JP2002267890A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical device which can optically couple an optical fiber to other optical components efficiently and without adjustment. SOLUTION: An optical device 61 fixes an optical semiconductor device 76 on a substrate upper surface on the basis of a mark which is not illustrated. An optical fiber 75 is placed in a V-groove 63. A rectangular groove 62 is formed at the tip part of the V-groove 63 so as to be orthogonal in a longitudinal direction, and the lower part of the slope of a small V-groove 64 in a left- hand vertical wall surface is cut off in the Figure. Since an optical fiber 75 is positioned by pushing the tip part on the vertical wall surface at the left side, the positional relationship between the optical fiber 75 and an optical semiconductor device 76 is accurately set. Since the slope of small V-groove 64 is present, light advancing downward from the optical semiconductor device 76 is coupled to the optical fiber 75 without being kicked on the way, and coupling efficiency is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device for optically coupling an optical component such as an optical fiber, and more particularly to an optical device for optically coupling an optical fiber to another optical component by using a V-groove. The present invention relates to an optical device such as a V-groove substrate and an optical module using the same.

[0002]

2. Description of the Related Art Development of optical devices using optical fibers has been active with the speeding up of communication networks such as the Internet. At the same time, there is an increasing need to optically couple an optical fiber with another device for transmitting or receiving light with high precision. In such an optical device, a V-groove is generally used to fix an optical fiber in position.

FIG. 6 shows how an optical fiber is attached to a conventional optical device using a V-groove. Optical device 1 disclosed in JP-A-11-258446
Numeral 1 fixes the core wire 15 of the optical fiber drawn out of the sheath 14 between the V-groove substrate 12 and the flat holding plate 13. In this proposal, the V-groove 16 of the V-groove substrate 12 is formed along the <100> direction of the substrate material. Thus, by fixing between the V-groove substrate 12 and the holding plate 13, the core wire 15 of the optical fiber can be accurately fixed in the direction orthogonal to the axial direction of the optical fiber.

However, in this proposal, the positioning of the optical fiber core wire 15 in the axial direction is performed by abutting the stepped portion 17 formed on the V-groove substrate 12 and the end of the sheath 14. For this reason, it is difficult to accurately determine the distance between the tip of the core wire 15 of the optical fiber and an optical component such as a light emitting element or a light receiving element not shown in the figure. If the positioning of the optical fiber is not performed with sufficient accuracy in the axial direction, a situation may occur in which the optical fiber comes into contact with another optical component disposed opposite thereto, and the optical component may be destroyed. Further, if the display unit and the optical component are too far apart in position, there is a problem that optical loss occurs.

FIG. 7 shows an optical device for solving such a positioning problem. Patent No. 298474
In this proposal disclosed in No. 7, a core line of an optical fiber (not shown) is placed in a V-groove 22 provided in a right half portion of the V-groove substrate 21 in a direction perpendicular to the axial direction (up and down in the figure). Direction). The positions of these optical fibers in the axial direction are determined by marking a predetermined position of an inclined portion 23 having an inclined surface provided at the end of the V-groove 22 with a mark (not shown) so as to position the optical fiber. ing. Further, with respect to the other optical component 24 arranged to face the end of the core of the optical fiber, the positioning is performed by aligning with the alignment markers 25 and 26 arranged on the surface of the V-groove substrate 21.

The V-shaped groove 22 shown in FIG. 7 is formed by wet etching utilizing the crystal orientation of silicon. Therefore, as shown in FIG. 7, the inclined portion 23 is formed at the position where the tip of the fiber is located. For this reason, the tip of the fiber can be freely moved in the axial direction at this inclined portion, and it is necessary to perform an operation of positioning the fiber at the position marked by the marker. However, in such an alignment work, the interval between both parts cannot be set with sufficiently high accuracy. Therefore, when an optical fiber is optically coupled to an edge emitting type light emitting element or an edge incident type light receiving element, it is proposed to mount these optical components on a substrate different from the V-groove substrate. .

FIG. 8 shows a main part of an optical device according to this proposal. A V-groove substrate 34 in which an optical fiber 32 is fixed in a V-groove 33 is provided on a base 31 of an optical device package, and a carrier is provided on the base 31 of the package at a predetermined distance from the V-groove substrate 34. 35 are arranged. The light receiving area 37 of the optical element 36 is disposed at a portion of the carrier 35 facing the end face of the optical fiber 32. In the proposal shown in FIG.
By moving the position of the carrier 35 on 1, the distance between the end face of the optical fiber 32 and the light receiving area 37 of the optical element can be adjusted.

