JPH0476505A - Grating element - Google Patents

Abstract

PURPOSE:To facilitate the easy control of the film thickness of waveguide layer with high accuracy and to improve optical characteristics by forming the film of an inorg. material by a thin film forming technique, such as sputtering or CVD, as the waveguide layer on a substrate and forming a grating layer of an org. material. CONSTITUTION:A stamper 9 made of nickel is first formed by an electrocasting method using a master disk 6 formed with grating patterns consisting of an electron beam resist 8 on a glass substrate 7 by an electron ray plotting method. The waveguide layer 3 is then formed on a glass substrate 2 by a sputtering or CVD method using a transparent inorg. material, such as ZnS or ZnO so as to attain a desired film thickness. The substrate 2 formed with the waveguide layer 3 is disposed to face the stamper 9 via a slight spacing and a UV curing type resin 10 is injected therebetween. The resin is irradiated with UV rays 1 and is thereby cured, by which the grating layer 4 is formed. A grating coupler 1 is thus produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a grating element, which is a type of optical element. Specifically, the present invention provides an input/output coupler;
The present invention relates to condensing couplers, optical path converters, optical path deflectors, waveguide lenses, reflectors, mode converters, and other grating elements.

[Background Art] What is shown in FIG. 5 is a perspective view of a conventionally used condensing grating coupler 31.

FIGS. 6 and 7 are a perspective view and a sectional view of a conventionally used linear grating coupler 32.

These grating couplers 31 and 32 have a waveguide layer 34 made of ultraviolet curing resin on the surface of a glass substrate 33.
and a grating 35, and a stamper (not shown) having a grating pattern recessed therein.
An uncured ultraviolet curable resin is injected between the glass substrate 33 and the glass substrate 33, and the ultraviolet curable resin is cured by being irradiated with ultraviolet rays through the glass substrate 33, and then the stamper is peeled off from the grating coupler 31 and 32. How to do it (2P
(method).

[Problems to be Solved by the Invention] In the grating coupler 31, 32, the waveguide layer thickness d is an important parameter that determines the propagation constant of the guided light, and if this parameter deviates from the design value, the light input Since the output angle θ also deviates from the design value, the waveguide layer 3
4, highly accurate thickness control is important.

However, in the grating couplers 31 and 32 manufactured by the 2P method as described above, the thickness d of the waveguide layer 34 is
is determined by the distance between the stamper and the glass substrate 33, and since the distance is controlled by the injection pressure of the ultraviolet curable resin, it has been difficult to control the waveguide layer thickness d with high precision. Further, it is difficult to reduce the distance between the stamper and the glass substrate 33 to less than 2 pieces, and it is difficult to obtain the waveguide layer 34 with a thickness less than this.

For this reason, variations in the light exit angle θ tended to occur.

The present invention has been made in view of the drawbacks of the conventional examples described above, and its purpose is to be able to control the thickness of the waveguide layer with high precision, and to form an extremely thin waveguide layer. An object of the present invention is to provide a grating element that can perform the following steps.

``Means for Solving the Problems'' The grating element of the present invention consists of a waveguide layer formed of an inorganic material on a substrate using thin film forming techniques such as sputtering or CVD, and a waveguide layer formed of an organic material on the waveguide layer. It is characterized by comprising a formed grating layer.

In the present invention, the waveguide layer made of an inorganic material is formed on the substrate using a thin film forming technique such as sputtering or CVD, so the thickness of the waveguide layer can be easily controlled. In other words, the thickness of the waveguide layer can be controlled with high precision, and a thinner waveguide layer can also be produced.

Therefore, variations in optical properties such as the light exit angle due to variations in the thickness of the waveguide layer are reduced, and the optical properties of the grating element can be improved.

Furthermore, since the waveguide layer is formed of an inorganic material, its environmental resistance is more stable than that of a waveguide layer made of an organic material.

Furthermore, since the grating layer that needs to have an uneven shape (grating) is formed of an organic material, it can be easily formed by, for example, resin molding, and is excellent in mass productivity.

"Example] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

1 and 2 show a linear grating coupler 1 according to an embodiment of the present invention. This linear grating coupler 1 has a waveguide layer 3 made of a transparent inorganic material formed on the surface of a glass substrate 2, and a grating layer 4 made of an ultraviolet curable resin is laminated on the waveguide layer 3. It has been done.

Groove-shaped gratings 5 are formed in the grating layer 4 . The waveguide layer 3 is formed by a thin film forming technique such as sputtering or CVD using, for example, inorganic materials shown in Table 1 below. It is preferable to form it by a manufacturing method.

