WO2018012075A1

WO2018012075A1 - Optical module and method for manufacturing optical module

Info

Publication number: WO2018012075A1
Application number: PCT/JP2017/015795
Authority: WO
Inventors: 拓弥小田
Original assignee: 株式会社フジクラ
Priority date: 2016-07-15
Filing date: 2017-04-19
Publication date: 2018-01-18
Also published as: JP2018010225A

Abstract

The present invention makes it possible to position an optical fiber with high precision. This optical module (1) includes: an optical element (11) having a recess (11b) formed in the surface thereof, and an optical waveguide (11c) formed inside the optical element and extending from the inner surface of the recess (11b) along the surface; and an optical fiber (12) disposed in the recess (11b) so that the tip end thereof faces the end face of the optical element (11). The optical fiber (12) is secured by a wet first resin layer spread evenly inside the recess (11b) along the width direction thereof.

Description

Optical module and optical module manufacturing method

The present invention relates to an optical module that includes an optical waveguide and an optical fiber, and transmits an optical signal between them, and a method for manufacturing the optical module.

Conventionally, an optical module that includes an optical waveguide and an optical fiber and transmits an optical signal between them is known. In this type of optical module, an optical waveguide is formed on a substrate, and the optical waveguide and the optical fiber are optically connected so that an optical signal propagates between the end of the optical waveguide and the optical fiber.

Specifically, in the conventional optical module, as disclosed in Patent Document 1, a guide groove for arranging the optical fiber is formed on the substrate on which the optical waveguide is formed, and the optical fiber is arranged in the guide groove, The optical fiber in the guide groove is fixed with an adhesive. In the configurations described in

Patent Documents

2 and 3, a V-groove is formed as a guide groove in which the optical fiber is disposed, and the optical fiber disposed in the V-groove is fixed with an adhesive.

In the configurations disclosed in these Patent Documents 1 to 3, the optical fiber is arranged in the guide groove (V groove) in an unaligned state with respect to the optical waveguide. Therefore, the guide groove is formed so that the optical axis of the optical fiber arranged in the guide groove and the optical axis of the optical waveguide coincide.

Japanese Patent Publication “JP-A 63-58304” Japanese Patent Publication “JP-A-8-313756” Japanese Published Patent Publication "Japanese Patent Laid-Open No. 2006-350014"

Recently, very small and high-speed optical devices such as silicon photonics, in which a fine optical waveguide is formed on a silicon substrate, have been developed. In such an optical device, the optical fiber is required to have a high positioning accuracy of, for example, 1 μm or less with respect to the optical waveguide.

On the other hand, in the above-described conventional configuration, the optical fiber is positioned with respect to the optical waveguide by disposing the optical fiber in a guide groove (V groove) formed in the substrate in an unaligned state. For this reason, in the conventional optical fiber positioning method using the guide groove, the optical fiber positioning accuracy depends on the guide groove processing accuracy, and the optical fiber positioning accuracy required for the optical device cannot be obtained.

Therefore, a so-called active alignment method is adopted as a method for positioning the optical fiber with higher accuracy. In this method, alignment is performed as follows as an example. For example, an optical signal is incident on an optical fiber, the intensity of the optical signal is measured at the output side end of the optical waveguide (the end opposite to the incident side), and the optical signal is measured at the position where the intensity of the optical signal is maximum. Position the fiber. In this case, a recess is formed in the substrate instead of the guide groove, and the aligned optical fiber is fixed with an adhesive (resin) filled in the recess.

However, after the optical fiber is positioned, if the concave portion of the substrate is filled with an adhesive or the like, a mechanical force acts on the optical fiber when the adhesive is filled, and the optical fiber moves from the positioned position. In addition, since the adhesive shrinks upon curing, the optical fiber also moves from the position where it is positioned.

Note that the optical fiber movement from the positioning position due to adhesive shrinkage is predicted, and the optical fiber is positioned in advance so that the optical fiber is placed at the predetermined positioning position after the movement. It is conceivable to dispose at a position deviated from the position, that is, to place an offset. However, in the configuration in which the optical fiber is embedded and disposed in the adhesive layer, it is difficult to predict the moving direction and moving amount of the optical fiber due to the curing shrinkage of the adhesive. For this reason, even if the optical fiber is offset, it cannot cope with the deviation from the positioning position of the optical fiber due to curing shrinkage of the adhesive.

Therefore, an object of the present invention is to provide an optical module and an optical module manufacturing method capable of positioning an optical fiber with respect to an optical waveguide with high accuracy.

In order to solve the above problems, an optical module according to an aspect of the present invention is an optical module in which a concave portion is formed on a surface and an optical waveguide extending along the surface from the inner side surface of the concave portion is formed inside. And an optical fiber at least partially disposed in the recess so that the tip faces the end face of the optical waveguide, and the optical fiber wets and spreads evenly in the width direction in the recess. The first resin layer is fixed to the optical element.

According to one aspect of the present invention, there is an effect that the optical fiber can be positioned with respect to the optical waveguide with high accuracy.

