JP3994627B2 - Optical data bus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical data bus responsible for transmission of optical signals.
[0002]
[Prior art]
In recent years, the data processing speed of LSI has been dramatically increased due to improvements in semiconductor integration technology. Along with this, an improvement in signal transmission capability is required for a wiring board on which a semiconductor integrated circuit is mounted.
[0003]
In particular, recently, a so-called parallel processing architecture including a plurality of high-speed CPU chips has been adopted in a server type system corresponding to a higher-level model even in a personal computer. The classification of parallel processing architecture technology is described in, for example, “Hideharu Amano, Parallel Computer, Shosodo, pp. 6-13”. According to this, when configuring a system including a plurality of modules that perform data processing such as a CPU, the coupling method between modules is classified into a bus coupling type, a switch coupling type, and a coupling network type.
[0004]
Of these, the bus coupling type is not suitable for coupling a large number of modules, but has a merit that the coupling topology is simpler than other modules, it can be mounted compactly in the form of a backplane and the like, and has excellent extensibility. For this reason, it is widely used in commercial computers such as personal computers and computer application products. In that case, in the bus connection, communication performance proportional to the processing speed and the number of modules to be connected is required. Therefore, many multiplex bus systems that multiplex the buses themselves and improve communication performance have been proposed.
[0005]
On the other hand, in mounting a bus, a large number of wirings and connection connectors are required, so that communication capability and wiring density have been improved by multilayering and miniaturization of wirings. However, the limit is being reached due to signal delay and transmission waveform distortion caused by inter-wiring capacitance and connection wiring resistance. In addition, electromagnetic noise (EMI: Electromagnetic Interference) becomes a big problem due to the increase in operating speed. Obviously, multiplexing buses increases the number of connectors and wiring, and these problems become more prominent.
[0006]
As described above, the processing capability of the data processing apparatus is often limited by the transmission capability of the wiring board bus. In order to overcome the limitations of electronic circuit buses, the use of an in-system optical connection technology called optical interconnection has been studied. For an overview of optical interconnection technologies, see "Junji Uchida, Circuit Packaging Academic Lecture Meeting 15C01, pp.201-202" and "H. Tomimuro et al.," Packaging Technology for Optical Interconnects ", IEEE Tokyo No.33 pp.81. -86, 1994 ", various forms have been proposed depending on the contents of the system configuration.
[0007]
As an example of a conventionally proposed optical interconnection technique, there is a technique described in Japanese Patent Application No. 11-283565 (not disclosed at the time of filing this application). In this technique, when the signal light incident on the optical transmission medium is diffused and irradiated toward a plurality of light receiving parts, the spread angle in the diffusion characteristics at the diffusion part on the incident surface of the optical transmission medium is determined. Control according to the shape of the sheet of the emission part. A method is adopted in which a part of the diffused light is reflected on the side surface inside the optical transmission medium and overlapped with the directly incident light, so that the branching ratio for each fiber is substantially uniform.
[0008]
[Problems to be solved by the invention]
However, in the case of the method of Japanese Patent Application No. 11-283565, with the expansion of the system, the number of transmission / reception nodes mixedly mounted on the signal light incident / exit part increases, so that the entire surface of the signal light incident / exit part can be uniformly irradiated. There is a problem that a sufficient amount of light cannot be obtained in the light receiving part. Specifically, the increase in the number of light transmitting / receiving nodes increases the area of the signal light incident / exit surface, which reduces the amount of light received per light receiving node, resulting in a decrease in light receiving efficiency.
[0009]
In view of the above circumstances, the present invention provides an optical data bus that can efficiently receive incident signal light at a light receiving node in response to an increase in the number of nodes that receive and emit signal light from an optical transmission space. The purpose is to do.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an optical data bus according to the present invention described in claim 1 performs communication between a plurality of modules by performing optical transmission between a plurality of light transmitting and receiving units via an optical transmission space. The light transmission / reception unit includes a light transmission node that inputs signal light into the optical transmission space, and a plurality of light reception nodes that receive signal light from the optical transmission space. and, further, in the transmitting and receiving light section, irradiating the plurality of light receiving nodes, arranged in proximity region sandwiched between the plurality of light-sending node, the signal light incident from the light-sending node the proximity area It is characterized by being.
[0011]
According to the present invention having the above configuration, when signal light is incident on the optical transmission space from the light transmission node, the signal light is received by the plurality of light receiving nodes through the optical transmission space.
[0012]
In the present invention, since the signal light incident from the light-sending node with arranging a plurality of light receiving nodes adjacent region interposed between the plurality of light-sending node has to be irradiated to the proximal region, The amount of light received per light receiving node can be increased. Therefore, the light receiving efficiency at the light receiving node is improved.
