JPH0339703A - Optical coupling aiding device, optical coupling device, and its assembling method - Google Patents

Abstract

PURPOSE:To facilitate the aligning operation without spoiling the accuracy by forming positioning grooves for incidence-side optical fibers and positioning grooves for projection-side optical fibers in the surface of a base and interposing an optical waveguide at an intermediate position. CONSTITUTION:Couples of the 1st positioning grooves 7 which can position the optical axes of the incidence-side optical fibers 1a in the centers of waveguide formation parts 2b of the optical waveguide 2 and the 2nd positioning grooves 8 which can position the optical axes of the projection-side optical fiber 1b in the center of waveguide formation parts 2b of the optical waveguide are formed in the surface 3a of the base 3. Fixed grooves 4a and 4a which are sectioned in an inverted V shape are formed below respective fixed chips 4 opposite both the grooves 7 and 8 and fixed to the base 3 with bolts 10 on both sides of the optical fibers 1a and 1b so that the optical fibers are sandwiched. Consequently, the optical axes are adjusted automatically and the aligning operation is facilitated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical coupling auxiliary device used for optical coupling between a fiber end and an optical waveguide B, an optical coupling auxiliary device using the same, and a method for assembling the same. It is related to.

[Conventional technology]

Optical waveguides are used to construct various optical control elements, optical passive elements, etc., and are often coupled with optical fibers when actually used.

Here, FIG. 8 shows an optical coupling auxiliary device described in Japanese Patent Application No. 63-310739 filed by the applicant on December 8, 1988.

This device includes a base 81 on which an input side optical fiber 82, an output side optical fiber 83, and a planar optical waveguide 84 interposed between the two optical fibers 82 and 83 are positioned on a smoothly finished surface 81a; A pair of connectors 85 that fix both optical fibers 82 and 83 to the surface 81a of the base 81, respectively.
．． 85, and a holder 86 for fixing the planar optical waveguide 84 to the surface 81a of the base 81.

Each connector 85 consists of an upper half 85a and a lower half 85b. Optical fibers 82 and 83 are fixed with resin to the upper half 85g, and a guide groove is formed in the center of the base 81 in the lower half 85b. 81b.

The holder 86 is bolted to the surface 81a of the base 81, with the waveguide 84, which forms the optical path, with the waveguide forming portion 84a facing downward, fixed to the holder 86 with resin at its intermediate portion.

Then, the input side optical fiber 82 and the output side optical fiber 83
and the planar optical waveguide 84 are temporarily fixed to the base 81,
Light is input from one end of the input side optical fiber 82, and the optical axis is adjusted while monitoring it at one end of the output side optical fiber 83. When this is completed, the connectors 85 and 85 and the holder 86 are fully tightened to the base 81, and then the connector 85
．． 85 and the planar optical waveguide 84 are molded with resin, and the mounting of the planar optical waveguide 84 and both optical fibers 82 and 83 is completed.

[Problem to be solved by the invention]

In the conventional device described above, it was necessary to adjust the optical axes of both the planar optical waveguide and the optical fiber. In other words, the optical axis of a planar optical waveguide needs to be adjusted in a direction parallel to the surface of the base and perpendicular to the optical axis, and for an optical fiber, it is necessary to adjust the optical axis in a direction parallel to the surface of the base and perpendicular to the optical axis. It is necessary to perform optical axis adjustment in the direction and optical axis direction. As described above, alignment work requires time and effort, making it quite complicated.

An object of the present invention is to provide an optical coupling auxiliary device, an optical coupling device, and a method for assembling the same, which simplify alignment work without impairing accuracy.

[Means to solve the problem]

In order to achieve the above object, the invention of claim 1 includes interposing an optical waveguide between an input side optical fiber and an output side optical fiber,
An optical coupling auxiliary device that performs optical coupling by fixing these on the surface of a base so that the optical axis and optical path match,
A first positioning groove that can position the optical axis of the input optical fiber in the optical path of the optical waveguide, and a second positioning groove that can position the optical axis of the output optical fiber in the optical path of the optical waveguide, on the surface of the base. It is characterized by the formation of

In this case, each positioning groove is preferably formed so that the optical axis of each optical fiber can be positioned approximately in the middle of the optical path of the optical waveguide.

Further, the invention according to claim 3 is an optical coupling device in which an input side optical fiber, an output side optical fiber, and an optical waveguide are assembled to the optical coupling auxiliary device, wherein the end of each optical fiber on the optical waveguide side is , is characterized by a lens processing.

Furthermore, the invention of claim 4 provides an assembly in which an optical waveguide is interposed between the input side optical fiber and the output side optical fiber, and both optical fibers are assembled to the base of an optical coupling auxiliary device that optically couples them. This method is characterized by fixing a single optical fiber on the surface of a base at predetermined positions of an input side optical fiber and an output side optical fiber, and then cutting a portion where an optical waveguide is interposed. .

