JP2842046B2 - Optical connection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical connection device for connecting information signals using light.

[0002]

2. Description of the Related Art Compared with electrical wiring, wiring using light has less interference with wiring due to electromagnetic induction, does not require impedance matching, and has a small wiring delay. It is expected as a means to solve the problem.

[0003] For example, in optical connection between boards, FIG.
The configuration shown in FIG. In this configuration, a light output from a laser light source 21 set on one board 20 is transmitted to a plurality of photodetectors 2 set on another board 20 via a lens 4, a mirror 6, and a beam splitter 5.
It is configured to distribute to two. In another example shown in FIG. 10, a one-to-one optical connection using the lens 4 is provided between the light emitting and receiving devices 23 provided on the board 20, and a non-adjacent board is once connected via an electric circuit. A method of relaying by using a relay is also being studied.

[0004]

There are several problems with the above-mentioned conventional configuration. In the example of FIG. 9, a light source with high light intensity is required to distribute an optical signal from one light emitting source to a plurality of light receiving positions. In connection using free space, the connection distance cannot be made too long due to diffraction spread. In the example of FIG. 10, since it is necessary to pass through an electric circuit at the time of relaying, there are problems such as a signal delay and an increase in circuit scale when a parallel transmission line is used.

[0005]

The optical connection device of the present invention has a plurality of optical switch elements having a light emitting function, a light receiving function, and a light latching function, and an optical switch is provided between the optical switch elements. Cascade connection, the optical connection is in the form of a loop, and a drive circuit is provided for each optical switch element to periodically repeat a light receiving operation, a latch operation, a light emitting operation, and a reset operation. In the optical connection device, in the cascade connection, the traveling direction of the optical signal is one direction, and the phase of the operation cycle is delayed by a constant value T between adjacent elements with respect to the traveling direction of the light, and the cascaded light If the number of switches is N, N × T
Is an integral multiple of the operation cycle.

In another optical connection device of the present invention, a plurality of optical switch elements having a light emitting function, a light receiving function, and a light latching function are provided, and between the optical switch elements.
Subjected to light biological cascade connection, the optical connection has become looped, includes light-receiving operation for each optical switching element, latch operation, a drive circuit for periodically repeating the light emission operation and the reset operation In the optical connection device, the optical signal is configured to be bidirectionally connectable in the cascade connection, and the operation cycle of the adjacent device
The phase delay is a constant value T, and the number of connections from an optical switch element that transmits information to an optical switch element that receives information is M
Then, the light receiving the information such that the phase of the operation cycle is delayed by M × T with respect to the optical switch element transmitting the information.
It has a control circuit for controlling the switch element .

[0007]

The operation of the present invention will be described with reference to the drawings. As in the embodiment shown in FIG. 1, a plurality of optical switch elements 3 are cascaded by an optical system, and a loop is formed as a whole. The optical switch element 3 used here has a light emitting function, a light receiving function, and a latch function.
Specifically, it can be realized by introducing a compound semiconductor heterostructure into a pnpn thyristor configuration as shown in FIG. In FIG. 1, the element has a front surface input and a front surface output, but may have a rear surface input and a front surface output. As shown in FIG. 3, the optical switch element 3 shown in FIG. 2 exhibits a bistable characteristic in which a transition is made from an off state where a small amount of current flows to an on state where a large amount of current flows at the boundary of the switch voltage Vs, and an optical output is generated. Also, the presence of optical input reduces the switch voltage. Therefore, the set voltage V slightly smaller than Vs
By applying x, the element state can be controlled by the presence or absence of light input. The transition from the ON state to the OFF state can be performed by setting the applied voltage to be equal to or lower than the hold voltage Vh.

If eight optical switch elements 3 are connected as shown in FIG. 1, a drive circuit 2 applies a drive voltage having a phase difference T between adjacent elements as shown in FIG. The optical switch element 3 performs a light receiving operation, a latch operation, and a light emitting operation in a set period 10 and is reset to an off state in a reset period 11. The sum of the set period 10 and the reset period 11 is the drive cycle. By driving the elements with the phases shifted, optical information can be transmitted one after another. Now #
Assuming that 1 is a signal transmission source, as shown in FIG. 4, if the signal is " 1", a voltage higher than Vs is applied if the signal is " 1", and a voltage lower than Vh is applied if the signal is "0". The optical signal is sequentially transmitted from # 2 to # 8. If the phase difference T × the number N of optical switch elements is an integral multiple of the operation cycle, the phase difference between # 8 and # 1 also becomes T. Therefore, even if the source of the signal is any element, the drive between the elements remains unchanged. A signal can be transmitted to all the optical switch elements by the phase shift. Therefore, the same function as the bus of the electric circuit can be easily realized. By forming the optical switch elements 3 in a two-dimensional array, parallel connection can be easily realized.

[0009] FIG. 5, is another of the onset Ming embodiment. A control circuit 7 for controlling the timing of the drive signal is added to the previous embodiment. The optical connection system is different from the previous embodiment in that bidirectional connection is possible. FIG. 6 shows the phase of the drive signal. The optical switch element 3 is set for the same period as in FIG.
At 10, a light receiving operation, a latching operation, and a light emitting operation are performed.
In the reset period 11, it is reset to the off state. Set period
10 and the reset period 11 are the driving cycle (operating cycle)
Become. Here, the phase of the operation cycle between adjacent elements is constant
If it is delayed by the value T, the phase between adjacent elements is not T
To transmit optical information one after another by driving the device
I can do it. Assuming that # 1 is the source of the optical signal,
2 and # 8 receive this signal with a T phase delay. Thereafter, the information is sequentially transmitted to # 3, # 7, # 4, and # 6, and finally, # 5 receives. At this time, # 5 receives optical signals from # 4 and # 6 at the same time, but there is no problem since they are the same signal. Such a phenomenon does not occur if the number of optical switch elements is odd.
The drive circuit of each element is controlled by the control circuit 7 depending on which element transmits information. Optical switch element of light source
Let M be the number of connections to the optical switch element received from the slave
And the operating cycle of the receiving optical switch element is
Compared to the operation cycle of the optical switch element, its phase is set to the number
Is controlled by shifting by M × T corresponding to
Optical information transmitted to the contact element can be received. In this embodiment, information can be transmitted to all the optical switch elements faster than before.

