JP5842764B2 - Optical module and lens block - Google Patents

Description

  The present invention relates to an optical module having a plurality of optical fibers and a plurality of optical elements optically coupled to the plurality of optical fibers.

  2. Description of the Related Art Conventionally, an apparatus including a plurality of semiconductor laser arrays having a plurality of light emitting units that emit laser light and a plurality of optical fibers into which laser light is incident from each light emitting unit is known (for example, Patent Document 1) reference).

  In the apparatus described in Patent Document 1, a plurality of optical fibers are bundled together at a stacked portion (bundle portion) provided on the opposite side of the plurality of semiconductor laser arrays. When bundling a plurality of optical fibers, in order to make the bending radius of the optical fiber larger than a predetermined radius (the radius at which the optical fiber bending loss occurs), the plurality of semiconductor laser arrays are arranged in a fan shape with respect to the stacked portion. . As a result, the laser light guided from each light emitting portion of the semiconductor laser array into each optical fiber is confined in the optical fiber.

JP 2008-216839 A

  However, in the device described in Patent Document 1, since the end portions of the plurality of semiconductor laser arrays and the plurality of optical fibers on the semiconductor laser array side are arranged so as to spread in a fan shape, for example, the plurality of semiconductors on the substrate. When the laser array is arranged, the area occupied by the semiconductor laser array on the substrate becomes large. For this reason, the entire apparatus has been increased in size.

  Accordingly, an object of the present invention is to provide an optical module in which a plurality of optical element arrays having a plurality of optical elements and a plurality of optical fibers optically coupled to the respective optical elements can be arranged at high density. It is in.

In order to solve the above problems, the present invention provides a plurality of optical fibers each having a core and a clad covering the core, and a plurality of optical elements optically coupled to the plurality of optical fibers. A plurality of optical element arrays arranged; a lens block having a plurality of lenses for optically coupling the plurality of optical fibers and the plurality of optical elements; and a plurality of electrically connected to the plurality of optical elements. A semiconductor circuit element; and a plurality of optical element arrays and a substrate on which the plurality of semiconductor circuit elements are mounted on a mounting surface, wherein the plurality of optical element arrays are located between the plurality of semiconductor circuit elements on the mounting surface. at least partially disposed, said plurality of lenses are arranged such that their optical axes intersecting the mounting surface of the substrate, an end face of said core is opposite to the plurality of lenses, Serial plurality of light element array, arranged in a polygonal shape, to provide an optical module.

The plurality of optical element arrays may be arranged in a square shape.

A lens block having a plurality of lenses for optically coupling a plurality of optical fibers having a core and a clad covering the core and a plurality of optical element arrays in which a plurality of optical elements are arranged in a row; The lens block includes a lens unit in which the plurality of lenses are formed and a holding unit that holds the plurality of optical fibers. The lens unit includes a plurality of lenses arranged in a line in a straight line. A plurality of lens arrays in which a plurality of the lens arrays are arranged in a polygonal shape and are arranged in a polygonal shape with respect to the plurality of optical element arrays arranged in a polygonal shape. Provides a lens block arranged opposite to each other.

  The holding portion of the lens block has a plurality of grooves formed along the optical axes of the plurality of lenses, and at least a part of the plurality of optical fibers is accommodated in the plurality of grooves. A part of the front end surface of the clad contacts the end surface of the groove, and a gap is formed between the front end surface of the core of the plurality of optical fibers and the upper surface of the lens unit.

  According to the optical module of the present invention, a plurality of optical element arrays having a plurality of optical elements and a plurality of optical fibers optically coupled to the respective optical elements can be arranged at high density.

1 is an overall view of an optical module according to an embodiment of the present invention. It is the perspective view which looked at the optical module from the bottom side. The mounting surface of a board | substrate is shown, (a) is a perspective view, (b) is an enlarged view, (c) is a connection diagram. It is the perspective view which looked at the lens block from the bottom side. It is the perspective view seen from the upper surface side of a lens block. The trunk | drum and lens part of the holding | maintenance part of a lens block are shown, (a) is an enlarged view, (b) is an enlarged view of the end surface of a 1st groove part, (c) is AA sectional drawing in (a). . The mounting surface of the board | substrate which concerns on the modification 1 is shown, (a) is two optical element arrays, (b) and (c) are three optical element arrays, (d) is an optical element array. This is the case of six. It is sectional drawing which concerns on the modification 2 of FIG.6 (c).

