JP2016057383A - Optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical module capable of improving workability.SOLUTION: An optical module includes: an input/output section 30 that provides a plurality of first optical axes A1 at a first pitch P1; a waveguide section 35 that provides a plurality of second optical axes A2 at a second pitch P2 different from the first pitch P1; and an optical axis conversion section 40 that converts the first pitch P1 into the second pitch P2 through reflection on a first reflection section 42 and a second reflection section 43 to optically connect the first optical axes A1 with the second optical axes A2.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an optical module.

  Patent Document 1 discloses an optical module. This optical module optically connects an optical element and an optical fiber. The pitch of the optical element is larger than the pitch of the optical fiber. Therefore, the optical module includes a connector for converting the pitch of the optical fiber into the pitch of the optical element.

JP 2013-137343 A

  For optical modules that are becoming smaller and thinner, it is desired to improve workability in assembly. Therefore, an object of the present invention is to provide an optical module that can improve workability.

  An optical module according to an aspect of the present invention includes an input / output unit that provides a plurality of first optical axes at a first pitch, and a plurality of second optical axes at a second pitch different from the first pitch. The waveguide portion to be provided and the first pitch are converted to the second pitch by being reflected by the first reflecting portion and the second reflecting portion, and the first optical axis and the second optical axis are changed. An optical axis conversion unit that is optically connected is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the optical module which can improve workability | operativity at the time of an assembly is provided.

It is a perspective view of the optical module which concerns on 1st Embodiment. It is sectional drawing of an optical cable. It is a disassembled perspective view of an optical module. It is a top view of a lens module. It is sectional drawing of a lens module. It is a figure which shows the optical system in a lens module. It is a figure which shows the relationship between a 1st reflective surface and a 2nd reflective surface. It is a figure which shows total optical length. It is a figure which shows the reflection conditions in a 2nd reflective surface. It is a top view of the lens module concerning a 2nd embodiment. It is a figure which shows the optical system in a lens module. It is a top view of the lens module which concerns on 3rd Embodiment of this invention. It is a figure which shows the optical system in a lens module. It is sectional drawing which shows the lens module which concerns on a modification. It is a figure which shows the lens module which concerns on a modification.

[Description of Embodiment of Present Invention]
First, embodiments of the present invention will be listed and described.

  An optical module according to an aspect of the present invention includes an input / output unit that provides a plurality of first optical axes at a first pitch, and a plurality of second optical axes at a second pitch different from the first pitch. The waveguide portion to be provided and the first pitch are converted to the second pitch by being reflected by the first reflecting portion and the second reflecting portion, and the first optical axis and the second optical axis are changed. An optical axis conversion unit that is optically connected is provided.

  According to this optical module, the first optical axis and the second optical axis are optically connected by the optical axis converter. The optical axis conversion unit optically converts the first pitch to the second pitch by reflecting the first reflection unit and the second reflection unit. This eliminates the need to physically convert the first pitch to the second pitch in the connection between the first optical axis and the second optical axis. Therefore, workability at the time of assembling the optical module can be improved.

  The optical axis conversion unit may provide a first optical axis and a third optical axis that is not parallel to the second optical axis between the first reflecting unit and the second reflecting unit. According to this optical axis conversion unit, the first optical axis and the second optical axis can be optically connected by the third optical axis.

  The plurality of optical axes that optically connect the input / output unit and the waveguide unit may have the same optical length. According to this configuration, the degree of optical change that can occur between the input / output unit and the waveguide unit is made uniform between the optical axes. Therefore, the optical component for correcting the optical change can be shared.

  The first reflecting portion is disposed along a first axis that intersects the plurality of second optical axes, and the second reflecting portion is disposed along a second axis that is parallel to the first axis. It may be. According to this configuration, the first reflecting portion and the second reflecting portion can be easily formed.

  The plurality of third optical axes are parallel to each other, and the optical lengths may not be equal. According to this configuration, the design of the optical axis in the optical axis conversion unit can be simplified.

  When a first surface intersecting with a plurality of second optical axes and a first surface extending by the second optical axis are defined, the third optical axis is included in the first surface, and the first optical axis is It may be parallel to the normal direction of the first surface. According to this configuration, the design of the optical axis in the optical axis conversion unit can be simplified.

