JPS59222820A - Optical integrated circuit - Google Patents

Abstract

PURPOSE:To attain high speed operation by driving a switching means by a driving means on the basis of a control signal detected by a control signal detecting means and supplying power necessary for said operation from an accumulating means accumulating power from an optical power genertaing means. CONSTITUTION:A control signal switching light is inputted to the control signal detecting means 23 consisting of a photodiode through an optical fiber 25. The detected control signal is amplified by the driving means 24. Power for these circuits is supplied from the accumulating means 22 consisting of a capacitor or the like by converting light projected from a power supplying optical fiber 26 into power by the optical power generating means 21 consisting of a photocell or the like and accumulating power in the means 22. Output voltage from the driving means 24 is apllied to an electrode 7 of an optical changeover switch consisting of a substrate 1, an optical waveguide 2, a branch 3, optical fibers 4-6 and the electrode 7, so that the optical switch operates at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical integrated circuit, and more particularly to an optical integrated circuit having an optical changeover switch function.

Conventional configurations and their problems In information communication systems that use light, optical switches that change the connection of optical information are systems that mechanically move mirrors, etc.
There are methods that use diffraction due to the acousto-optic effect, methods that use the electro-optic effect, etc., and they play an important role in system configuration. Among the above methods, total internal reflection (TIR) type switches that utilize electro-optic effects and waveguide coupler type switches are not practical because they can switch at high speed and consume very little power. expensive. Recently, optical fibers have been used in information and communication systems that use light for remote detection and control, taking advantage of the fact that they are not susceptible to the effects of electromagnetic induction. To control this, wavelength multiplexing or optical signals from a separate optical fiber was used.

FIG. 1 is a schematic diagram showing an optical integrated circuit having such a conventional optical changeover switch function. An optical waveguide 2 is formed in a Y-shape on a substrate 1, and its branches 3 are each connected to an optical fiber 4.
, 5 and 6 through a lens or the like (not shown here). Here, when a material with a strong electro-optic effect, such as lithium niobate, is used as the substrate 1 and a voltage is applied between the electrodes 7, the light incident from the optical fiber 4 is totally reflected and guided to the branch 3, and the light is guided to the optical fiber 5. reach.

When no voltage is applied, it reaches the optical fiber 6. This constitutes an optical switch. This voltage varies depending on the material and configuration, but is generally required to be several tens of volts (Az) or more.

In order to obtain this voltage, in this conventional example, a photovoltaic cell 9 was provided, and the photovoltaic cell 9 was irradiated through the optical fiber 8 to generate an electromotive force. In the conventional experimental example, an abnormal photovoltage of about 30V was obtained using cadmium telluride and ram as the photovoltaic cell 9. As a result of applying this voltage to the electrode 7, it can be operated as a switch. However, the operating speed of this switch was slow, and it took about 1 second to turn on and off, and several tens of seconds or more to turn on and off. This is presumed to be because tellurium has a high internal resistance, about 6 gigaohms for light irradiation and about 100 gigaohms for non-irradiation, resulting in a long time constant. Using gallium arsenide PIN structure, open-circuit power is 3.9 millivolts, short-circuit current is 3.
・6 microamperes were obtained, but even if this photovoltaic cell was used, the switching speed of the switch was slow at several hundred microseconds, and its use was limited to low-speed applications.

OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned problem, that is, the problem of slow switching speed, and to provide an optical integrated circuit capable of high-speed operation.

Structure of the Invention The present invention provides, in addition to a photovoltaic power generation means (such as a photovoltaic cell) and an optical switching means (such as a total reflection type optical switch), a power storage means for storing electric power newly obtained by the photovoltaic power generation means, and a control signal detecting device. and a drive means for operating the optical switching means based on the detected signal.
It is constructed so that it is operated by being supplied with electric power stored in the electricity storage means mentioned above.

Description of examples The present invention will be described below based on examples.

FIG. 2 is a schematic diagram for explaining one embodiment of the present invention. In the figure, the substrate 1, the optical waveguide 2, its branch 3, the optical fibers /<4.5 and 6, and the electrode 7 are the same as in the conventional example.

A control signal for switching the light is guided via an optical fiber μ26 to a control signal detection means 23 consisting of a photodiode (indicated by P and D in FIG. 2). The detected signal is amplified by drive means 24 to a level /I/ sufficient to drive electrode 7. This driving means 24 is a 4th complementary M
When constructed using O3 type transistors, power consumption is reduced and it is effective. The power supply for these circuits is such that the light emitted from the optical fiber 26 for power supply is connected to the photocell means 21.
This is converted into a staining force and supplied via a power storage means 22 consisting of a capacitor or the like. According to the results of experiments conducted by the present inventors, a silicon photodiode is used as the photodetection means 23, a complementary MOS type integrated circuit is used as the drive means 24, and a gallium arsenide photocell pile (open) is used as the photovoltaic means 21. (voltage: 30 volts), and a 1 microfarad capacitor was used as the electricity storage means 22.