[Embodiment]
FIG. 1 is an overall view of an optical module 1 according to an embodiment of the present invention.

  The optical module 1 includes a plurality of (32 in the present embodiment) optical fibers 8 having a core and a cladding, a lens block 3 that accommodates a part of the optical fibers 8, and a rectangular substrate 6. The plurality of optical fibers 8 extend in a direction perpendicular to the substrate 6.

  The lens block 3 integrally includes a holding unit 30 that holds the optical fiber 8 and a disk-shaped lens unit 31. The holding part 30 is integrally formed with a cylindrical part 30a having a cylindrical shape and a body part 30b having a rectangular parallelepiped shape. The cylindrical portion 30a has a plurality (32 in the present embodiment) of insertion holes 300 in the axial direction of the optical fiber 8, and guides the optical fiber 8 to the trunk portion 30b. Each of the plurality of optical fibers 8 is pressed by the pressing plate 10 from the outer four sides of the body portion 30b and fixed with a resin-based (for example, epoxy resin-based) adhesive.

  A part of the optical fiber 8, the lens block 3, and the substrate 6 are accommodated in a rectangular parallelepiped case 2. The case 2 is formed of a cylindrical tube portion 20, a box portion 22 as a storage part, and an attachment portion 21 that attaches the tube portion 20 to the box portion 22. The box part 22 is covered with the substrate 6 at the opening end opposite to the cylindrical part 20. A plurality of (four in this embodiment) driver ICs 5 as semiconductor circuit elements are mounted on the mounting surface 6 a of the substrate 6. A bottom surface 6b located opposite to the mounting surface 6a faces the mounting surface 7a of the mother board 7 on which the optical module 1 is mounted. The optical fiber 8 extends from the cylindrical portion 20 to the outside of the case 2.

  FIG. 2 is a perspective view of the optical module 1 viewed from the bottom side.

  A plurality of terminals 9 are arranged in a grid pattern on the bottom surface 6 b of the substrate 6. The terminal 9 is electrically connected to the electrode 50 of the driver IC 5 and is also electrically connected to a terminal (not shown) mounted on the mounting surface 7 a of the motherboard 7, and an electrical signal between the motherboard 7 and the driver IC 5. Intervening in the exchange of.

  3A and 3B show the mounting surface 6a of the substrate 6, where FIG. 3A is a perspective view, FIG. 3B is an enlarged view, and FIG. 3C is a connection diagram.

  The substrate 6 has a rectangular recess 61 formed in the center thereof. Inside the recess 61, a plurality (four in the present embodiment) of optical elements 40 in which a plurality (eight in the present embodiment) of optical elements 40 are arranged in an array are opposed to the lens unit 31. Has been implemented. In the present embodiment, the optical element 40 is a light emitting element, and for example, a laser diode, a VCSEL (Vertical Cavity Surface Emmitting LASER), or the like is applied. The four optical element arrays 4 are arranged at positions facing the respective surfaces of the inner peripheral surface 61 a formed of the four surfaces in the recess 61. That is, the optical element array 4 is arranged in a square shape. In other words, the four optical element arrays 4 are arranged such that the center line along the longitudinal direction of each optical element array 4 forms a quadrangle.

  The driver IC 5 is made of a rectangular thin plate. The four driver ICs 5 are arranged outside the recess 61 and along the outer edge of the recess 61 at positions facing the respective optical element arrays 4. That is, the driver IC 5 is disposed so as to surround the optical element array 4. Therefore, the four optical element arrays 4 are arranged between the four driver ICs 5 on the mounting surface 6 a of the substrate 6.

