JPH04343304A - Connecting method for optical waveguide and optical fiber - Google Patents

Abstract

PURPOSE:To provide the connecting method for an optical waveguide and an optical fiber by which the alignment of the optical waveguide and the optical fiber can be executed efficiently and with high precision. CONSTITUTION:This connecting method constitutes a characteristic feature of attaching an optical waveguide material onto an SiO2 layer 11 formed on a silicon substrate 10, patterning this optical waveguide material and forming a waveguide circuit 13 and a marker 14 positioned at a prescribed distance from the waveguide circuit 13, manufacturing an optical waveguide 12 by attaching SiO2 onto an area excluding the marker 14, manufacturing an optical fiber block by placing an optical fiber 23 on an optical fiber groove 21 of a base body on which plural optical fiber grooves 21 whose cross section is roughly a V-shape and a marker groove 22 whose cross section is roughly a V-shape are formed, and connecting the respective optical fibers 23 and waveguide circuits 13 by aligning the market of the optical waveguide 12 and the marker groove 22 of the optical fiber block.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for connecting an optical waveguide and an optical fiber in optical communication technology.

0002

BACKGROUND OF THE INVENTION In recent years, various optical waveguides have been studied and some have been put into practical use. Furthermore, as the performance of optical waveguide chips improves, research is underway to improve the reliability of the connection between the optical waveguide chip and optical fiber and to reduce the cost of the connection work.

A conventional method for connecting an optical waveguide and an optical fiber is a so-called monitor method as shown in FIG. That is, this monitoring method is performed as follows. First, the optical fibers 51 for incident light at both ends inserted into the optical fiber core 50 into which a plurality of optical fibers have been inserted are connected to the light source 52, and similarly inserted into the optical fiber core 53. Optical fiber 5 for output light at both ends
4 is connected to an optical detector 55, and the respective optical fiber cores 50 and 53 are temporarily connected to a waveguide chip 56. In this state, light is input from the light source 51 to the optical fiber 51 for incident light, and the light that passes through the optical waveguide chip 55 and is emitted is detected by the optical detector 55. While monitoring the power of the emitted light, the core of the optical fiber is The optical waveguide section and the circuit section of the optical waveguide are aligned and connected.

In addition to the monitoring method, a method has also been proposed in which a mechanical reference point is provided on the optical waveguide chip and the optical waveguide and optical fiber are connected based on this reference point. Although this method eliminates the need for alignment between the core portion of the optical fiber and the circuit portion of the optical waveguide, it has not yet been put to practical use.

[0005]

However, in the monitoring method, since the core portion of the optical fiber and the circuit portion of the optical waveguide are aligned three-dimensionally, the process becomes complicated and the manufacturing cost increases. Furthermore, even if the alignment process were streamlined, the optical fiber must be connected to the light source and the optical detector, making mass production very difficult.

On the other hand, in the method of providing a mechanical reference point on an optical waveguide chip, the reference point must be provided in a separate process after the optical waveguide chip is manufactured, which not only increases the number of steps but also The disadvantage is that the positional accuracy between the reference point and the reference point is poor.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a method for connecting an optical waveguide and an optical fiber, which allows efficient and highly accurate positioning of the optical waveguide and optical fiber. purpose.

[0008]

[Means for Solving the Problems] The present invention deposits an optical waveguide material on a SiO2 layer formed on a silicon substrate, and patterns the optical waveguide material by photolithography to form a predetermined interval. A waveguide circuit corresponding to a plurality of optical fibers arranged in parallel and a marker positioned at a predetermined distance from the waveguide circuit are formed, and SiO2 is coated on the area excluding the marker to form a light guide. A wave path is prepared, and a plurality of optical fiber grooves each having a substantially V-shaped cross section for mounting the optical fiber and a marker groove having a substantially V-shaped cross section for alignment with the marker are formed on the base optical fiber. An optical fiber block is produced by placing an optical fiber in a groove, and each optical fiber is connected to a waveguide circuit by aligning the marker of the optical waveguide and the marker groove of the optical fiber block. A method for connecting an optical waveguide and an optical fiber is provided. Here, as the optical waveguide material, SiO2 +
TiO2, SiO2 +GeO2, etc. can be used. Examples of the method for depositing SiO2 on the area excluding the marker include a method in which the area including the marker is covered with a mask.