  When the first surface intersecting the plurality of second optical axes, the first surface extending by the second optical axis, and the second surface inclined to the first surface are defined, the third optical axis is the second optical axis. The first optical axis included in the surface may be parallel to the normal direction of the first surface. According to this configuration, the position of the second optical axis can be set to a desired position in the direction of the first optical axis.

  An optical module according to an aspect of the present invention further includes a transmission lens formed on the first optical axis, and the input / output unit includes a light emitting element that emits transmission light along the first optical axis, The waveguide section includes a transmission optical fiber that receives transmission light at the second optical axis, and the transmission lens transmits transmission light with a spot diameter smaller than the core diameter of the transmission optical fiber and a numerical aperture. It is good also as condensing so that it may become smaller than the numerical aperture of a trust optical fiber. According to this transmission lens, transmission light loss is reduced. Therefore, transmission light can be efficiently transmitted between the light emitting element and the transmission optical fiber.

  An optical module according to an aspect of the present invention further includes a receiving lens formed on a first optical axis, the input / output unit includes a light receiving element that receives received light on the first optical axis, and a waveguide The unit includes a reception optical fiber that emits reception light at the second optical axis, and the reception lens may collect the reception light so that the spot diameter is smaller than the light reception diameter of the light receiving element. Good. According to this receiving lens, the loss of received light is reduced. Therefore, the received light can be efficiently transmitted between the receiving optical fiber and the light receiving element.

In the optical module according to one aspect of the present invention, the first reflecting portion is the second optical axis on the first surface intersecting with the plurality of second optical axes and the first surface extending by the second optical axis. An angle (X) formed with the direction along the second axis, an angle (Y) formed with the second reflecting portion along the direction along the second optical axis, the first optical axis, the second optical axis, and the third light. The refractive index (n1) of the medium through which the axis propagates may satisfy the following formulas (1) to (3).
-90 ° <X <90 ° (1)
Y = −X / 2 (2)
45 ° + X / 2 ≧ arcsin (1 / n1) × (180 / π) (3)
According to this configuration, loss due to reflection can be reduced.

[Details of the embodiment of the present invention]
Specific examples of the optical module according to the present invention will be described below with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to the claim are included. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
As shown in FIG. 1, the optical module 1 according to the first embodiment is connected to an electronic device such as a personal computer. The optical module 1 includes an optical cable 2 and a connector module 3. The optical module 1 converts an optical signal transmitted through the optical cable 2 into an electrical signal and outputs it to an electronic device. In addition, the optical module 1 converts an electrical signal output from the electronic device into an optical signal and outputs the optical signal to the optical cable 2. The optical cable 2 transmits optical signals in both directions. The connector module 3 is attached to the end of the optical cable 2.

  As shown in FIG. 2, the optical cable 2 includes an optical fiber tape 4, an inner tube 7, an intervening layer 8, and a metal layer 9. The optical fiber tape 4 is formed by arranging a plurality of optical fibers 6 in parallel and integrating them in a tape shape with a coating resin. The optical fiber tape 4 is accommodated in the inner tube 7. Furthermore, the inner tube 7 is covered with an intervening layer 8 which is a tensile strength fiber. The intervening layer 8 is covered with a metal layer 9 made of a plurality of metal fibers. The metal layer 9 is covered with an outer cover 11 made of an insulating resin.

  The optical fiber 6 is a small diameter HPCF (HPCF: Hard Plastic Clad Fiber). The optical fiber 6 has a glass core and a hard plastic clad. The diameter of the core is 80 μm as an example. According to this optical fiber 6, even when the optical fiber 6 is bent to a small diameter, it is difficult to break. Moreover, according to the optical fiber 6, the increase in the optical loss by bending can be suppressed. The optical fiber 6 may be an AGF (AGF: All Glass Fiber) having a glass core and a glass cladding.

  The inner tube 7 is made of an insulating resin. Examples of the insulating resin include PVC (Polyvinylchloride) which is a non-halogen flame retardant resin. The intervening layer 8 is a tensile fiber such as an ultrafine aramid fiber. The metal layer 9 is a metal braid obtained by braiding a plurality of tin-plated conductive wires. The jacket 11 is made of an insulating resin. Examples of this insulating resin include polyolefin.