It is a perspective view which shows the structure of the optical module of embodiment of this invention. 2A is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 2B is a cross-sectional view taken along the line BB in FIG. It is explanatory drawing which shows the manufacturing process of the optical module shown in FIG. FIG. 4A is a longitudinal sectional view of the optical module showing a state where the resin forming the first resin layer shown in FIG. 1 is injected in a state of being biased in the width direction of the concave portion of the optical element. (B) is a longitudinal section of the optical module showing a state in which the optical fiber is fixed at a position shifted from the normal positioning position due to the curing shrinkage of the resin of the first resin layer from the state shown in FIG. FIG. FIG. 5A is a longitudinal sectional view of the optical module showing a state in which the optical fiber has moved from the normal positioning position when the resin of the first resin layer is injected into the concave portion of the optical element, and FIG. ) Is a longitudinal sectional view of the optical module showing a state in which the optical fiber is fixed at a position shifted from the normal positioning position due to the curing shrinkage of the resin of the first resin layer from the state shown in FIG. It is. (A) of FIG. 6 is a longitudinal sectional view of the optical module of the present embodiment showing a state in which the resin is injected into the concave portion of the optical element so as to be wet and spread in the width direction when the first resin layer is formed, FIG. 6B shows a state in which the optical fiber is fixed by suppressing the deviation from the normal positioning position by the curing shrinkage of the resin of the first resin layer from the state shown in FIG. It is a longitudinal cross-sectional view of the optical module of this embodiment shown. 7A is a longitudinal sectional view of the optical module showing a state in which the optical fiber is embedded in the resin of the first resin layer 13, and FIG. 7B is a view from the state of FIG. It is a longitudinal cross-sectional view of the optical module which shows the state which resin hardened | cured and contracted. FIG. 8B shows another example of the shape of the concave portion shown in FIG. 2B. FIG. 8A shows a case where the concave portion is U-shaped, and FIG. 8 (e) shows a semicircular shape, FIG. 8 (e) shows a case where the concave portion is V-shaped, FIG. 8 (g) shows a case where the concave portion is a trapezoidal shape, and FIG. In the case of a trapezoidal shape in which the concave portion spreads downward (upside down with respect to (g) in FIG. 8), FIG. 8 (k) shows a shape in which the concave portion changes in two steps (the lower portion is narrower). It is a longitudinal cross-sectional view of the optical element in the case of (shape). 8 (b), FIG. 8 (d), FIG. 8 (f), FIG. 8 (h), FIG. 8 (j), and FIG. 8 (l) are respectively shown in FIG. ), FIG. 8C, FIG. 8E, FIG. 8G, FIG. 8I, and FIG. 8K are provided with the first resin layer and the optical fiber. FIG. It is a perspective view which shows the structure of the optical module of other embodiment of this invention. 10A is a cross-sectional view taken along the line AA in FIG. 9, and FIG. 10B is a cross-sectional view taken along the line BB in FIG. It is explanatory drawing which shows the manufacturing process by the 1st manufacturing method of the optical module shown in FIG. It is explanatory drawing which shows the manufacturing process by the 2nd manufacturing method of the optical module shown in FIG.

Embodiment 1
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the configuration of the optical module of the present embodiment. 2A is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 2B is a cross-sectional view taken along the line BB in FIG.

(Configuration of optical module)
As shown in FIGS. 1 and 2A and 2B, the optical module 1 includes an optical element 11 and an optical fiber 12.

The optical element 11 has a rectangular parallelepiped substrate shape whose end face in the longitudinal direction is a rectangle whose width is longer than the height, and has an optical waveguide 11c and a recess 11b.

The concave portion 11b has a length that reaches the first end surface 11d on one side in the longitudinal direction from the vicinity of the central portion of the optical element 11, and on the upper surface (front surface) 11a of the optical element 11, for example, the center in the width direction of the optical element 11 It is formed in the part. The shape of the concave portion 11b seen in the longitudinal section of the optical element 11 is a rectangle having a longer width than a height.

The optical waveguide 11c is formed in a region on the opposite side of the region where the concave portion 11b is formed in the longitudinal direction of the optical element 11. The optical waveguide 11c extends in the longitudinal direction along the upper surface 11a of the optical element 11 from the inner surface parallel to the width direction of the recess 11b, and reaches the second end surface 11e opposite to the first end surface 11d. The end portion on the concave portion 11b side of the optical waveguide 11c is a light incident portion, and the end portion on the second end face 11e side is a light emitting portion. The light incident part and the light emitting part may be reversed.

1 and 2 show a structure in which the optical fiber 12 is connected to the end of the optical waveguide 11c via the recess 11b only at one end of the optical element 11. FIG. However, various structures for connecting the optical fiber 12 to the end of the optical waveguide 11c via the recess 11b are conceivable. For example, at both ends of the optical element 11, the optical fiber 12 is connected to both ends of a linearly extending optical waveguide 11c via a recess 11b. Alternatively, the optical waveguide 11c extends from one end portion of the optical element 11 toward the other end portion and then folds before reaching the other end portion to reach the one end portion, that is, both end portions exist on one end portion side of the optical element 11. In this structure, the optical fiber 12 is connected to the optical waveguide 11c through the recess 11b. Accordingly, FIGS. 1 and 2 may be regarded as only one of the structures in which the optical fiber 12 is connected to the end of the optical waveguide 11c of the optical element 11 via the recess 11b.

The first resin layer 13 is provided inside the recess 11b, and the optical fiber 12 is provided on the first resin layer 13. The optical fiber 12 is arranged in a state extending in the longitudinal direction of the optical element 11, and the end surface on the optical waveguide 11c side faces the end surface of the light incident portion of the optical waveguide 11c with a predetermined interval. That is, the optical fiber 12 is positioned with respect to the optical waveguide 11c, and is optically connected to the optical waveguide 11c so that an optical signal propagated through the optical fiber 12 enters the optical waveguide 11c. Ideally, the optical fiber 12 is arranged so that the optical axis coincides with the optical axis of the optical waveguide 11c.

In this embodiment, the recess 11b is symmetrical with respect to the center in the width direction, and the optical fiber 12 is disposed at the center position in the width direction of the recess 11b.

The first resin layer 13 is formed by filling the resin in a wet and spread state without unevenness in the width direction of the recess 11b. The first resin layer 13 covers the optical fiber 12 in a state where a portion located on the upper side of the side surface of the optical fiber 12 is exposed. That is, the optical fiber 12 is embedded in the first resin layer 13 except for the portion located on the upper side of the side surface. However, the first resin layer 13 is not provided at the tip portion that is the end portion of the optical fiber 12 on the optical waveguide 11 c side and the vicinity thereof, and is not covered with the first resin layer 13.

