JPH05224041A - Optical waveguide and its production - Google Patents

Abstract

PURPOSE:To highly integrate devices and to obtain stable optical coupling characteristics by providing a specific core layer and lifting the prescribed region of the core layer in a perpendicular direction by a first clad layer. CONSTITUTION:The prescribed region of an optical waveguide layer 2 is removed and the clad layer 3a lifted in the perpendicular direction is formed while the removed end of the layer 2 is exposed to this removed region. The optical waveguide coupling layer 2a coupling the removed and exposed end face of the layer 2 is formed on the layer 3a lifted in the perpendicular direction. A second clad layer 7 is formed on this coupled layer 2. The prescribed region of the core layer 2 is lifted in the perpendicular direction by the first clad layer 1 in such a manner and the lifted core part easily couples optically with another optical parts. Then, the optical waveguide formed on the horizontal plane and the optical waveguide lifted in the perpendicular direction are combined, by which the three-dimensional waveguide structure is formed and a variety of the optical devices are obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide which is an optical component used for communication information processing and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventional optical waveguides are formed on the same horizontal substrate surface.

[0003]

Therefore, conventionally, it has been difficult to optically couple only a part of the one-dimensionally formed optical waveguide to another optical component. For this reason,
Conventional optical waveguides are difficult to combine with other optical components, and it is difficult to apply the optical waveguides to various devices, and various optical devices have not been provided.

[0004]

The present invention has been made in order to solve such a problem, and is formed on a first clad layer having a vertically raised region and formed on the first clad layer. An optical waveguide is configured by including a core layer having a vertically raised region and a second cladding layer formed on the core layer.

Further, a step of forming a core layer on the first cladding layer, a step of removing a predetermined region of the core layer to partially expose the first cladding layer, and a step of exposing the exposed first cladding layer. A step of vertically forming a cladding material while exposing the removed end surface of the core layer on the layer, and lifting the exposed first clad layer in the vertical direction; First lifted in the direction
The step of forming an optical waveguide on the clad layer and the step of forming a second clad layer on the combined core layer.

[0006]

The predetermined area of the core layer is vertically lifted by the first cladding layer.

Further, such an optical waveguide structure is realized through a series of manufacturing steps.

[0008]

1 to 4 are process sectional views showing a method of manufacturing an optical waveguide according to an embodiment of the present invention. Hereinafter, the method of manufacturing the optical waveguide according to the present embodiment will be described with reference to these drawings.

First, quartz to which germanium is added is deposited on the substrate 1 made of pure quartz by the flame deposition (FHD) method, and the optical waveguide layer (core layer) is formed to a thickness of about 10 μm.
2 is formed (see FIG. 2A). The quartz substrate 1 is the first
Corresponding to the clad layer. Next, a predetermined region of the optical waveguide layer 2 is partially removed by dry etching (see FIG. 6B). As a result, the quartz substrate 1 under the waveguide region to be bent is partially exposed. Next, the cladding layer 3 for lifting the optical waveguide in the vertical direction is formed of pure quartz to a thickness of about 30 μm (see FIG. 3C). Next, a resist film 4 having a thickness of 1 to 2 μm is formed on the cladding layer 3 corresponding to the removed region of the optical waveguide layer 2 (see FIG. 3D).

Next, heat treatment is applied to the resist film 4, so that the peripheral edge portion of the resist film 4 is sagged, and the resist film 4 is shaped into a curved shape (see FIG. 3E). Next, resist walls 5 are formed on both sides of the shaped resist film 4a so as to have a thickness of 3 μm or more (see FIG. 6F). Next, dry etching is performed using the resist film 4a and the resist wall 5 as a mask. This dry etching is performed with the clad layer / resist etching selection ratio set to 10. After the curved resist film 4a completely disappears, a layer having a thickness of 10 μm is further etched. As a result, the pattern of the curved resist film 4a is transferred to the clad layer 3, and the curved clad layer 3a is formed (see FIG. 6G). The curved clad layer 3a constitutes the lowermost first clad layer together with the quartz substrate 1. At this time, the removed end surface of the optical waveguide layer 2 is exposed. Next, the remaining portion of the resist wall 5 on the clad layer 3 is removed (see FIG. 6 (h)).