  As shown in FIG. 1, the connector module 3 includes a housing 12, an electrical connector 18, and a board unit 13 (see FIG. 3). In the following description, for convenience of explanation, the electrical connector 18 side is called “front” and the optical cable 2 side is called “rear”.

  As shown in FIG. 3, the housing 12 includes a metal housing 14 and a resin housing 16.

  The metal housing 14 dissipates heat generated from the substrate unit 13 and the like to the outside. The metal housing 14 includes a cover 14a having a substantially U-shaped cross section and a base plate 14b having a substantially U-shaped cross section, and defines an internal space for accommodating the substrate unit 13 and the like. An electrical connector 18 is disposed at the front end of the metal housing 14. An optical cable holding part 17 is attached to the rear end of the metal housing 14. The metal housing 14 is made of a metal material having a high thermal conductivity. The thermal conductivity of the metal material is preferably 100 W / m · K or more. For example, the metal housing 14 is made of steel (Fe-based), tin (tin-plated copper), stainless steel, copper, brass, aluminum, or the like.

  A heat dissipation sheet 29 is disposed between the metal housing 14 and the board unit 13. The heat dissipation sheet 29 transmits heat generated in the substrate unit 13 to the metal housing 14.

  The resin housing 16 covers the metal housing 14 and is formed of a resin material. Examples of the resin material include polycarbonate. The boot 15 is attached to the rear end of the resin housing 16 and covers the optical cable holding portion 17. The rear end of the boot 15 is bonded to the jacket 11 of the optical cable 2.

  The optical cable holding part 17 mechanically fixes the optical cable 2 to the housing 12. The optical cable holding part 17 has a base part 17a and a cylindrical part 17b. The base portion 17 a has a plate shape and is attached to the housing 12. The cylinder portion 17b protrudes rearward from the base portion 17a. The optical cable 2 is inserted into the cylindrical portion 17b. The optical cable holding part 17 holds the optical cable 2 by sandwiching the outer cover 11 and the metal layer 9 with the crimping part.

  The electrical connector 18 ensures electrical connection by being inserted into a connection port provided in the electronic device. The electrical connector 18 is inserted into a connection port provided in the electronic device. The electrical connector 18 protrudes forward from the front end of the board unit 13. The electrical connector 18 and the connection port of the electronic device are electrically connected when a contact terminal provided on the board unit 13 touches the contact terminal of the connection port.

  As shown in FIG. 4, the substrate unit 13 includes an input / output unit 30, a waveguide unit 35, and an optical axis conversion unit 40.

  The input / output unit 30 provides a plurality of first optical axes A1 at a first pitch P1. The input / output unit 30 includes a light emitting element 21a and a light receiving element 21b. The light emitting element 21a and the light receiving element 21b are arranged at the first pitch P1 along the width direction D2 on the mounting surface 13b. The light emitting element 21a and the light receiving element 21b provide the first optical axis A1 in the direction (height direction D3) perpendicular to the mounting surface 13b (see FIG. 5). Examples of the light emitting element 21a include a laser diode (LD) or a surface emitting laser (VCSEL: Vertical Cavity Surface Emitting LASER). An example of the light receiving element 21b is a photodiode (PD: PhotoDiode).

  The waveguide section 35 provides a plurality of second optical axes A2 at a second pitch P2. Unlike the first pitch P1, the second pitch P2 is smaller than the first pitch P1. The waveguide section 35 has a plurality of optical fibers 6. The plurality of optical fibers 6 include a transmission optical fiber and a reception optical fiber, and are fixed to the lens module 22.

  The lens module 22 optically connects the transmission optical fiber 6 and the light emitting element 21a. The lens module 22 optically connects the receiving optical fiber 6 and the light receiving element 21b. The lens module 22 is made of a material that is transparent to the wavelength of the optical signal transmitted through the optical fiber 6. The lens module 22 includes a main body 25 having a rectangular parallelepiped shape. The main body 25 has a front end 25a, a rear end 25b, an upper surface 25c, and a bottom surface 25d (see FIG. 5). A recess 24 is provided on the upper surface 25c. The lens module 22 can be integrally formed by, for example, resin injection molding.