However, according to the optical device according to this proposal, two types of substrates, that is, a V-groove substrate 34 and a carrier 35 are used. Therefore, the steps for its manufacture and adjustment are complicated. Therefore, there is a problem that it is difficult to apply to an optical device such as a low-cost optical module. Therefore, it has been proposed to form a concave portion at the end of the V-groove at a right angle to the longitudinal direction of the V-groove, and to use this to position the end face of the optical fiber.

FIG. 9 shows the principle of this proposal. In this proposal, as shown in this cross-sectional view, the V-groove substrate 4
At the tip of the V-groove 43 on which the first optical fiber 42 is placed, V
The concave groove 44 is formed in a direction orthogonal to the longitudinal direction of the groove 43. The height of the wall face of the concave groove 44 facing the tip of the optical fiber 42 is slightly higher than the height of the lower end of the optical fiber 42 placed in the V groove 43. Since the concave groove 44 is processed by a dicing blade (not shown), its wall surface is vertical unlike the V groove 43. Therefore, positioning can be performed accurately by abutting the tip of the optical fiber 42 against this portion.

Further, the groove 44 formed by this proposal is used.
As in the case of the groove disclosed in JP-A-8-292345, excess adhesive for fixing the core of the optical fiber is poured, and the adhesive reaches the core of the end face of the optical fiber. And the effect of preventing the efficiency of optical coupling from being reduced.

[0011]

However, in the proposal shown in FIG. 9, the portion immediately below the core of the optical fiber 42 is abutted against the wall of the concave groove 44. Therefore, V connected to the upper end portion of the abutted wall portion
There is a problem that the upper portion 45 of the groove 43 lowers the efficiency of optical coupling between the optical fiber 42 and other optical components not shown in this figure. That is, if this optical component is, for example, a laser diode, of the light emitted from it, the light that spreads downward is kicked by the silicon substrate on the upper portion 45 of the V-groove, and enters the optical fiber 42. Can not.

Of course, the upper part 45 of the V-groove is
If the height is not higher than the lower end of the optical fiber 2, the tip of the optical fiber 42 cannot be positioned, and there is a risk that the optical component such as a laser diode may be broken by contact with the optical component.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical device that can efficiently and optically couple an optical fiber and other optical components without any adjustment.

[0014]

According to the first aspect of the present invention, there are provided (a) a substrate on which an optical component optically coupled to an optical fiber is arranged at a predetermined position on the upper surface thereof, and (b) an optical component of the substrate. (C) one or more V-grooves formed along a specific direction for mounting an optical fiber at a position facing
A small V-groove formed on the upper surface of the substrate at an intermediate position between the end of the V-groove and the optical component in one-to-one correspondence with the V-groove; (d) formed so as to be orthogonal to the specific direction of the substrate. And the cut surface when the substrate is cut along the above-described specific direction includes the end of the V-groove on the optical component side and the end of the small V-groove on the optical fiber side, and has a rectangular shape. Are provided in the optical device.

That is, in the first aspect of the present invention, the small V-groove is disposed between the V-groove and the optical component, and the end of the V-groove on the optical component side and the end of the small V-groove on the optical fiber side are arranged. A rectangular groove having a rectangular shape is provided on the substrate. By positioning the tip of the optical fiber placed in the V-groove against the vertical wall of the rectangular groove, the optical fiber can be positioned. In addition, since the small V-groove is arranged on the optical component side, the ratio of light that travels from the optical component toward the substrate or vice versa from the position below the upper surface of the substrate toward the optical component is obstructed. Is smaller than before,
Good optical coupling can be achieved.

According to the second aspect of the present invention, (a) a substrate on which an optical component to be optically coupled to an optical fiber is disposed at a predetermined position on the upper surface thereof; One or more V-grooves formed along a specific direction for mounting a fiber, and (c) a V-groove formed so as to be orthogonal to the above-described specific direction of the substrate. The optical device is provided with a rectangular groove having a rectangular shape, in which the cut surface when cut includes the vicinity thereof except for the end of the V groove on the optical component side.

