JPH08166842A - Optical bus circuit device - Google Patents

Abstract

(57) [Abstract] [Purpose] The number of dedicated circuits that can be reused for conventional dedicated circuits
The load condition of the shared circuit does not change depending on the layout, and the optical bus circuit device is fast and easy to connect. [Structure] The circuit board 11 includes a shared circuit 1 including an optical transmission circuit 5, an optical star coupler 61, and an optical fiber 71. A connector 3 connected to the electric circuits of the optical transmission circuit 4 and the optical reception circuit 5 is attached to the circuit board 11. The dedicated circuit 2 formed on the circuit board 21 is detachably connected to the connector 3. The electric signal output from the one dedicated circuit 2 is sent to the optical transmission circuit 4 via the connector 3 to become an optical signal, and this optical signal is transmitted via the optical star coupler 61 and the optical fiber 71 to the optical reception circuit 5.
To the connector 3 and becomes an electric signal, and this electric signal is sent to the connector 3
Is sent to another dedicated circuit 2 via.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical bus circuit device and is effectively applied to a high speed electronic circuit device or the like.

[0002]

2. Description of the Related Art In electronic circuit devices, a system is constituted by many dedicated circuits having different functions and a so-called bus circuit in which they are connected to a shared circuit. For example, in a computer or the like, a central processing unit (CPU), a memory device, a magnetic disk device, an external interface device, etc. are usually connected to a shared circuit called a system bus to form an entire system. In this case, each dedicated circuit is composed of a part that performs a function unique to the circuit and a part that performs a function of inputting / outputting a signal to / from the shared circuit. Such a dedicated circuit is connected to the shared circuit by a connector so that it can be attached and detached. According to this configuration method, it is possible to easily replace the dedicated circuit when it is out of order, and it is possible to add a new dedicated circuit or remove an unnecessary dedicated circuit. Therefore, it is widely applied to electronic circuit devices. .

In recent years, as electronic circuit devices have become multifunctional, the number of dedicated circuits connected to the bus circuit has increased, and the length of the shared circuit tends to increase. At this time, if the number of dedicated circuits is changed, the load fluctuation on the input / output circuit section of each dedicated circuit also becomes large, which becomes an obstacle to speeding up the bus circuit. For example, H. Satoh et al. "Analysis ofhig
h-speed bus lines printed circuit boards "(Proceedi
ngs of 1989 Electronic Manufacturing Technology Sy
mposium, pp.299-302, April 1989),
It has also been reported that a bus operating at 30 MHz when the number of dedicated circuits is 5 operates only at about 10 HMz when the number of dedicated circuits reaches 20. This is so that the bus operates even if the load state changes due to the change in the number of dedicated circuits.
The main reason is that there is a large operating margin.

Further, as long as the shared circuit is composed of an electric circuit, it is impossible to completely reduce the length of the lead line for inputting / outputting from the dedicated circuit to the shared circuit, and this portion is a parallel stub circuit. As the frequency of the signal increases, the shared circuit largely deviates from the ideal characteristics of the transmission line, and the reflection of the signal at the lead wire portion cannot be ignored. Such deterioration of the characteristics of the shared circuit also becomes an obstacle to speeding up the bus circuit. For this reason, the so-called electric bus in which the shared circuit is configured by an electric circuit has a limit in speeding up in principle due to its structure, and it will be necessary in the future in GHz.
It may not be possible to handle ultra-high-speed signal processing beyond the order.

As a method for overcoming such a limitation in speeding up the electric bus, a method in which the shared circuit is composed of an optical transmission circuit and an optical signal is used instead of the electric signal is considered. 12
An example of a conventional optical bus circuit device is shown in FIG. Reference numeral 1 denotes a shared circuit composed of an optical transmission circuit, which is formed on the circuit board 11.
Reference numeral 2 is a dedicated circuit that performs its own function.
1 is formed on. Reference numeral 71 is an optical fiber connecting the shared circuit 1 and the dedicated circuit 2. However, when the shared circuit 1 is composed of only the optical transmission circuit as described above, it becomes necessary to provide an electric-optical conversion circuit in each dedicated circuit 2, which makes it impossible to divert the conventional dedicated circuit and partially As a result, the advantage of the bus circuit device that can be replaced is greatly impaired. Further, as shown in the figure, it is necessary to connect the shared circuit 1 and each dedicated circuit 2 by two optical fibers 71 for transmission and reception, which is a disadvantage that the wiring for configuring the bus becomes very complicated. there were.