  A plurality (nine in this embodiment) of first electrodes 51 and a plurality (nine in this embodiment) of second electrodes 52 are mounted on the upper surface 5 a of the driver IC 5. The first electrode 51 is arranged on the optical element array 4 side, and the second electrode 52 is arranged on the opposite side of the first electrode 51. The nine first electrodes 51 are electrically connected to the nine bonding pads 41 of the optical element array 4 by the bonding wires 11, and an electric signal is sent from the first electrode 51 to the optical element 40.

  As shown in FIG. 3C, the anode of each optical element 40 is connected to each bonding pad 41, and the cathode of each optical element 40 is connected to one common bonding pad 41. On the mounting surface 6 a of the substrate 6, a plurality (9 in this embodiment) of electrodes 62 that are electrically connected to the nine second electrodes 52 are mounted. The nine electrodes 62 are electrically connected to the terminals 9 on the bottom surface 6 b of the substrate 6.

  In addition, a plurality (four in this embodiment) of fitted portions 60 for positioning when the lens block 3 is attached to the substrate 6 are formed on the mounting surface 6 a of the substrate 6. The four to-be-fitted parts 60 are respectively arranged in the vicinity of the four corners in the recess 61 of the substrate 6. In the present embodiment, the fitted portion 60 is a recess.

  FIG. 4 is a perspective view of the lens block 3 as seen from the bottom side.

  The bottom surface 31b of the lens block 3 is used for positioning a plurality of (in the present embodiment, 32) lenses 12 that are optically coupled to the optical elements 40 of the optical element array 4 and the lens block 3 when the lens block 3 is attached to the substrate 6. A plurality of (four in this embodiment) fitting portions 310 are provided. The lens 12 is disposed at a position facing the optical element 40. In the present embodiment, 32 lenses 12 constitute four lens arrays 120. Each lens array 120 is configured by arranging eight lenses 12 in a straight line. The lens array 120 is arranged in a square shape so as to face the optical element array 4.

  The light emitted from the optical element 40 is collected by the lens 12 and enters the core of the optical fiber 8 corresponding to each optical element 40. The fitting part 310 is formed between adjacent lens arrays 120. In the present embodiment, the fitting portion 310 is a convex portion that is fitted to the fitted portion 60.

  FIG. 5 is a perspective view seen from the upper surface side of the lens block 3.

  A plurality of (as many as the lenses 12) insertion holes 300 are formed in the cylindrical portion 30 a of the holding portion 30 along the normal direction of the mounting surface 6 a of the substrate 6. In the present embodiment, a quadrangular shape in which eight insertion holes 300 form one side so that the extension line of the central axis of each insertion hole 300 matches the optical axis L of the corresponding lens 12. Is arranged.

  The outer surface 30c formed of four planes of the body portion 30b includes a first groove portion 301 as a groove portion that accommodates a part of the optical fiber 8, an end surface 301a on the lens portion 31 side of the first groove portion 301, and the lens portion 31. A second groove 302 formed as a gap between the upper surface is provided. In the present embodiment, eight first groove portions 301 and eight second groove portions 302 are arranged on each plane of the outer surface 30c. That is, 32 first groove portions 301 and 32 second groove portions 302 are formed on the outer surface 30 c along the extension line of the central axis of the insertion hole 300. The second groove portion 302 extends from the end surface 301 a of the first groove portion 301 toward the upper surface of the lens portion 31. That is, the width of the second groove portion 302 is formed to be narrower than the width of the first groove portion 301. Further, the depth in the central axis direction of the insertion hole 300 of the second groove portion 302 is formed to be shallower than the depth of the first groove portion 301. The first groove portion 301 and the second groove portion 302 are disposed at positions facing each lens 12.

  6A and 6B show the body portion 30b and the lens portion 31 of the holding portion 30 of the lens block 3, wherein FIG. 6A is an enlarged view, FIG. 6B is an enlarged view of an end surface 301a of the first groove portion 301, and FIG. It is AA sectional drawing in a).