In the second aspect of the present invention, unlike the first aspect, no small V-groove is provided in addition to the V-groove. Instead, the rectangular groove is provided so as to leave the end on the optical component side of the V groove. Therefore, by abutting the tip of the optical fiber against the vertical wall of the rectangular groove, positioning in the length direction can be performed in the same manner as in the first aspect of the present invention, and the end of the V groove on the optical component side. Can be used to prevent the light between the optical component and the optical fiber from being kicked by the substrate surface in the same manner as the small V-groove.

According to a third aspect of the present invention, in the optical device according to the first or second aspect, the V-groove is formed by wet etching and has a predetermined inclination angle with respect to the length direction of the V-groove at an end thereof. The inclined surface that has become
At least a part of the inclined surface is cut by a dicing blade to form a rectangular groove.

That is, according to the third aspect of the present invention, the V-groove is formed by wet etching, and as a result, an inclined surface having a predetermined inclination angle with respect to its length direction is arranged. If this portion is left as it is, it is difficult to position the tip of the optical fiber. Therefore, in the invention according to the third aspect, a rectangular groove is formed by cutting at least a part of the optical fiber with a dicing blade, and light is applied to the vertical wall portion. Positioning is possible without adjustment by abutting the tip of the fiber. Note that the method of forming the rectangular groove may be another method. The formation of the V-groove is not limited to wet etching.

According to a fourth aspect of the present invention, in the optical device according to the first aspect, the small V-groove is formed by wet etching, and between the end portion and the rectangular groove in the longitudinal direction of the small V-groove. It is characterized in that an inclined surface having a predetermined inclination angle is arranged.

That is, the invention according to claim 4 is characterized in that the small V-groove is formed by wet etching. Thereby, an inclined surface having a predetermined inclination angle with respect to the length direction of the small V groove is formed. By using this inclined surface, the angle range in which light reaches can be widened, and the optical coupling between the optical component and the optical fiber can be improved.

According to the fifth aspect of the present invention, in the optical device according to the third aspect, the height of the intersection of the inclined surface and the wall surface of the rectangular groove is higher than the lower end of the optical fiber placed in the V-groove. It is characterized by:

That is, according to the fifth aspect of the present invention, the height of the intersection of the inclined surface and the wall surface of the rectangular groove is made higher than the lower end of the optical fiber placed in the V-groove, so that the tip of the optical fiber is formed. Butts against this wall.

According to a sixth aspect of the present invention, in the optical device according to the first or second aspect, the rectangular groove is deeper than the V groove.

In other words, according to the sixth aspect of the present invention, since the rectangular groove is deeper than the V-groove, the adhesive flowing to the tip of the optical fiber when the optical fiber is fixed to the V-groove with the adhesive can be prevented. The rectangular groove can be more effectively accommodated, and the loss of optical coupling due to the adhesive can be prevented.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

FIG. 1 shows the appearance of an optical device as a V-groove substrate in one embodiment of the present invention. This optical device 61 is a flat silicon substrate, and one rectangular groove 62 is formed so as to cross the substantially central portion thereof. A rectangular groove 62 is provided on the upper surface of the right side of the drawing.
V-grooves 63 for four channels are formed at regular intervals in a direction perpendicular to the vertical direction. A core wire of an optical fiber (not shown) is placed in these V grooves 63. Rectangular groove 62
A small V-groove 64 is engraved on the left side of each of the V-grooves at a position in contact with the V-groove 63 and facing each V-groove 63. Further, an electrode pattern 65 is formed at a position corresponding to each small V-groove 64 on an extension of the V-groove 63.

FIG. 2 shows a cross section of the optical device of this embodiment shown in FIG.
Both the V-groove 63 and the small V-groove 64 of the optical device 61 are formed by wet etching utilizing the crystal orientation of silicon. For this reason, the tip of the V-groove 63 has an inclined surface as described with reference to FIG. 7, and the lower portion is cut off by a dicing blade to form a rectangular groove 62.

FIG. 3 is an enlarged view of the vicinity of the cut-off portion. Inclined surface 7 generated when V-shaped groove 63 is formed
The portions of the 1 and small V-grooves 64 on the V-groove 63 side are cut off by dicing as indicated by broken lines 72. Since dicing mechanically processes a silicon substrate using a blade, its cross section is rectangular.

FIG. 4 shows a state in which an optical fiber and an optical semiconductor element as an optical component are mounted on the optical device of this embodiment. The optical fiber 75 is placed in the V-groove 63, and at this time, its tip abuts against the vertical wall of the rectangular groove 62 connected to the lower end of the small V-groove 64, and in this state, the position is fixed with an adhesive (not shown). Is done. Thereby, the optical fiber 75 is not only in the direction orthogonal to its axial direction,
Accurate positioning is performed without adjustment in the axial direction.

