JPS63202723A - Optical connecting device for connection between substrates - Google Patents

Abstract

PURPOSE:To vary a connection point by providing a light emitting element, an optical waveguide, and a diffraction grating, supplying an electric signal and varying an angle of deflection, and converging projection light on a light receiving element on a substrate for reception. CONSTITUTION:The optical deflector 11 consisting of an optical waveguide layer 2, the light emitting element 3, and the diffraction grating 1 formed at the other end side of the layer 2 is provided on a substrate 10 for transmission. Further, a converging lens 12 is arranged above the grating 1 and the substrate 13 for reception is arranged opposite on the focal plane of the lens 12; and a couple of electrodes 4A and 4B are provided across the grating 1 and also connected to a voltage controller 6. Then a voltage applied to the electrodes 4A and 4B is varied to vary the interference relation between light propagated in the layer 2 and the grating 1, and the angle of the projection light 7 to the substrate surface normal is varied to switch light incident on the substrate 13 from a light receiving element 8 to another element 8. Consequently, optical connections between the substrates are changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to optical connections between electronic device boards, and particularly to a device that allows optical connection points to be changed at high speed.

[Conventional technology]

BACKGROUND ART The technology of replacing a large number of electrical wirings that connect the boards of electronic devices such as VLSIs with optical connections is important from the viewpoints of speeding up, noise countermeasures, etc., and several methods have been proposed in the past.

For example, the device shown in FIG. 3 is known as a typical device (J. W. Goodman et al., proc. I
EEE Vol. 72, 1qra, tSO page).

In this device, in order to make the light emitted from the light source 21 on the transmitting side substrate 20 enter the light receiving element 23 on the receiving side substrate 22, holograms are placed facing each other above these substrates λ0.22, and the light source light is directed to the hologram 22. By distributing the light in a desired direction with 'l', it is possible to optically connect to a large number of light receiving elements 3.

The above-mentioned device is installed according to the location of the required connection point.

By designing the hologram J41, it has the advantage of allowing complex connections to be made relatively easily.
You can also change the connection by replacing the .

[Problem that the invention seeks to solve]

The conventional optical connection system described above has a problem in that it is not possible to change the connection point at high speed while the device is operating, and it cannot be used in a device that switches between multiple optical circuits as needed.

[Means for solving the problem] An optical deflector capable of deflecting the light emitted from the transmitting light source by an electric signal is connected to a light emitting element, an optical waveguide that guides the light of the light emitting element, and an optical deflector that is attached to the optical waveguide and is attached to the optical waveguide to guide the light of the light emitting element. It consists of a diffraction grating coupler that emits the light out of the waveguide, and the direction of the light output is controlled by an external electrical signal.The output light is converged by an optical system, and multiple light receivers on the receiving board are connected to each other. Switch the circuit by making the light incident on one of the elements.

This will be explained in more detail below.

As shown in FIG. The exit angle of , n is the effective refractive index, ? is the order of diffraction, λ is the wavelength of light in free space, and t is the period of the diffraction grating.

As can be seen from equation (1), by changing λ or n, θ can be changed, that is, light can be deflected, and any of the above methods can be used in the present invention. For example, when changing the wavelength λ, a light source with variable output wavelength is used.

Further, in order to change the effective refractive index n, it is sufficient to form the diffraction grating l and the optical waveguide l from a semiconductor or an electro-optic material, provide an electrode for applying a voltage to the diffraction grating, and change the applied voltage.

[For production]

According to the present invention, the parallel light deflected by the optical deflector on the transmitting side substrate is sufficiently focused on the receiving side substrate placed on the focal plane of the optical system. Therefore, the light receiving element on the receiving side substrate can be miniaturized and can perform switching between multiple points with a sufficiently high extinction ratio.

Furthermore, since the connected light receiving elements are switched by deflecting the light from the light emitting elements using electrical signals, the connection points can be changed at extremely high speed.

〔Example〕

An embodiment of the present invention is shown in FIG.

In FIG. 1, reference numeral 10 denotes a transmitting side substrate, and an optical deflector // is provided on this transmitting side substrate 10.

The optical deflector 1/ includes an optical waveguide layer provided on the substrate IO,
A light emitting element 3 made of a semiconductor laser is laminated on one end side of the optical waveguide layer λ, and an optical waveguide F! It is composed of a diffraction grating for outputting guided light formed on the other end side of I2.

