JPS61182002A - Production of two-dimensional optical waveguide device provided with concave lens function - Google Patents

Abstract

PURPOSE:To obtain a simple and small-sized device and to improve the reliability and dulability of the device by diffusing a diffusing material into a substrate or an optical waveguide formed on one surface of the substrate. CONSTITUTION:A diffusing material 11 such as Ti is evaporated on the whole surface of one side of a substrate 10 and the diffusing material 11 is repeatedly evaporated so that the number of layers is increased in the direction to center of the axial direction, i.e. in the separating direction from the optical axis. Then, the substrate 10 on which the diffusing material 11 is laminated is held at about 1,000 deg.C for a several period to thermally diffuse the diffusing material 11 into the substrate 10 and to obtain an optical waveguide device. In the waveguide 12 on the obtained optical waveguide device, the diffusion density on the center part of the width direction is low and the diffusion density is increased in accordance with separation from the center part. When the diffusing material is Ti, the refractive index is increased in accordance with the increment of the diffusion density, so that the optical waveguide 12 has refractive index distribution increasing the refractive index in accordance with the separation from the center part of the width direction. Consequently, the optical waveguide has a concave lens function.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for manufacturing a two-dimensional optical waveguide device having a concave lens function.

Conventional technology and problems L 1Nbo3, Sio□, etc.
It is sometimes desirable to provide a concave lens function in a planar two-dimensional optical waveguide formed by diffusing a diffusing material for increasing the refractive index, such as (titanium).

For example, various deflectors can be constructed using electro-optic effects or diffraction effects caused by ultrasonic waves in a two-dimensional optical waveguide, but since the deflection ability of such deflectors is small, a concave lens is installed at the rear of the deflector. It is necessary to provide a deflection angle amplification section with a function integrally within the two-dimensional optical waveguide.

Although it is also possible to provide a concave lens or the like separately from the substrate, in such a case the device becomes large.

Means for Solving the Problems The present invention has been made against the background of the above circumstances.
The gist thereof is a method for manufacturing a two-dimensional optical waveguide device having a concave lens function that refracts light passing through an optical waveguide formed in a layer on one surface of a substrate according to a concave lens action, the substrate, Alternatively, by diffusing a diffusing material into an optical waveguide formed on one surface of the substrate, the light is diffused in a direction that intersects with the traveling direction of the light passing through the optical waveguide and in the surface direction of the substrate. The reason is that the refractive index within the optical waveguide increases as the distance from the optical axis increases.

Operation and Effect of the Invention In this way, the refraction within the optical waveguide increases as the distance from the optical axis of the light in the plane direction of the substrate increases in the direction crossing the traveling direction of the light passing through the optical waveguide. Optical waveguide devices with high index are easily fabricated by diffusing a diffusing material that changes the index of refraction within the optical waveguide. Light traveling through the optical waveguide of this optical waveguide device is diffused by the effect of a concave lens. Therefore, for example, by providing a deflector within such an optical waveguide, a deflection device capable of obtaining a relatively large deflection angle can be constructed integrally with the substrate.

The above-mentioned effect of easily manufacturing an optical waveguide having a concave lens function by diffusing a diffusing material is applicable not only to substrates made of electro-optic materials but also to other types of transparent substrates. It is also possible to obtain

Furthermore, the diffusion material may be not only a substance that increases the refractive index within the optical waveguide through diffusion, but also a substance that decreases the refractive index within the optical waveguide through diffusion.

Examples of substances that increase the refractive index in the optical waveguide by diffusion include Ti (titanium), Nb (on),
Materials such as (vanadium), Ni (nickel), and Cu (copper) can be used, and in the case of such materials, the diffusion concentration increases as the distance from the optical axis of light traveling in the optical waveguide increases. Spread it. On the other hand, as a substance that lowers the refractive index within the optical waveguide by diffusion, a material such as B (boron) can be used, and in the case of such a material, the optical axis of the light traveling within the optical waveguide Diffusion is performed so that the closer it gets to , the higher the diffusion concentration becomes.

Furthermore, since the optical waveguide is a region where a part of the substrate has a higher refractive index than other parts, the diffusion material used to provide the concave lens function is diffused into the substrate on which the optical waveguide is already formed. Alternatively, it may be diffused at the same time as forming an optical waveguide.

Example An embodiment of the present invention will be described below.