In this embodiment, solder is used to fix the optical fiber 75 in the V-shaped groove 63. In order to enable soldering between the two, a metal film is formed on the upper surface of the silicon substrate located on both sides of the V-shaped groove 63. V groove 63
No metal film is formed on itself. This is because if the metal film is present when the optical fiber 75 is slid on the V-groove 63 when adjusting the position or the like, there is a disadvantage that the metal film is cut off, the portion is damaged, and metal chips are generated. .

Unlike the present embodiment, an adhesive can be used to fix the optical fiber 75 to the V-shaped groove 63. In this case, the adhesive moving from the V groove 63 toward the tip of the optical fiber 75 is dropped into the rectangular groove 62. Therefore, the adhesive does not adhere to the tip of the optical fiber 75, and optical loss due to this can be avoided.

As shown in FIG. 4, an optical semiconductor element 76 is fixed on the electrode pattern 65 while being positioned by a marker (not shown). Therefore, the positional relationship between the optical semiconductor element 76 and the optical fiber 75 is accurately determined along with the positioning of the optical fiber 75. Moreover, a small V groove 6 is provided between the optical semiconductor element 76 and the optical fiber 75.
4 are formed. Therefore, the light component emitted downward from the light emitted from the optical semiconductor element 76 can be prevented from being kicked on the surface of the silicon substrate by the presence of the inclined surface, even to the light component directed downward than before.
To reach. Thereby, the optical coupling is performed efficiently.

The tip of the optical fiber 75 and the optical semiconductor element 76
Can be set freely according to the positional relationship between the small V-groove 64 and the rectangular groove 62. Therefore, even if a simple operation of abutting the optical fiber 75 against the vertical wall portion of the rectangular groove 62 is performed, if the positional relationship is properly set in advance, the fiber end face will contact the optical semiconductor element 76. The situation can be reliably prevented. In addition, by arbitrarily selecting the position of the rectangular groove 62, the coupling distance between the tip of the optical fiber 75 and the optical semiconductor element 76 can be freely determined.

Next, an outline of a method for manufacturing the optical device of the present embodiment shown in FIG. 1 will be described. First, the silicon <100
> V-groove 63 and small V-groove 64 are simultaneously formed on a silicon substrate by anisotropic etching using KOH (potassium hydroxide) or the like utilizing the crystal direction. By utilizing the crystal orientation in this way, an optical device having excellent productivity can be manufactured.

After the V-groove 63 and the small V-groove 64 are formed, dicing is performed in a direction perpendicular to the direction of these V-grooves 63 and 64 so that the V-grooves 63 and the small V-grooves 64 are partially cut simultaneously. The rectangular groove 62 is formed by such a method. All the processes up to the formation of the rectangular groove 62 can be performed collectively for a plurality of optical devices on one wafer (not shown). Therefore, it is possible to keep the manufacturing cost of the optical device of this embodiment sufficiently low.

Deformability of the invention

In the embodiment described above, the small V-groove 64 is provided in addition to the V-groove 63. However, only the V-groove 63 is formed, and a part of the inclined surface is deleted to mount the optical fiber in the rectangular groove. It is also possible to leave an inclined surface on the side opposite to the installation side.

FIG. 5 is an enlarged view of the vicinity of the cut-off portion of the optical device corresponding to FIG. 3 of the embodiment. The same parts as those in FIG. 3 are denoted by the same reference numerals. In this modification, the upper part of the inclined surface 71 generated at the time of forming the V groove 63 is
A vertical surface for positioning is formed by removing from the region cut by dicing indicated by the broken line 72A.

In the embodiments and the modified examples, the inclined surface is arranged on the silicon substrate on the optical component side facing the optical fiber. However, when the optical coupling between the optical component and the optical fiber is sufficient. Does not necessarily have to be provided with this inclined surface. Further, although the optical semiconductor element is used as the optical component in the embodiment, the invention is not limited to this. Of course, the optical component is not limited to a component that sends light to the optical fiber, but may be a component that receives light output from the optical fiber. Further, in the embodiment, the optical device for four channels in which four optical fibers are mounted has been described, but it is needless to say that the number of channels is one or more, and the number of channels is not limited to the embodiment.

