JP2930066B1 - Optical module and manufacturing method thereof - Google Patents

Abstract

An optical module and a method of manufacturing the same are provided. SOLUTION: An element installation step of installing an optical element 1 facing a first end of a V-shaped groove 32 provided on one main surface of a platform 3, and a carbon-coated optical fiber 2 inserted and fixed in a ferrule are provided. A fiber installation step of bending the optical fiber 2 so that the end portion of the optical fiber 2 faces the V-groove 32 and the end surface of the optical fiber 2 facing the optical element 1; 3 and a ferrule 4 into which the optical fiber 2 is inserted.
A ferrule installation step of installing the remaining optical fiber 2 not installed in the V-groove 32 in the fiber installation step in the V-groove 32 while installing the optical fiber 2 in the trapezoidal groove 31 provided in the main surface of
Is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module having an optical fiber whose cladding side surface is coated with carbon and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a conventional optical module, a resin covering a side surface of an optical fiber is peeled off, and an optical fiber in a so-called bare wire state having a clad side surface exposed is inserted and fixed in a ferrule. I was using. The optical fiber inserted into and fixed to the ferrule and the ferrule are
They were installed in the V groove for the optical fiber and the V groove for the ferrule.

[0003]

However, when the optical fiber is mounted on the platform substrate, the optical fiber is bent in a predetermined radius of curvature without being applied with excessive bending stress and is set in the V-groove. However, it is not possible to shorten the portion of the optical fiber where the cladding whose coating has been stripped is exposed by bending the optical fiber, so that the substrate on which the optical fiber is mounted cannot be reduced in size. Therefore, the size of the optical module cannot be reduced.

An object of the present invention is to provide an optical module and a method for manufacturing the same, which can reduce the size of the device.

[0005]

Means for Solving the Problems In order to solve the above problems, the present invention has been made as follows.

According to the method of manufacturing an optical module of the present invention, there is provided an element installing step of installing an optical element facing a first end of an optical fiber supporting portion provided on one main surface of a substrate, Bending the optical fiber covered with the ferrule inserted and fixed in the ferrule, facing the end face of the optical fiber to the optical element, and installing a part of the end side of the optical fiber on the optical fiber supporting portion; A fixing step of fixing the end portion of the optical fiber provided on the optical fiber support to the base, and installing the ferrule in which the optical fiber is inserted on the ferrule support provided on the main surface of the base, A ferrule installation step of installing the remaining optical fibers not installed on the optical fiber support in the fiber installation step on the optical fiber support.

As described above, when the optical fiber provided on the optical fiber supporting portion is coated with carbon, the optical fiber is bent. When the optical fiber is bent and installed in accordance with the optical fiber supporting portion, The optical fiber can be bent with a smaller radius of curvature than before. For this reason, since the portion of the optical fiber that is not inserted into the ferrule can be shortened, the length of the optical fiber supporting portion on which the optical fiber is installed can also be shortened. Therefore, the length of the base can be reduced.

In the method of manufacturing an optical module according to the present invention, the fixing step includes disposing an ultraviolet curable resin between the fixing member through which ultraviolet light passes and the base, and determining the installation position of the optical fiber. A step of irradiating the optical fiber with ultraviolet light to fix the optical fiber.

As described above, when the fixing member that transmits ultraviolet light and the ultraviolet curable resin are used, the positioning and fixing of the optical fiber to the base are facilitated.

In the method for manufacturing an optical module according to the present invention, the bending of the optical fiber in the fiber installation step may be in a range of 10 mm or more and 30 mm or less in radius of curvature.

[0011] Within such a range, the size of the base can be reduced while ensuring sufficient reliability.

An optical module according to the present invention has a base having an optical fiber supporting portion extending in one direction, an element mounting portion provided facing one end of the optical fiber supporting portion on one main surface, and an element mounting surface provided on one end surface. The optical fiber is fixed to the optical fiber support portion facing the portion, and the cladding side surface is coated with carbon, and the optical fiber is inserted and fixed in the ferrule, and installed on the element mounting portion facing one end surface of the optical fiber, An optical element optically coupled to the end face of the optical fiber.