The second resin layer 14 is provided on the first resin layer 13 and on the portion of the optical fiber 12 located on the first resin layer 13. However, the second resin layer 14 is not on the first resin layer 13 and not on the entire portion of the optical fiber 12 located on the first resin layer 13, but near the first end surface 11 d of the optical element 11. Is provided. Therefore, the second resin layer 14 does not cover the tip portion of the optical fiber 12 and the vicinity thereof.

Here, the first resin layer 13 fixes the optical fiber 12 at a position where the optical fiber 12 can be optically connected to the optical waveguide 11c. The second resin layer 14 prevents the optical fiber 12 from peeling upward from the first resin layer 13.

The first resin layer 13 and the second resin layer 14 are made of, for example, an epoxy resin. Moreover, the 1st resin layer 13 and the 2nd resin layer 14 may contain the filler, for example. When the first resin layer 13 and the second resin layer 14 contain a filler, the shrinkage rate during curing decreases and the strength increases. On the other hand, the larger the amount of filler, the lower the function of the first resin layer 13 and the second resin layer 14 as an adhesive.

When the first resin layer 13 and the second resin layer 14 contain a filler, the first resin layer 13 may contain a larger amount of filler than the second resin layer 14. In this case, the contraction rate when the first resin layer 13 is cured decreases. Therefore, in the process of positioning and arranging the optical fiber 12 on the first resin layer 13 and curing the first resin layer 13, the movement of the optical fiber 12 from the positioning position can be suppressed. On the other hand, since the amount of filler in the second resin layer 14 is small, it is possible to adhere to the first resin layer 13 with a high adhesion function, and to make it difficult to peel the optical fiber 12 from the first resin layer 13.

The filler content is, for example, 70% to 90% for the first resin layer 13 and 10% to 30% for the second resin layer 14.

(Optical module manufacturing method)
In the above configuration, a method for manufacturing the optical module 1 will be described below. FIG. 3 is an explanatory diagram showing a manufacturing process of the optical module 1.

When the optical module 1 is manufactured, the optical element 11 in the state where the optical waveguide 11c and the recess 11b are formed, the optical fiber 12, the resin 13a that becomes the first resin layer 13, the resin 14a that becomes the second resin layer 14, A UV light source 21 is prepared. Here, a UV curable resin is used for the resin 13a and the resin 14a.

Next, the optical module 1 is manufactured by the steps (1) to (8) shown in FIG.

(1) The resin 13a of the first resin layer 13 is injected (applied) into the recess 11b of the optical module 1.

(2) Wait for the resin 13a to be sufficiently wet and spread in the width direction of the recess 11b. Thereby, the resin 13a is filled in a state where the resin 13a is wet and spread in the width direction of the recess 11b. The waiting time in this case varies depending on the viscosity of the resin 13a. For example, the resin 13a having a viscosity of 100,000 cps takes about 1 minute.

(3) The optical fiber 12 is held right above the recess 11b.

(4) The optical fiber 12 is lowered toward the concave portion 11b and disposed on the resin 13a of the first resin layer 13. As a result, the optical fiber 12 is attached to the resin 13a, and a state where the optical fiber 12 is embedded in the resin 13a except for a portion located on the upper side of the side surface is obtained.

(5) The optical fiber 12 is positioned with respect to the optical waveguide 11c. This positioning is performed by the active alignment method described above. The positioning position of the optical fiber 12 is preferably determined in consideration of the amount of movement of the optical fiber 12 due to the curing shrinkage of the resin 13a of the first resin layer 13.

(6) The resin 13a of the first resin layer 13 is irradiated with UV light 21a from the UV light source 21 to cure the resin 13a. Thereby, the first resin layer 13 is formed.

(7) On the first resin layer 13 and on the portion of the optical fiber 12 located on the first resin layer 13, in the vicinity of the first end surface 11 d of the optical element 11, the second resin layer 14 Resin 14a is injected (coated).

(8) The resin 14a of the second resin layer 14 is irradiated with UV light 21a from the UV light source 21 to cure the resin 14a. Thereby, the second resin layer 14 is formed.

(Advantages of optical module and optical module manufacturing method)
The optical module 1 of the present embodiment has the following first configuration. That is, the optical element 11 and the optical fiber 12 are provided. The optical element 11 has a recess 11b formed on the upper surface (front surface) 11a, and an optical waveguide 11c extending along the upper surface 11a from the inner surface of the recess 11b. At least a part of the optical fiber 12 is disposed in the recess 11b so that the tip thereof faces the end face of the optical waveguide 11c. In addition, the optical fiber 12 is fixed to the optical element 11 by the first resin layer 13 that spreads wet in the concave portion 11b without deviation in the width direction.

In the optical module 1 having the first configuration, the optical fiber 12 is fixed to the optical element 11 by the first resin layer 13 wetted and spread in the concave portion 11b without deviation in the width direction. In manufacturing, the optical fiber 12 can be positioned with high accuracy with respect to the optical waveguide 11c.

That is, as shown in FIG. 4A, when the resin 13a forming the first resin layer 13 is injected in a state of being biased in the width direction of the concave portion 11b of the optical element 11, the first resin layer 13 Is formed in a biased state in the width direction of the recess 11b. In addition, the arrow in a figure has shown the stress which acts on the optical fiber 12 at the time of hardening shrinkage | contraction of resin 13a. In this case, when the resin 13a is cured and contracted, the optical fiber 12 moves in the direction in which the resin 13a is biased and is fixed at a position shifted from the normal positioning position, as shown in FIG. As a result, the positioning accuracy of the optical fiber 12 decreases.

Further, in the manufacture of the optical module 1, when the resin 13a of the first resin layer 13 is injected into the concave portion 11b after the optical fiber 12 is arranged at the regular positioning position, as shown in FIG. A situation occurs in which the fiber 12 moves from a normal positioning position (a position indicated by a two-dot chain line). Also in this case, as shown in FIG. 5B, the optical fiber 12 is fixed at a position shifted from the normal positioning position after the resin 13a is cured and contracted (after the formation of the first resin layer 13). As a result, the positioning accuracy of the optical fiber 12 decreases.

