JP4126310B2 - Optical components - Google Patents

Description

  The present invention relates to an optical component, and more particularly to an optical component that accurately and passively mounts a substrate provided with an optical element and a waveguide circuit element.

  In recent years, optical communication systems capable of transmitting large volumes of information at high speed have attracted attention because of the desire to transmit large volumes of information with the advancement of information technology. In such an optical communication system, an optical fiber is used as a transmission medium for constructing a high-speed and large-capacity communication network. As a technique for increasing the capacity of this optical fiber, a WDM (Wavelength Division Multiplexing) technique is used. Attention has been paid.

  In this WDM, for example, an optical element such as a semiconductor laser or an optical fiber and a waveguide circuit element may be mounted on the optical module. Patent Document 1 describes passively mounting a substrate on which a waveguide is formed and a support substrate on which an optical fiber fitting groove is formed. In Patent Document 1, passive mounting is performed by fitting a protrusion formed as a positioning notch structure at the time of passive mounting on a substrate to a protrusion fitting portion formed on a support substrate.

  Further, the optical module substrate and the optical waveguide may be passively mounted by fitting a convex portion having a shape in which the height of the convex portion changes along the optical axis direction and the concave portion. FIG. 1 is a side view of a conventional optical module.

  In FIG. 1, the optical module 1 is provided with a semiconductor laser 2, and a V-groove 3 is formed at a predetermined distance from the semiconductor laser 2 in the longitudinal direction of the optical module. An optical fiber 4 is fitted and mounted in the V groove 3. A recess 5 parallel to the longitudinal direction of the optical module is formed in a region between the semiconductor laser 2 and the V-groove 3 on the optical module.

  On one surface of the optical waveguide 6, a convex portion 7 (positioning notch structure) having a structure like a rocking chair, the height of which gradually increases from both ends in the longitudinal direction of the waveguide 6 toward the center. Is formed. In Patent Document 2, the concave portion 7 is fitted into the concave portion 5 to adjust the thickness (height) direction when the waveguide is mounted on the optical module.

Japanese Patent No. 3221541

  Conventionally, however, when a warped waveguide circuit element is mounted on a substrate, good positioning may not be performed. Even if a plurality of notch structures are formed in a waveguide circuit element having a warp for positioning, only a part of the plurality of notch structures functions due to the warp when mounted on a substrate. (Such as a chair placed on a non-floored floor), causing rattling and unstable mounting.

  FIG. 2 is a diagram showing a state in which a conventional waveguide circuit element having a warp is mounted on a substrate. As can be seen from FIG. 2, when the waveguide circuit element 21 having a warp and having the notch structure 22 is mounted on the substrate 23, the notch structure 22 is fitted into the fitting groove 24 formed in the substrate 23. become. At this time, only the portion of the notch structure 22 on the center side of the warp of the waveguide circuit element 21 comes into contact with the fitting groove 24. That is, when the waveguide circuit element is warped, the notch structure and the fitting groove are in contact with each other at a point.

  That is, in a waveguide circuit element having a warp, if a design similar to that without a warp is performed, the state becomes exactly the same as the state in which the chair legs are uneven, which causes backlash during mounting. Therefore, it is difficult to accurately position the waveguide circuit element on the substrate during the mounting.

  The present invention has been made in view of such problems, and an object thereof is to provide an optical component capable of improving the stability of mounting a waveguide circuit element on a substrate provided with an optical element. There is.

  In order to achieve such an object, the present invention is characterized in that a substrate having one of a V-groove structure or a notch structure fitted to the V-groove structure, and the V-groove structure or A waveguide circuit element including a waveguide core in which the other of the notch structures fitted to the V-groove structure is formed, and comprising a waveguide circuit element having a warp, and the notch structure and the V-groove structure The longitudinal direction is substantially parallel to the direction in which the warp occurs, and the waveguide circuit element is mounted on the substrate by fitting the notch structure and the V-groove structure, and the V The width of one of the groove structure or the notch structure is made substantially constant, and the other width of the V groove structure or the notch structure is set from the region where the warp of the waveguide circuit element is least generated. The most warped element By varying gradually in the area, it said notch structure over substantially the entire longitudinal direction of the notch structure is characterized by being in contact with the wall surface of the V-shaped groove structure.

  The invention according to claim 2 is the invention according to claim 1, wherein the width of the V-groove structure is constant, and the width of the notch structure is changed from the region where the warp of the waveguide circuit element is least generated. The waveguide circuit element is characterized by being gradually increased toward the region where the warp is most generated.