[0013]
Further, the object of the present invention can also be achieved by the invention of claim 2 and below which is a specific example of the present invention of claim 1. That is, the optical data bus according to the present invention of claim 2 is the optical data bus according to claim 1, wherein the optical transmission space has an optical transmission medium and an irradiation direction of signal light inside the optical transmission medium. And a light diffusing unit to be controlled.
[0014]
Furthermore, in the optical data bus according to the present invention described in claim 3, in the invention described in claim 1 or claim 2, both the light transmitting node and the light receiving node are connected to the same module. The light transmitting node and the light receiving node are arranged at positions close to each other.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
[0016]
FIG. 1 schematically shows the concept of the optical data bus according to the present embodiment. As shown in this figure, the optical data bus includes an optical transmission medium 1 formed in a rectangular parallelepiped shape as an example. Signal light incident portions 23 and 24 into which signal light is incident are provided on the upper and lower stages of one end surface 31 of the optical transmission medium 1 (in this case, the end surface 31 functions as an incident surface). Become). Further, the signal light emitting portion 11 from which the signal light is emitted is provided in the middle stage of the opposite other end face 32 (in this case, the end face 32 functions as an emission face). Although not shown in the figure, a plurality of light transmitting nodes are connected to the signal light incident portions 23 and 24, respectively, and a plurality of light receiving nodes are connected to the signal light emitting portion 11. .
[0017]
The above relationship is the same for irradiation in the opposite direction. That is, in order to perform bidirectional optical transmission, signal light incident portions 21 and 22 into which signal light is incident are provided on the upper and lower stages of the end face 32 of the optical transmission medium 1 (in this case, the end face 32 concerned). Will serve as the entrance surface). Further, a signal light emitting portion 12 from which signal light is emitted is provided in the middle stage of the opposed end surfaces 31 (in this case, the end surface 31 functions as an emission surface). Although not shown in the drawing, a plurality of light transmission nodes are connected to the signal light incident portions 21 and 22, respectively, and a plurality of light receiving nodes are connected to the signal light emission portion 12. .
[0018]
In addition, an electrical / optical conversion device such as an LD or an LD array can be used as the light transmission node, and a photoelectric conversion device such as a PD or PD array can be used as the light receiving node.
[0019]
Here, in this embodiment, taking the end face 31 side of the optical transmission medium 1 as an example, a plurality of light receiving nodes (that is, a total of 12 light receiving elements constituting the signal light emitting unit 12 in FIG. 1) The light source nodes (that is, the signal light incident portions 21 and 22 in FIG. 1) are irradiated with signal light that is gathered and arranged in a proximity region called the middle stage of the end surface 31. It has come to be.
[0020]
Conversely, taking the end face 32 side of the optical transmission medium 1 as an example, a plurality of light receiving nodes (that is, a total of 12 light receiving elements constituting the signal light emitting section 11 in FIG. The signal light incident from the light transmission node (that is, the signal light incident portions 23 and 24 in FIG. 1) is emitted toward the adjacent region. ing.
[0021]
Next, the operation and effect of this embodiment will be described.
[0022]
Assuming that signal light is incident from the signal light incident portions 21 and 22 on the end face 32 of the optical transmission medium 1, the signal light is irradiated toward the middle stage of the opposite end face 31 through the optical transmission medium 1. The 1 indicate the irradiation range of the signal light incident from the signal light incident portion 22, that is, the signal extends with the spread from the arrow A to the arrow D. It means that the light is irradiated to the opposite end face 31. Such a method of narrowing the irradiation range will be described in a second embodiment to be described later. As an example, the direction of the transmission optical fiber itself is directed to the middle of the end face 31, or the signal light is not changed without changing the direction of the transmission optical fiber itself. Note that it is possible to apply a technique such as arranging a light diffusion layer in the signal light incident portions 21 and 22 in advance so that the diffusion angle becomes a predetermined angle.
[0023]
As described above, the signal light incident from the signal light incident portions 21 and 22 is applied to the middle stage of the opposite end face 31, and the signal light emitting sections 12 are collectively arranged (concentrated) in the proximity region such as the middle stage. Therefore, the amount of received light per one light receiving element (one light receiving node) constituting the signal light emitting unit 12 can be increased. As a result, according to the present embodiment, the incident signal light can be efficiently received by the light receiving node in response to the increase in the number of nodes that receive and emit the signal light from the optical transmission space.
[0024]
[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. In addition, the same number is attached | subjected about the part substantially common with embodiment mentioned above, and the description is abbreviate | omitted.
[0025]
FIG. 2 shows the optical data bus according to the first embodiment described above, in which the technique disclosed in Japanese Patent Laid-Open No. 10-123350 is applied as an optical transmission medium, and an optical fiber is used as a light transmission / reception node connected to an input / output unit. It is the figure which showed roughly the used signal communication apparatus.
