JPH10133041A - Waveguide with filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a waveguide with a filter which facilitates the insertion of a filter into a groove formed on an waveguide element by working the groove so that its upper part in the depth direction is wider than its lower part. SOLUTION: Four markers 5 on the waveguide element are formed on a silicon substrate 1 or a clad layer 4 so that the center of a square obtained by connecting respective markers 5 coincides with the combining/branching point 6 of the waveguide. The groove 7 on the waveguide element is engraved so that the center line of the groove 7 passes the combining/branching part 6 and divides the four markers 5 into two parts. In this case, a groove is formed by a conventional diamond blade and another groove is formed on the same position by a diamond blade of which edge thickness is thicker than that of the conventional one. In the case of inserting a filter 8, the filter 8 is moved so as to form prescribed positional relation between the filter 8 and the markers 5 on the waveguide element, inserted into the upper part of the groove 7 and then depressed to insert the filter 8 up to the lower part of the groove 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a waveguide with a filter,
In particular, the present invention relates to a waveguide with a filter obtained by forming a groove on a waveguide element and inserting a filter.

[0002]

2. Description of the Related Art Recently, in the field of bidirectional optical fiber communication, wavelength multiplex transmission using wavelengths of 1.3 μm and 1.55 μm has been performed. In performing wavelength division multiplexing transmission, a waveguide with a filter is an essential optical component.

FIG. 3 is a perspective view for explaining a method of manufacturing a conventional waveguide with a filter. A clad layer 2 is deposited on a silicon substrate 1. A core layer is deposited on the cladding layer 2, and a waveguide 3 is formed on the core layer by using a photolithographic technique and an etching technique. Further, a cladding layer 4 is deposited on the waveguide 3.
A groove 7 is formed on the waveguide element, a filter 8 is inserted, and fixed with an adhesive having the same refractive index as the waveguide 3. This completes the waveguide with a filter.

The filter 8 is generally formed by alternately laminating a dielectric and a metal thin film.
Has the function of transmitting / receiving light 11 and reflecting light 12 having a wavelength of 1.55 μm.

[0005] The above-mentioned adhesive may be any of ordinary ultraviolet curable resin or thermosetting resin, and its main component may be either epoxy-based adhesive or silicone-based adhesive.

The groove 7 formed on the waveguide element has a width of 16 μm.
m, depth 200 μm, both wall surfaces of the groove 7 are perpendicular to each other,
A filter 8 having a thickness of 15 μm is inserted using both walls of the groove 7 as a guide. Although the grooves 7 are formed using a diamond plate, techniques such as etching may be used.

[0007]

The conventional method of manufacturing a waveguide with a filter has a serious problem when the filter 8 is inserted into the groove 7 provided on the waveguide element. FIG. 4 shows the problem. The groove width provided on the waveguide element is 16 μm,
The thickness of the filter 8 to be inserted is 15 μm, and the difference is only 1 μm. Therefore, when the filter 8 is inserted into the groove 7, the filter 8 is caught on the end face of the groove 7 and
There was difficulty in the work of inserting. In the worst case, there is a problem that the filter 8 is damaged.

Accordingly, an object of the present invention is to solve the above-mentioned disadvantages of the prior art and to provide a waveguide with a filter capable of easily inserting a filter into a groove provided on a waveguide element.

[0009]

According to the present invention, in order to achieve the above object, first, a groove provided on a waveguide element is processed so that an upper portion in a depth direction is wider than a lower portion. Second, the groove was machined so that at least one end in the horizontal direction was wider than the center.

[0010]

FIG. 1 shows a first embodiment of a waveguide with a filter according to the present invention. FIG. 1A is a perspective view thereof,
(B) is a cross-sectional view of a groove provided on the waveguide element.
A clad layer 2 is deposited on a silicon substrate 1. A core layer is deposited thereon, and the waveguide 3 is formed on the core layer using a photolithographic technique and an etching technique.
Further, a cladding layer 4 is deposited on the waveguide 3.

The four markers 5 on the waveguide element are
The square formed by connecting the markers is formed on the silicon substrate 1 or the cladding layer 4 so that the center of the square coincides with the junction 6 of the waveguide. The forming method may be any method such as etching or paint. In the case of etching, only the surface of the cladding layer 4 needs to be cut off by several μm, and the transmission characteristics of the waveguide 3 are not affected at all.