The invention according to claim 3 is the invention according to claim 2, wherein the angle of the V-groove structure is φ, and the waveguide circuit element is most warped from the least warped portion of the waveguide circuit element. A distance variable with the least warped portion being zero toward the portion where the warp is generated is defined as x, the height of the warp with respect to the substrate at x is H (x), and the x When the width of the notch structure at = 0 is W ₀ , the width W (x) of the notch structure at x satisfies the relationship of W (x) = W ₀ + 2H (x) / arctan (φ). Features.

  According to a fourth aspect of the present invention, in the first aspect of the invention, the width of the notch structure is constant, and the width of the V-groove structure is changed from the region where the warp of the waveguide circuit element is least generated. The waveguide circuit element is characterized by being gradually reduced toward the region where the warp is most generated.

The invention according to claim 5 is the invention according to claim 4, wherein the angle of the V-groove structure is φ, and the waveguide circuit element is most warped from the least warped portion of the waveguide circuit element. The variable of the distance with the least warped portion being zero toward the portion where the warp is generated is set to x, the height of the warp with respect to the substrate at x is H (x), and the x When the width of the V-groove structure at = 0 is V ₀ , the width V (x) of the V-groove structure at x is expressed by a relational expression of V (x) = V ₀ −2H (x) / arctan (φ). It is characterized by satisfying.

  As described above, according to the present invention, the width of one of the V-groove structure or the notch structure is made substantially constant, and the other width of the V-groove structure or the notch structure is set to have the most warp of the waveguide circuit element. Since the waveguide circuit element is gradually changed from the non-existing region to the region where the warp of the waveguide circuit element is generated most, the notch structure is in contact with the wall surface of the V-groove structure over almost the entire longitudinal direction of the notch structure. Can do. Therefore, it is possible to improve the stability of mounting the waveguide circuit element on the substrate.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings described below, components having the same function are denoted by the same reference numerals, and repeated description thereof is omitted.

(First embodiment)
FIG. 3A is a cross-sectional view showing a state in which a waveguide circuit element having warpage according to the present embodiment is mounted on a substrate, and FIG. 3B is a waveguide circuit element of FIG. FIG.
3A, a waveguide circuit element 31 including a clad 36 and a waveguide core 37 embedded in the clad 36 has a warp in a direction P in which the warp is generated. In FIG. 3A, the warp of the waveguide circuit element 31 is clearly illustrated as being excessively larger than the actual warp in order to clearly illustrate the warp.

  The waveguide circuit element 31 includes a notch structure 32 whose longitudinal direction is substantially parallel to a direction P in which warpage occurs. The center portion of the notch structure 32 is formed so that the vicinity of the center portion of the notch structure 32 is on the portion where the waveguide circuit element 31 is most warped (the portion that is most depressed in the waveguide circuit element). Yes. Further, the notch structure 32 has the smallest (narrow) width in the vicinity of the center thereof, and the width gradually increases (thicker) toward both ends.

  In this specification, the “direction in which the warp is generated” is a direction from the portion where the warp is least generated to the portion where the warp is most generated. In FIG. is there.

  In the waveguide circuit element 31 having such a configuration, the upper surface before mounting on the substrate 33 is as shown in FIG.

  A substrate 33 made of silicon or the like is provided with a V-groove 34 whose longitudinal direction is substantially parallel to the direction P in which warpage occurs. The width of the V groove 34 is substantially constant along the longitudinal direction. When the notch structure 32 is fitted into the V-groove 34, the waveguide circuit element 31 is mounted on the substrate 33.

  FIG. 4 is an enlarged view of a fitting portion between the notch structure of FIG. 5A is a cross-sectional view taken along the line AA ′ in the vicinity of the end of the notch structure of FIG. 4, and FIG. 5B is a cross section taken along the line BB ′ in the vicinity of the center of the notch structure of FIG. FIG. 5C is a cross-sectional view taken along the line CC ′ in the vicinity of the end of the notch structure of FIG.

  When the notch structure 32 having a narrow width near the center and gradually becoming wider toward the end is fitted into a V-groove 34 having a substantially constant width, the center of the notch structure 32 is obtained. In the vicinity, as shown in FIG. 5B, the notch structure 32 and the wall surface of the V-groove 34 come into contact with each other. Also, in the vicinity of the end of the notch structure 32, as shown in FIGS. 5A and 5C, the width of the notch structure 32 is made larger than the width near the center portion. It is in contact with the wall surface of the V groove 34 at a position shallower than the vicinity of the portion.

  As described above, the width of the notch structure 32 is gradually increased from the vicinity of the center toward the end thereof, so that the wall surface of the V-groove 34 extends over almost the entire longitudinal direction of the notch structure 32. Come in contact with. That is, the notch structure 32 and the V groove 34 come into contact with each other along the broken line 35 in FIG.