1 and 2 illustrate electro-optic materials such as Li
Substrate I of about Q,5+n made of N b O3 crystal
An optical waveguide device having an optical waveguide 12 with a concave lens function on one surface of the optical waveguide is shown. The optical waveguide 12 generally has a thickness of several μ
It is a layer with a thickness of about m, has a higher refractive index than other parts of the substrate 10, and is configured so that light is suitably guided due to the property of confining light in the thickness direction, and
The refractive index is increased as the distance from the center increases in the width direction, and the light traveling within the optical waveguide 12 is also configured to diverge by a concave lens function. In FIG. 2, the state of light divergence is shown by broken lines. Note that the straight lines shown in the optical waveguide 12 in FIGS. 1 and 2 represent the refractive index distribution, and the linear density thereof indicates the height of the refractive index.

The optical waveguide device is manufactured as follows.

First, a diffusion material 1 such as Ti is applied to the entire surface of the substrate 10.
As shown in FIG. 3, the diffusing material 11 is laminated by depositing the diffusing material 1 and then repeatedly depositing the diffusing material in multiple layers as the distance from the center in the width direction, that is, the optical axis increases.

Next, the substrate 10 on which the diffusion material 11 is laminated is held at 100°.
When the diffusion material 11 is thermally diffused into the substrate 10 by holding it at about C for several hours, the optical waveguide device shown in FIGS. 1 and 2 is obtained.

In the optical waveguide 12 of the optical waveguide device obtained in this way, the diffusion concentration is low at the center in the width direction, and the diffusion concentration increases as the distance from the center increases. In this case, the higher the diffusion concentration, the higher the refractive index. Therefore, the optical waveguide 12 has a refractive index distribution in which the refractive index increases as the distance from the center in the width direction increases, and the optical waveguide 12 has a concave lens function. .

Further, in order to increase the diffusion concentration as the distance from the center in the width direction increases, the diffusion material 11 may be applied only to both sides of the substrate IO as shown in FIG. 4, or as shown in FIG. The thickness of the diffusion material 11 applied to both sides of the substrate 10 may be increased continuously as the distance from the center in the width direction increases. In addition, in the above manufacturing method, the substrate 10 on which a normal optical waveguide with a uniform refractive index in the plane direction is already provided may be used, and the refraction of the entire optical waveguide after diffusion to provide a concave lens function may be used. Diffusion may be performed over the entire surface to increase the rate.

Further, the diffusion material 11 may be of a type that lowers the refractive index by diffusion, and in this case, contrary to FIGS. 3, 4, and 5, the diffusion material 11 becomes closer to the center in the width direction of the substrate
In this case, even if the refractive index is lowered by the diffusion of the diffusing material 11, the entire optical waveguide 12 has a higher refractive index than other parts of the substrate 10. , it is necessary that the optical waveguide 12 with a relatively high refractive index be formed in advance.

Furthermore, as shown in FIG. 6, the mode of diffusion may be such that the diffusion portion expands in the direction of propagation of the light, or diffusion of multiple types of concentration distributions so that multiple types of concave lens functions are provided. may be provided at multiple locations in series in the direction in which the light travels.

Furthermore, diffusion for providing the concave lens function as described above may be applied to a part of the substrate 10. FIG. 8 is an example of this, and shows the state in which the diffusion material 11 is attached. Substrate lO
In the place where the concave lens function is to be provided, that is, the deflection angle amplifying part 20, the diffusion material 11 is laminated so as to become thicker as the distance from the optical axis L1, which will be described later, increases. The diffusion material 11 is laminated thinner as the distance from the axis L0 increases. When this substrate 10 is passed through a thermal diffusion process, as shown in FIG. 9, a light collecting section 16 having a convex lens function and a deflection angle amplifying section 20 having a concave lens function are formed at the same time.

An optical waveguide device (substrate 10) equipped with such a concave lens function
) is used, for example, to construct the optical deflection device 40 shown in FIGS. 10 and 11.

The optical deflection device 40 will be explained below.

10 and 11, an optical fiber (optical fiber) 14 as a light source device is connected to one end of an optical waveguide 12 of a substrate 10 made of LiNb0i, and an optical fiber 14 is connected on the substrate 10. A light focusing section 16 converges the laser beam incident from the source into parallel light, an optical deflection section 18 that deflects the laser beam, and a deflection angle amplification section 20 that amplifies the deflection angle, and the laser beam is focused at one point regardless of the deflection angle. A luminous flux correction unit 22 that converges the luminous flux is integrally provided.