(Hereinafter, blank spaces) Table 1 and FIG. 3 show a method of manufacturing the linear grating coupler 1 described above. First, FIG. 3(a) shows the manufacturing process of the master 6, in which a grating pattern of electron beam resist 8 is formed on a glass substrate 7 by electron beam lithography. Next, using the master disk 6, a nickel stamper 9 as shown in FIG. 3(b) is produced by electroforming.

Once the stamper 9 is produced in this way, as shown in FIG. 3(C), a transparent inorganic material as shown in Table 1 is deposited on the glass substrate 2 by sputtering or CVD to obtain a desired film thickness. A waveguide layer 3 is formed. As shown in FIG. 3(d), the glass substrate 2 on which the waveguide layer 3 is formed is opposed to the standby bar 9 with a small gap therebetween.
An uncured ultraviolet curable resin 10 is injected between the waveguide layer 3 and the waveguide layer 3. When the ultraviolet curable resin 10 is injected, ultraviolet rays 11 are irradiated from the glass substrate 2 side. The ultraviolet rays 11 pass through the glass substrate 2 and the waveguide layer 3, and the ultraviolet rays 11 pass through the glass substrate 2 and the waveguide layer 3.
0, the ultraviolet curable resin 10 is cured and the grating layer 4 is formed by the 2P method. In this way, when the ultraviolet curable resin 10 is cured, as shown in FIG. 3(e).
As shown in the figure, the linear grating coupler 1 is peeled off from the stamper 9, and the linear grating coupler 1
is manufactured.

Further, the present invention can be implemented in various other embodiments in addition to the above-mentioned embodiments. In particular, by forming the waveguide layer by a sputtering method, a CVD method, etc., inorganic materials such as those shown in Table 1 having an acousto-optic effect or electro-optic effect, or even magnetic materials can be used in the waveguide layer. Since these materials can be used as materials, it is also possible to create active optical waveguide devices that take advantage of the physical properties of these materials.

For example, the linear grating coupler 1 shown in FIG.
2 is a comb-shaped IDT (interdigital transducer) 1 in which a waveguide layer 3 is formed using ZnO having an acousto-optic effect, and an @polar material is deposited on the surface of the waveguide layer 3.
3 was prepared, and a grating layer 4 having a protruding 2 M grating 14 was formed on the waveguide layer 3.

When an electric signal is applied to the IDT 13, a surface acoustic wave (SAW) 15 is propagated on the surface of the waveguide layer 3 between the gratings 14.

As a result, when the surface acoustic wave 15 is not propagated from the IDT 13, it enters from one grating 14 and propagates through the waveguide layer 3, and the surface acoustic wave 15 enters from the other grating 14 and propagates through the waveguide layer 3.
When the surface acoustic wave 15 is propagated from the IDT 13, the light ray 16 emitted in the direction
The light is deflected by the beam, and is emitted from the grating 14 on the emission side in the Q direction.

In the above example, the acousto-optic effect was used, but it is also possible to form the waveguide layer using other materials, such as an inorganic material that has an electro-optic effect, and give the waveguide layer the function of an optical shutter. It is.

Although not shown, there is a gap between the waveguide layer and the glass substrate.
A buffer layer made of an optical material having a smaller refractive index than the waveguide layer may be provided.

It goes without saying that the present invention can be applied to various grating elements such as leaf tip grating couplers in addition to linear grating couplers.

[Effects of the Invention] According to the present invention, the film thickness of the waveguide layer can be controlled easily and with high precision, and submicron film thickness control is also possible.

Therefore, variations in optical properties such as the angle of incidence and output of light due to variations in the thickness of the waveguide layer are reduced, and the optical properties of the grating element can be improved.

In addition, the waveguide layer made of inorganic material has stable environmental resistance, and
Since the grating layer is made of an organic material, it can be easily formed by, for example, resin molding.
It is also suitable for mass production.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a partially cutaway sectional view of the same, FIG. 3 is an explanatory view showing a method of manufacturing the grating coupler of the above, and FIG. 4 is a diagram of the present invention. FIG. 5 is a perspective view of a conventional example, FIG. 6 is a perspective view of another conventional example, and FIG. 7 is a partially broken sectional view of the same. 2... Glass substrate 3... Waveguide layer 4... Grating layer

Claims (1)

[Claims] (1) A grating element comprising a waveguide layer formed of an inorganic material on a substrate using a thin film forming technique such as sputtering or CVD, and a grating layer formed of an organic material on the waveguide layer.