Next, on the curved clad layer 3a, germanium-doped quartz is deposited to a thickness of about 10 μm by the FHD method. Therefore, the curved cladding layer 3a
A curved optical waveguide coupling layer 2a is formed on the upper portion of the optical waveguide coupling layer 2a in the same thickness as the optical waveguide layer 2. As a result, the linear optical waveguide layer 2 and the curved coupling layer 2a are connected, and the optical waveguide layer 2
The removed areas are connected (see FIG. 4 (i)). At this time, the unnecessary coupling layer 2a is formed on the cladding layer 3. Next, a resist layer 6 that covers the optical waveguide coupling layer 2a is formed on the optical waveguide coupling layer 2a (see FIG. 11 (j)). Next, the remaining portion of the unnecessary coupling layer 2a on the clad layer 3 is removed by dry etching (see FIG. 3 (k)). At this time, the curved optical waveguide coupling layer 2a in the optical coupling region is protected by the resist layer 6 and is not affected by etching.
Next, the resist layer 6 on the required optical waveguide coupling layer 2a is removed (see FIG. 1 (l)).

Next, a second cladding layer 7 made of pure quartz is formed on the bonding layer 2a (see FIG. 1). As a result, the optical waveguide layer 2 having a part thereof lifted up in the vertical direction is completed on the quartz substrate 1.

The optical waveguide layer 2 according to the present embodiment is thus lifted in the vertical direction in the optical waveguide coupling layer 2a. Therefore, the optical waveguide layer 2 is the optical waveguide coupling layer 2
At a, it becomes easy to optically couple with other optical components. Therefore, the optical waveguide according to the present embodiment can be applied to various devices, and various optical devices can be provided. An example of an optical device to which this optical waveguide is applied will be described below.

FIG. 5 is a view showing an optical coupler constructed by using the optical waveguide according to this embodiment. In the figure, parts that are the same as or correspond to those in FIG. 1 are assigned the same reference numerals and explanations thereof are omitted.

As described above, the optical waveguide coupling layer 2a forms a vertically curved waveguide which is lifted in the vertical direction.
The surface of the clad layer 7 is processed flat. By thus bonding the two waveguide chips 8 having the vertically bent waveguides so that the surfaces of the cladding layers 7 face each other, an optical coupler for optically coupling is formed in each optical waveguide coupling layer 2a. .. At this time, the light emitted from the light source 9 is input to the optical waveguide 2 of one waveguide chip 8 via the optical fiber 10, and a part of this optical input power is input to the optical waveguide 2 of the other waveguide chip 8. Branch off. Then, the branched optical input is taken into the power meter 12 through the optical fiber 11, and the branched optical power is measured. The coupling length is controlled by adjusting the mutual distance between the optical waveguide coupling layers 2a and aligning them while monitoring the guided light by this measurement. At the centering position where a predetermined branching ratio can be obtained,
By mechanically fixing each of the two waveguide chips 8 with UV resin or the like, a directional coupler having an arbitrary branching ratio can be easily formed. When the longitudinally bent waveguide chip 8 is used in this way to construct a directional coupler having various branching ratios, many manufacturing processes can be made common.

FIG. 6 is a sectional view showing an optical coupling configuration of a longitudinally curved optical waveguide and an optical fiber according to this embodiment. In addition,
In this figure as well, parts that are the same as or correspond to those in FIG. This optical coupling is performed not on the waveguide end face of the optical waveguide, but on the substrate surface, and light is incident and emitted via this substrate surface. Due to the difference in the shape of the optical fiber to be optically coupled, the following two types of optical coupling configurations can be considered.

The first type is shown in FIG. That is, the end of the optical fiber 13 is obliquely cut, and the cut surface is in contact with the surface of the waveguide chip 8 on the optical waveguide coupling layer 2a. The cut end of the optical fiber 13 is fixed to the surface of the second cladding layer 7 by the fixing base 14 in this state. The optical output from the optical fiber 13 is given to the optical waveguide coupling layer 2a lifted in the vertical direction, and a part of the light propagating through the optical waveguide coupling layer 2a is given to the optical fiber 13 for optical coupling.

The second type is the optical tap method shown in FIG. That is, a part of the optical fiber 15 is bent, and this bent state is held by the optical fiber bent substrate 16. Moreover, this bent portion is the optical waveguide coupling layer 2
It is fixed near a. With this optical tap method,
The optical waveguide coupling layer 2a of the vertically curved waveguide chip 8 and the bent portion of the optical fiber 15 are optically coupled.

According to this embodiment, since such optical coupling can be performed, it is possible to perform optical fiber wiring in which a plurality of waveguides are connected by an optical fiber.