As described above, when the optical fiber whose cladding side surface is coated with carbon is used as the optical fiber installed on the optical fiber support provided on the base of the optical module, the length of the base can be reduced. Accordingly, a miniaturized optical module is provided.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical module according to an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a perspective view of an optical module depicting main members.

The optical module includes a base 5 having a ferrule support portion 31 extending in a predetermined axial direction on one main surface, and an end portion of the ferrule support portion 31 extending in the axial direction and having the center axis aligned with the ferrule support portion 31. An optical fiber supporting portion 32 joined to the ferrule supporting portion 31 and an element mounting portion provided on another end different from one end of the optical fiber supporting portion 32 joined to the end of the ferrule supporting portion 31. An optical fiber (carbon-coated optical fiber) 2 having a main surface, a platform 3, one end faced to the other end, which is installed on the optical fiber support 32, and whose cladding side face is coated with carbon; An optical element having a first end face that is mounted on the element mounting portion facing one end face of the optical fiber and is optically coupled to the end face of the optical fiber; The platform 3 is mounted on a base 5, and the two 3 and 5 constitute an integral base. Ferrule 4 is ferrule support 3
1 and the optical fiber 2 is fixed to the optical fiber support 32. The platform 3 is preferably formed by processing a silicon substrate, for example, because fine processing is easy. Further, the base 5 is preferably formed of, for example, a metal. Platform 3
Is provided with a groove 15 having a rectangular parallelepiped or square concave section extending in a direction orthogonal to the direction of the optical fiber supporting portion, and an optical fiber end face is in contact with a side surface 13 of the groove. Further, the ferrule 4 has a cylindrical shell shape having a cylindrical hollow portion for inserting the optical fiber 2 at the center along the direction in which the ferrule 4 extends.
Are fixedly inserted into the ferrule 4.

When the optical element 1 is a light emitting element, the optical module has a second end face different from the first end face of the light emitting element 1.
A light receiving element 6 for monitoring, which is disposed facing the end face of the light emitting element 1 and optically coupled to the light emitting element 1. According to FIG. 1, the optical module comprises a platform 3 and a base 5
A light receiving element 6 for monitoring mounted on a side surface of a chip carrier 9 different from the one described above. The chip carrier 9 has a light receiving surface of the light receiving element 6 for monitoring on a second end face which is a back surface of the first end face of the optical element 1. Arrange so that they face each other. Further, the optical axis of the incident light and the light receiving surface are so set that the laser light (incident light) from the second end face of the optical element 1 is reflected in a direction different from the incident light so as to prevent the oscillation of the laser from becoming unstable. May be arranged to be inclined at a predetermined angle from a right angle.

As an example of a light emitting element as the optical element 1,
For example, an edge emitting type laser diode (LD) is preferable because optical coupling with an optical fiber can be easily performed. In the case of a light receiving element, for example, a waveguide type photodiode into which light enters from an end face is an optical diode. This is preferable because optical coupling with the fiber is easy. Further, the monitoring light receiving element 6 is preferably a surface light receiving type photodiode (PD). Hereinafter, a case where a light emitting element is used as the optical element will be described.

The optical fiber 2 has a cladding side surface coated with a carbon film. For this reason, the carbon-coated optical fiber 2 is more resistant to bending stress than an uncoated carbon fiber. The thickness of the carbon film is
For example, it is about 0.03 to 0.05 μm.