[Effect]

According to claim 1, on the surface of the base, there is provided a first positioning bay in which the optical axis of the input side optical fiber can be positioned in the optical path of the optical waveguide, and the optical axis of the output side optical fiber can be positioned in the optical path of the optical waveguide. By forming a second positioning groove, it is possible to easily fix both optical fibers to their respective positioning grooves.
Its positioning, that is, optical axis adjustment, can be performed automatically.

In this case, if each positioning groove is formed so that the optical axis of each optical fiber is located in the middle of the optical path of the optical waveguide, the optical axis can be aligned with the part of the optical path where the coupling loss is minimized. .

As in claim 3, at the end of each optical fiber on the optical waveguide side,
If the lens is processed, the optical axis of the optical fiber can be aligned with the optical path even if the optical axis of the optical fiber is slightly angularly or misaligned with the optical path of the optical waveguide due to the lens effect. .

According to claim 4, after fixing a single optical fiber to the surface of the base at predetermined positions of the input side optical fiber and the output side optical fiber, the portion where the optical waveguide is interposed is cut. , input optical fiber and output 1. The I-side optical fiber can be fixed to the base under the same conditions.

〔Example〕

An optical coupling auxiliary device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

This optical coupling auxiliary device is a single mode optical fiber 1
A planar optical waveguide 2 is interposed between a pair of input-side optical fibers 1a and an output-side optical fiber 1b, each of which is configured as shown in FIG. (not shown) to perform a light switching action between both optical fibers 1as1b.

This device includes a base 3 on which an input side optical fiber 1b, a1 output side optical fiber 1b, and a planar optical waveguide 2 optically coupled to these are mounted on a surface 3a, and both optical fibers la and 1b are placed on the base 3. A pair of fixed chips fixed to the surface 3a 4.
4, and a holder 5 for fixing the planar optical waveguide 2 to the surface 3a of the base 3. Then, the end surfaces of each optical fiber 1 are made to face both end surfaces of the planar optical waveguide 2 through a minute gap, respectively, for optical coupling.

Each pair of optical fibers 1aqla and lb, each lb is
They are fixed in parallel across the surface 3a of the base 3 at the same intervals with the planar optical waveguide 2 in between.

On the other hand, the planar optical waveguide 2 uses a substrate 2a of LI Nb O3 crystal, for example, and thermally diffuses TI on the surface thereof to form two waveguide forming portions 2b, 2b which are optical paths. The waveguide forming portions 2b, 2b are formed substantially parallel to each other at the same spacing as the pair of optical fibers la, lb.

The surface 3a of the base 3 is finished smoothly and serves as a reference surface for the waveguide forming portion 2b of the planar optical waveguide 2.

Further, in the center thereof, a long wire 6 is formed in which a wire (not shown) connected to the electrode of the planar optical waveguide 2 is arranged.

On the other hand, on the surface 3a of the base 3, there is a first positioning groove 7 that can position the optical axis of the input side optical fiber 1a at the center of the waveguide forming part 2b of the optical waveguide 2, and a first positioning groove 7 that allows the optical axis of the input side optical fiber 1a to be positioned at the center of the waveguide forming part 2b of the optical waveguide 2, and
A pair of second positioners 8 are each formed to allow the optical axis of the optical waveguide to be positioned at the center of the waveguide forming portion 2b of the optical waveguide. This positioning part 7.8 is formed in a V-shaped cross section,
As shown in FIG. 4, it is formed so that its axis vA9 coincides with the optical axis of the input side optical fiber 1a and the output side optical fiber 1b, which are parallel to each other. Furthermore, the height direction is also the fifth
As shown in the figure, both optical fibers la.

The optical axis of 1b is located near the center of the waveguide forming portion 2b where the electromagnetic field distribution strength of light is maximum. Therefore, both optical fibers la and lb are connected to both positioning grooves 7.
．． 8, positioning can be performed automatically, that is, optical axis adjustment can be performed automatically.

A fixing groove 4a s4a having an inverted V-shaped cross section is formed on the lower side of each fixing tube 4 so as to face each positioning groove 7. It is fixed to the base 3 with 10 bolts. in this case,
Both the optical fibers 1 a s 1 b may be fixed with resin at the respective positions 7.8 prior to fixing with the bolts 10.

The holder 5 has a holding groove 5a formed at the lower center,
This presser foot? The planar optical waveguide 2 is secured to the base 3 with bolts 10 by M5a so as to fit therein. In this case too,
Both optical fibers la and lb may be fixed in the holding groove 5a with resin before the bolts 10 are fixed. Further, the holder 5 has a long hole 11 formed therein for the bolt 10, so that the planar optical waveguide 2 can be moved minutely in a direction perpendicular to the optical axis from a temporarily fixed state, thereby facilitating optical axis adjustment. There is.