  The first groove 301 has a trapezoidal shape in a cross section perpendicular to the extending direction. The cross-sectional shape may be V-shaped. That is, any shape may be used as long as the outer peripheral surface of the optical fiber 8 is in contact with the inner surface of the first groove 301 at a plurality of locations. The first groove portion 301 accommodates a strand 80 from which the covering portion 83 of the optical fiber 8 is peeled off. In the optical fiber 8, a resin-based (for example, epoxy resin-based) adhesive is applied to the strand 80, and the optical fiber 8 is pressed and fixed inside the first groove 301 by the pressing plate 10. Thereby, the optical fiber 8 is held inside the first groove 301.

  Similarly to the first groove 301, the second groove 302 has a trapezoidal shape in a cross section perpendicular to the extending direction. The second groove 302 is formed so that the width in the direction orthogonal to the extending direction is smaller than the width of the first groove 301, and the length in the extending direction is also shorter than the first groove 301. An end surface 301a is formed between the first groove 301 and the second groove 302, and the end surface 82a of the clad 82 of the optical fiber 8 is in contact with the end surface 301a. The tip surface 8a of the optical fiber 8 on the lens portion 31 side is such that the tip surface 82a of the cladding 82 is in contact with the end surface 301a. The front end surface 81 a of the core 81 is exposed from the end surface 301 a and faces the lens unit 31 through the second groove 302.

  As shown in FIG. 6C, the second groove 302 is filled with a refractive index adjusting agent 13 as a light transmitting member having a refractive index larger than that of air (1.0003). . The refractive index adjusting agent 13 is filled so as to fill the optical path between the end surface 81 a of the core 81 of the optical fiber 8 and the end surface 302 a of the second groove portion 302. In the present embodiment, the refractive index of the refractive index adjusting agent 13 is equal to the refractive index of the core 81.

(Operation and effect of the embodiment)
According to the embodiment described above, the following operations and effects can be obtained.

(1) The optical element array 4 is configured by arranging a plurality of optical elements 40 in a line. When the number of channels is increased, the optical element array 4 is disposed between the driver ICs 5 mounted on the mounting surface 6a of the substrate 6 to reduce the area surrounded by the plurality of optical elements 40 on the mounting surface 6a. This leads to downsizing of the block 3 and the optical module 1. Further, when the bonding pad 41 of the optical element array 4 and the first electrode 51 of the driver IC 5 are connected by the bonding wire 11, the connection distance is shortened, so that the connection can be easily made. Further, since the connection distance of the bonding wire 11 is shortened, signal transmission loss between the bonding pad 41 and the first electrode 51 can be reduced.

(2) The lens 12 has an optical axis L that intersects the mounting surface 6 a of the substrate 6 and faces the tip surface 81 a of the core 81. Since the tip of the optical fiber 8 on the lens portion 31 side is not parallel to the mounting surface 6a of the substrate 6, there is no possibility that the optical fiber 8 interferes with components mounted on the mother board 7 or the like.

(3) By disposing the optical element array 4 in a polygonal shape, the mounting density of the optical elements 40 on the mounting surface 6a is increased, leading to further miniaturization of the optical module 1. Moreover, compared with the case where the optical element array 4 is arranged in a line, the influence on the deviation of the optical axis L due to the linear expansion of the optical element array 4 and the lens block 3 can be suppressed, and the decrease in optical coupling efficiency is suppressed. It becomes possible to do.

(4) In the lens block 3, the holding portion 30 including the cylindrical portion 30 a and the body portion 30 b and the lens portion 31 having the lens 12 are integrally formed. When the lens block 3 is manufactured, it can be integrally formed with a mold, leading to a reduction in the assembly process of each component.

(5) The width of the second groove 302 formed in the holding portion 30 of the lens block 3 in the extending direction is smaller than the width of the first groove 301. Thereby, the clad 82 of the optical fiber 8 is supported by the end surface 301 a of the first groove 301. The core 81 faces the lens portion 31 through the second groove portion 302, and the light incident from the lens 12 can be captured by the core 81.