Methods for depositing the optical waveguide material vary depending on the type of optical waveguide material, but include sputtering, spin coating, electron beam evaporation, resistance heating evaporation, and chemical vapor deposition (CVD). , electron beam epitaxy method,
Any method such as a flame deposition method or a sol-gel method may be used. The deposition of SiO2 can be carried out by a method commonly used in semiconductor manufacturing processes.

As the material for the base of the optical fiber block, silicon single crystal, crystallized glass, ceramics such as aluminum trioxide, zirconium dioxide, etc. can be used. Further, as a method for forming a plurality of optical fiber V-grooves and marker V-grooves on the base, precision grinding, etching, etc. can be used, although this varies depending on the material of the base.

[0011]

[Operation] The method for connecting an optical waveguide and an optical fiber of the present invention is as follows:
The optical waveguide shown in FIG. 4(A) is fabricated using a normal semiconductor manufacturing method, and an optical fiber block is fabricated in one step using a method such as precision grinding or etching. 40 is aligned one-dimensionally using a marker 41.

Since a normal semiconductor manufacturing method is used to manufacture the optical waveguide, the waveguide circuit 4 is formed from the top surface of the optical waveguide.
It has been found that the distance X1 to the center of 0 can be controlled with high precision. Therefore, by processing the bottom surface of the silicon substrate 42 using this top surface as a reference surface, the distance X2 from the bottom surface of the silicon substrate 42 to the center of the waveguide circuit 40 can also be controlled with high precision.

Furthermore, since a normal semiconductor manufacturing method, that is, a photolithography method, is used, the distance between the centers of adjacent waveguide circuits 40 and the distance between the center of the waveguide circuit 40 and the center of the marker 41 are also highly accurate. can be controlled.

Furthermore, since the optical fiber block is also manufactured by precision grinding, etching, etc., the distance between the optical fiber V grooves and the distance between the optical fiber V groove and the marker V groove can be controlled with high precision. be able to.

[0015] Since the optical waveguide and the optical fiber block manufactured with high precision can be aligned while moving in one direction, the core portion of the optical fiber and the waveguide of the optical waveguide can be easily and precisely aligned. Can be connected to the circuit.

[0016]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, an optical waveguide chip is manufactured as follows.

As shown in FIG. 1(A), a silicon substrate 1
A SiO2 layer 11 is formed on the substrate 0 by a flame deposition method. As shown in FIG. 1B, an optical waveguide layer 12 is formed by depositing SiO2 +TiO2 as an optical waveguide material on the SiO2 layer 11 by flame deposition.

This optical waveguide layer 12 was patterned by ordinary photolithography to form a waveguide circuit 13 and markers 14 as shown in FIG. 1(C). That is, a resist layer (not shown) is formed on the optical waveguide layer 12.
is formed and etched using a mask corresponding to the waveguide circuit 13 and marker 14, and then the resist layer is removed.

Next, as shown in FIG. 1(D), a mask 15 is placed above the region including the marker 14 to form the waveguide circuit 13 and the marker 14 on the SiO2 layer 11.
SiO2 is deposited thereon by flame deposition. In this way, an optical waveguide chip 1 as shown in FIG. 1(E) is manufactured. Next, an optical fiber core, which is an optical fiber block, is produced.

A plate-shaped body made of silicon single crystal is processed with high accuracy so that its top surface and bottom surface are parallel to each other to form a substrate, and as shown in FIGS.
V-grooves 21 for optical fibers and V-grooves 22 for markers are formed. At this time, each optical fiber V-groove 21 is
In order to align the core portion 24 of the optical fiber 23 placed in the groove 21 and the waveguide circuit 13 of the optical waveguide chip, that is, the distance Y1 between the core portions 24 and the distance between the centers of the waveguide circuit 13 are adjusted. Form it so that it is the same. In addition, the V groove 22 for marker is the marker 1 of the optical waveguide chip.
4, that is, the distance Y2 between the core portion 24 and the center of the marker V-groove 22 is the same as the distance between the center of the waveguide circuit 13 and the center of the marker 14.