  The recess 24 is formed in a rectangular shape that is recessed with respect to the upper surface 25c. The recess 24 is a region surrounded by the bottom surface 24a, the abutting surface 23, and the pair of side walls 24b. An alignment groove having a V-shaped cross section is formed on the bottom surface 24a. The alignment groove aligns the optical fiber 6. The alignment grooves extend from the abutting surface 23 to the rear end 25b of the main body 25 along the front-rear direction D1. A plurality of alignment grooves are formed so as to be separated from each other in the width direction D2. The interval between the alignment grooves in the width direction D2 is the second pitch P2. By fixing the optical fiber 6 in the alignment groove, the second optical axis A2 is defined.

  The optical axis conversion unit 40 optically connects the first optical axis A1 and the second optical axis A2. The optical axis conversion unit 40 includes a first reflection unit 42 and a second reflection unit 43. The 1st reflection part 42 and the 2nd reflection part 43 are provided in the upper surface 25c. The third optical axis A3 extends between the first reflecting part 42 and the second reflecting part 43.

  The first reflection unit 42 causes the transmission light emitted from the light emitting element 21 a to enter the second reflection unit 43. The first reflecting unit 42 causes the received light emitted from the optical fiber 6 to enter the light receiving element 21b. Accordingly, the first reflecting section 42 is disposed on the first optical axis A1 and the third optical axis A3. The position of the first reflecting portion 42 is determined by the position of the light emitting element 21a or the light receiving element 21b. As shown in FIG. 5, the first reflecting portion 42 is a concave portion whose cross section is a right triangle. The inclined surface of the recess is the first reflecting surface 42 a in the first reflecting portion 42. The first reflecting surface 42a totally reflects transmission light or reception light. The first reflecting surface 42a may be a metal film deposited on an inclined surface.

  When the lens module 22 is viewed from the side, the third optical axis A3 is included in the first surface R1. The first surface R1 is a surface on which the first optical axis A2 and the second optical axis A2 intersect with the plurality of second optical axes A2. The first axis is an axis along the width direction D2. The height from the mounting surface 13b to the third optical axis A3 matches the height from the mounting surface 13b to the second optical axis A2. The first reflecting surface 42a and the first optical axis A1 form an angle K1. The size of the angle K1 is 45 °. The first reflecting surface 42a and the third optical axis A3 form an angle K2. The size of the angle K2 is also 45 °. According to the angles K1 and K2, the angle K3 formed between the first optical axis A1 and the third optical axis A3 is 90 °.

  As shown in FIG. 6, when the lens module 22 is viewed in plan, the transmission light reflected by the first reflection unit 42 travels along the third optical axis A3. The third optical axis A3 is inclined with respect to the virtual axis A2a. The virtual axis A2a is parallel to the second optical axis A2 and intersects the first reflecting surface 42a.

  The second reflecting portion 43 optically connects the third optical axis A3 to the second optical axis A2. The second reflection unit 43 causes the transmission light to enter the optical fiber 6. Further, the second reflection unit 43 causes the received light to enter the first reflection unit 42.

  As shown in FIG. 7, the magnitude of the angle Ka between the first reflecting surface 42a and the virtual axis A2a is X °. This X ° is larger than −90 ° and smaller than + 90 ° (−90 <X ° <+90). In this case, the size of the angle K4 between the third optical axis A3 and the virtual axis A2a is (90−X) °. An angle K6 between the third optical axis A3 and the second optical axis A2 is an isometric angle of the angle K4. Accordingly, the size of the angle K6 is (90−X) °. The size of the angle K7, which is the complementary angle of the angle K6, is ((90 + X) = 180− (90−X)) °. The corner K7 is obtained by adding the corner K8 and the corner K9. The angle K8 is an incident angle on the second reflecting surface 43a. The angle K9 is a reflection angle at the second reflection surface 43a. The corner K8 and the corner K9 are equal to each other. Therefore, the magnitude of the corner K8 is (45 + X / 2) ° = ((90 + X) / 2) °. The size of the angle K9 is also (45 + X / 2) °. The size of the angle K5 between the second reflecting surface 43a and the second optical axis A2 is (X / 2) °. Note that when the rotation direction of the first reflecting surface 42a is taken into consideration with the virtual axis A2a as a reference, the size of the angle Ka is (+ X) °. In that case, the size of the angle K5 of the second reflecting surface 43a is (−X / 2) °.