[0042]

As described above, according to the first or fourth aspect of the present invention, the small V-groove is arranged between the V-groove and the optical component, and the end of the V-groove on the optical component side. And the rectangular groove including the end of the small V-groove on the optical fiber side and having a rectangular shape is provided on the substrate. The positioning of the optical fiber can be performed accurately without any adjustment. In addition, since the small V-groove is provided on the optical component side, the influence of surrounding optical noise can be minimized, and the optical coupling between the optical component and the optical fiber can be improved.

According to the second aspect of the present invention, since the small V-groove is omitted by providing the rectangular groove so as to leave the end of the V-groove, optical coupling can be performed while simplifying the structure of the optical device. Can be good. In addition, by abutting the tip of the optical fiber against the vertical wall of the rectangular groove,
The positioning of the optical fiber can be performed accurately without any adjustment.

According to the fifth aspect of the present invention, the height of the intersection of the inclined surface and the wall surface of the rectangular groove is made higher than the lower end of the optical fiber placed in the V-groove. The tip of this can be abutted against this wall surface to simplify positioning. Further, since the position where the optical fiber can move in the direction of the optical component can be restricted, there is no possibility that the optical fiber comes into contact with the optical component and breaks it.

According to the sixth aspect of the present invention, in the optical device according to the first or second aspect, since the rectangular groove is deeper than the V-groove, the optical fiber is fixed to the V-groove with an adhesive. In this case, the adhesive flowing into the tip of the optical fiber can be more effectively accommodated in the rectangular groove, and loss of optical coupling due to the adhesive can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of an optical device as a V-groove substrate according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the optical device of the present embodiment shown in FIG.

FIG. 3 is an enlarged cross-sectional view illustrating the vicinity of a cut-off portion of the optical device according to the present embodiment.

FIG. 4 is a cross-sectional view showing a state in which an optical fiber and an optical semiconductor element as an optical component are mounted on the optical device of the present embodiment.

FIG. 5 is an enlarged cross-sectional view showing the vicinity of a cut-off portion of an optical device according to a modification of the present invention.

FIG. 6 is a perspective view showing a main part of a conventional optical device using a V-groove.

FIG. 7 is a perspective view of a main part of an optical device that performs positioning using a conventionally proposed marker.

FIG. 8 is a perspective view of a main part of an optical device according to another conventional proposal.

FIG. 9 is a sectional view of a main part of an optical device according to still another conventional proposal.

[Explanation of symbols]

 Reference Signs List 61 optical device 62 rectangular groove 63 V groove 64 small V groove 71 inclined surface 72, 72A broken line (rectangular cut area) 75 optical fiber 76 optical semiconductor element (optical component)

Claims (6)

[Claims] 1. A substrate on which an optical component optically coupled to an optical fiber is disposed at a predetermined position on an upper surface thereof, and a specific direction for mounting the optical fiber at a position of the substrate facing the optical component. One or a plurality of V-grooves formed along; a small V-groove formed on the upper surface of the substrate at an intermediate position between the end of the V-groove and the optical component in one-to-one correspondence with the V-groove; Formed so as to be orthogonal to the specific direction of the substrate,
A cut surface when the substrate is cut along the specific direction includes an end on the optical component side of the V-groove and an end on the optical fiber side of the small V-groove, and has a rectangular shape. An optical device comprising: a rectangular groove. 2. A substrate on which an optical component optically coupled to an optical fiber is disposed at a predetermined position on an upper surface thereof, and a specific direction for mounting the optical fiber on a position of the substrate facing the optical component. One or more V-grooves formed along, and are formed to be orthogonal to the specific direction of the substrate,
The cut surface when the substrate is cut along this specific direction includes a rectangular groove including a vicinity thereof except for an end of the V groove on the optical component side and having a rectangular shape. An optical device characterized by the above. 3. The V-groove is formed by wet etching, and an inclined surface having a predetermined inclination angle with respect to the length direction of the V-groove at an end thereof is disposed. 3. The optical device according to claim 1, wherein at least a part of the optical device is cut by a dicing blade to form a rectangular groove. 4. The small V-groove is formed by wet etching, and an inclined surface having a predetermined inclination angle with respect to the length direction of the small V-groove is arranged between the end and the rectangular groove. The optical device according to claim 1, wherein: 5. The optical device according to claim 3, wherein the height of the intersection of the inclined surface and the wall surface of the rectangular groove is higher than the lower end of the optical fiber placed in the V groove. 6. The optical device according to claim 1, wherein the rectangular groove is deeper than the V groove.