On the other hand, in the first configuration in which the optical fiber 12 is fixed to the optical element 11 by the first resin layer 13 wetted and spread in the concave portion 11b without deviation in the width direction, as shown in FIG. In addition, when the first resin layer 13 is formed, the resin 13a is injected into the concave portion 11b so as to be wet and spread in the width direction. Therefore, as shown in FIG. 6B, the optical fiber 12 has a width within the recess 11b of the resin 13a when the resin 13a of the first resin layer 13 is cured and contracted (when the first resin layer 13 is formed). The movement due to the deviation in the direction hardly occurs, and the displacement of the optical fiber 12 from the normal positioning position can be suppressed. As a result, the optical fiber 12 can be positioned with high accuracy with respect to the optical waveguide 11c.

In this case, in particular, if the optical fiber 12 is disposed at the center position in the width direction of the recess 11b, it is difficult to move in the width direction of the recess 11b when the resin 13a is cured and contracted (when the first resin layer 13 is formed). Further, the positional deviation of the optical fiber 12 from the regular positioning position can be further suppressed.

Further, in the first configuration, the movement of the optical fiber 12 at the time of curing shrinkage of the resin 13a need only consider mainly the downward movement. Therefore, the optical fiber 12 is arranged in advance at a position deviated from the normal positioning position mainly considering the amount of movement only in the downward direction, and is arranged at the normal positioning position after the resin 13a is cured and contracted. It is also possible to do so.

Moreover, it can be expressed that the optical module 1 of the present embodiment has the following second configuration. That is, the optical module 1 includes an optical element 11, an optical fiber 12, a first resin layer 13, and a second resin layer 14. The optical element 11 has a recess 11b formed on the upper surface (front surface) 11a, and an optical waveguide 11c extending along the upper surface 11a from the inner surface of the recess 11b. The optical fiber 12 is disposed in the recess 11b so that the tip thereof faces the end surface of the optical waveguide 11c. The first resin layer 13 is provided in the recess 11b and covers and fixes the optical fiber 12 in a state in which a portion located above the side surface of the optical fiber 12 is exposed. The second resin layer 14 is provided on the first resin layer 13 and on a portion of the optical fiber 12 located on the first resin layer 13.

In the optical module 1 having the second configuration, the first resin layer 13 is provided in the recess 11b and covers and fixes the optical fiber 12 in a state where the portion located on the upper side of the side surface of the optical fiber 12 is exposed. The second resin layer 14 is provided on the first resin layer 13 and on the portion of the optical fiber 12 located on the first resin layer 13. Therefore, in manufacturing the optical module 1, the optical fiber 12 can be positioned with respect to the optical waveguide 11c with high accuracy.

That is, when the optical fiber 12 is fixed to the optical element 11, that is, the recess 11 b only by the first resin layer 13, for example, the optical fiber 12 needs to be embedded in the first resin layer 13. In this case, as shown in FIG. 7A, in the step of fixing the optical fiber 12 with the first resin layer 13, the resin 13a of the first resin layer 13 exists around the optical fiber 12, and the light Curing shrinkage of the resin 13a occurs around the entire periphery of the fiber 12. For this reason, as shown in FIG. 7B, when the resin 13a is cured and contracted, it is difficult to predict the moving direction and the moving amount of the optical fiber 12 when the resin 13a is cured and contracted. Accordingly, it is difficult to predict the moving direction and moving amount of the optical fiber 12 when the resin 13a is cured and contracted, and to dispose the optical fiber 12 in advance from the normal positioning position. For this reason, the positioning accuracy of the optical fiber 12 is lowered. Furthermore, the problems described with reference to FIGS. 4A and 4B and FIGS. 5A and 5B are likely to occur.

On the other hand, in the optical module 1 having the second configuration, as shown in FIG. 6A, first, the resin 13a of the first resin layer 13 is injected into the recess 11b, and the optical fiber 12 is placed thereon. The optical fiber 12 can be covered and fixed by the first resin layer 13 in a state where the first resin layer 13 is positioned and the portion located above the side surface of the optical fiber 12 is exposed. In addition, when the resin 13a is injected, the resin 13a can be injected into the recess 11b so as to be wet and spread in the width direction without being biased.

Therefore, as shown in FIG. 6B, the optical fiber 12 has a width within the recess 11b of the resin 13a when the resin 13a of the first resin layer 13 is cured and contracted (when the first resin layer 13 is formed). The movement due to the deviation in the direction hardly occurs, and the displacement of the optical fiber 12 from the normal positioning position can be suppressed. As a result, the optical fiber can be positioned with respect to the optical waveguide 11c with high accuracy.

In this case, if the optical fiber 12 is arranged at the center position in the width direction of the recess 11b, it is difficult to move in the width direction of the recess 11b when the resin 13a is cured and contracted (when the first resin layer 13 is formed). The positional deviation of the optical fiber 12 from the positioning position can be further suppressed.

Further, the movement of the optical fiber 12 at the time of curing and shrinking of the resin 13a is mainly considered only in the downward direction. Therefore, the optical fiber 12 is arranged in advance at a position deviated from the normal positioning position mainly considering the amount of movement only in the downward direction, and is arranged at the normal positioning position after the resin 13a is cured and contracted. It is also possible to do so.

Further, by providing the second resin layer 14 on the first resin layer 13 and on a portion of the optical fiber 12 located on the first resin layer 13, the optical fiber 12 is separated from the first resin layer 13. The situation where it peels off can be prevented.