In the above description, the optical switching element 3
The two-dimensional array enables easy parallel information transmission.

[0011]

FIG. 1 shows an embodiment of the present invention. A drive circuit 2 and an optical switch element 3 are provided for each signal processing circuit 1. The optical switch elements 3 are optically coupled by a lens 4, a beam splitter 5, and a mirror 6. Since this optical coupling is one-way, the polarization emitted by the optical switch element 3 is set to linear polarization, and the beam splitter 5
If a polarization beam splitter is used, it is also possible to suppress the light amount loss. That is, if the polarization beam splitter is P
Assuming polarized light transmission and S-polarized light reflection, # 1, # 3, # 5, #
7 may be S-polarized light emission, and # 2, # 4, # 6, and # 8 may be P-polarized light emission. Even if the number of optical switch elements is other than this number, the optical connection device can be similarly configured.

FIG. 2 shows a configuration example of the optical switch element 3 used in the present invention. By combining a pnpn thyristor structure with a compound semiconductor heterostructure, light emission, light reception, and latch functions can be realized.

Another embodiment of the present invention is shown in FIG. A drive circuit 2 and an optical switch element 3 are provided for each signal processing circuit 1. The optical switch elements are optically coupled to each other by a lens 4, a beam splitter 5, and a mirror 6 so that they can be interconnected. The drive circuits are connected by a control circuit 7 for controlling the drive phase. The control circuit 7 may be located anywhere.

FIG. 7 shows another example of an optical switch element that can be used in the present invention. The configuration is such that the optical switch elements 3 having the pnpn structure described above are connected in parallel. In this configuration, a digital signal can be represented by two optical signals of positive logic and negative logic. In the light receiving operation and the latching operation, only the optical switch element on the side where light is input is turned on. Compared to the single configuration, the differential configuration is employed, so that it is possible to operate with a small signal. A drive signal may be applied to the terminal C during the light receiving operation, and a signal may be applied to the terminal A or B during the information signal oscillation operation.

FIG. 8 shows another example of the optical switch element. M
An optical modulator of a QW (Multiple Quantum Well) 14 and an HPT (Hetero Phototransistor) 15 are coupled to each other.
2, the HPT 15 operates to change the voltage applied to the MQW, so that the light reflectance of the MQW changes. Since there is no self-luminous function, reading light input from outside is required,
By using the reflected light input / output 13, the same function as that of the optical switch element of the previous embodiment can be realized.

In the above embodiment, the free space connection is used, but the connection may be made by a fiber. It is also possible to use a planar optical system.

[0017]

According to the present invention, it is possible to easily configure an optical connection device having a bus connecting a large number of signal processings.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a specific example of an optical switch element used in the present invention.

FIG. 3 is a diagram illustrating an operation of the optical switch element.

FIG. 4 is a view for explaining the operation of the embodiment in FIG. 1;

FIG. 5 is a diagram showing another embodiment of the present invention.

FIG. 6 is a view for explaining the operation of the embodiment in FIG. 5;

FIG. 7 is a diagram showing a specific example of an optical switch element used in the present invention.

FIG. 8 is a diagram showing another specific example of the optical switch element used in the present invention.

FIG. 9 is a diagram showing an optical connection device according to a conventional technique.

FIG. 10 is a diagram showing an optical connection device according to a conventional technique.

[Explanation of symbols]

 Reference Signs List 1 signal processing circuit 2 drive circuit 3 optical switch element 4 lens 5 beam splitter 6 mirror 7 control circuit 10 set period 11 reset period 12 optical input 13 reflected light output 14 MQW modulator 15 HPT 20 board 21 laser light source 22 photodetector 23 Light receiving and emitting device

Claims (2)

(57) [Claims] An optical cascade connection is provided between the optical switch elements, the optical switch elements having a plurality of optical switch elements having a light emission function, a light reception function, and a light latch function. Is a loop-shaped optical connection device comprising a drive circuit for periodically repeating a light receiving operation, a latch operation, a light emitting operation, and a reset operation for each optical switch element. The traveling direction is one direction, the phase of the operation cycle is delayed by a fixed value T between adjacent elements with respect to the traveling direction of light, and when the number of cascaded optical switches is N, N × T is the above. An optical connection device having an integral multiple of an operation cycle. 2. A light emitting function, a plurality of optical switching element having a light receiving function and a light of latch function of light, subjected to light biological cascade connected between the optical switching element, a said optical An optical connection device, wherein a connection is formed in a loop, and a drive circuit that periodically repeats a light receiving operation, a latch operation, a light emitting operation, and a reset operation for each optical switch element is provided. It has become a two-way connection configurable, adjacent element
An optical switch element to receive information phase lag of the operating cycle between the child from the optical switch element for a fixed value T, outgoing <br/> information
If the number of connections to the child is M, the optical switch that transmits the information
Phase of the operating cycle to switch elements as delayed M × T
An optical connection device comprising a control circuit for controlling an optical switch element that receives the information .