(6) As shown by the two-dot chain line in FIG. 6C, the light incident from the lens 12 is filled by filling the second groove 302 with the refractive index adjusting agent 13 having a refractive index larger than that of air. Can be made incident on the core 81 of the optical fiber 8. Further, even when the distal end surface 81a of the core 81 is rough, reflection at the distal end surface 81a can be suppressed. In addition, since a gap is provided between the end surface 302a of the second groove 302 and the tip surface 81a of the core 81, it is possible to suppress peeling of the refractive index adjusting agent 13 and generation of bubbles. Therefore, the light coupling efficiency between the front end surface 81a of the core 81 and the lens 12 can be suppressed.

(7) The optical fiber 8 is smoothly inserted into the first groove portion 301 through the insertion hole 300 formed in the cylindrical portion 30 a of the holding portion 30 of the lens block 3. Further, since the holding part 30 has the cylindrical part 30a, the strength of holding the optical fiber 8 in the holding part 30 is increased.

(8) Since the pressing plate 10 presses the optical fiber 8 inward of the first groove 301, the optical fiber 8 can be prevented from falling outward from the lens block 3.

(9) A fitting portion 310 is formed on the bottom surface 31 b of the lens portion 31 of the lens block 3, and a fitting portion 60 is formed on the mounting surface 6 a of the substrate 6. By fitting the fitting portion 310 and the fitted portion 60 together, the attachment position can be uniquely determined when the lens block 3 is attached to the mounting surface 6 a of the substrate 6.

  The optical module 1 according to the embodiment can be implemented with the following modifications, for example.

(Modification 1)
FIG. 7 shows a mounting surface 6a of the substrate 6 according to the modified example 1. FIG. 7A shows a case where two optical element arrays 4 are provided. FIGS. 7B and 7C show a case where three optical element arrays 4 are provided. (D) is a case where the number of optical element arrays 4 is six.

  As shown in FIG. 7A, the two optical element arrays 4 are arranged such that the center lines along the longitudinal direction of the respective optical element arrays 4 are parallel to each other. Two driver ICs 5 corresponding to each optical element array 4 are arranged so as to sandwich these two optical element arrays 4.

  As shown in FIG. 7B, the three optical element arrays 4 are arranged such that center lines along the longitudinal direction of the respective optical element arrays 4 form a triangle. Three driver ICs 5 corresponding to each optical element array 4 are arranged so as to surround the optical element array 4. Therefore, similarly to the embodiment, the three optical element arrays 4 are arranged between the three driver ICs 5 on the mounting surface 6 a of the substrate 6.

  As shown in FIG. 7C, two of the three optical element arrays 4 are arranged such that the center lines along the longitudinal direction of the respective optical element arrays 4 are parallel to each other. ing. The remaining one optical element array 4 is disposed so as to be sandwiched between the two optical element arrays 4 on the end side. The center lines along the longitudinal direction of the remaining one optical element array 4 are respectively orthogonal to the center lines along the longitudinal direction of the two optical element arrays 4. Three driver ICs 5 corresponding to each optical element array 4 are arranged so as to surround the optical element array 4.

  As shown in FIG. 7D, the six optical element arrays 4 are arranged such that the center lines along the longitudinal direction of the respective optical element arrays 4 form a hexagon. Six driver ICs 5 corresponding to each optical element array 4 are arranged so as to surround the optical element array 4. Accordingly, as in the embodiment, the six optical element arrays 4 are arranged between the six driver ICs 5 on the mounting surface 6a of the substrate 6.

  The lens block 3 and the optical fiber 8 are formed and arranged so as to correspond to the arrangement of the optical element array 4 in each of the cases of FIGS.

(Modification 2)
FIG. 8 is a cross-sectional view according to Modification 2 of FIG.

  The end surface 301 </ b> Aa of the first groove 301 </ b> A is formed to be inclined toward the upper surface of the lens unit 31. The first groove 301A has a gap between its end surface 301Aa and the tip surface 8a of the optical fiber 8, and the refractive index adjusting agent 13 is filled in this gap. The refractive index adjuster 13 is filled so as to fill the optical path between the end surface 81a of the core 81 of the optical fiber 8 and the end surface 301Aa of the first groove 301A.

  These modifications also have the same operations and effects as the operations (1) to (9) described in the embodiment.