The optical fiber supporting portion 32 is a groove having a concave cross section provided on the main surface of the platform 3 while supporting the optical fiber in contact with two side surfaces, and has a V-shaped cross section, for example. May have a trapezoidal shape that opens in the main surface direction. The center axis of the core of the optical fiber 2 installed on the optical fiber support 32 and the optical axis of the light emitting element 1 are aligned in the horizontal direction so that the light emitting element 1 and the optical fiber 2 are optically coupled. And is positioned. The depth of the concave portion 32 of the optical fiber supporting portion is determined by the optical axis of light emitted from the end face of the light emitting element 1 facing the end face of the optical fiber so that the light emitting element 1 and the optical fiber 2 are optically coupled. And the central axis of the core of the optical fiber 2 are aligned in the up-down direction and positioned. For this reason, the optical coupling between the optical fiber 2 and the light emitting element 1 becomes close.

The ferrule supporting portion 31 is a groove having a concave cross section provided on the main surface of the base 5 for supporting the ferrule 4 on two sides, and having a V-shaped cross section or a main surface, for example. It can be a trapezoidal shape that opens in the direction. When the optical fiber inserted and fixed in the ferrule 4 is installed in the optical fiber support portion 32 and the ferrule 4 is installed in the ferrule support portion 31, the depth of the concave portion 31 The position of the center of the core is determined so that the position of the center of the core of the optical fiber in the ferrule support portion 31 matches. With such a cross-sectional concave structure, the concave portion 32 comes into contact with the outer periphery of the ferrule 4 at two lines and supports the ferrule 4,
The concave portion 31 is in contact with the outer periphery of the optical fiber 2 by two lines,
This optical fiber 2 is supported.

Next, a method for manufacturing an optical module according to an embodiment of the present invention will be described. 2 to 5 are assembly side views of the optical module according to the embodiment of the present invention, and FIG. 6 is an explanatory top view of FIG. The case where the optical fiber supporting portion 32 has a V-shaped cross-sectional shape and the ferrule supporting portion 31 has a trapezoidal cross-sectional shape opened toward the main surface will be described below.

According to the optical module manufacturing method of the present invention, the base 5 having the ferrule support portion 31 extending along the first axis on one main surface, and the respective central axes extending along the first axis. And one end is ferrule support 3
A platform 3 having, on one main surface, an optical fiber supporting portion 32 joined to one end of the optical fiber supporting portion 1 and an element mounting portion provided on another end of the optical fiber supporting portion 32 which is different from the one end. Are used.

First, the light emitting device 1 is mounted and fixed on the device mounting portion on one main surface of the substrates 3 and 5 so as to face the first end of the optical fiber support portion. FIG. 2 shows the substrate 3,
5, a light-emitting element 1 fixed on the base 5, a carbon-coated optical fiber 2 before being placed on an optical fiber support 31 formed on the main surface of the bases 3, 5, and the optical fiber 2 inserted into the center. 3 shows a fixed ferrule 4. Since FIG. 2 is a side view, the optical fiber support portion 32 and the ferrule support portion 31 do not appear in the drawing, but in FIG. 2 these are particularly indicated by broken lines.

Next, the end surface of the carbon-coated optical fiber 2 inserted and fixed in the ferrule, which is not covered by the ferrule, is brought into contact with one side surface 13 of the groove 15 having a concave cross section, and the optical fiber 2 is bent. Then, a portion having a length L of the distal end side of the optical fiber 2 is disposed in a V-groove 32 which is an optical fiber supporting portion. FIG. 3 shows the optical fiber 2 arranged in the V-groove 32 in this manner.
The end face including the end face on the front end side is disposed to face one end face of the light emitting element 1. According to FIG.
A portion having a length L of the tip portion is set along the inside of the V groove 32. The portion on the ferrule side subsequent to the length L of the tip portion extends while being bent away from the V-groove 32 within a range of a predetermined radius of curvature R, reaches the end face B of the ferrule 4, where it is joined to the ferrule 4. Inserted. The optical fiber 2 keeps a straight line in the ferrule 4 without bending. A first straight line portion from the end on the distal end side of the fiber 2 to the point A and a second straight line portion in the ferrule are connected to the point A (the fiber horizontal portion and the bent portion) existing on both sides of the bent portion of the optical fiber 2. ) And point B (the position where the optical fiber 2 is inserted into the end face of the ferrule 4) are tangent to each other. Therefore, the points A and B are so-called smooth.