[0006]

As described above, when the electronic circuit device is made multi-functional, the number of dedicated circuits connected to the bus circuit increases, and the length of the shared circuit becomes long, so that each dedicated circuit is dedicated. There is a problem in that the bus circuit device cannot be operated at a high speed because the load variation on the input / output circuit portion of the circuit increases, which becomes an obstacle to speeding up the bus circuit.

Further, as long as the shared circuit is composed of an electric circuit, the extraction portion for inputting / outputting from the dedicated circuit to the shared circuit functions as a parallel stub circuit, so that the characteristics of the shared circuit deteriorate as the signal frequency increases. However, this also hinders the speedup of the bus circuit, so that there is a problem that the bus circuit device cannot be speeded up.

Further, if the shared circuit is composed of an optical circuit for speeding up the bus, it becomes necessary to provide an electric-optical conversion circuit in each dedicated circuit, which makes it impossible to divert the conventional dedicated circuit. However, there is a drawback that the connection of the optical fiber for constructing is very complicated.

In view of the above-mentioned prior art, the present invention prevents the load state of the shared circuit from changing depending on the number and arrangement of the dedicated circuits, overcomes the theoretical speedup limit of the electric bus, and It is an object of the present invention to provide an optical bus circuit device capable of operating a large number of dedicated circuits at high speed while permitting the diversion of conventional ones and with less complexity of optical fiber connection.

[0010]

The structure of the present invention which achieves the above-mentioned object is a plurality of dedicated circuits each performing a unique function, and a common use for collecting and distributing input / output electric signals of the plurality of dedicated circuits. In a bus circuit device having a circuit, a plurality of optical transmission circuits for converting output electric signals from the dedicated circuit into optical signals, and a plurality of optical reception circuits for converting optical signals into input electric signals to the dedicated circuit. , An optical transmission circuit network for exchanging signals between the dedicated circuits by connecting the plurality of optical transmission circuits and the plurality of optical reception circuits via optical signals on an integrated substrate. A connector for detachably connecting the dedicated circuit to the electric circuit of the optical transmitter circuit and the electric circuit of the optical receiver circuit is provided as the shared circuit, and the connector is integrated with the arrangement of the dedicated circuit. On board It is characterized in that the column.

Further, the configuration of the present invention is characterized in that the optical transmission circuit network connecting the plurality of optical transmission circuits and the plurality of optical reception circuits is configured by using an optical star coupler.

Further, according to the structure of the present invention, the connector for detachably connecting the dedicated circuit and the electric circuit of the optical transmission circuit and the electric circuit of the optical reception circuit is a cascade connection of connectors arranged on another substrate. It is characterized by a structure.

According to the structure of the present invention, the optical transmission network connecting the plurality of optical transmission circuits and the plurality of optical reception circuits has an external output terminal for outputting optical output signals of all the optical transmission circuits, An external input terminal for inputting an optical input signal to all the optical receiving circuits is provided.

Further, in the configuration of the present invention, the optical transmission circuit network connecting the plurality of optical transmission circuits and the plurality of optical reception circuits is composed of a planar lightwave circuit in which an optical element and an optical waveguide are formed on a planar substrate. It is characterized by

[0015]

In the bus circuit device of this type, the major factors that hinder the speedup are the load fluctuations of the input / output circuit part when the number of dedicated circuits is changed and the characteristics of the shared circuit when the signal frequency is increased. It is deterioration. The cause of the load fluctuation of the input / output circuit part is that the load of the shared circuit on the input / output circuit part of each dedicated circuit increases or disappears when the dedicated circuit is attached or detached. This is because, as long as the shared circuit is configured by an electric circuit, the leader line portion that inputs and outputs from the dedicated circuit to the shared circuit functions as a parallel stub circuit.

Therefore, in the present invention, an optical transmission / reception circuit is connected to each dedicated circuit, and signals are exchanged between the dedicated circuits via an optical signal propagating in an optical transmission network formed between the optical transmission / reception circuits. Each dedicated circuit is attached and detached by a connector installed between the dedicated circuit and the optical transceiver circuit. Further, the optical transmission / reception circuit and the optical transmission circuit network are provided as a shared circuit on an integrated substrate, and the connectors are arranged on the same integrated substrate in accordance with the arrangement of the dedicated circuit. By doing so, the dedicated circuits are electrically separated from each other, so that the attachment / detachment of a certain dedicated circuit does not cause load fluctuations to other dedicated circuits, and the theoretical speed limit of the electric bus is limited. In addition to being able to overcome the above problem, the dedicated circuit can be reused, the complexity of optical fiber connection can be reduced, and a large number of dedicated circuits in the bus circuit device can be operated at high speed.

Further, the optical transmission circuit network connecting the plurality of optical transmission circuits and the plurality of optical reception circuits is constructed by using an optical star coupler. The optical star coupler is an optical portion having a plurality of input / output terminals and having a function of dividing light incident from any of the input terminals into substantially equal parts and emitting the light to all output terminals. Therefore, it is possible to easily realize broadcast communication in which signals having the same content are sent to a plurality of dedicated circuits.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIGS. 1 and 2 show a first embodiment of the present invention, which is applied to a back panel type bus circuit. FIG. 1 is a view seen from a dedicated circuit side. FIG. 2 shows a view as seen from the shared circuit side. In both figures,
A common circuit 1 is formed on the circuit board 11. Denoted at 2 is a dedicated circuit that performs a unique function, and is formed on the circuit board 21. Reference numeral 3 denotes a connector arranged on the circuit board 11 for detachably connecting the common circuit 1 and the dedicated circuit 2. In FIG. 2, 4 and 5 are an optical transmission circuit and an optical reception circuit, respectively, and 61 and 71 are an optical star coupler and an optical fiber, respectively, which form an optical transmission network. In this embodiment, the optical star coupler 61 has eight input / output terminals so that eight dedicated circuits 2 can be connected. With this configuration, it is possible to easily realize broadcast communication in which signals having the same content are sent to the plurality of dedicated circuits 2. Further, as can be seen from FIGS. 1 and 2, the optical transceiver circuit 4,
Since the optical transmission circuit networks 61, 71 and the connector 3 are all provided on the integrated substrate 11, the complexity of optical fiber connection, which has been a problem in the past, is eliminated.

FIG. 3 and FIG. 4 respectively show one dedicated circuit or a 1 Gb / s pseudo-random pattern digital signal output to another dedicated circuit in this embodiment and the passive electric bus (the number of dedicated circuits is 4). The waveform of the signal input to the circuit is measured and displayed as an eye pattern. The eye pattern in this embodiment shown in FIG. 3 has a larger opening than the eye pattern in the electric bus shown in FIG. 4, which shows that high-speed and high-quality signal transmission can be realized by the present invention.

FIG. 5 shows that in this embodiment and in the passive electric bus (the number of dedicated circuits is 2, 3, and 4), when a pseudo random pattern digital signal is output from one dedicated circuit, it is input to another dedicated circuit. 6 is a graph showing the change in the eye pattern opening with respect to the signal transmission rate when the waveform of the signal is measured and the eye pattern is displayed. However, the vertical axis of the graph is a value normalized by the maximum value of the eye pattern opening in each of the present embodiment and the passive electric bus. When the transmission speed is increased, the opening of the eye pattern sharply decreases in the electric bus, whereas it does not decrease so much in this embodiment and hardly changes up to 1 Gb / s. From this, it is understood that the present invention can realize high-speed and high-quality signal transmission as compared with the electric bus. Further, in the electric bus, the opening of the eye pattern is reduced by increasing the number of dedicated circuits to be connected. This is because the attachment / detachment of the dedicated circuit affects the load of other dedicated circuits. On the other hand, in this embodiment,
Even if the number of dedicated circuits to be connected was changed, no change was observed in the eye pattern, that is, the waveform of the transmission signal. From this, in the present invention, it can be confirmed that the attachment / detachment of a certain dedicated circuit does not cause a load change with respect to another dedicated circuit.

[Second Embodiment] FIGS. 6 and 7 show a second embodiment of the present invention. In the second embodiment, the shared circuit 1 and the dedicated circuits 2 are included in the bus circuit of the first embodiment. The connectors between and are of a two-stage cascade structure. FIG. 6 shows a view from the dedicated circuit side, and FIG. 7 shows a view from the shared circuit side. In both figures, 1 is a shared circuit and is formed on the circuit board 11. Denoted at 2 is a dedicated circuit that performs a unique function, and is formed on the circuit board 21. Reference numeral 12 is an auxiliary substrate for connecting the shared circuit 1 and the dedicated circuit 2. Reference numerals 3 and 31 denote connectors arranged on the circuit board 11 and the auxiliary board 12, respectively, and connected in cascade to connect the shared circuit 1 and the dedicated circuit 2 in a detachable manner. Reference numerals 4 and 5 are an optical transmission circuit and an optical reception circuit, respectively, and 61 and 71 are an optical star coupler and an optical fiber forming an optical transmission network.

