JP3393761B2 - Optical waveguide module and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide module excellent in long-term reliability without destabilizing optical characteristics.

[0002]

2. Description of the Related Art A conventional optical waveguide module is mainly composed of an optical waveguide chip and a connecting optical component. As the connecting optical component, for example, a V groove is formed on a quartz substrate and a desired position is provided. An optical fiber is used which is arranged and fixed with an adhesive or the like. Further, the optical waveguide chip has a portion having a high refractive index and confining and guiding light in the optical waveguide substrate, and has a function such as branching and switching.

FIG. 5 (a) is a view showing an example of connection between the 1 × 4 branch type optical waveguide chip 3 and the optical fiber block 1, and the connection end faces of the optical waveguide chip 3 and the optical fiber block 1 are optical. The optical fiber block 1 is end-polished at a desired angle to prevent reflected return light from the axis.
The core intervals of the four-core optical fiber block, which is, are manufactured so as to match the intervals of the optical waveguides 4 of the optical waveguide chip 3. In addition, the optical waveguide chip 3 and the optical fiber block 1 generally have the optical axes aligned with each other,
They are connected and fixed by an adhesive (for example, an ultraviolet curable adhesive) or the like.

Therefore, an adhesive layer 7 is present at the connecting portion between the optical waveguide chip 3 and the optical fiber block 1, and the adhesive layer 7 absorbs moisture in the presence of water, so that the adhesive force decreases with time. And, it will cause deterioration of the material. As a result, an increase in optical loss occurs at the connection part.

As a countermeasure against this, a measure is taken such that the heat-shrinkable tube 8 is used to seal the side surface including the connection portion, which is connected and fixed as shown in FIG. 5C.

[0006]

Conventionally, as shown in FIG.
The optical waveguide module composed of the components as shown in FIG. 1 prevents chipping on the upper portion of the optical waveguide chip 3, increases the bonding area of the adhesive, and has the same height as the optical fiber block 1. Therefore, a protective cover (not shown) is provided, and as shown in FIG. 5B, a pressing cover 11 is provided above the optical fiber block 1 to press the tape fiber 5.

However, when the pressing cover 11 is bonded and fixed to the optical fiber block 1 and the bonding position is displaced, there is a portion where the pressing cover 11 protrudes from the side surface portion A in the direction parallel to the optical axis direction of the optical fiber block 1. There was a case where the assembly was defective when it was used as an optical waveguide module. This also poses a problem when the protective cover is bonded and fixed to the optical waveguide chip. In addition, when the side surface portion B spline cover 11 in the direction perpendicular to the optical axis direction protrudes, it does not matter even if it protrudes because it is polished together when the connection end surface is polished.

When the heat shrinkable tube 8 is used for sealing, heat is applied to the entire optical waveguide module and stress is applied to the connection portion when the heat shrinkable tube is contracted.
The heat and the stress cause a positional shift, which causes a problem that the characteristics of the optical waveguide module are deteriorated and the reliability is deteriorated.

Further, after the heat-shrinkable tube is shrunk, openings are formed at both ends of the heat-shrinkable tube, so that in the presence of water, water penetrates into the inside of the heat-shrinkable tube, and the adhesive force of the connecting portion changes with time. And the deterioration of the material, which results in an increase in optical loss at the connection.

The present invention has been made in view of the above points, and an object thereof is to provide an optical waveguide module having excellent long-term reliability without destabilizing optical characteristics.

[0011]

The present invention has been made to solve these problems, and an optical waveguide chip on which an optical waveguide is formed, both end surfaces of the optical waveguide chip, and an optical axis on the optical waveguide are provided. In an optical waveguide module including an optical fiber block in which optical fibers to be connected and fixed so as to match are provided, a protective cover for the optical waveguide is provided above the optical waveguide chip, and a cover for the optical fiber is provided above the optical fiber block. Are each provided with a protective cover and /
Alternatively, the optical waveguide module is one in which the lateral width of the pressing cover is shorter than the lateral width of the optical waveguide chip and / or the optical fiber block.

With such a configuration, even if the adhesive fixing positions of the pressing cover and the optical fiber block or the optical waveguide chip and the protective cover are deviated, the pressing cover and the protective cover are still attached to the optical axis of the optical fiber block and the optical waveguide chip. It is possible to prevent it from protruding from the side surface in the direction parallel to, and it is not necessary to perform a process for making the substrates parallel to each other or to perform alignment by providing a special shape such as a guide groove and a convex portion, and It is possible to prevent excess adhesive from sticking out from the side surface during adhesive fixing.