The groove 7 on the waveguide element is dug so that the center line of the groove 7 passes through the junction 6 of the waveguide and divides the four markers 5 into two. First, a groove having a depth of 200 μm and a width of 16 μm is formed using a conventionally used diamond blade. Thereafter, using a diamond blade having a blade thickness greater than that of the previously used diamond blade, the width 21
A groove having a thickness of about 50 μm and a depth of about 50 μm is formed at the same position. Then, the shape of the groove is substantially as shown in FIG. 1B, and the upper part of the groove has a width of 21 μm and the lower part has a width of 16 μm.

When the filter 8 is inserted into the groove 7, the filter 8 is moved so that the filter 8 and the marker 5 on the waveguide element have a predetermined positional relationship, and inserted into the upper part of the groove 7. By further pushing, the filter 8 is correctly inserted to the lower part of the groove 7. Normally, this works by setting the filter 8 to x, y,
three axes of z and θ, φ, and ψ
It can be mounted on a fine movement table that can move on a total of six axes, and can be automatically controlled using image processing technology.

An ultraviolet curing resin was used for fixing the filter 8 to the groove 7. The refractive index is adjusted to be the same as the refractive index of the waveguide 3.

As described above, the filter 8 could be easily inserted into the groove 7 provided on the waveguide element. This method can be applied to any other type of filter or waveguide regardless of the shape of the waveguide 3 or the function of the filter 8.

FIG. 2 is a perspective view illustrating a second embodiment of the present invention. A clad layer 2 is deposited on a silicon substrate 1, and a core layer is deposited thereon. In the core layer,
The waveguide 3 is formed by employing a photolithographic technique and an etching technique. Further, a cladding layer 4 is deposited on the waveguide 3. These are the same as in FIG.

The shape of the groove 7 is different from that of FIG. The formation of the groove 7 is as follows. First, the width 15μ
A groove having a depth of 200 μm and a depth of 200 μm is formed with a diamond blade. Thereafter, both ends of the formed groove are etched or machined by a short radius of 10 μm, a long radius of 30 μm, and a depth of 20 μm.
An 0 μm oval hole 9 is machined.

When inserting the filter 8 into the groove 7, first, the filter 8 is inserted into the oval hole 9. Then, by further pushing, the filter 8 is correctly inserted up to the center of the groove 7.

These operations can be controlled automatically by mounting the filter 8 on a six-axis fine adjustment table as described above and using an image processing technique. In this case, a marker for aligning the filter 8 and the elliptical hole 9 can be provided on the side surface of the waveguide element or near the end face of the elliptical hole 9.

[0020]

According to the present invention, the groove provided on the waveguide element is first processed so that the upper part in the depth direction of the groove is wider than the lower part, and second, the groove in the horizontal direction is formed. By processing so that at least one end is wider than the central part, the work of inserting the filter into the groove provided on the waveguide element is facilitated, and the time for mounting the filter can be greatly reduced. In addition, the filter was not damaged at all during the insertion operation, and the product yield was improved.

[Brief description of the drawings]

FIGS. 1A and 1B show a first embodiment of a waveguide with a filter according to the present invention, wherein FIG. 1A is a perspective view and FIG. 1B is a sectional view of a groove.

FIG. 2 is a perspective view showing a second embodiment of the present invention.

FIG. 3 is a perspective view showing a conventional waveguide with a filter.

FIG. 4 is an explanatory diagram showing a problem of a conventional waveguide with a filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Cladding layer 3 Waveguide 4 Cladding layer 5 Marker 6 Joint branch point 7 Groove 8 Filter 9 Elliptical hole 10 Incident light 11 Wavelength 1.3 μm light 12 Wavelength 1.55 μm light

Claims (2)

[Claims] 1. A waveguide with a filter in which a filter is inserted into a groove formed on a waveguide element, wherein the upper part in the depth direction of the groove is wider than the lower part. . 2. A waveguide with a filter in which a filter is inserted into a groove formed on a waveguide element, wherein at least one end of the groove in the horizontal direction is wider than a center portion. Wave path.