8b, 9a, 9b signal light 10 optical axis 11 optical bus 13a, 13b Cylindrical lens 14 Optical bus body 14a, 14b End face 15 Air gap 16 Light diffusing section 17a, 17b, 18a, 18b, 19a, 19b
Signal light 20 Signal processing device 21 Optical bus 22a, 22b Signal light input / output unit 23a, 23b Cylindrical lens 24 Optical bus main body 25 Cladding layer 26 Light absorbing layer 27 Light emitting element 28 Light receiving element 29 Base 30 Base fixing part 31 Circuit board 32 Electronics circuit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Gowa Shioya 430 Nakai-cho Sakai, Ashigara-gun, Kanagawa Prefecture Inside Green Tech Nakamura Fuji Xerox Co., Ltd. In company

Claims (4)

[Claims] 1. An optical bus main body for receiving signal light from one end face, propagating through the inside and emitting the signal light from the other end face, and transmitting the incident signal light provided on the one end face side to the Converging means for converging to a predetermined point in the optical bus main body, and a converging means provided near the predetermined point in the optical bus main body for collimating signal light propagating in the optical bus main body via the converging means. 1 collimating means, light diffusing means provided inside the optical bus main body, for diffusing the signal light collimated by the first collimating means, and the light diffusing means provided on the other end face side A second collimating means for collimating the signal light diffused by the second end face and emitted from the other end face. 2. The optical bus according to claim 1, wherein said first collimating means comprises a concave cylindrical lens. 3. The method according to claim 1, wherein the first collimating means includes:
The optical bus body comprises a circular gap filled with a substance having a lower refractive index than the refractive index of the optical bus body, and the light diffusing means is built in the gap. Item 2. The optical bus according to item 1. 4. A base, a signal light emitting end for emitting signal light, a circuit for generating a signal carried by the signal light emitted from the signal light emitting end, a signal light incident end for receiving signal light, and the signal A plurality of circuit boards on which at least one of a signal processing circuit based on a signal carried by the signal light incident from the light incident end is mounted, the signal light being incident from one end face and propagating inside and the other An optical bus main body that emits the signal light from an end face, converging means provided on the one end face side for converging incident signal light to a predetermined point in the optical bus main body, First collimating means provided near a predetermined point for collimating the signal light propagating in the optical bus main body via the converging means, and the first collimating means provided inside the optical bus main body Collimation by means And a second collimating means provided on the other end face side for collimating the signal light diffused by the light diffusing means and emitted from the other end face. A plurality of base fixing portions for fixing the optical bus and the circuit board on the base such that a signal light emitting end or a signal light incident end mounted on the circuit board is optically coupled to the optical bus. A signal processing device comprising: