JPS59208953A - Transmitting and receiving system of optical signal - Google Patents

Abstract

PURPOSE:To reduce the optical power loss and therefore to reduce the transmission electric power by transmitting selectively the optical signals to plural optical signal receivers from optical signal transmitters via a hologram. CONSTITUTION:Both optical transmitters and receivers are unified into a unit via a optical transmitting/receiving device as shown by TR1-TRn in the figure. In this case, a mirror M is adhered close to the back of a hologram H. The light delivered from any of optical transmitting/receiving devices TR1-TRn is reflected by the mirror M through the hologram H and forms a light spot over the photodetecting part of each of devices TR1-TRn. For this purpose, the hologram H has a specific structure. As a result, the communication lines are formed among devices TR1-TRn to secure the exchange of information among these devices under the proper control.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical signal transmission/reception system in which optical signals are transmitted via a hologram.

As is well known, multiprocessor systems with hundreds of processor units are being developed, but the shared bus used for communication between processors requires a large communication capacity.In order to increase processing speed, Increasing the number of processors in a network will increase bus communication congestion, and a lack of communication capacity will degrade system performance. It is inevitable that V-) will be required, and the only possible way to realize it is to transmit information using an optical medium.Normally, optical fibers are used to transmit optical signals. Although it has excellent characteristics, it has drawbacks such as large attenuation when splitting light and expensive connectors.Of course, optical fibers can also be used as a shared bus in multiprocessor systems. However, connecting hundreds of processors requires a large amount of optical fiber connections, which causes the above-mentioned drawbacks and makes it impractical.
As a solution to the above problem, an optical information exchange system using a cylindrical mirror (see Japanese Patent Laid-Open No. 10551/1983) was proposed. This is shown in FIG. In this figure, an application to a broadcast bus used for exchanging information between processors in a multiprocessor system is considered.

In this case, a cylindrical concave mirror is selected as the member of the cylindrical mirror 1 that defines the cylindrical mirror surface A', and a plurality of optical signal transceivers are mounted on the virtual curved surface B of the cylindrical mirror 1, which faces the cylindrical mirror surface A. (hereinafter referred to as optical transceiver) TR+, TR+, TR,
, will be established. Each optical transceiver TR+, TR+, T
R, is a convenient position P,,P,,P” on the curved surface B.
3 - LA is only shown for convenience,
Actually, the required number can be distributed on the curved surface B as described later.

The configuration of the optical transmitter/receiver itself is arbitrary and is not specified, but for example, a light emitting element such as a light emitting diode or a semiconductor laser, and a light receiving element such as a PIN photodiode or an avalanche photodiode are housed in a suitable housing. It is conceivable that the system is integrated into the system. Each processor 3 is connected to the electrical signal input/output line group 2 for these light emitting and light receiving elements via a suitable interface circuit.

Therefore, there are the same number of optical transceivers as there are processors 3.

In this way, the area between the cylindrical mirror surface A and the [1111 surface B] becomes a shared transmission path between the respective optical transmitters/receivers TR+, TR+, and TRo, but this point will be further explained below.

In Fig. 1, light emitted from curved surface B to cylindrical mirror surface A at a radiation angle θ is transmitted to center point 4 of cylindrical mirror surface A and center point 5 of the circular arc.
Just passing between 0 and 51. Optical transceiver T on p I
When R+ is placed and light is sent by a light emitting element, the cylindrical mirror surface A
The light reflected at the center point BP and the center point 4. A position P that is symmetrical to the position P1 with respect to the axis ic connecting the center point 5,
It spreads between and returns. This is clear from the nature of light. Further, for example, there is a position P2 where light emitted from a position on the axis C at a radiation angle θ spreads and returns between positions 21 to 23 on the curved surface B.

There are consecutive points on the curved surface B that satisfy the condition that the light emitted at the radiation angle θ is reflected by the cylindrical mirror surface A, spreads between the positions p+ and ps, and returns, and this curve is It can be easily determined by optics and geometry. The required number of transmission and reception Bk is distributed and installed on the curved surface obtained in this way.

Since this device is based on a broadcast bus, this type of known system allows only one transmitter to transmit at a given time, while all others are receivers. When data is broadcast, each of the many receivers takes in the data if it contains the data they need, and discards the data if it is unnecessary.

In this way, no matter how many recipients need the data, data transmission can be completed with at least one transmission. If there is a reception error, a retransmission is requested and the same data is sent again. If this is done, the reliability will be sufficiently high.Furthermore, the fanout of the transmitter is very large compared to one that uses electric wires, and the fanout of a TTL bus driver, which is a normal semiconductor logic element, is 10 to 30. However, it has been confirmed that more than 1,000 can be harvested.

By the way, the above-mentioned optical information exchange system does not have the drawbacks of optical fibers because it transmits information by emitting optical signals into space without using the original fiber. However, as shown in Fig. 1, this method utilizes the fact that the light emitted at the radiation angle θ is reflected by the cylindrical mirror 1 and spreads between the necessary devices PIpP3. ...,TR,,...
・, TRゎ light emitting element.

There was a restriction that all the light receiving elements had to be arranged on a straight line. In addition, the light reflected from the cylindrical mirror 1 reaches unnecessary parts such as light emitting parts other than the light receiving part and gaps, resulting in a large loss of optical power and causing a large loss of optical power to the optical signal transmitter (hereinafter referred to as
This has led to a reduction in the fan-out of optical transmitters (optical transmitters), which in turn has led to a reduction in the number of boats attached to the bus.

This invention was made in consideration of the above points, and it does not use 9 fibers, but directly radiates light (No. By selectively sending optical signals only to the light receiving section of the optical receiver (hereinafter referred to as an optical receiver), optical power loss is reduced. Therefore, by reducing transmission power and increasing fan-out, good efficiency is achieved and the structure is simple. The present invention is intended to provide an economical path.The principles and embodiments of the present invention will be described below.

FIG. 2 is an explanatory diagram showing the principle of this invention.

In this figure, sl 1 St J ..., sI
, l is a light source that emits coherent light, H is a hologram,
sc is screen, 1□, 17. . . , +n are the light spots on the screen SC. However, screen S
C does not have to be a plane1. The hologram H receives light emitted from, for example, a light source SI, and forms n light spots 1□j 12. on the screen SC. It is well known that it can be made to obtain 7In'<. In this case, ideally the power of light emitted from light #S is 117127 at each light point.
. . , +n can be equally divided and reached. Further, the hologram H is a light source Sl.

S2. ..., IIF on the screen SC regardless of the light emitted from any position on S Yu +27...7 I
It can be made to obtain a light spot at position n. Using such a hologram H, light sources S, , S, . . .

Optical transmitters are placed at the positions of S□, light points 12 and 1□.

..., 1. If an optical receiver is installed at each position, then
Korin S,,S2. . +2. . . . Optical signals can be sent to all optical receivers of g In at the same time. At this time, the optical power of the optical transmitter is at the light point 11125...
It is sent only to the +n yt receiver and is not scattered to other unnecessary parts.

FIG. 3 is another explanatory diagram showing the principle of the invention, and shows a case where a mirror M is closely attached to the back surface of a hologram H. In this case, the light hitting the hologram H from the light sources S, , S, . l',
, . . . , 1'o.

A diode is suitable as a coherent light source for the light emitting part of the optical transmitter. Moreover, an avalanche photodiode, a PIN photodiode, etc. are suitable as the light receiving element of the optical receiver.

FIG. 4 is based on the above-mentioned principle of the present invention, and shows a first embodiment of an optical signal transmission/reception system using light as a medium. In this figure, TR,,TR2,・
..., TR11 are optical transceivers, which combine the aforementioned optical transmitter and optical receiver into one, and there is a mirror M7 on the back of the hologram H! l - placed in close contact. In this case, the optical transceiver TR,.

The light emitted from any of TR, ..., TR1+ is hop
gram H'& reflected by mirror M, and optical transmitter/receiver TR.

A hologram H is created so as to connect light points on each of the light receiving parts of TR, . . . , TRn. If you do this,
A communication path is established between the optical transceivers TR, TR2,..., TR1l, and the optical transceivers TR,..., TR1l are connected under appropriate control.
Information can be exchanged between TR2, . . . +TRiTR.

At this time, as shown in FIG. 5, optical transceivers TR, TR2, .

If it is possible to arrange each optical transceiver TR,.

The optical path lengths between TR, . Therefore, the reliability of information transmission due to the phase difference of signals is eliminated, and at the same time, the optical transceiver TR,
Since it is possible to omit a device for correcting the phase difference of the signals in TR, .

FIG. 6 is an explanatory diagram showing a second embodiment of the present invention, in which the configuration of the hologram H is changed to selectively form communication paths between a large number of optical transmitters and receivers.

For convenience of explanation, there are six optical transceivers TR,,TR,.

..., TR, Y layout, but of course the number of units! There are no special limitations. In this figure, the hologram H is constructed as follows. That is, the optical signal emitted from the optical transceiver TR, passes through the hologram H and is reflected by NM, as shown by the dotted line, and is reflected by the optical transceiver TRI! T R4
, T R! The light is focused only on the light receiving section of 1. Similarly, the optical signal transmitted from the optical transceiver TR is also focused on the light receiving part of the optical transceiver TR, , TR, , TR, and the optical signal emitted by the optical transceiver TR is also focused on the optical transceiver TR1, TR, TR, , T
The light is focused on the light receiving section of R. Next, the optical signal originating from the optical transceiver TR passes through the hologram H and the mirror M as shown by the solid line.
and is focused only on the light receiving sections of the optical transmitters/receivers TR, JTR, , TR. Similarly, optical transceiver ■R3
The optical signals emitted by , TR, are also transmitted to optical transceivers TR, , TR, respectively.
The light is focused only on the light receiving section of TR, , TR. When the hologram H configured in this way is used, an optical transceiver T Rt
s TR4v TR11 can exchange information with each other, but other optical transceivers TR2,.

It is impossible to exchange information with both TRs and TR.

Similarly, attack exchange is possible between optical transceivers TR2, TRs and R6, but other optical transceivers TR1 and T
Both R,, TR5 and li ('iv?11 cannot be exchanged.

The feature of this second embodiment is that a large number of optical transceivers TR,
In some cases, information can be exchanged only between specific groups among TR2, . . . , TR11. By this method, the optical transceiver TR,,TR,.

..., TR1, in a multiprocessor system consisting of many processor units, the hologram H
By replacing the , you can easily change the communication network of the multiplexer.

FIG. 7 is an explanatory diagram showing a third embodiment of this understanding, in which an optical transceiver is formed that exchanges information consisting of a plurality of bits by parallel transfer. In this embodiment, three optical transceivers transmit two bits in parallel.

Of course, there is no particular limit to the number of bits or the number of optical transceivers. In FIG. 7, T I+, "12 p Tl'J
y T22 y731p TR2 is an optical transmitter, R1
□y R121R211R22*R31s R32 is an optical receiver. The optical transmitter T11 and the optical receiver R11 are paired as shown in FIG. 1 in FIG. M4, FIG. 5, and FIG. Optical transceiver TR in the second embodiment.

The optical transmitter Tn and the optical receiver Rft have the same functions as the optical transmitter Tn and optical receiver Rft.
Furthermore, the first optical transmitter/receiver is composed of the forward transmitter, receiver "11°R□" and 711JR12. In this case, the optical transmitters Tll and Lt are respectively f
The receiver has the transmission of the first bit and the second bit of the optical transceiver of jlE>. Further, the optical receivers R11 and Ru each receive the first and second bits. Similarly, forward transmission, receiver Ttjp R2++ T2□R22s
T31 + F? sr 4 Tit + R11*
That's the second one. A third optical transceiver is configured. The hologram H has a mirror M closely attached to the back, and if any optical transmitter emits an optical signal toward the hologram HK, the hologram H
The optical signal reflected by the mirror M is condensed onto the light receiving portion of each corresponding bit of all the optical receivers. In this way, two-focus information can be exchanged between the three optical transceivers.

FIG. 8 is an explanatory diagram showing a fourth embodiment of the present invention, in which a large number of hologram H lights are used. This figure also shows an example of three optical transceivers for 2-bit parallel transfer. Of course, there is no particular limit to the number of parallel transfer bits or the number of optical transceivers. In this figure, the optical transmitter, receiver Tll a
T+21 T217722J ”31 pT32t R
11R1+! s R21s R22J R31! Rs.
t are respectively the same as in the third embodiment of FIG. H
1□p H+27H21rH22y H3L * H3
Reference numeral 2 denotes a hologram, and a mirror M is closely attached to the back surface of the hologram, and is provided independently for each focus of each optical transmitter/receiver. That is, in the case of the fourth embodiment, since there are three 2-bit optical transceivers, there are six holograms H1l p l"'1
12 s...v HR□ is made on -H of one board. Each hologram HII, HI! ,...

Ha2 is configured as follows. That is, the optical signal emitted from the optical transmitter T11 is transmitted from the hologram H11 to R2.
1, T12 said to R12, ``J responsibility, T22 said to R22, T
s+! , LH31, and T32 send optical signals to R32, respectively. The optical signal emitted by the forwarding 4M volumes Tl+ passes through the polarizer; ÷iH1+, is reflected by the mirror M, and is focused on the light receiving section of the light receiver 1-1 RII p R21e R3+. Also, optical transmitter ■2. .

The optical signals emitted by T31 are each hologram H2++H
Optical receiver R11t R2 by i'll and mirror M
+ 1 The light is focused on the light receiving section of R31. Similarly, the optical signals emitted by the optical transmitter TI27Tnp'rs2 are also focused on the light receiving sections of the optical receivers R12+ R22vR12+ by the holograms H1□H22y R32 and the mirror M, respectively.

Holograms H1l and R12y configured as above
..., the fourth embodiment with R32 has the same effects as the third embodiment shown in FIG. 7, and at the same time has the following advantages. Although the emission angles of the optical signals from the optical transceivers to the holograms were different, in the fourth embodiment, the optical transmitter T11, the hologram R11, and the optical receivers R1, , R□.

R31 and the optical transmitter T12. If the positional relationship between the hologram R12 and the optical receiver R12F R22+R32 is formed such that only the height h differs, each bit of one optical transceiver will emit an optical signal at the same angle. will be possible.

This is very convenient when creating an optical transmitter for transferring a large number of bits in parallel, and is suitable for mass production.

Also, each hologram H1l and 812p H21 and 82
2z l"131 and 832 can be exactly the same, so they can be easily made by photocopying.

As explained above in detail 1, this invention has at least
In the Optical I-J transmission/reception method that sends optical signals from one optical transmitter to multiple optical receivers, optical signals are selectively transmitted from the optical transmitter to multiple optical receivers via holograms. As a result, the following advantages, which are essential for realizing a high-speed, large-capacity electronic computer, especially a multiprocessor system, can be obtained.

(1) The number of optical transceivers can be increased without being limited in the number of transmission lines between the optical transceivers.

(2) By using light as a medium for information transmission, extremely high transfer rates of several gigabits/second or more can be used.

(3) Since communication is based on light, it is not affected by external electromagnetic noise, so high reliability can be achieved.

(4) By using a hologram, optical signals can be sent only to where they are needed, so there is almost no loss of optical power and high efficiency can be obtained.

(5) By using a hologram with a mirror on the back, the optical transmitter and optical receiver can be installed in adjacent locations, which shortens the wiring length between the transmitter and receiver, simplifying the overall structure. This makes the system faster and more reliable.

(6) By creating a hologram, it is possible to design a hologram so that information can be exchanged only between a specific group of a large number of optical transceivers.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of a conventional optical information exchange system, and FIGS. 2 and 3 are explanatory diagrams each showing the principle of the present invention.
4 and 5 are explanatory diagrams showing the first embodiment of the invention, FIG. 6 is an explanatory diagram showing the second embodiment of the invention, and FIG. 7 is an explanatory diagram showing the second embodiment of the invention.
The figure is an explanatory diagram showing a third embodiment of the invention, and FIG. 8 is an explanatory diagram showing a fourth embodiment of the invention. In the figure, Sit 827"・, So is the light source, H is the hologram, SC is the screen, lI, 12) ・-, +n is the light point, M is the mirror, TR,, TR,..., TRゎ is the light It is a transmitter/receiver. Fig. 1 Fig. 2 Fig. 5 Fig. 6

Claims (1)

[Claims] A source for transmitting an optical signal from at least one optical signal transmitter to a plurality of original signal receivers (in the p-oblique transmission/reception method, transmission of an optical signal from the optical signal transmitter to the plurality of optical signal receivers) Can it be performed selectively through holograms? <%
An optical signal transmission and reception method.