As shown in FIG. 8, the second reflecting portion 43 is a concave portion having a rectangular cross section. In the rectangular cross section, the surface that intersects the second optical axis A2 and the third optical axis A3 is the second reflecting surface 43a in the second reflecting portion 43. The second reflecting surface 43a totally reflects received light and transmitted light. According to Snell's law,
n1 × sin (θ1 × π / 180 °) = n2 × sin (θ2 × π / 180 °) (4)
It is. Here, n1 is the refractive index of the resin material constituting the main body 25. n <b> 2 is the refractive index of air in the concave portion constituting the second reflecting portion 43. The angle θ1 is the incident angle. The angle θ2 is a refraction angle. In equation (4), it is assumed that the angle θ2 is 90 ° and the refractive index n2 is 1. Then, when formula (4) is arranged, formulas (5) and (6) are obtained.
sin (θ1 × π / 180) = 1 / n1 (5)
θ1 ≧ arcsin (1 / n1) × 180 / π (6)
Here, when θ1 is an angle K8 (see FIG. 7), Expression (7) is obtained.
(45 + X / 2) ° ≧ arcsin (1 / n1) × (180 / π) (7)
Therefore, according to the arrangement of the second reflecting portion 43 that satisfies Expression (7), it is possible to totally reflect light while connecting the first optical axis A1 and the second optical axis A2. Therefore, loss due to reflection is reduced. In addition, the 2nd reflection part 43 may be the reflective surface by the metal film vapor-deposited on the inclined surface.

  As shown in FIG. 9, the total optical length SA is an optical length from the first reflecting portion 42 to the end face 6a. Therefore, the total optical length SA is a length obtained by adding the first optical length S1a and the second optical length S1b. The first optical length S1a is a length from the first reflecting portion 42 to the second reflecting portion 43. The second optical length S1b is a length from the second reflecting portion 43 to the end surface 6a. The optical module 1 of the present embodiment has four optical systems 41A to 41D (see FIG. 6). In these optical systems 41A to 41D, the total optical lengths SA are equal to each other. The total optical length SA can be adjusted by the size of the corner K4. When the total optical length SA is aligned between the optical systems 41A to 41D, the third optical axes A3 are not parallel to each other.

  As shown in FIG. 5, the lens module 22 further includes a transmission lens 28a and a reception lens 28b. The transmission lens 28 a condenses the transmitted light so that the spot diameter is smaller than the core diameter of the optical fiber 6 and the numerical aperture is smaller than the numerical aperture of the optical fiber 6. The receiving lens 28b condenses the received light so that the spot diameter is smaller than the light receiving diameter of the light receiving element 21b. A cover 27 is provided on the bottom surface 25 d of the lens module 22. The cover 27 covers the driving IC 20, the light emitting element 21a, and the light receiving element 21b. The transmission lens 28a and the reception lens 28b are provided on the first optical axis A1 on the ceiling surface 27a of the cover 27. The lens module 22 may have a lens system composed of a plurality of lenses on the optical axis between the light emitting element 21 a and the transmission optical fiber 6.

  The transmitted light is emitted from the light emitting element 21a in the direction of the first optical axis A1. The transmission light travels along the first optical axis A1 while the spot diameter is enlarged, and passes through the transmission lens 28a. After passing through the transmission lens 28a, the transmission light further proceeds along the first optical axis A1 while the spot diameter is reduced. And it arrives at the 1st reflective surface 42a. The traveling direction of the transmitted light that has reached the first reflecting surface 42a is converted to the direction of the third optical axis A3. The transmitted light travels along the third optical axis A3 while the spot diameter is reduced, and reaches the second reflecting surface 43a. The traveling direction of the transmitted light that has reached the second reflecting surface 43a is converted to the direction of the second optical axis A2. The transmission light travels along the second optical axis A2 while the spot diameter is reduced, and enters the end surface 6a of the transmission optical fiber 6. Here, the spot diameter of the transmission light incident on the end face 6 a is smaller than the core diameter of the transmission optical fiber 6. Further, the transmission light incident on the end face 6 a is smaller than the aperture ratio of the transmission optical fiber 6.