FIG. 7 shows a line changeover switch constructed by using a vertically curved optical waveguide according to this embodiment. A plurality of vertically curved optical waveguides 18A, B, C are formed in the quartz substrate 17, and each optical waveguide 18 constitutes signal lines 1, 2, 3. Further, one longitudinally curved optical waveguide 20 is formed in the waveguide chip 19, and the optical waveguide 20 is joined to the optical fiber 21. The lifted waveguide region of the vertically curved optical waveguide 20 is arranged so as to face the vertically curved optical waveguide 18 in the substrate 17, and the waveguide chip 19 moves along the arrow shown in the figure, so that the optical fiber 21 receives each signal. Switched to lines 1-3. That is, each vertically curved optical waveguide portion according to this embodiment functions as a signal input / output switching port.

FIG. 8 shows an example in which the longitudinally curved optical waveguide according to this embodiment is applied to an optical signal bus line. Board 22
The optical waveguide 23 formed therein has a plurality of vertically curved waveguide regions. The optical signal input from the bus line is amplified in the first vertically curved waveguide region. That is, the first longitudinally curved waveguide region is optically coupled to the optical fiber 23 according to the same principle as in FIG.
The optical amplifier excitation light emitted from the optical waveguide 3 passes through the first longitudinally curved waveguide region and the optical waveguide region 2 to which the rare earth element is added
The optical signal input from the bus line is amplified by being incident on 3a. Further, the second longitudinally curved waveguide region is optically coupled to the optical fiber 24, and when a predetermined light is input from the optical fiber 24, the optical signal amplified in the first longitudinally curved waveguide region is generated. Erased. That is, this second vertically curved waveguide region constitutes an erasing port. The third vertically curved waveguide region is optically coupled with the optical fiber 25 to form a read port, and a part of the optical signal input propagated through the optical waveguide 23 without being erased by the erase port is It is branched to the optical fiber 25. The optical signal input from the bus line is read by this branched optical input. The fourth vertically curved waveguide region constitutes a switching port according to the same principle as that of FIG. 7, and the optical signal input propagated through one optical waveguide of the bus line is selected.

As described above, by using the longitudinally curved optical waveguide according to this embodiment, various optical devices can be provided.

[0023]

As described above, according to the present invention, the predetermined region of the core layer is vertically lifted by the first cladding layer. The vertically raised core portion is easily optically coupled to other optical components. Therefore, by combining the conventional optical waveguide formed in the horizontal plane with the optical waveguide lifted in the vertical direction according to the present invention, the waveguide structure can be made three-dimensional and various optical devices can be provided. Become.

[Brief description of drawings]

FIG. 1 is a sectional view of a fourth manufacturing process of an optical waveguide according to an embodiment of the present invention.

FIG. 2 is a sectional view of a first manufacturing process of an optical waveguide according to an embodiment of the present invention.

FIG. 3 is a sectional view of a second manufacturing process of the optical waveguide according to the embodiment of the present invention.

FIG. 4 is a sectional view of a third manufacturing process of the optical waveguide according to the embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of an optical coupler configured using the optical waveguide according to the present embodiment.

FIG. 6 is a cross-sectional view showing an optical coupling configuration of an optical waveguide and an optical fiber according to this example.

FIG. 7 is a perspective view showing a line changeover switch configured by using the optical waveguide according to the present embodiment.

FIG. 8 is a cross-sectional view showing an optical signal bus line configured by using the optical waveguide according to the present embodiment.

[Explanation of symbols]

1 ... Quartz substrate (first clad layer), 2 ... Optical waveguide layer (core layer), 2a ... Optical waveguide coupling layer, 3 ... Clad layer (second clad layer), 3a ... Curved clad layer 3
(First clad layer) 4 ... Resist film, 4a ... Curved resist film 4, 5 ... Resist wall, 6 ... Resist layer for protecting optical waveguide coupling layer 2a, 7 ... Clad layer (second clad layer) ..

Claims (2)

[Claims] 1. A first cladding layer having a vertically raised region, a core layer having a vertically raised region formed on the first cladding layer, and a core layer formed on the core layer. And a second clad layer. 2. A step of forming a core layer on the first cladding layer, a step of removing a predetermined region of the core layer to partially expose the first cladding layer, and a step of exposing the exposed first layer. A step of forming a cladding material on the clad layer while exposing the removed end surface of the core layer, and lifting the exposed first clad layer in a vertical direction; and a core coupling the exposed removed end surface of the core layer. A method of manufacturing an optical waveguide, comprising: forming a coupling layer on the first cladding layer lifted in the vertical direction; and forming a second cladding layer on the coupled core layer.