In addition, it is preferable to use photocurable resin, such as UV curable resin, for the 1st resin layer 13 and the 2nd resin layer 14 as mentioned above. When a thermosetting resin is used for the first resin layer 13 and the second resin layer 14, the resin of the first resin layer 13 and the second resin layer 14 due to a temperature change during the heat curing, the optical element 11, etc. Due to thermal expansion, the optical fiber 12 may be displaced before the first resin layer 13 and the second resin layer 14 are cured. Such a problem can be avoided when UV curable resin is used for the first resin layer 13 and the second resin layer 14.

In addition, as described above, the resin 13a of the first resin layer 13 uses a resin having a smaller curing shrinkage than the resin of the second resin layer 14 in order to suppress the displacement of the optical fiber 12 due to the curing shrinkage. Is preferred. Therefore, the first resin layer 13 may contain a larger amount of filler than the second resin layer 14, and the curing shrinkage rate may be smaller than that of the second resin layer 14.

Further, when the optical module 1 is manufactured, the optical fiber 12 is properly positioned in consideration of the shift amount and the shift direction due to the curing shrinkage of the resin 13a of the first resin layer 13 when positioning with respect to the optical waveguide 11c. You may arrange | position in the position shifted | deviated from the position. In this case, it becomes easy to place the optical fiber 12 at a regular position after the resin 13a of the first resin layer 13 is cured and contracted. The operation of disposing the optical fiber 12 at a position shifted from the normal positioning position is performed in the above-described manufacturing process (5).

Further, as described above, it is preferable that the concave portion 11b of the optical element 11 is bilaterally symmetric with respect to the center in the width direction, and the optical fiber 12 is disposed at the center position in the width direction of the concave portion 11b. In this case, the thickness of the first resin layer 13 can be made the same on the left and right in the width direction of the recess 11b, and the movement of the optical fiber 12 in the left and right direction when the resin 13a of the first resin layer 13 is cured and contracted is prevented. can do. Further, the depth of the recess 11b is preferably as thin as possible in order to suppress downward movement of the optical fiber 12 when the resin 13a is cured and contracted.

Moreover, since the front-end | tip part of the optical fiber 12 is not covered with the 1st resin layer 13 and the 2nd resin layer 14, for example, the 1st resin layer 13 and the 2nd resin layer 14 resulting from a temperature change, or these It is difficult for the tip portion of the optical fiber 12 to be displaced due to one expansion or contraction. Thereby, the favorable positioning accuracy of the optical fiber 12 with respect to the optical waveguide 11c can be maintained. Further, even when the first resin layer 13 and the second resin layer 14 contain a filler, the transmission of the optical signal between the tip portion of the optical fiber 12 and the end portion of the optical waveguide 11c is performed by the filler. There is no hindrance.

The shape of the recess 11b is not limited to a rectangle, but is a shape that is symmetrical in the width direction, and in the state in which the resin 13a of the first resin layer 13 is injected, the position adjustment of the optical fiber 12 disposed on the resin 13a Any size that can be used. FIG. 8 shows a specific example of the shape of the recess 11b other than the rectangle.

8A shows a case where the recess 11b is U-shaped, FIG. 8C shows a case where the recess 11b is semicircular, and FIG. 8E shows a case where the recess 11b is V-shaped. 8 (g) shows a trapezoidal shape in which the concave portion 11b is widened upward, and FIG. 8 (i) shows that the concave portion 11b is widened downward (upside down from FIG. 8 (g)). In the case of a trapezoidal shape, (k) in FIG. 8 is a vertical cross-sectional view of the optical element 11 when the concave portion has a shape whose width has changed in two steps (a shape in which the lower side is narrower). 8 (b), FIG. 8 (d), FIG. 8 (f), FIG. 8 (h), FIG. 8 (j), and FIG. 8 (l) are respectively shown in FIG. ), FIG. 8C, FIG. 8E, FIG. 8G, FIG. 8I, FIG. 8K, the first resin layer 13 and the optical fiber in the recess 11b shown in FIG. 12 is a longitudinal sectional view of the optical element 11 in a state where 12 is provided.

In addition, the recessed part 11b shown to (c) and (d) of FIG. 8 can make the thickness of the 1st resin layer 13 (resin 13a) substantially uniform in all directions. Therefore, compared with the other recessed part 11b, it is easy to assume the influence by expansion | swelling and shrinkage | contraction resulting from hardening shrinkage | contraction and heat of resin 13a. Moreover, since there is no corner | angular part in the recessed part 11b, injection | pouring (application | coating) of the resin 13a is easy.

In the recess 11b shown in (i) and (j) of FIG. 8, the angle formed between the bottom surface and the side surface is an obtuse angle (an angle greater than 90 degrees). Therefore, the resin 13a can be injected (applied) more easily than the recesses 11b shown in FIGS. 8 (a) and 8 (b) and FIGS. 8 (g) and 8 (h).

[Embodiment 2]
Another embodiment of the present invention will be described below with reference to the drawings. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

FIG. 9 is a perspective view showing the configuration of the optical module of the present embodiment. 10A is a cross-sectional view taken along the line AA in FIG. 9, and FIG. 10B is a cross-sectional view taken along the line BB in FIG.

(Configuration of optical module)
As shown in FIGS. 9 and 10 (a) and 10 (b), the optical module 2 of this embodiment includes an end face of the light incident portion of the optical waveguide 11c formed in the optical element 11 and a tip portion of the optical fiber 12. A connecting resin layer 15 is provided between the two. The connection resin layer 15 connects the end face of the light incident portion of the optical waveguide 11c formed in the optical element 11 and the tip portion of the optical fiber 12, and the tip portion of the optical fiber 12 is positioned with respect to the optical waveguide 11c. It is fixed in position. The connection resin layer 15 is formed of a translucent adhesive. Other configurations of the optical module 2 are the same as those of the optical module 1.

(First manufacturing method of optical module)
In the above configuration, a first manufacturing method of the optical module 2 will be described below. FIG. 11 is an explanatory diagram illustrating a manufacturing process of the optical module 2 according to the first manufacturing method.