  The optical module 1 includes an input / output unit 30 that provides a plurality of first optical axes A1 at a first pitch P1, and a plurality of second optical axes A2 at a second pitch P2 different from the first pitch P1. The waveguide section 35 to be provided and the first pitch P1 are converted to the second pitch P2 by being reflected by the first reflecting section 42 and the second reflecting section 43, and the first optical axis A1 and The optical axis conversion part 40 which optically connects 2nd optical axis A2 is provided. According to the optical module 1, the first optical axis A 1 and the second optical axis A 2 are optically connected by the optical axis conversion unit 40. The optical axis conversion unit 40 optically converts the first pitch P1 to the second pitch P2 by being reflected by the first reflection unit 42 and the second reflection unit 43. This eliminates the need to physically convert the first pitch P1 to the second pitch P2 in the connection between the first optical axis A1 and the second optical axis A2. Therefore, workability at the time of assembling the optical module 1 can be improved.

  The optical axis conversion unit 40 provides a third optical axis A3 that is non-parallel to the first optical axis A1 and the second optical axis A2 between the first reflecting unit 42 and the second reflecting unit 43. . According to the optical axis conversion unit 40, the first optical axis A1 and the second optical axis A2 can be optically connected by the third optical axis A3.

  The plurality of optical axes that optically connect the input / output unit 30 and the waveguide unit 35 have the same total optical length SA. According to this configuration, the degree of optical change that can occur between the input / output unit 30 and the waveguide unit 35 is uniform between the optical axes. Therefore, the optical component for correcting the optical change can be shared. Examples of the optical component include a transmission lens 28a and a reception lens 28b.

  When a first axis (width direction D2) intersecting with the plurality of second optical axes A2 and a first surface R1 stretched by the second optical axis A2 are defined, the third optical axis A3 is on the first surface R1. The first optical axis A1 is included and is parallel to the normal N of the first surface R1. According to this configuration, the design of the optical axis in the optical axis conversion unit 40 can be simplified.

  The optical module 1 further includes a transmission lens 28a formed on the first optical axis A1. The input / output unit 30 includes a light emitting element 21a that emits transmission light along the first optical axis A1. The waveguide section 35 includes a transmission optical fiber 6 that receives transmission light at the second optical axis A2. The transmission lens 28 a condenses the transmission light so that the spot diameter is smaller than the core diameter of the transmission optical fiber 6 and the numerical aperture is smaller than the numerical aperture of the transmission optical fiber 6. According to the transmission lens 28a, loss of transmission light is reduced. Therefore, transmission light can be efficiently transmitted between the light emitting element 21a and the transmission optical fiber 6.

The optical module 1 further includes a receiving lens 28b formed on the first optical axis A1. The input / output unit 30 includes a light receiving element 21b that receives received light at the first optical axis A1. The waveguide section 35 includes a reception optical fiber 6 that emits reception light at the second optical axis A2. The receiving lens 28b condenses the received light so that the spot diameter is smaller than the light receiving diameter of the light receiving element 21b.
According to the receiving lens 28b, the loss of received light is reduced. Accordingly, the received light can be efficiently transmitted between the receiving optical fiber 6 and the light receiving element 21b.

In the optical module 1, the first reflecting portion 42 extends along the second optical axis A <b> 2 on the first surface that intersects the plurality of second optical axes A <b> 2 and the second optical axis A <b> 2. The angle (X) formed with the direction, the angle (Y) formed with the second reflector 43 along the second optical axis A2, the first optical axis A1, the second optical axis A2, and the third The refractive index (n1) of the medium through which the optical axis A3 propagates satisfies the following formulas (1) to (3). According to this configuration, loss due to reflection can be reduced.
-90 ° <X <+ 90 ° (1)
Y = −X / 2 (2)
45 ° + X / 2 ≧ arcsin (1 / n1) × (180 / π) (3)

(Second Embodiment)
An optical module according to the second embodiment will be described. In the optical axis conversion unit 40 of the first embodiment, the first reflection unit 42 is arranged so that the total optical lengths SA are equal to each other. On the other hand, as shown in FIG. 10, in the lens module 22A of the optical module 1A according to the second embodiment, the first reflecting portion 42A is disposed on the first axis M1.