Next, when an intermittent optical control signal was applied via the optical fiber 25, the rise time and fall time of the optical switch were both as fast as 0.1 microseconds, indicating that it operated several thousand times faster than the conventional example. confirmed.

Considering the results of this experiment, the power to drive the electrode 7 is:
Since it is a capacitive load, the inrush current for charging and discharging is the only one, and almost no power is consumed while the operation is maintained, so the power stored in the storage means 22 is approximately 500%.
This is thought to be due to the fact that it was able to supply sufficient inrush current even though it was a micro unit.

As the photovoltaic means 21, in addition to gallium arsenide shown in the above embodiment, Ge, Si, PbS, In
P.

GaP, CdS, ZnS, Z
Photocell piles made of n Se or Cd Te can be used. Still, using power generation means using the extraordinary photovoltaic effect of these materials, it is possible to generate several tens of volts.
) is effective because the voltage can be easily obtained. It is not a problem even if the photovoltaic power generation means has a slow response, that is, a long time constant, and it is desirable that the photovoltaic power generation means has good power generation efficiency.

Although the control signal can be transmitted as an electrical signal, it is more advantageous to transmit it as an optical signal since it is less affected by electromagnetic induction and the like. Since the speed of light switching is controlled by the control signal detection means, driving means, and light switching means, it is desirable that the control signal detection means be an element with a sufficiently fast response speed and a small time constant.

If the photovoltaic power generating means has a sufficient function of receiving light and generating electricity,
It is also possible to provide it on the substrate 2 or the back surface, and to generate electricity by the light leaking from the optical waveguide 2, the branch 3, and their end faces. When light is used as a control signal, a portion of this light can also be used for power generation. Furthermore, it is also possible to transmit the switching light, the control signal light, and the power generation light at different wavelengths through a single optical fiber, and then separate the lights again by filtering them. It is possible, has a simple configuration, and is effective. More complex switching operations can be performed using pulse-coded signals as control signals.

The optical switching means may have a waveguide coupler type configuration in addition to the total reflection type, and the modifications and changes described in Embodiment 2 of the present invention are naturally included in the scope of the present invention. .

Effects of the Invention According to the present invention, electric power generated by light is constantly charged and a large inrush current is supplied when switching operation is required, so the switching response speed is significantly faster and high-speed operation is possible. Ta. It has a wide range of applications, including remote measurement, remote control, and other optical information communication systems.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a conventional optical integrated circuit, and FIG. 2 is a schematic diagram showing an optical integrated circuit according to an embodiment of the present invention. 1...substrate, 2...optical waveguide, 4,
5, 6. 25+26...optical fiber, 7...electrode,
21...Photovoltaic power generation means, 22...Electricity storage means, 23...Control signal detection means, 24...
...Driving means. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2? ! 22

Claims (1)

[Scope of Claims] (1) A photovoltaic power generation means, a power storage means electrically connected to the photovoltaic power generation means, a control signal detection means, an optical switching means, and a driving means connected to the optical switching means. an optical integrated circuit, characterized in that the driving means drives the optical switching means using the output signal of the control signal detection means and the electric power stored in the electricity storage means. (2) As a photovoltaic means, Ge, Si, a mixture thereof, or a compound containing at least one of Al, Ga, and In and at least one of P, As, and Sb, or Pb, Zn, and Cd.
The optical integrated circuit according to claim 1, characterized in that a single crystal or a thin film of a compound containing at least one of S, Se, and Te is used. (3) The optical integrated circuit according to claim 1, wherein an optical signal is used as the control signal. (4) The optical integrated circuit according to claim 1, wherein the time constant of the control signal detection means is shorter than the time constant of the integrated photovoltaic means and the power storage means. (6) The optical integrated circuit according to claim 1, characterized in that the photovoltaic power generating means is arranged integrally with a substrate constituting the optical switching means. (6) There is a plurality of optical switching means, and the control signal is composed of a plurality of optical signals with different wavelengths, and the optical switching means is switched in response to the combination of the two optical signals. Characteristic feature ♂1 - The optical integrated circuit according to claim 1. The optical integrated circuit according to claim 1, characterized in that (a) an encoded intermittent signal is used. (8) The optical integrated circuit according to claim 1, characterized in that the control signal and the light for the photovoltaic power generation means are transmitted by a fully open optical line. (9) The optical integrated circuit according to claim 1, characterized in that the driving means is constituted by a circuit including a gold complementary metal oxide field effect transistor (CMO5FICT). (1o) The light switched by the optical switching means, the light serving as a control signal, and the light supplied to the photovoltaic power generation means are transmitted as different wavelengths through the same optical path, respectively. The optical integrated circuit described in . (11) The optical integrated circuit according to claim 1, wherein an electro-optic effect is utilized as the optical switching means.