In this embodiment, the shared circuit 1 and its circuit board 11 can be collectively attached / detached by providing the auxiliary board 12 between the two connectors 3 and 31 in a two-stage cascade structure. With such a configuration, it is possible to easily realize the exchange of the shared circuit necessary for the function update such as the improvement of the transmission speed.

[Third Embodiment] FIGS. 8 and 9 show a third embodiment of the present invention. The third embodiment can be connected by connecting a plurality of bus circuits of the first embodiment. 8 is a diagram viewed from the dedicated circuit side, and FIG. 9 is a diagram viewed from the shared circuit side. In both figures, 1 is a shared circuit and is formed on the circuit board 11. Denoted at 2 is a dedicated circuit that performs a unique function, and is formed on the circuit board 21. Reference numeral 3 denotes a connector arranged on the circuit board 11 for detachably connecting the common circuit 1 and the dedicated circuit 2. Further, 4 and 5 are optical transmission circuits and optical reception circuits, respectively, and 61, 17, 81, 82, and 83 are optical star couplers, optical fibers, external output terminals, external input terminals, and optical fibers which respectively constitute optical transmission circuit networks. It is an amplifier.

Here, the external output terminal 81 outputs the optical output signal of all the optical transmission circuits 4 on one circuit board 11, and the external input terminal 82 outputs the optical input signal to one circuit board 1
It is to be inputted to all the optical receiving circuits 5 on 1. Such a function is provided by the optical star coupler 6 when the optical transmission circuit network is configured by using the optical star coupler 61 as in this embodiment.
This can be easily realized by assigning one of the output terminals of 1 as the external output terminal 81 and one of the input terminals of the optical star coupler 61 as the external input terminal 82.
Further, the optical amplifier 83 may be of a type that directly amplifies an optical signal, or may be of a type that once converts an optical signal into an electric signal, amplifies it, and then converts it into an optical signal again. The operation / non-operation of the optical amplifier 83 is controlled by software so that an optical signal transmitted from a certain dedicated circuit 2 is transmitted to another necessary dedicated circuit 2 and a loop is not drawn in the optical transmission network. Or hardware.

When an optical signal is branched by a passive optical circuit such as an optical star coupler as in the first embodiment, the intensity of the optical signal is reduced due to branch loss, so that as the number of connectable dedicated circuits is increased, The SN ratio of the transmission signal may deteriorate and the data error rate may increase. Therefore, when a large number of branches are required, the number of branches of an optical signal in a single passive optical circuit such as an optical star coupler is kept to a small number as in this embodiment, and the once branched optical signal is amplified. If the required number is further branched, the SN ratio of the transmission signal can be kept good.

[Fourth Embodiment] FIGS. 10 and 11 show a fourth embodiment of the present invention. The fourth embodiment is an optical transmission circuit network in a shared circuit in the bus circuit of the first embodiment. Is replaced with a so-called planar lightwave circuit in which an optical element and an optical waveguide are formed on a flat substrate. FIG. 10 shows a view from the exclusive circuit side, and FIG. 11 shows a view from the shared circuit side. There is. In FIG. 10, reference numeral 1 denotes a shared circuit, which is a circuit board 1.
1 is formed on. Denoted at 2 is a dedicated circuit that performs a unique function, and is formed on the circuit board 21. 3 is a circuit board 1
The shared circuit 1 and the dedicated circuit 2 are detachably connected by a connector arranged on the connector 1. Further, 4 and 5 are an optical transmission circuit and an optical reception circuit, respectively. Reference numerals 62 and 72 respectively denote a waveguide type optical star coupler and an optical waveguide which form an optical transmission circuit network, and are formed on the planar lightwave circuit 9.

In the present embodiment, the optical star coupler and the optical fiber in the first embodiment are replaced by a waveguide type optical star coupler and an optical waveguide formed on one plane lightwave circuit 9, respectively, to thereby realize an optical transmission circuit. The net could be miniaturized.

[0029]

As described above, the present invention is commonly used in a bus circuit device having a plurality of dedicated circuits each having a unique function, and a shared circuit for collecting and distributing the input / output electric signals thereof. A plurality of optical transmission / reception circuits and an optical transmission circuit network connecting them are provided in the circuit, the optical transmission / reception circuit is connected to each dedicated circuit, and the transmission / reception of signals between the dedicated circuits is configured between the optical transmission / reception circuits. This is done via an optical signal propagating in the optical transmission network, and these optical transmission circuit and optical transmission circuit are provided on a substrate integrated as a shared circuit,
Since the connectors are arranged on the same integrated board in accordance with the layout of the dedicated circuit, the attachment / detachment of one dedicated circuit does not cause load fluctuations with respect to other dedicated circuits. It is possible to overcome the limitation of high speed, and to reduce the complexity of optical fiber connection while operating the conventional dedicated circuit, and to operate a large number of dedicated circuits in the bus circuit device at high speed.

Further, since the optical transmission circuit network connecting the plurality of optical transmitting circuits and the plurality of optical receiving circuits is constituted by using the optical star coupler, the broadcast which sends the signals of the same contents to the plurality of dedicated circuits is broadcast. Communication can also be easily realized.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention viewed from a dedicated circuit side.

FIG. 2 is a perspective view of the first embodiment of the present invention viewed from the shared circuit side.

FIG. 3 is a characteristic diagram showing an eye pattern of a transmission signal according to the first embodiment of the present invention.

FIG. 4 is a characteristic diagram showing an eye pattern of a transmission signal in the electric bus device.

FIG. 5 is a characteristic diagram showing a relationship between an eye pattern opening and a transmission rate.

FIG. 6 is a perspective view of a second embodiment of the present invention viewed from the dedicated circuit side.

FIG. 7 is a perspective view of a second embodiment of the present invention viewed from the shared circuit side.

FIG. 8 is a perspective view of a third embodiment of the present invention viewed from a dedicated circuit side.

FIG. 9 is a perspective view of a third embodiment of the present invention viewed from the shared circuit side.

FIG. 10 is a perspective view of a fourth embodiment of the present invention viewed from the dedicated circuit side.

FIG. 11 is a perspective view of a fifth embodiment of the present invention viewed from the shared circuit side.

FIG. 12 is a perspective view showing a conventional optical bus circuit device.

[Explanation of symbols]

 1 shared circuit 11 circuit board forming a shared circuit 12 auxiliary board 2 dedicated circuit 21 circuit board forming a dedicated circuit 3 connector 31 connector 4 optical transmitter circuit 5 optical receiver circuit 61 optical star coupler 62 waveguide type optical star coupler 71 optical Fiber 72 Optical waveguide 81 External output terminal 82 External input terminal 83 Optical amplifier 9 Planar lightwave circuit

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akinori Watanabe 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (5)

[Claims] 1. A bus circuit device having a plurality of dedicated circuits each performing a unique function and a shared circuit for collecting and distributing input / output electric signals of the plurality of dedicated circuits, wherein an output from the dedicated circuit is provided. A plurality of optical transmitting circuits for converting an electric signal into an optical signal; a plurality of optical receiving circuits for converting the optical signal into an input electric signal to the dedicated circuit; the plurality of optical transmitting circuits and the plurality of optical receiving circuits And an optical transmission circuit network for exchanging signals between the dedicated circuits by connecting the dedicated circuits to each other through an optical signal to form the shared circuit, and the dedicated circuit and the optical transmission An optical bus circuit device, wherein connectors for detachably connecting an electric circuit of a circuit and an electric circuit of the optical receiving circuit are arranged on the integrated substrate so as to match the arrangement of the dedicated circuit. 2. The optical transmission circuit network connecting between a plurality of optical transmission circuits and a plurality of optical reception circuits is configured using an optical star coupler. Bus circuit device. 3. The connector for detachably connecting a dedicated circuit to an electric circuit of an optical transmitter circuit and an electric circuit of an optical receiver circuit has a structure in which connectors arranged on another substrate are connected in cascade. The optical bus circuit device according to claim 1, which is characterized in that. 4. The optical transmission circuit network connecting between a plurality of optical transmission circuits and a plurality of optical reception circuits has an external output terminal for outputting optical output signals of all optical transmission circuits and all optical input signals. The optical bus circuit device according to claim 1, further comprising an external input terminal for inputting to the optical receiving circuit. 5. The optical transmission circuit network connecting between a plurality of optical transmission circuits and a plurality of optical reception circuits comprises a planar lightwave circuit in which an optical element and an optical waveguide are formed on a planar substrate. The optical bus circuit device according to claim 1.