  As illustrated in FIG. 11, the optical axis conversion unit 40A includes a first reflection unit 42A and a second reflection unit 43A. The first reflecting portions 42A are arranged with a first pitch P1 along the first axis M1. The first axis M1 is orthogonal to the plurality of second optical axes A2.

  The sizes of the corners K4c to K4f are different from each other depending on the distance between the first axis M1 and the second axis M2 in the front-rear direction D1. The sizes of the corners K4c and K4d differ from each other depending on the distance between the light emitting element 21a and the optical fiber 6 connected to each other. This distance is the distances SB1 and SB2 between the light emitting element 21a and the optical fiber 6 in the width direction D2. The sizes of the corners K4e and K4f vary depending on the distance between the light receiving element 21b and the optical fiber 6 connected to each other. This distance is the distances SB3 and SB4 between the light receiving element 21b and the optical fiber 6 in the width direction D2. Thus, when the first reflecting portion 42A is disposed on the first axis M1, the corners K4c to K4f are different from each other. Accordingly, the third optical axes A3 are not parallel to each other.

  The second reflecting portion 43A is disposed along the second axis M2. The second axis M2 is set between the light emitting element 21a and the light receiving element 21b and the end face 6a in the front-rear direction D1. The second axis M2 is parallel to the first axis M1. The sizes of the angles K5c to K5f between the second reflecting portion 43A and the second optical axis A2 are determined by the incident angle of the third optical axis A3.

  In the optical module 1A, the first reflecting portion 42A is disposed along the first axis M1 that intersects the plurality of second optical axes A2. The second reflecting portion 43A is disposed along a second axis M2 that is parallel to the first axis M1. According to this configuration, the first reflecting portion 42A and the second reflecting portion 43A can be easily formed.

(Third embodiment)
An optical module according to the third embodiment will be described. In the optical axis conversion unit 40 of the first embodiment, the third optical axes A3 are not parallel to each other. On the other hand, as shown in FIG. 12, in the optical module 1B according to the third embodiment, the third optical axes A3 in the lens module 22B are parallel to each other.

  As shown in FIG. 13, the optical axis conversion unit 40B includes a first reflection unit 42B and a second reflection unit 43B. The size of the corner K4g is equal to the size of the corner K4h. The size of these angles K4g and K4h is a precondition. Based on the sizes of the corners K4g and K4h, the position of the second reflecting portion 43B and the sizes of the corners K5g and K5h are set. Similarly, the size of the corner K4j is equal to the size of the corner K4k. The size of these corners K4j and K4k is a prerequisite. Based on the sizes of the corners K4j and K4k, the position of the second reflecting portion 43B and the sizes of the corners K5j and K5k are set. In the optical module 1B, the optical axis conversion unit 40B is designed based on the precondition that the third optical axes A3 are parallel to each other. In this case, the total optical length SA is not equal to each other.

  The plurality of third optical axes A3 in the optical module 1B are parallel to each other, and the total optical lengths SA are not equal. According to this configuration, the design of the optical axis in the optical axis conversion unit 40B can be simplified.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

  In the above-described embodiment, as shown in FIG. 5, the third optical axis A3 and the second optical axis A2 are included in the first surface. However, the optical module is not limited to the configuration of the above embodiment. For example, as illustrated in FIG. 14, in the optical module 1C, the first axis (width direction D2) intersecting the plurality of second optical axes A2 and the first surface R1 stretched by the second optical axis A2, When the second surface R2 inclined to the first surface R1 is defined, the third optical axis A3 is included in the second surface R2, and the first optical axis A1 is parallel to the normal line N of the first surface R1. It is.

  In this case, the second reflecting surface 43b is converted so that the traveling direction of the transmission light is parallel to the second optical axis A2. Here, it is assumed that the size of the corner K3a is X1 °. The angle K3a is an angle between the first optical axis A1 and the third optical axis A3 in the height direction D3. In this case, the size of the corner K3b is (90−X1) °. The angle K3b is an angle between the third optical axis A3 and the second optical axis A2 in the height direction D3. According to the lens module 22C, the optical fiber 6 can be disposed at a desired position in the height direction D3. For example, the optical fiber 6 can be disposed close to the circuit board 13a. According to this arrangement, the load due to bending of the optical fiber 6 is reduced. Accordingly, it is possible to suppress the deterioration of the optical characteristics in the optical fiber 6. Further, since the probability that the optical fiber 6 is broken is reduced, the reliability of the optical module can be increased.