Further, a common substrate for fixing the optical waveguide and the optical fiber block together is provided on the bottom surface of the optical waveguide block, and the width of the common substrate is shorter than that of the optical waveguide chip and the optical fiber block. is there.

With such a configuration, even if the common substrate and the optical waveguide chip and the protective cover are bonded and fixed to each other at different positions, the pressing cover and the protective cover have side surfaces parallel to the optical axes of the optical fiber block and the optical waveguide chip. It is possible to prevent the adhesive from sticking out, and it is also possible to prevent excess adhesive from sticking out from the side surface during adhesive fixing.

Further, by using quartz as the base of the optical waveguide chip, all the constituent members of the optical waveguide module before sealing can be made the same, and the positional deviation due to the difference in linear expansion coefficient at the time of contraction of the heat-shrinkable tube can be prevented. Is possible.

Further, the optical waveguide chip, the optical fiber block, the protective cover, the pressing cover, and the optical waveguide module in which at least one corner portion parallel to the optical axis direction of the common substrate is an inclined surface.

With this structure, when the components are connected and fixed by covering the periphery with the cured shrink resin or the heat shrink tube, it is possible to reduce the concentration of stress during shrinkage.

Furthermore, the entire optical waveguide module, or at least the connecting portions at both ends of the optical waveguide chip are sealed with a heat-shrinkable tube to provide an optical waveguide module.

When the heat-shrinkable tube is used in the above structure, the protective cover above the optical waveguide chip, the pressing cover above the optical fiber block, and the common substrate below the optical fiber block and the optical waveguide chip become the optical waveguide chip and the optical fiber. Since it is shorter than the block width, the cross-sectional shape of the optical waveguide module can be made closer to the circle that is the cross-sectional shape of the heat-shrinkable tube, and the stress when the shrinkable tube shrinks can be made uniform on the side surface of the optical waveguide module. Becomes

Further, the optical waveguide type module is formed by filling both openings of the heat shrinkable tube with resin.

With such a structure, it is possible to prevent the adhesive strength of the connection portion and the deterioration of the material with the passage of time in the presence of moisture, and thus to prevent the problem of an increase in light loss at the connection portion. Is possible.

Further, an optical waveguide provided with an optical waveguide chip having an optical waveguide formed therein and an optical fiber block having fixed end portions of the optical waveguide chip and an optical fiber connected and fixed to the optical waveguide so that their optical axes coincide with each other. A waveguide module,
The optical waveguide chip and the bottom surface of the optical fiber block are provided with a common substrate for fixing them together, the optical waveguide chip upper part is provided with an optical waveguide protective cover, and the optical fiber block upper part is provided with an optical fiber pressing cover.
Manufacture of an optical waveguide module in which the width of each of the common substrate, the protective cover, and the pressing cover is shorter than that of the optical waveguide chip and the optical fiber block, and the entire module or at least the connection parts at both ends of the optical waveguide chip are sealed with heat shrink tubes. In the method, at least the optical waveguide chip of the optical waveguide module and the connecting portions at both ends thereof are completely inserted into the heat-shrinkable tube, the heat-shrinkable tube is fixed outside the both connecting portions, and the heat-shrinkable tube is heat-shrinkable. It is a method of manufacturing a waveguide module.

With this, since the heat-shrinkable tube is contracted while the heat-shrinkable tube is fixed, it is possible to prevent the fine movement of the tube at the time of shrinkage, and it is possible to prevent the fluctuation of the stress due to the fine movement.

Furthermore, in the method of manufacturing an optical waveguide module, a heating source used for heat shrinkage is arranged in the vertical direction of the optical waveguide module so that heating is performed evenly from at least the vertical direction.

As a result, the heat-shrinkable tube contracts symmetrically, and it becomes possible to apply symmetrical stress to the optical waveguide module, so that the stress on the connection portion is uniform and symmetrical without changing on the side surface of the optical waveguide module. It is possible to prevent the deterioration of the characteristics of the optical waveguide module and the problem of reliability caused by the positional displacement due to the stress. [Detailed Description of the Invention]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1A is a sectional view of an optical waveguide chip 3 portion of an optical waveguide module 10 according to the present invention,
FIG. 1B is a sectional view of a part of the optical fiber block. Further, FIG. 1C is a configuration diagram of the optical waveguide module 10.