When the optical module 2 is manufactured, the optical element 11 in the state in which the optical waveguide 11c and the recess 11b are formed, the optical fiber 12, the resin 13a that becomes the first resin layer 13, the resin 14a that becomes the second resin layer 14, A resin to be the connection resin layer 15 and a UV light source 21 are prepared. Here, a UV curable resin is used for the resin 13a and the resin 14a.

Next, the optical module 2 is manufactured by the steps (1) to (9) shown in FIG. The steps (1) to (8) are the same as the steps (1) to (8) shown in FIG.

(9) A resin for forming the connection resin layer 15 is applied and cured between the end face of the light incident portion of the optical waveguide 11c formed in the optical element 11 and the end portion of the optical fiber 12, and the connection resin layer 15 is cured. Form. In this case, when the resin forming the connection resin layer 15 is a UV curable resin, the resin is cured by irradiating the UV light 21 a from the UV light source 21. When the resin forming the connection resin layer 15 is a thermosetting resin, the resin is cured by applying heat.

(Second manufacturing method of optical module)
Next, a second manufacturing method of the optical module 2 will be described below. FIG. 12 is an explanatory diagram showing a manufacturing process of the optical module 2 according to the second manufacturing method.

When the optical module 2 is manufactured, the optical element 11 in the state in which the optical waveguide 11c and the recess 11b are formed, the optical fiber 12, the resin 13a that becomes the first resin layer 13, the resin 14a that becomes the second resin layer 14, A resin 15a to be the connection resin layer 15 and a UV light source 21 are prepared. Here, UV curable resin is used for the resin 13a, the resin 14a, and the resin 15a.

Next, the optical module 2 is manufactured by the steps (1) to (9) shown in FIG.

(3) The optical fiber 12 is held right above the recess 11b. In this case, a resin 15 a that forms the connection resin layer 15 is applied to the tip of the optical fiber 12 in advance.

(4) The optical fiber 12 is lowered toward the concave portion 11b and disposed on the resin 13a of the first resin layer 13. In this case, a gap is secured between the end face of the light incident portion of the optical waveguide 11 c (the inner wall surface of the recess 11 b) and the resin 15 a at the tip of the optical fiber 12. In addition, by placing the optical fiber 12 on the resin 13a of the first resin layer 13, the optical fiber 12 is attached to the resin 13a, and a state where the optical fiber 12 is embedded in the resin 13a except for a portion located on the upper side surface; To do.

(5) The optical fiber 12 is positioned with respect to the optical waveguide 11c. This positioning is performed by the active alignment method described above. The positioning position of the optical fiber 12 is preferably determined in consideration of the amount of movement of the optical fiber 12 due to the curing shrinkage of the resin 13a of the first resin layer 13. Thereafter, the optical fiber 12 is moved in the direction of the optical waveguide 11c, and the resin 15a is abutted against the end face of the light incident portion of the optical waveguide 11c (the inner wall surface of the recess 11b).

(6) The resin 13a of the first resin layer 13 and the resin 15a of the connection resin layer 15 are irradiated with UV light 21a from the UV light source 21 to cure the resin 13a and the resin 15a. Thereby, the first resin layer 13 and the connection resin layer 15 are formed.

When the resin 15a is a thermosetting resin, it is not necessary to irradiate the resin 15a with the UV light 21a in the step (6), and the following step (9) is performed.

(9) Heat is applied to the resin 15a to cure it, and the connection resin layer 15 is formed.

(Advantages of optical module and optical module manufacturing method)
In the optical module 2 of the present embodiment, the end face of the light incident portion of the optical waveguide 11c and the tip of the optical fiber 12 are connected by the connecting resin layer 15, and the tip of the optical fiber 12 is positioned with respect to the optical waveguide 11c. It is fixed at the position. Therefore, the optical fiber 12 does not deviate from the positioning position with respect to the optical waveguide 11c. Thereby, the optical module 2 can maintain the state in which the optical fiber 12 is positioned with high accuracy with respect to the optical waveguide 11c.

In the second manufacturing method of the optical module 2, the resin 15 a is applied to the optical waveguide 11 c after the resin 15 a for forming the connection resin layer 15 is applied to the tip of the optical fiber 12. By doing so, it is possible to avoid a situation in which the optical fiber 12 is displaced from the positioning position. Further, by making the refractive index of the connection resin layer 15 close to the refractive index of the optical fiber 12 or the optical waveguide 11c, light attenuation due to light reflection at the material interface between the connection resin layer 15 and the optical fiber 12 or the optical waveguide 11c is suppressed. can do.

Other advantages of the optical module 2 and the manufacturing method of the optical module 2 are the same as the advantages of the optical module 1 and the manufacturing method of the optical module 1.

[Summary]
An optical module according to an aspect of the present invention includes an optical element in which a recess is formed on a surface and an optical waveguide extending along the surface from an inner surface of the recess, and a tip of the optical waveguide. An optical fiber at least partially disposed in the recess so as to face the end face, and the optical fiber is formed by the first resin layer wetted and spread in the width direction in the recess without unevenness. It is the structure fixed to.

According to the above configuration, since the optical fiber is fixed to the optical element by the first resin layer that is wet and spread in the width direction in the concave portion of the optical element, the optical fiber for the optical waveguide is manufactured in the manufacture of the optical module. Can be positioned with high accuracy.

That is, at the time of forming the first resin layer, the resin forming the first resin layer is injected into the concave portion of the optical element so as to be wet and spread in the width direction without unevenness. Therefore, the optical fiber hardly moves due to the bias in the width direction of the concave portion when the resin is cured and contracted, and the positional deviation of the optical fiber from the normal positioning position can be suppressed. As a result, the optical fiber can be positioned with respect to the optical waveguide with high accuracy.

Further, the movement of the optical fiber at the time of curing shrinkage of the resin forming the first resin layer is mainly considered only in the downward direction. Therefore, the optical fiber is arranged in advance at a position deviated from the normal positioning position mainly in consideration of the amount of movement only in the downward direction, and is arranged at the normal positioning position after the resin is cured and contracted. It is also possible to do.