According to FIG. 3, the point B is located at a height δ from the main surface of the platform 3, and the extension of the central axis of the optical fiber 2 in the ferrule 4 and the platform 3
Is defined as θ. The length when the bent portion of the optical fiber 2 is projected onto the main surface of the platform 3 is defined as I.

In this step, in the portions A and B in FIG. 3, the tangents at both ends of the bent portion are arranged so as to coincide with the central axis of the fiber or the central axis of the ferrule. In order to achieve such an arrangement, it is necessary to appropriately set R, δ, I, and θ. When θ is very small, this relationship is approximately expressed as follows: R = (3δ) / (2θ ² ) I = (3δ) / θ This is shown in FIGS. 8 and 9. FIG. 8 is a graph showing the relationship between I and δ for R, and FIG. 9 is a graph showing the relationship between δ and θ for R. For example, if it is intended to realize a bending of R = 10 mm at a height of δ = 0.1 mm, the angle θ can be obtained by using FIG. 9, and it is understood that it is necessary to set θ to about 7 °. The value of I at this time can be obtained using FIG. 8, and it is possible to realize about I = 2.5 mm.

If I can be reduced in this way, the length of the platform 3 (silicon substrate) in the longitudinal direction can be shortened. For example, when the platform 3 is formed of silicon, the yield of the platform 3 that can be manufactured from one silicon substrate can be increased, and the cost can be reduced.

In order to reduce I, it is effective to reduce R and δ. On the other hand, it is preferable for the characteristics of the optical fiber not to make R too small. Generally, it is considered desirable to secure R of 30 mm or more in a silica-based fiber having a cladding diameter of 125 μm, while the carbon-coated optical fiber 2 exhibits excellent static fatigue characteristics. 10 as R
It is permissible up to about 15 mm.

After the above steps, the optical fiber 2 is fixed to the platform 3. For fixing the optical fiber, for example,
As shown in FIG. 4, there is a method in which a fixing member 10 (for example, a pressing plate) for transmitting an ultraviolet ray and fixing an optical fiber is fixed to the platform 3 with an ultraviolet curing resin. Referring to FIG. 6, the platform 3 on which the distal end of the optical fiber 2 is disposed
The ultraviolet curing resin 11 is dropped on the main surfaces on both sides of the V-groove with the optical fiber 2 interposed therebetween, and the resin 11 and the optical fiber 2 are covered with the fixing member 10. In this manner, the positioning of the optical fiber 2 is performed. When an appropriate position of the optical fiber is determined, the optical fiber 2 can be fixed by irradiating the ultraviolet curable resin 11 with ultraviolet light while pressurizing to solidify the resin 11. In addition, as a material of the fixing member, quartz or the like is preferable. FIG. 7 is a perspective view of the optical module after fixing the optical fiber 2 to the platform 3. in this way,
When the fixing member 10 and the ultraviolet curing resin 11 that transmit ultraviolet light are used, the positioning and fixing of the optical fiber 2 to the bases 3 and 5 are facilitated.

Next, the ferrule 4 into which the optical fiber 2 is inserted is inserted into the groove 31 having a trapezoidal cross section provided on the main surface of the base 5.
And the remaining optical fibers 2 that were not installed in the optical fiber V-groove 32 in the process of installing the fiber are installed in the V-groove 32.

According to such a method, the optical fiber 2 is not bent at an extremely small R (radius of curvature), but is formed in the groove 32 having a V-shaped cross section provided on the substrate miniaturized in the longitudinal direction. The carbon-coated optical fiber 2 can be reliably brought into contact.

The subsequent steps can be performed in the same manner as in the conventional optical module manufacturing process, and a description thereof will be omitted.