The optical waveguide chip 3 is a 1 × 8 branch type optical waveguide chip, and a quartz optical waveguide 4 is formed on a quartz base 16. A protective substrate 9 for the optical waveguide 4 is fixed on the optical waveguide chip 3 with an ultraviolet curable adhesive.

The optical fiber block 1 connected to the eight optical waveguides 4 has a tape fiber 5 in the eight V-grooves on the V-groove substrate 17a formed by cutting with the same precision as the spacing of the optical waveguides 4. There are 8 optical fibers of
In the optical fiber block 1 connected to the optical waveguide 4 of this book, one optical fiber 2 is arranged in one V groove on the V groove substrate 17b manufactured by the same processing method. In this state, a pressing cover 11 is pressed from above the optical fibers arranged in both V-grooves to bond and fix them using an ultraviolet curable adhesive, and thereafter, a connecting cross section is produced at a desired angle with respect to the optical axis by polishing. ing.

Optical waveguide chip 3 and optical fiber block 1
For example, after the optical axis is adjusted on each connection side, an ultraviolet curable adhesive is applied, ultraviolet rays are irradiated to form an adhesive layer 7 between the connection cross sections, and the connection is fixed. The substrate 6 is arranged and fixed by, for example, the same ultraviolet curable adhesive.

The widths of the common substrate 6, the pressing cover 11 of the optical fiber block 1, and the protective substrate 9 on the optical waveguide chip 3 are shorter than the widths of the optical waveguide chip 3 and the optical fiber block 1, and the x and y axes are the same. It is arranged and fixed symmetrically with respect to. The thickness is also the same, and the curve connecting the vertices has a circular shape.

FIG. 2 shows a heat shrinkable tube 8 according to the present invention.
It is a side view which shows the sealing method by. Heat shrink tube 8
The two connection parts of the optical waveguide module 10 are inserted so as to be hidden therein, and both ends of the heat-shrinkable tube 8 are fixed by the clamps 14 on the fixing base 13. Further, in the vertical direction of the optical waveguide module 10, the heat source 1 is symmetric with respect to the center line of the cross section of the optical waveguide module 10 parallel to the optical axis.
5 is arranged, and the heat-shrinkable tube 8 is shrunk by applying an appropriate temperature in this state. After shrinking the heat-shrinkable tube 8 inside the fixed portion by the clamp 14, the clamp 14 is removed, and both ends of the heat-shrinkable tube 8 are heated and shrunk.

FIG. 3 shows a heat shrinkable tube 8 according to the present invention.
3 is a side view of the optical waveguide module in which both openings are sealed with resin 12. FIG. After sealing with the heat-shrinkable tube 8, for example, a silicone resin 12 having excellent water resistance is filled in both openings of the tube for further sealing.

FIG. 4 is a sectional view showing another embodiment according to the present invention, in which each side parallel to the optical axis of the optical waveguide module 10 is provided with an inclined portion 17.

[0034]

As described in detail above, in the optical waveguide module according to the present invention, the lateral width of the protective cover and / or the pressing cover is shorter than the lateral width of the optical waveguide chip and / or the optical fiber block, Alternatively, a holding cover and an optical fiber block, an optical waveguide chip and a protective cover, or a common substrate and an optical waveguide chip and protection are provided by using an optical waveguide module in which the width of the common substrate is shorter than the width of the optical waveguide chip and the optical fiber block. Even if the adhesion position with the cover is displaced, the pressing cover, the protective cover, or the common substrate will not stick out from the side surface of the optical fiber block or the optical waveguide chip in the direction parallel to the optical axis. In addition, excess adhesive will not stick out from the side.

Further, since at least one corner portion parallel to the optical axis direction of the optical waveguide chip, the optical fiber block, the protective cover, the pressing cover, and the common substrate is an inclined surface, the periphery is hardened and shrunk resin or heat shrunk. When connecting and fixing with a tube, the concentration of stress is relieved.