The entire optical waveguide 12 has a larger refractive index than other parts of the substrate 10 so that light can be guided appropriately, and the optical waveguide 12 formed therein as described above
is in the plane direction of the substrate 10 and the optical axis L0 of the laser beam
In the direction perpendicular to the optical waveguide 12, the diffusion concentration is increased as it approaches the leading axis L0, and as shown in FIG. The refractive index is increased as it approaches , and a convex lens function is provided. In addition, the deflection angle amplifying section 20
is the leading axis L1 in the direction perpendicular to the optical axis of the laser beam located at the center of the amplitude in the optical deflection unit 18.
As shown in FIG. 13, as shown in FIG. 13, the refractive index of the optical waveguide 12 increases as the distance from the optical axis increases, providing a concave lens function.

The optical deflection unit 18 deflects the optical axis L of the laser beam within the optical waveguide 12 by a surface acoustic wave 28 excited by a pair of comb-shaped electrodes 24 and 26 provided at one end of the optical deflection unit 18.
A periodic refractive index change is formed in a direction crossing zero, and a laser beam passing through this is diffracted by Bragg diffraction. Then, the comb-shaped electrode 24.2 is connected to the deflection control device 34.
As the driving frequency supplied to the light deflector 6 is changed, the deflection angle in the light deflector 18 is controlled. therefore,
The laser beam passes through the optical deflection section 18 to have a deflection angle of θ1, and further passes through the deflection angle amplification section 20, where the deflection angle is amplified to θ2.

As shown in FIG. 11, the light flux correction section 22 is configured to form a convex lens by a large number of electrodes 32 arranged on the optical waveguide 12 via a buffer layer 30 made of, for example, 5 in 2. .

That is, as shown in FIG. 14, the electrode 32 is composed of a large number of pairs of electrodes 32a and 32b that are close to each other and arranged at predetermined intervals.

32b is applied with a voltage that increases as the distance from the optical axis L1 increases, and the polarity of the voltage is opposite across the optical axis L1, so that the electric field distribution in the direction perpendicular to the optical axis L1 is It is formed in a sawtooth shape corresponding to the position of the electrode 32, and due to the electro-optic effect, the distribution of the refractive index change Δn is formed in a sawtooth shape inclined in one direction, similar to the distribution of the electric field E, as shown in FIG. A convex lens for convergence is constructed. The voltage applied from the deflection control device 34 between each electrode 32a and the electrode 32b is applied to the light deflection section 18.
When the signal frequency supplied to the laser beam 36 changes, the slope of the sawtooth refractive index distribution formed between the electrodes 32 changes over time, and the laser beam 36
Since the focal point of the laser beam 36 is changed, the laser beam 36 can be focused on a single point on an object (not shown) regardless of the deflection angle.

Therefore, according to the device configured as described above, there is no need for mechanically movable parts such as a rotation mechanism and its drive device, which are provided in conventional devices. Moreover, since the light converging section 16, the light deflecting section 18, the deflection angle amplifying section 20, and the light flux correcting section 22 are integrally provided within the single substrate 10,
The device becomes simpler and smaller, and its reliability and durability are improved.

Note that the above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

1 and 2 are a perspective view and a plan view showing an optical waveguide device according to an application example of the present invention. FIG. 3 is a perspective view illustrating the manufacturing process of the optical waveguide device shown in FIGS. 1 and 2. FIG. FIG. 4 and FIG. 5 are diagrams corresponding to FIG. 3 showing other application examples of the present invention, respectively. FIGS. 6 and 7 are plan views showing other application examples of the present invention, respectively. 8th
9 and 9 are a perspective view and a plan view, respectively, showing the manufacturing process of another application example of the present invention. Figure 10 and 1
FIG. 1 is a plan view and a side view of an optical deflection device using an example of application of the present invention. FIGS. 12 and 13 are main parts of FIG. 10, and are diagrams illustrating the configuration of the light converging section and the deflection angle amplifying section. FIG. 14 is a diagram for explaining the configuration of the luminous flux correction section in FIG. 10, and FIG. 15 is a diagram showing an example of the electric field distribution and the distribution of refractive index change in the luminous flux correction section. 10: Substrate 11: Diffusion material 12: Optical waveguide Applicant Brother Industries, Ltd. Figure 1 Figure 8 Figure 1o Figure 14

Claims (1)

[Scope of Claims] A method for manufacturing a two-dimensional optical waveguide device having a concave lens function that refracts light passing through the optical waveguide according to a concave lens action in an optical waveguide formed in a layer on one surface of a substrate, , by diffusing a diffusion material into the substrate or an optical waveguide formed on one surface of the substrate, a direction intersecting the traveling direction of light passing through the optical waveguide and in a direction along the surface of the substrate. A method for manufacturing a two-dimensional optical waveguide device having a concave lens function, characterized in that the refractive index within the optical waveguide increases as the distance from the optical axis of the light increases.