  As described above, according to the present embodiment, even when the waveguide circuit element mounted on the substrate has a warp, the waveguide circuit element can be brought into close contact with the wall surface of the V-groove over almost the entire longitudinal direction of the notch structure. Therefore, the stability can be improved in mounting the waveguide circuit element having warpage on the substrate.

  In the present embodiment, as described above, the notch structure is not limited to be formed so as to include a portion where the waveguide circuit element is most warped, and in any region as long as it is on the waveguide circuit element. It may be formed. For example, as shown in FIG. 6, a notch structure may be provided on both sides of the direction P in which the warp is generated with respect to the portion where the warp of the waveguide circuit element is least generated.

  In FIG. 6, a waveguide circuit element 61 including a clad and a waveguide core (not shown) embedded in the clad has a warp in a direction P in which the warp occurs. In FIG. 6, the warp of the waveguide circuit element 61 is clearly illustrated as being excessively greater than the actual warp in order to clearly illustrate the warp.

  The waveguide circuit element 61 includes notch structures 62a and 62b whose longitudinal direction is substantially parallel to the direction P in which warpage occurs. The widths of the notch structures 62a and 62b are the portions where the warp is most generated from the portion where the waveguide circuit element 61 is least warped (in FIG. 6, near the center of the waveguide circuit element 61). , And gradually increases toward the end portion of the waveguide circuit element 61 along the direction P in which the warp occurs.

  The substrate 63 such as silicon is formed with two V grooves 64 whose longitudinal direction is substantially parallel to the direction P in which the warp occurs. The width of the V-groove 64 is substantially constant along the longitudinal direction. The notch structures 62a and 63b are fitted in the V-groove 64, whereby the waveguide circuit element 61 is mounted on the substrate 63.

  Also in this case, since it is possible to make line contact with the wall surface of the V-groove 64 over almost the entire area of the notch structures 62a and 62b, the stability of mounting the waveguide circuit element 61 on the substrate 63 can be improved. .

  As can be seen from the above, in the present embodiment, it is important to change the width of the notch structure so that almost the entire area of the notch structure is in contact with the wall surface of the V-groove according to the degree of warping of the waveguide circuit element. Therefore, if the notch structure and the longitudinal direction of the V-groove are made to coincide with the direction in which the warp occurs, and the notch structure formed in the waveguide circuit element having the warp, the width of the notch structure is increased in the region where the warp is large. It ’s good.

The function shape of the notch width of the notch structure included in the waveguide circuit element when the waveguide circuit element having warpage is mounted on the substrate will be described below.
In FIG. 7A, a waveguide circuit element 71 having a warp is mounted on a substrate 72 so as to be in contact with a portion where the warp is least caused. The waveguide circuit element 71 and the substrate 72 are each formed with a notch structure and a V-groove according to the present embodiment, but are omitted in FIG.

Here, it is assumed that the warp of the waveguide circuit element 71 is a part of the circumference of the radius R. Further, the distance variable x is set with zero being the least warped portion from the least warped portion of the waveguide circuit element 71 toward the most warped portion. At this time, the height H (x) with respect to the substrate 72 at the distance x is
H (x) = R (1-cos θ) = R (1-cos (arcsin (x / R)))
It can be expressed.

As can be seen from FIG. 7B, when the angle of the V-groove is φ, and the width of the notch structure when x = 0 in the portion where the warp is the least, that is, W ₀ , The width W (x) of the notch structure is
W (x) = W ₀ + 2H (x) / arctan (φ) (Formula 1)
If it is good.

(Second Embodiment)
In the first embodiment, the width of the V-groove formed in the substrate is made substantially constant and the width of the notch structure formed in the waveguide circuit element is changed. However, in this embodiment, the width of the waveguide circuit element is changed. The width of the notch structure to be formed is made substantially constant, and the width of the V groove formed in the substrate is changed.

FIG. 8A is a cross-sectional view showing a state in which a waveguide circuit element having warpage according to the present embodiment is mounted on a substrate, and FIG. 8B is a waveguide circuit element of FIG. It is a top view of the board | substrate with which is mounted.
In FIG. 8A, a waveguide circuit element 81 including a clad and a waveguide core (not shown) embedded in the clad has a warp in a direction P in which the warp occurs. In FIG. 8 (a), the warp of the waveguide circuit element 81 is clearly shown to be much larger than the actual warp in order to clearly show the warp.