Next, referring to FIG. 6, the steps for assembling this device, particularly the steps for assembling the optical fiber 1, will be explained.

First, as shown in FIGS. 6(a) and 6(b), 2
The optical fiber 1.1 of the book is passed through a first positioning groove 7 and a second positioning groove 8 formed on the surface 3a of the base 3, respectively,
This is fixed with a fixing chip 4.4. In this state, as shown in FIG. 6(C), a part of both optical fibers 1.1 is cut according to the length of the flat curved optical waveguide 2, and the input side optical fiber 1a and the output side optical fiber 1b are separated. Configure. Next, the sixth
As shown in Figure (d), lens processing is applied to the ends of both optical fibers la and 1b. This lens processing is performed by etching or electrical discharge machining, and the ends of both optical fibers la and lb are formed into substantially hemispherical shapes as shown in FIG.

Thereafter, the fixed chip 4 and the holder 5 are attached, but the bolts 10 of the holder 5 are temporarily tightened, and light is input from one end of the input side optical fiber 1a, and then it is connected to one end of the output side optical fiber 1b. The optical axis: I3 is adjusted while monitoring, and when this is completed, the holder 5 is finally tightened to the base 3. In this way, the planar optical waveguide 2 and both optical fibers la.

Completes optical coupling with 1b.

Optical axis adjustment in this case can be performed by moving only the planar optical waveguide 2 on the base 3 in a direction perpendicular to the optical axis of the optical fiber 1.

〔Effect of the invention〕

As described above, according to the first aspect of the invention, optical axis adjustment can be performed automatically by simply fixing both optical fibers at both positions, and alignment work can be simplified.

According to the invention of claim 2, the optical axis can be aligned with the portion where the coupling loss of the waveguide forming portion is minimized, the optical coupling loss can be reduced, and the alignment work can be facilitated. I can do it.

According to the third aspect of the invention, the optical axes can be made to match even if some angle or positional deviation occurs with respect to the optical waveguide due to the lens effect, and the optical coupling efficiency can be improved.

According to the invention of claim 4, the optical fibers can be fixed in the first positioning groove and the second positioning groove under the same conditions, and the optical axes of both optical fibers are adjusted in stages during assembly. This has the effect of further simplifying the alignment work.

[Brief explanation of drawings]

FIG. 1(a) is a perspective view of an optical coupling auxiliary device according to an embodiment of the present invention, FIG. 1(b) is an exploded perspective view thereof, FIG. 2 is a plan view thereof, and FIG. Fig. 4 is a plan view showing the relationship between each positioning groove of the base and the optical axis;
The figure is a side view showing the height relationship between the optical axis and the optical path, Figure 6 is a perspective view showing how to assemble the optical fiber, Figure 7 is a plan view showing the state of pressurizing the end face of the optical fiber, FIG. 8 is a perspective view of a conventional optical coupling auxiliary device. 1a...Incidence side optical fiber, 1b...Output side optical fiber, 2...Planar optical waveguide, 2b...Waveguide forming part, 3...Base, 3a...Surface, 4...・Fixed chip, 550. Holder, 7...first positioning groove, 8...
Second positioning groove.

Claims (1)

[Claims] 1. Optical coupling by interposing an optical waveguide between the input side optical fiber and the output side optical fiber and fixing them to the surface of the base so that their optical axes and optical paths coincide. In the optical coupling auxiliary device for performing this, a first positioning groove that can position the optical axis of the input optical fiber on the optical path of the optical waveguide on the surface of the base;
An optical coupling auxiliary device comprising: a second positioning groove capable of positioning the optical axis of the output side optical fiber in the optical path of the optical waveguide. 2. The optical coupling auxiliary device according to claim 1, wherein each of the positioning grooves is formed such that the optical axis of each of the optical fibers can be positioned approximately in the middle of the optical path of the optical waveguide. 3. An optical coupling device in which the optical coupling auxiliary device of claim 1 is assembled with an input side optical fiber, an output side optical fiber, and an optical waveguide, wherein the end of each optical fiber on the optical waveguide side is processed with a lens. An optical coupling device characterized by: 4. An assembling method in which an optical waveguide is interposed between an input optical fiber and an output optical fiber, and the optical fibers are assembled to a base of an optical coupling auxiliary device that optically couples the optical fibers. A method for assembling an optical fiber, the method comprising: fixing a single optical fiber at predetermined positions of the input side optical fiber and the output side optical fiber on the surface thereof, and then cutting the portion where the optical waveguide is interposed. .