In the above optical module, a part of the optical fiber may protrude outside the recess without being embedded in the first resin layer.

According to the above configuration, the optical fiber can be positioned with respect to the optical waveguide with higher accuracy.

That is, when the entire periphery of the optical fiber is embedded in the first resin layer, the first resin layer is formed around the optical fiber in the step of fixing the optical fiber with the first resin layer at the time of manufacturing the optical module. Resin that cures and shrinks in the entire circumference of the optical fiber. Therefore, when the resin is cured and contracted, it is difficult to predict the moving direction and the moving amount of the optical fiber when the resin is cured and contracted.

On the other hand, when a part of the optical fiber is configured to protrude out of the recess without being embedded in the first resin layer, the movement of the optical fiber at the time of curing shrinkage of the resin forming the first resin layer is There is no need to consider movement in the direction protruding out of the recess of the optical fiber. Therefore, it is easy to predict the moving amount and moving direction of the optical fiber at the time of curing shrinkage of the resin forming the first resin layer, and the optical fiber is arranged in advance at a position deviated from the normal positioning position to cure the resin. After contraction, it can be arranged at a normal positioning position. Thereby, positioning of the optical fiber with respect to the optical waveguide can be performed with higher accuracy.

In the above optical module, the first resin layer may be configured so as to spread symmetrically with respect to an axis orthogonal to the surface in each cross section orthogonal to the optical axis of the optical fiber.

According to the above configuration, the first resin layer wets and spreads symmetrically with respect to the axis orthogonal to the surface on which the recess is formed in each cross section orthogonal to the optical axis of the optical fiber.

Accordingly, the movement of the optical fiber at the time of curing shrinkage of the resin forming the first resin layer does not need to consider movement in a direction symmetric with respect to an axis orthogonal to the surface on which the concave portion of the optical element is formed. . This makes it easy to predict the amount and direction of movement of the optical fiber when the resin forming the first resin layer is cured and contracted, and the optical fiber is placed in advance at a position deviated from the normal positioning position. After the curing shrinkage, it can be arranged at a normal positioning position. As a result, the optical fiber can be positioned with respect to the optical waveguide with higher accuracy.

In the above optical module, the first resin layer may be spread so as not to contact the first section including the tip of the optical fiber.

According to said structure, since the 1st resin layer has spread so that it may not contact the 1st area containing the front-end | tip part of an optical fiber, even if it is a case where the 1st resin layer contains the filler. The transmission of the optical signal between the tip portion of the optical fiber and the end portion of the optical waveguide is not hindered by the filler.

In the above optical module, in addition to the first resin layer, the optical fiber is covered with a part of the optical fiber so as not to contact the second section including the tip portion of the optical fiber. It is good also as a structure fixed to the said optical element with the layer.

According to the above configuration, the optical fiber is fixed to the optical element by the second resin layer that covers a part of the optical fiber so as not to contact the second section including the tip of the optical fiber. Therefore, for example, the optical fiber is unlikely to be displaced due to expansion or contraction of the first resin layer and the second resin layer due to temperature change, and the optical fiber is peeled off from the first resin layer, that is, an optical element. It is possible to prevent the optical fiber from being peeled off.

The optical module includes a translucent connecting resin that fixes the tip of the optical fiber to the optical waveguide between an end face of the optical waveguide facing the optical fiber and the tip of the optical fiber. It is good also as a structure in which the layer is provided.

According to the above configuration, the tip portion of the optical fiber is fixed in a state of being positioned with respect to the optical waveguide by the connecting resin layer, so that the optical fiber is not displaced from the positioning position with respect to the optical waveguide. Thereby, the state in which the optical fiber is positioned with high accuracy with respect to the optical waveguide can be maintained.

In the above optical module, the side surface of the optical fiber may be separated from the bottom surface and the inner surface of the recess.

According to the above configuration, since the optical fiber can be actively aligned in the manufacture of the optical module, the optical fiber can be positioned with respect to the optical waveguide with high accuracy. In the active alignment, the optical signal is incident on the optical fiber, and the intensity of the optical signal is measured at the output side end (the end opposite to the incident side) of the optical waveguide. The optical fiber is positioned at a position where

In the above optical module, the first resin layer may be formed of a resin having a smaller shrinkage rate when cured than the second resin layer.

According to the above configuration, the first resin layer is formed of a resin having a smaller shrinkage rate when cured than the second resin layer. The movement amount of the accompanying optical fiber can be reduced, and the displacement of the optical fiber can be suppressed. This facilitates positioning of the optical fiber with respect to the optical waveguide with high accuracy.

In the above optical module, the first resin layer may include more filler than the second resin layer.

According to the above configuration, since the first resin layer contains more filler than the second resin layer, the shrinkage rate during curing can be made smaller than that of the second resin layer. Thereby, for example, even when the same resin is used in the first resin layer and the second resin layer, the shrinkage rate when the first resin layer is cured can be easily reduced. In addition, since the first resin layer contains a large amount of filler, the first resin layer has high strength and can hold the optical fiber firmly.

An optical module according to another aspect of the present invention includes an optical element in which a recess is formed on a surface, an optical waveguide extending along the surface from the inner side surface of the recess, and a tip portion of the optical element. An optical fiber disposed in the recess so as to face the end face of the optical waveguide, and the optical fiber provided in the recess and covered with the portion located on the upper side of the side surface of the optical fiber are covered and fixed. It is the structure provided with the 1st resin layer and the 2nd resin layer provided on the part located on the 1st resin layer and the 1st resin layer in the optical fiber.