  The waveguide circuit element 81 includes a notch structure 82 whose longitudinal direction is substantially parallel to the direction P in which warpage occurs. The notch structure 82 has a substantially constant width along its longitudinal direction.

  A substrate 83 made of silicon or the like is provided with a V-groove 84 whose longitudinal direction is substantially parallel to the direction P in which warpage occurs. The V-groove 84 has the largest (thick) width in the vicinity of the center thereof, the width gradually decreases (thinner) toward both ends, and the V-groove 84 has the largest width. On the upper side, the notch structure 82 and the groove 84 are fitted so that the most warped part of the waveguide circuit element 81 (the most depressed part in the waveguide circuit element) is formed.

  In the waveguide circuit element 83 having such a configuration, the upper surface before the waveguide circuit element 81 is mounted is as shown in FIG.

  FIG. 9 is an enlarged view of a fitting portion between the notch structure of FIG. 10A is a cross-sectional view taken along the line DD ′ in the vicinity of the end of the notch structure in FIG. 9, and FIG. 10B is a cross-sectional view along the line EE ′ in the vicinity of the center of the notch structure in FIG. FIG. 10C is a cross-sectional view taken along the line FF ′ in the vicinity of the end of the notch structure of FIG. 9.

  When the notch structure 82 having a substantially constant width is fitted into the V-groove 84 whose width near the center is thicker and gradually narrower than the width of the center toward the end, the vicinity of the center of the notch structure 82 Then, as shown in FIG. 10B, the notch structure 82 and the wall surface of the V groove 84 come into contact with each other. Also, in the vicinity of the end of the notch structure 82, as shown in FIGS. 10A and 10C, the width of the V-groove 84 is made smaller than the width near the center portion. It is in contact with the wall surface of the V groove 84 at a position shallower than the vicinity of the portion.

  As described above, the width of the V-groove 84 is gradually reduced from the vicinity of the center toward the end thereof, so that the wall surface of the V-groove 84 extends over almost the entire length in the longitudinal direction of the notch structure 82. Come in contact with. That is, the notch structure 82 and the V groove 84 come into contact with each other along the broken line 85 in FIG.

  As described above, according to the present embodiment, as in the first embodiment, stability can be improved in mounting a waveguide circuit element having warpage on a substrate.

  In the present embodiment, as described above, the notch structure is not limited to be formed so as to include a portion where the waveguide circuit element is most warped, and in any region as long as it is on the waveguide circuit element. It may be formed. For example, a notch structure may be provided on both sides of the direction P in which the warp is generated with respect to the portion where the warp of the waveguide circuit element is not generated. At this time, the width of the V-groove should be gradually reduced from the side of the waveguide circuit element where the warp is least generated toward the side where the warp is most generated.

Hereinafter, the function shape of the groove width of the V groove formed on the substrate when the waveguide circuit element having warpage is mounted on the substrate will be described.
In FIG. 11A, a waveguide circuit element 111 having a warp is mounted on a substrate 112 so as to be in contact with a portion where the warp is not the most. The waveguide circuit element 111 and the substrate 112 are each formed with a notch structure and a V-groove according to this embodiment, but are omitted in FIG.

Here, it is assumed that the warp of the waveguide circuit element 111 is a part of the circumference of the radius R. Further, the distance variable x is set with zero being the least warped portion from the least warped portion of the waveguide circuit element 111 toward the most warped portion. At this time, the height H (x) with respect to the substrate 112 at the distance x is
H (x) = R (1-cos θ) = R (1-cos (arcsin (x / R)))
It can be expressed.

As can be seen from FIG. 11 (b), when the angle of the V groove is φ and the width of the V groove when x = 0 is V ₀ at the least warped portion, The width V (x) of the V groove is
V (x) = V ₀ −2H (x) / arctan (φ) (Formula 2)
If it is good.

  In the first and second embodiments, the groove formed in the substrate and fitted with the notch structure is not limited to the V groove, and any structure may be used as long as it is a V groove structure.

  In this specification, the “V-groove structure” is a groove that fits with the notch structure, and a wall surface that is in contact with the notch structure when fitted with the notch structure in a cross section substantially perpendicular to the longitudinal direction of the groove. Refers to a groove structure with a slope. Therefore, the V-groove structure includes a V-groove. Further, the “slope” is a wall surface of the groove in which an inner angle between the plane of the substrate on which the groove is formed and the wall surface of the groove is greater than 90 ° and less than 180 °.

  In the first and second embodiments, a V-groove structure is formed on the substrate side of silicon or the like, and a rectangular or trapezoidal notch structure is formed on the waveguide circuit element. However, the present invention is not limited to this. That is, a rectangular or trapezoidal notch structure may be formed on the substrate side, and a V-groove structure may be formed on the waveguide circuit element side.