The semiconductor laser 3 includes, for example, a GaAS active layer and an AIo, 3
The optical waveguide layer 2 is made of Ga0.85 As between this active layer and the lower cladding layer.

In the optical deflector /l described above, the light emitted from the semiconductor laser 3 propagates within the optical waveguide N2, and then is emitted to the outside through the diffraction grating l.

The period of the diffraction grating l can be calculated from the above-mentioned equation (1) by setting the emission center angle. Further, if the length of the diffraction grating l is 3008 m, approximately IIO% of the incident light is emitted.

A converging lens 12 is disposed above the diffraction grating l of the optical deflector/7, and a receiving substrate 13 is disposed facing the elongated point surface of this lens 12.

Further, as shown in the plan view in FIG. 2, a pair of electrodes ψA, 4El are provided with the diffraction grating l in between, and these electrodes A, 4El are provided.
DaB is a conductor! is connected to the voltage controller O through.

In the above device, when the voltages applied to the electrodes A and IIB are changed, the interference relationship between the light propagating in the optical waveguide layer 2 and the diffraction grating l changes, and the angle of the emitted light 70 with respect to the normal to the substrate surface changes. As a result, the light receiving element t on the receiving board 13 on which the emitted light 7 is convergently incident is switched to a light receiving element t at another position.

According to the above device, since the parallelism of the light emitted from the diffraction grating is high, the light incident on the lens /J is converged on the receiving side substrate 13 in the focal plane regardless of the emitted angle, and the diffraction grating l The distance between the lens 12 and the lens 12 can also be arbitrarily selected.

Therefore, if the focal length f of the lens 12 is determined in accordance with the required distance between the substrates, a light spot with a diameter of several μm can be
It can move by anθm.

Here, ±θm is the maximum deflection angle. θm-±3 degrees, f-
If it is 7M, L will be approximately 100 μm.

Therefore, by arranging 10 light receiving elements each having a diameter of 10 μm on the receiving side board/3, an inter-board optical connection capable of switching 10 points is made possible.

In the present invention, the distance between the lens /2 and the diffraction grating / may be extremely small, so the light emitting element 3, the guiding waveguide 2, and the diffraction grating l are integrated on the semiconductor substrate /4j as shown in FIG. In addition to providing the optical deflector //, the lens 2 is closely and integrally formed by, for example, depositing a substance transparent to the output light on the top layer of the output surface of the diffraction grating l and processing it into a dome shape. , the entire structure including the optical system can be integrated.

The example in Fig. 3 uses the fact that the waveguide refractive index depends on the carrier concentration as an optical deflection method, and a transparent IE& is laminated on the diffraction grating l to change the amount of current injected into this electrode. , shows a structure in which a lens 12 is laminated on the above electrode layer.

Such integration allows for miniaturization of the device and ease of alignment.

In the embodiment described above, the receiving side board 13 is arranged opposite to the sending side board io, but the side board 10, /3
are placed on the same plane, and a reflecting mirror is installed facing the side board, so that the light emitted from this connection device is reflected by the reflecting mirror and enters the light receiving element on the receiving board. You can also do that.

〔Effect of the invention〕

According to the present invention, it is possible to realize an optical connection between boards with variable connection points, which was previously impossible.

[Brief explanation of the drawing]

#/The figure is a side view showing one embodiment of the present invention, Fig. 2 is a plan view showing an example of the optical deflector used in the present invention, and Fig. 3 is a perspective view showing another embodiment of the present invention. FIG. 4 is a side sectional view of a main part explaining the deflection of light emitted from a waveguide by a diffraction grating, and FIG. 5 is a perspective view showing a conventional optical connection device between substrates. l... Diffraction grating 2... Optical waveguide 3.
...Light emitting element lA, daB ... Electrode 6
...Voltage controller 7...Emitted light!・・・
・・・・Photo-receiving element 10・・・・Transmission-side board//・
...Light deflector /J...Lens 13...
・・・Receiving side board Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Procedures Correction Book March 1988 170

Claims (2)

[Claims] (1) It has a light emitting element, an optical waveguide that guides the light emission of the element, and a diffraction grating that is attached to the optical waveguide and emits the propagating light to the outside of the waveguide, and the angle of the emitted light is deflected by applying an electric signal. An inter-board optical connection device comprising an optical deflector and a light converging optical system for converging the emitted light into a light receiving element on a receiving side board. (2) The inter-substrate optical connection device according to claim 1, wherein the light emitting element, the optical waveguide, and the light focusing optical system are integrated on a single semiconductor substrate.