  While the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

  There is no limit to the number of optical elements 40 mounted on the optical element array 4.

  Moreover, the lens block 3 does not need to be a rectangular parallelepiped, and the shape thereof is not limited.

  All or some of the plurality of optical elements 40 may be light receiving elements. In this case, a semiconductor circuit element that amplifies a signal, such as a preamplifier IC, can be used instead of the driver IC.

  Further, the fitting part 310 may be a concave part instead of the convex part, and the fitted part 60 may be a convex part instead of the concave part.

  Moreover, the lens part 31 does not need to be disk-shaped and may be polygonal.

  Further, the refractive index adjusting agent 13 does not necessarily fill the second groove 302 (gap).

  Further, the substrate 6 does not have to be rectangular.

DESCRIPTION OF SYMBOLS 1 ... Optical module, 2 ... Case, 3 ... Lens block, 4 ... Optical element array, 5 ... Driver IC (semiconductor circuit element), 5a ... Upper surface, 6 ... Board | substrate, 6a ... Mounting surface, 6b ... Bottom surface, 7 ... Motherboard 7a ... mounting surface, 8 ... optical fiber, 8a ... tip surface, 9 ... terminal, 10 ... pressing plate, 11 ... bonding wire, 12 ... lens, 13 ... refractive index adjusting agent (light transmitting member), 20 ... cylindrical portion , 21 ... mounting part, 22 ... box part, 30 ... holding part, 30a ... cylindrical part, 30b ... trunk part, 30c ... outer surface, 31 ... lens part, 31b ... bottom face, 40 ... optical element, 41 ... bonding pad, 50 DESCRIPTION OF SYMBOLS ... Electrode, 51 ... 1st electrode, 52 ... 2nd electrode, 60 ... Fit part, 61 ... Recessed part, 61a ... Inner peripheral surface, 62 ... Electrode, 80 ... Elementary wire, 81 ... Core, 81a ... Tip Surface, 82 ... clad, 82a ... tip surface, 83 ... coating , 120 ... lens array, 300 ... insertion hole, 301,301A ... first groove (groove), 301a, 301aA ... end face, 302 ... second groove, 310 ... fitting portion, L ... optical axis

Claims (4)

A plurality of optical fibers having a core and a clad covering the core;
A plurality of optical element arrays in which a plurality of optical elements optically coupled to the plurality of optical fibers are arranged in a line;
A lens block having a plurality of lenses for optically coupling the plurality of optical fibers and the plurality of optical elements;
A plurality of semiconductor circuit elements electrically connected to the plurality of optical elements;
A substrate on which a plurality of optical element arrays and the plurality of semiconductor circuit elements are mounted on a mounting surface;
The plurality of optical element arrays are arranged at least partially between the plurality of semiconductor circuit elements on the mounting surface,
The plurality of lenses are arranged such that their optical axes intersect the mounting surface of the substrate,
The end surface of the core faces the plurality of lenses,
The plurality of optical element arrays are arranged in a polygonal shape,
Optical module. The plurality of optical element arrays are arranged in a square shape,
The optical module according to claim 1. A lens block having a plurality of lenses for optically coupling a plurality of optical fibers having a core and a clad covering the core and a plurality of optical element arrays in which a plurality of optical elements are arranged in a row. The block includes a lens unit in which the plurality of lenses are formed and a holding unit that holds the plurality of optical fibers. The lens unit includes a lens array in which the plurality of lenses are arranged in a straight line. The plurality of lens arrays are arranged in a polygonal shape, and the plurality of lens arrays arranged in a polygonal shape are opposed to the plurality of optical element arrays arranged in a polygonal shape. A lens block arranged as The holding portion of the lens block has a plurality of grooves formed along the optical axes of the plurality of lenses,
At least a part of the plurality of optical fibers is accommodated in the plurality of grooves, and a part of the end surface of the clad is in contact with an end surface of the groove,
The lens block according to claim 3, wherein a gap is formed between a front end surface of the core of the plurality of optical fibers and an upper surface of the lens unit.

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