As described above, when a carbon-coated optical fiber is used for the optical fiber 2 installed on the optical fiber support 32, the optical fiber 2 is bent and the optical fiber support 3
2, the optical fiber can be bent with a smaller radius of curvature R as compared with an optical fiber in which the resin coating is peeled off and the side surfaces of the cladding are exposed and not coated with carbon. Therefore, the portion of the optical fiber that is not inserted into the ferrule can be shortened. That is, since the length of the optical fiber supporting portion on which the optical fiber is installed can be shortened, I can be shortened. That is, the optical module can be downsized by shortening the platform substrate 3.

According to the optical module according to the embodiment of the present invention, since the optical fiber installed on the platform substrate 3 of the optical module is the carbon-coated optical fiber 2, the optical fiber is hardly damaged, so that the optical fiber is not damaged. Precautions in handling can be reduced as compared with conventional optical fibers, and the fiber has durability against bending stress. For this reason,
Reliability can be further improved. Further, since the platform substrate 3 can be shortened, the size of the optical module can be reduced. Therefore, cost can be reduced.

Further, according to the method of manufacturing the optical module, the optical fiber is hardly damaged, so that it is not necessary to pay attention to the handling of the optical fiber as compared with the conventional one. The performance can be improved, and the platform substrate 3 can be shortened. Therefore, it is possible to provide a manufacturing method capable of reducing the size of the optical module.

[0037]

As described above in detail, according to the method for manufacturing an optical fiber of the present invention, the optical fiber installed on the substrate of the optical module is a carbon-coated optical fiber, so that the platform can be shortened. A manufacturing method capable of reducing the size of the optical module can be provided.

Further, according to the optical module of the present invention, since the platform can be shortened, the optical module can be downsized.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an optical module according to the present invention.

FIG. 2 is an assembled side view of the optical module according to the embodiment of the present invention.

FIG. 3 is an assembled side view of the optical module according to the embodiment of the present invention.

FIG. 4 is an assembled side view of the optical module according to the embodiment of the present invention.

FIG. 5 is an assembled side view of the optical module according to the embodiment of the present invention.

FIG. 6 is a top view of FIG. 4;

FIG. 7 is a perspective view of FIG. 4;

FIG. 8 is a graph showing the relationship between I and δ with respect to R.

FIG. 9 is a graph showing the relationship between R and δ and θ.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... LD, 2 ... Carbon coated optical fiber, 3 ... Platform substrate, 4 ... Ferrule, 5 ... Base, 6 ... Monitor PD, 10 ... Holding plate, 31 ... Ferrule support part,
32 ... Optical fiber support

Claims (4)

(57) [Claims] 1. An element installation step of installing an optical element facing a first end of an optical fiber supporting portion provided on one main surface of a base, and a cladding side surface is coated with carbon and inserted and fixed in a ferrule. Bending the bent optical fiber, facing the optical element with the end face of the optical fiber, and installing a part of the end of the optical fiber on the optical fiber support, A fixing step of fixing an end portion side of the optical fiber installed in the portion to the base, and installing the ferrule into which the optical fiber is inserted on a ferrule support provided on the main surface of the base. A ferrule installation step of installing, on the optical fiber support, the remaining optical fibers that are not installed on the optical fiber support in the fiber installation step. How to make joules. 2. The fixing step, comprising arranging an ultraviolet curable resin between a fixing member through which ultraviolet light is transmitted and the base, and irradiating the ultraviolet curable resin with ultraviolet light after an installation position of the optical fiber is determined. 2. The method according to claim 1, further comprising the step of fixing the optical fiber. 3. The method for manufacturing an optical module according to claim 1, wherein the bending of the optical fiber in the fiber setting step is in a range of 10 mm to 30 mm in radius of curvature. 4. A base having on one main surface an optical fiber supporting portion extending in one direction and an element mounting portion provided facing one end of the optical fiber supporting portion, and an end surface facing the element mounting portion. An optical fiber fixed to the optical fiber support portion and clad side surfaces are coated with carbon and inserted and fixed in a ferrule, and installed on the element mounting portion facing one end surface of the optical fiber, An optical module, comprising: an optical element optically coupled to an end face of the optical fiber.