Further, the entire optical waveguide type module, or at least the connecting portions at both ends of the optical waveguide chip are sealed with the heat shrinkable tube, so that the periphery is adhered and fixed by the curing shrinkable resin or the heat shrinkable tube. In doing so, the concentration of stress during contraction is relieved.

Further, by sealing the above structure with a heat-shrinkable tube, it becomes possible to make the cross-sectional shape of the optical waveguide module close to the circle which is the cross-sectional shape of the heat-shrinkable tube, and the stress when shrinking the shrinkable tube is reduced. Is uniform on the side surface of the optical waveguide module.

By filling both openings of the heat-shrinkable tube with resin, it is possible to prevent the adhesive strength of the connection part and the deterioration of the material with the passage of time in the presence of water.
It is possible to prevent the problem that the optical loss increases at the connection portion.

Further, at least the optical waveguide chip of the optical waveguide module and the connecting portions at both ends thereof are completely inserted into the heat-shrinkable tube, the heat-shrinkable tubes are fixed on the outside of both the connection portions, and the heat-shrinkable tube is heat-shrinkable. Depending on the manufacturing method
It is possible to prevent the fine movement of the tube at the time of contraction, and to prevent the fluctuation of the stress due to the fine movement.

Further, by the manufacturing method in which the heat source used for heat shrinkage is arranged in the vertical direction of the optical waveguide module and the heating is performed at least evenly from the vertical direction, the heat shrinkable tube contracts symmetrically and is symmetrical to the optical waveguide module. It becomes possible to apply various stresses.

[Brief description of drawings]

1A, 1B, and 1C show a configuration of an optical waveguide module according to the present invention, wherein FIG. 1A is a sectional view of an optical waveguide chip, and FIG. 1B is a sectional view of an optical fiber block. ,
(C) is a block diagram of an optical waveguide module.

FIG. 2 is a side view showing a method for sealing an optical waveguide module according to the present invention.

FIG. 3 is a side view showing a sealed state of the optical waveguide module according to the present invention.

FIG. 4 is a sectional view of an optical fiber block portion showing another embodiment according to the present invention.

FIG. 5 shows a conventional example, (a) is a top view of an optical waveguide module in which a 1 × 4 branch type optical waveguide chip and an optical fiber block are connected and fixed, and (b) is a press cover adhered and fixed to the optical fiber block. FIG. 3C is a sectional view of the optical waveguide module in which the optical waveguide module is sealed with a heat shrink tube.

[Explanation of symbols]

1: Optical fiber block 2: Optical fiber 3: Optical waveguide chip 4: Optical waveguide 5: Tape fiber 6: Common board 7: Adhesive layer 8: Heat shrink tube 9: Protective substrate (protective cover) 10: Optical waveguide module 11: Press cover 12: Silicone resin 13: Fixed stand 14: Clamp 15: Heat source 16: Quartz base 17: Inclined part 17a, 17b: V-groove substrate

Claims (2)

(57) [Claims] 1. An optical waveguide chip on which an optical waveguide is formed, and an optical fiber block on which both end faces of the optical waveguide chip and an optical fiber connected and fixed so that the optical axis is aligned with the optical waveguide are fixed. in the optical waveguide module, the
Put these together on the bottom of the optical waveguide and the optical fiber block.
The common substrate to be fixed is provided with an optical waveguide protection cover above the optical waveguide chip and an optical fiber pressing cover above the optical fiber block .
The width is the width of the optical waveguide chip and the optical fiber block
Shorter than, and the width of the protective cover and pressing cover is shorter than the width of the optical waveguide chip and an optical fiber block, the optical waveguide chip, optical fibers Bro
Light on the rack, protective cover, pressure cover, and common substrate.
At least one corner parallel to the axial direction is an inclined surface,
The entire optical waveguide module, or at least the above
The connection parts on both ends of the optical waveguide chip are sealed with heat-shrinkable tubes
At the same time, fill both openings of the heat shrink tube with resin.
Optical waveguide module, characterized by Hama. 2. The method for manufacturing an optical waveguide module according to claim 1 , wherein at least the optical waveguide chip of the optical waveguide module and the connecting portions of both ends thereof are completely inserted into the heat-shrinkable tube, Fix the heat shrink tube on the outside and place the heat source in the vertical direction of the optical waveguide module.
The method for manufacturing an optical waveguide module, wherein the heat-shrinkable tube is evenly heated and shrunk from at least the vertical direction .