[0026]
The above publication discloses an example of an optical interconnection technology (sheet-like optical data bus). In short, the sheet-like optical data bus disclosed in the publication is a common signal path. It diffuses and propagates incident signal light. According to the technology disclosed in this publication, a plurality of circuit boards having light receiving and emitting portions can be attached by a simple method, and precise optical alignment is not required at the time of mounting. The position can be freely changed, and a highly flexible system that is rich in expandability can be constructed.
[0027]
Returning to FIG. 2, in the present embodiment, an “optical transmission space” is configured by the optical transmission medium 1 and the plurality of diffusion units 61 a, 61 b, 62 a, 62 b. The latter plurality of diffusing parts 61a, 61b, 62a, 62b correspond to the “ light diffusing part ”. Transmitting optical fibers 41 a and 41 b as “light transmitting nodes” for receiving signal light are connected to the end face 32 of the optical transmission medium 1 and receiving optical fibers 51 a and 51 b as “light receiving nodes” for emitting signal light. Is connected. Similarly, the end face 31 of the optical transmission medium 1 is connected to transmission optical fibers 42a and 42b as “light transmission nodes” that receive signal light, and receives optical fibers as “light reception nodes” that emit signal light. 52a and 52b are connected. Thus, it is the structure which performs bidirectional | two-way optical transmission by taking a symmetrical form on both sides.
[0028]
More specifically, the transmission optical fiber 42a is connected to the signal light incident part 23 via the diffusion part 62a, and the transmission optical fiber 42b is connected to the signal light incident part 24 via the diffusion part 62b. Similarly, the transmission optical fiber 41a is connected to the signal light incident part 21 via the diffusion part 61a, and the transmission optical fiber 41b is connected to the signal light incident part 22 via the diffusion part 61b. These diffusion parts 62a, 62b, 61a, 61b are bonded to the corresponding signal light incident parts 23, 24, 21, 22 respectively.
[0029]
As described above, the end surface 31 of the optical transmission medium 1 includes the signal light emitting unit 12 in which the plurality of receiving optical fibers 52a and 52b are arranged close to each other and the signal light incident units 23 and 24. Similarly, the end face 32 of the optical transmission medium 1 includes the signal light emitting unit 11 in which a plurality of receiving optical fibers 51a and 51b are arranged close to each other, and the signal light incident units 21 and 22.
[0030]
According to the present embodiment having the above configuration, on the end face 31 side of the optical transmission medium 1, the signal light incident on the optical transmission medium 1 from the transmission optical fiber 42a via the diffusion unit 62a is diffused by the diffusion unit 62a. Then, the signal light emitting part 11 on the opposite end face 32 is irradiated. Similarly, the signal light incident on the optical transmission medium 1 from the transmission optical fiber 42b via the diffusing unit 62b is also diffused by the diffusing unit 62b and applied to the signal light emitting unit 11 on the opposite end face 32. In other words, the light diffusion characteristics of the diffusion units 62a and 62b are adjusted so that the signal light is emitted toward the signal light emitting unit 11.
[0031]
The same applies to irradiation in the opposite direction. On the end face 32 side of the optical transmission medium 1, the signal light incident on the optical transmission medium 1 from the transmission optical fiber 41 a via the diffusion section 61 a is diffused by the diffusion section 61 a and is opposed to the signal light emitting section on the end face 31. 12 is irradiated. Similarly, the signal light incident on the optical transmission medium 1 from the optical fiber 42b via the diffusion part 62b is also diffused by the diffusion part 61b and applied to the signal light emitting part 12 on the opposite end face 31. In other words, the light diffusion characteristics of the diffusion portions 61a and 61b are adjusted so that the signal light is emitted toward the signal light emitting portion 12.
[0032]
As described above, by using the diffusion portions 61a, 61b, 62a, and 62b, it is possible to easily adjust the irradiation direction of the signal light.
[0033]
In addition to the technology described in Japanese Patent Laid-Open No. 10-123350, the optical transmission medium 1 described above includes all means such as a star coupler that receives signal light inside the same optical transmission medium at a plurality of light receiving nodes. included.
[0034]
Moreover, although a spreading | diffusion part is also the technique described in 10-123350, the method of mounting | wearing a film-like thing can be used as a spreading | diffusion part. Concavities and convexities are formed on the signal light incident side surface of the diffusion portion. In addition, the diffuser has a concavo-convex size and a pitch between the concavo-convex portions, and signal light incident on the signal light diffused into the optical transmission medium according to the concavo-convex size and pitch. The spread angle in the long side direction of the end surface on the part side and the spread angle of the signal light in the thickness direction of the optical transmission medium are determined independently. As an alternative to this diffusing unit, means for controlling the optical path, such as a lens or a hologram, may be used.
[0035]
[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. In addition, the same number is attached | subjected about the part substantially common with embodiment mentioned above, and the description is abbreviate | omitted.