According to the above configuration, since the optical fiber is fixed to the optical element by the first resin layer and the second resin layer, the resin for forming the first resin layer is injected into the recess in the manufacture of the optical module. The optical fiber can be positioned and disposed thereon, and the first resin layer can cover and fix the optical fiber in a state where the portion located above the side surface of the optical fiber is exposed. Moreover, when inject | pouring resin which forms a 1st resin layer, resin can be inject | poured in the state which got wet and spread in the recessed part evenly in the width direction.

Therefore, the optical fiber hardly moves due to the resin bias in the width direction of the recess when the resin of the first resin layer is cured and contracted, and the optical fiber can be prevented from being displaced from the normal positioning position. As a result, the optical fiber can be positioned with respect to the optical waveguide with high accuracy.

Moreover, the situation where an optical fiber peels from a 1st resin layer is prevented by providing a 2nd resin layer on the part located on the 1st resin layer and the 1st resin layer in an optical fiber. Can do.

An optical module manufacturing method according to an aspect of the present invention includes: an optical element in which a recess is formed on a surface; and an optical waveguide extending along the surface from an inner surface of the recess; In a manufacturing method for manufacturing an optical module comprising an optical fiber at least partially disposed in the recess so as to face the end face of the optical waveguide, an injection step of injecting uncured resin into the recess, After the injecting step, the optical fiber waits until the uncured resin wets and spreads in the recess without unevenness, and after the waiting step, the optical fiber is arranged so that the tip portion faces the end face of the optical waveguide. An arrangement step of arranging at least a part of the optical fiber in the recess, and a curing step of fixing the optical fiber to the optical element by curing the uncured resin after the arrangement step. Nde is a configuration you are.

According to the above configuration, in the injection process, the uncured resin is injected into the concave portion of the optical element. In the standby process, after the injection process, the process waits until the uncured resin spreads evenly in the recess. In the placement step, after the standby step, at least a part of the optical fiber is placed in the recess so that the tip portion faces the end face of the optical waveguide. In the curing step, the optical fiber is fixed to the optical element by curing the uncured resin after the placing step.

Therefore, in the injection process, since the uncured resin is injected into the recess without the optical fiber being disposed in the recess, a situation occurs in which the positioned optical fiber moves when the uncured resin is injected into the recess. Absent.

Further, in the standby process, it waits until the uncured resin spreads evenly in the recess, and in the placement process, the optical fiber is placed in the recess so that the tip portion faces the end face of the optical waveguide. When the uncured resin is cured, it is difficult for the optical fiber to move from the positioning position due to the unevenness of the uncured resin in the recess. Thereby, positioning of the optical fiber with respect to the optical waveguide can be performed with high accuracy.

Also, the movement of the optical fiber at the time of curing shrinkage of the uncured resin only needs to consider only the downward movement. Therefore, the optical fiber is arranged in advance at a position deviated from the normal positioning position mainly in consideration of the amount of movement only in the downward direction, and is arranged at the normal positioning position after the uncured resin is cured and contracted. It is also possible to do so.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

DESCRIPTION OF

SYMBOLS

1, 2 Optical module 11 Optical element 11a Upper surface 11b Recessed part 11c Optical waveguide 11d 1st end surface 11e 2nd end surface 12 Optical fiber 13 1st resin layer 13a Resin 14 2nd resin layer 14a Resin 15 Connection resin layer 15 Resin 21 UV light source 21a UV light

Claims

An optical element in which a recess is formed on the surface and an optical waveguide extending along the surface from the inner surface of the recess is formed inside,
An optical fiber at least partially disposed in the recess so that the tip portion faces the end face of the optical waveguide,
The optical module, wherein the optical fiber is fixed to the optical element by a first resin layer wetted and spread in the width direction in the recess without unevenness.
2. The optical module according to claim 1, wherein a part of the optical fiber protrudes outside the recess without being embedded in the first resin layer.
3. The optical module according to claim 1, wherein the first resin layer wets and spreads symmetrically with respect to an axis orthogonal to the surface in each cross section orthogonal to the optical axis of the optical fiber. .
The optical module according to any one of claims 1 to 3, wherein the first resin layer spreads wet so as not to contact the first section including the tip of the optical fiber.
In addition to the first resin layer, the optical fiber includes a second resin layer that covers a part of the optical fiber so as not to contact the second section including the tip of the optical fiber. The optical module according to claim 1, wherein the optical module is fixed to the optical module.
Between the end face of the optical waveguide facing the optical fiber and the tip of the optical fiber, a translucent connecting resin layer for fixing the tip of the optical fiber to the optical waveguide is provided. The optical module according to claim 1, wherein the optical module is an optical module.
The side surface of the optical fiber is separated from the bottom surface and the inner surface of the recess,
The optical module according to claim 1, wherein:
6. The optical module according to claim 5, wherein the first resin layer is formed of a resin having a smaller shrinkage rate when cured than the second resin layer.
The optical module according to claim 8, wherein the first resin layer contains more filler than the second resin layer.
An optical element in which a recess is formed on the surface and an optical waveguide extending along the surface from the inner surface of the recess is formed inside,
An optical fiber disposed in the recess so that the tip portion faces the end face of the optical waveguide;
A first resin layer provided in the recess and covering and fixing the optical fiber in a state in which a portion located on the upper side of the side surface of the optical fiber is exposed;
An optical module comprising: a second resin layer provided on the first resin layer and on a portion of the optical fiber positioned on the first resin layer.
An optical element in which an optical waveguide extending along the surface from the inner side surface of the concave portion is formed inside the concave portion, and at least a part so that the tip portion faces the end surface of the optical waveguide. In a manufacturing method for manufacturing an optical module including an optical fiber disposed in the recess,
An injection step of injecting an uncured resin into the recess,
After the injection step, a standby step for waiting until the uncured resin spreads wet in the recess without unevenness, and
After the standby step, an arrangement step of disposing at least a part of the optical fiber in the recess so that the tip portion faces the end face of the optical waveguide;
And a curing step of fixing the optical fiber to the optical element by curing the uncured resin after the arranging step.