It is a side view of the conventional optical module. It is a figure which shows a mode that the conventional waveguide circuit element which has curvature is mounted on a board | substrate. (A) is sectional drawing which shows a mode that the waveguide circuit element which has curvature based on one Embodiment of this invention is mounted on a board | substrate, (b) is a top view of the waveguide circuit element of (a). It is. FIG. 4 is an enlarged view of a fitting portion between the notch structure of FIG. 5A is a cross-sectional view taken along the line AA ′ in the vicinity of the end of the notch structure of FIG. 4, and FIG. 5B is a cross-sectional view taken along the line BB ′ in the vicinity of the center of the notch structure of FIG. 4. FIG. 5C is a cross-sectional view taken along the line CC ′ in the vicinity of the end of the notch structure of FIG. It is sectional drawing which shows a mode that the waveguide circuit element which has curvature based on one Embodiment of this invention is mounted in a board | substrate. (A) And (b) demonstrates the function shape of the notch width of the notch structure with which the waveguide circuit element with which the waveguide circuit element which has curvature based on one Embodiment of this invention is mounted on a board | substrate is equipped. It is a figure to do. (A) is sectional drawing which shows a mode that the waveguide circuit element which has curvature based on one Embodiment of this invention is mounted to a board | substrate, (b) is mounted with the waveguide circuit element of (a). FIG. FIG. 9 is an enlarged view of a fitting portion between the notch structure of FIG. FIG. 10A is a cross-sectional view taken along line DD ′ in the vicinity of the end of the notch structure of FIG. 9, and FIG. 10B is a cross-sectional view taken along line EE ′ in the vicinity of the center of the notch structure of FIG. FIG. 10C is a sectional view taken along line FF ′ in the vicinity of the end of the notch structure of FIG. (A) And (b) demonstrates the function shape of the notch width of the notch structure with which the waveguide circuit element with which the waveguide circuit element which has curvature based on one Embodiment of this invention is mounted on a board | substrate is equipped. It is a figure to do.

Explanation of symbols

31, 61, 71, 81, 111 Waveguide circuit element 32, 62a, 62b, 82, 112 Notch structure 33, 63, 72, 83 Substrate 34, 64, 84 V-groove 36 Clad 37 Waveguide core

Claims (5)

A substrate on which one of a V-groove structure or a notch structure fitting with the V-groove structure is formed;
A waveguide circuit element including a waveguide core, on which the other of the V-groove structure or the notch structure fitted to the V-groove structure is formed, and a waveguide circuit element having a warp,
The longitudinal direction of the notch structure and the V-groove structure is substantially parallel to the direction in which the warp occurs,
By fitting the notch structure and the V-groove structure, the waveguide circuit element is mounted on the substrate,
The width of one of the V-groove structure or the notch structure is made substantially constant, and the other width of the V-groove structure or the notch structure is set from the region where the warp of the waveguide circuit element is least generated. The notch structure is in contact with the wall surface of the V-groove structure over almost the entire length in the longitudinal direction of the notch structure by gradually changing toward the region where the waveguide circuit element is most warped. Features optical components. The width of the V-groove structure is constant,
The width of the notch structure is gradually increased from a region where the warp of the waveguide circuit element is least generated toward a region where the warp of the waveguide circuit element is most generated. The optical component according to 1. An angle of the V-groove structure is φ, and a portion of the waveguide circuit element that is least warped is directed from a portion of the waveguide circuit element that is least warped to a portion of the waveguide circuit element that is most warped. The distance variable set to zero is x, the height of the warp with respect to the substrate at x is H (x), and the width of the notch structure at x = 0 is W _0. 3. The optical component according to claim 2, wherein the width W (x) of the notch structure satisfies a relational expression of W (x) = W ₀ + 2H (x) / arctan (φ). The width of the notch structure is constant,
The width of the V-groove structure is gradually reduced from a region where the warp of the waveguide circuit element is least generated toward a region where the warp of the waveguide circuit element is most generated. Item 1. The optical component according to Item 1. An angle of the V-groove structure is φ, and a portion of the waveguide circuit element that is least warped is directed from a portion of the waveguide circuit element that is least warped to a portion of the waveguide circuit element that is most warped. When the distance variable set to zero is x, the height of the warp with respect to the substrate at x is H (x), and the width of the V groove structure at x = 0 is V ₀ , 5. The optical component according to claim 4, wherein the width V (x) of the V-groove structure at x satisfies the relational expression of V (x) = V ₀ −2H (x) / arctan (φ).

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