[0036]
FIG. 3 schematically shows a signal communication system in which the signal communication apparatus using the optical data bus described in the first embodiment and the module are connected by an optical fiber.
[0037]
As shown in this figure, a module 81 is connected to the end face 32 of the optical transmission medium 1 via optical fibers 41 and 51. A module 82 is connected to the end face 31 of the optical transmission medium 1 via optical fibers 42 and 52. As a result, optical signals are transmitted bi-directionally between the modules 81 and 82. The modules 81 and 82 are modules on which an electrical / optical conversion device and a photoelectric conversion device are mounted, and include all components that are generally connected by a bus such as a printed board and a chip.
[0038]
Here, in this embodiment, a plurality of light receiving nodes are arranged close to each other, and the light transmitting node (optical fiber 41) and the light receiving node (optical fiber 51) connected to the same module 81 are grouped as shown in 71. It is comprised so that it may adjoin. Similarly, the light transmitting node (optical fiber 42) and the light receiving node (optical fiber 52) connected to the same module 82 are configured to be arranged close to each other as a group indicated by 72.
[0039]
According to the present embodiment configured as described above, the wiring for connecting the optical data bus and the module using an optical fiber is simplified, and a timing shift due to a difference in signal propagation distance can be avoided. That is, according to the present embodiment, not only the light receiving nodes are arranged together, but also the light transmission node connected to the same module and the light receiving nodes are arranged at close positions, thereby shortening the signal propagation distance. , Signal waveform disturbance and delay can be suppressed.
[0040]
[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIG. In addition, the same number is attached | subjected about the part substantially common with embodiment mentioned above, and the description is abbreviate | omitted.
[0041]
FIG. 4 schematically shows a signal communication system in which the signal communication apparatus using the optical data bus described in the first embodiment and the module are connected by an electric signal cable.
[0042]
As shown in this figure, the present embodiment is basically configured in the same manner as the third embodiment described above. However, in the third embodiment described above, the optical signal cables 91, 92, 93, 94 are connected in the present embodiment, whereas the optical fibers 41, 42, 51, 52 are used to connect to the modules 81, 82. Are different from each other in that they are connected to the modules 83 and 84.
[0043]
Also in the present embodiment having the above-described configuration, the same operations and effects as those of the third embodiment described above can be obtained.
[0044]
【The invention's effect】
Or optical data bus to the present invention as described, the signal light incident from the light-sending node with arranging a plurality of light receiving nodes adjacent region interposed between the plurality of light-sending node is irradiated to the proximity area As a result, the amount of light received per light receiving node can be increased, and as a result, the incident signal light is efficiently received at the light receiving node in response to an increase in the number of nodes that receive and emit signal light from the light transmission space. It has the outstanding effect that it can receive light automatically.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of an optical data bus according to a first embodiment.
FIG. 2 is a plan view showing a signal communication apparatus according to a second embodiment.
FIG. 3 is a perspective view showing a schematic configuration according to a third embodiment in which a signal communication device and a module are connected by an optical fiber.
FIG. 4 is a perspective view illustrating a schematic configuration according to a fourth embodiment in which a signal communication device and a module are connected by an electric signal cable.
[Explanation of symbols]
1 Optical transmission medium (optical transmission space)
11, 12 Signal light emitting sections 21, 22, 23, 24 Signal light incident sections 31, 32 End faces 41a, 41b, 42a, 42b Transmitting optical fibers (transmitting nodes)
51a, 51b, 52a, 52b Receiving optical fiber (light receiving node)
61a, 61b, 62a, 62b Diffusion part ( light diffusion part , light transmission space)
71, 72 Groups 81, 82 modules 83, 84 modules 91, 92 consisting of light transmitting nodes and light receiving nodes connected to the same module Electric signal cables (light receiving nodes) connected to photoelectric conversion devices
93, 94 Electrical signal cable connected to electrical / optical conversion device (light transmission node)

Claims (3)

An optical data bus for performing communication between a plurality of modules by performing optical transmission between a plurality of light transmitting / receiving units via an optical transmission space,
The light transmission / reception unit includes a light transmission node that makes signal light incident on the optical transmission space, and a plurality of light reception nodes that receive signal light from the optical transmission space,
Further, in the above transmitting and receiving light section, a plurality of light receiving nodes, arranged in proximity region sandwiched between the plurality of light-sending node, the signal light incident from the light-sending node is irradiated to the proximity area An optical data bus characterized by 2. The light according to claim 1, wherein the optical transmission space includes an optical transmission medium and a light diffusing unit that controls an irradiation direction of signal light inside the optical transmission medium. Data bus. Both the light transmitting node and the light receiving node are connected to the same module,
The optical data bus according to claim 1, wherein the light transmission node and the light reception node are arranged at positions close to each other.

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