V groove 21 for optical fiber and V for marker
An optical fiber 23 is placed in each optical fiber V-groove 21 of the substrate 20 in which the groove 22 is formed, and an optical fiber pressing plate 25 is installed on the area including the optical fiber V-groove 21 to hold the optical fiber. Create child 2.

Next, as shown in FIGS. 3A and 3B, an example of the connection between the optical waveguide chip 1 and the optical fiber core 2 will be described. First, the optical waveguide chip 1 and the optical fiber core 2 are placed on the support plate 30 whose surface has been processed to be flat. At this time, the optical waveguide chip 1 or the optical fiber core 2 may be fixed to the support plate 30 using an adhesive or the like.

Next, as shown in FIGS. 3(C) and (D), the connecting end surface of the optical waveguide chip 1 and the connecting end surface of the optical fiber core 2 are butted together, and the While applying pressure and further pressing the optical waveguide chip 1 and the optical fiber core 2 onto the support plate 30, as shown in FIG.
) Move the optical fiber core 2 in the direction of the arrow inside. This operation is performed until the center of the marker 14 of the optical waveguide chip 1 and the center of the marker V-groove 22 of the optical fiber core 2 are aligned. After the alignment between the waveguide circuit 13 of the optical waveguide chip 1 and the core portion 24 of the optical fiber 23 placed on the optical fiber core 2 is completed in this way,
As shown in FIGS. 3(E) and 3(F), the optical waveguide chip 1 and the optical fiber core 2 are fixed onto the support plate 30 using an adhesive or the like. Note that the support plate 30 may be removed after the optical waveguide chip 1 and the optical fiber core 2 are connected and fixed.

In this example, SiO2 + TiO2 is used as the optical waveguide material, and the optical waveguide layer is formed by flame deposition as the formation method. The effects of the present invention can also be obtained by using a forming method.

[0025]

As described above, according to the method for connecting an optical waveguide and an optical fiber of the present invention, the optical waveguide and the optical fiber can be aligned in a short period of time and with a small connection loss.

[Brief explanation of the drawing]

FIGS. 1A to 1E are explanatory diagrams showing the manufacturing process of an optical waveguide chip used in the method of the present invention.

[Fig. 2] (A) is a plan view of the optical fiber core used in the method of the present invention, (B) is a front view of the optical fiber core shown in (A), and (C) is a plan view of the optical fiber core shown in (A). FIG. 2 is a side view of the optical fiber core shown in FIG.

[Fig. 3] (A), (C), and (E) are plan views of the connection portion for explaining the connection method of the present invention, and (B), (D), and (F
) is a side view of the connection portion shown in (A), (C), and (E).

4(A) is a plan view of an optical waveguide chip used in the method of the present invention, and FIG. 4(B) is a sectional view of the optical waveguide chip shown in FIG. 4(A).

FIG. 5 is a schematic diagram for explaining a conventional method of connecting an optical waveguide and an optical fiber.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10... Silicon substrate, 11... SiO2 layer, 12... Optical waveguide layer, 13... Waveguide circuit, 14... Marker, 15... Mask, 20... Substrate, 21... V groove for optical fiber, 22... V groove for marker, 23 ...Optical fiber, 24...Core part, 25
...Optical fiber pressing plate, 30... Supporting plate.

Claims (1)

[Claims] Claim 1: SiO2 formed on a silicon substrate
A waveguide circuit compatible with a plurality of optical fibers arranged in parallel at a predetermined interval by depositing an optical waveguide material on a layer and patterning the optical waveguide material by photolithography, and the waveguide circuit A marker is formed at a predetermined distance from the center, and SiO2 is deposited on the area excluding the marker to produce an optical waveguide. An optical fiber block is prepared by placing an optical fiber in the optical fiber groove of a base body in which an optical fiber groove and a marker groove having a substantially V-shaped cross section for alignment with the marker are formed. A method for connecting an optical waveguide and an optical fiber, comprising connecting each optical fiber to a waveguide circuit by aligning a marker and a marker groove of the optical fiber block.