  In the above-described embodiment, the case where the first pitch P1 is larger than the second pitch P2 has been described as an example. However, as shown in FIG. 15A, in the optical module, the first pitch P1 may be smaller than the second pitch P2. As shown in FIG. 15B, the size (X °) of the angle K11 between the first reflecting surface 42a and the virtual axis A2a is not less than 90 ° and not more than 180 °. According to this angle K11, the size of the angle K12 between the third optical axis A3 and the virtual axis A2a is (X−90) °. An angle K13 between the third optical axis A3 and the second optical axis A2 is a complex angle of the angle K12. Accordingly, the size of the corner K13 is (X−90) °. The size of the angle K14 between the second reflecting surface 43a and the second optical axis A2 is (X / 2-45) °. Therefore, when the angle K11 of the first reflecting portion 42C is arranged to be X °, the angle K14 of the second reflecting portion 43C is arranged at (X / 2−45) °. The size of the angle K14 between the second optical axis A2 and the normal line N of the first reflecting surface 42a is an angle (135−X / 2) °.

  In the above embodiment, the optical module 1 has the light emitting element 21a and the light receiving element 21b. The optical module may not include the light receiving element 21b but may include only the plurality of light emitting elements 21a. The optical module may not include the light emitting element 21a but may include only the plurality of light receiving elements 21b.

DESCRIPTION OF SYMBOLS 1,1A, 1B, 1C ... Optical module, 2 ... Optical cable, 3 ... Connector module, 6 ... Optical fiber, 12 ... Housing, 13 ... Substrate unit, 18 ... Electrical connector, 21a ... Light emitting element, 21b ... Light receiving element, 22 , 22A, 22B, 22C ... lens module, 28a ... transmitting lens, 28b ... receiving lens, 30 ... input / output unit, 35 ... waveguide unit, 40, 40A, 40B ... optical axis converting unit, 42, 42A, 42B ... 1st reflection part, 43, 43A, 43B ... 2nd reflection part, A1 ... 1st optical axis, A2 ... 2nd optical axis, A2a ... Virtual axis, A3 ... 3rd optical axis, D1 ... Front-rear direction, D2 ... width direction, D3 ... height direction, SA ... total optical length, R1 ... first surface, R2 ... second surface, N ... normal.

Claims (10)

An input / output unit providing a plurality of first optical axes at a first pitch;
A waveguide section that provides a plurality of second optical axes at a second pitch different from the first pitch;
The first pitch is converted to the second pitch by being reflected by the first reflecting portion and the second reflecting portion, and the first optical axis and the second optical axis are optically converted. An optical module including an optical axis conversion unit to be connected.   The optical axis conversion unit provides a third optical axis that is non-parallel to the first optical axis and the second optical axis between the first reflective unit and the second reflective unit. The optical module according to claim 1.   The optical module according to claim 2, wherein the optical lengths of the plurality of optical axes that optically connect the input / output unit and the waveguide unit are equal to each other. The first reflecting portion is disposed along a first axis that intersects a plurality of the second optical axes,
The optical module according to claim 2, wherein the second reflecting portion is disposed along a second axis parallel to the first axis.   The optical module according to claim 2, wherein the plurality of third optical axes are parallel to each other and have optical lengths that are not equal. When a first axis intersecting a plurality of the second optical axes and a first surface extending by the second optical axis are defined, the third optical axis is included in the first surface,
The optical module according to claim 2, wherein the first optical axis is parallel to a normal direction of the first surface. When defining a first axis intersecting a plurality of the second optical axes, a first surface extending by the second optical axis, and a second surface inclined to the first surface, the third light The axis is included in the second surface,
The optical module according to claim 2, wherein the first optical axis is parallel to a normal direction of the first surface. A transmission lens formed on the first optical axis;
The input / output unit includes a light emitting element that emits transmission light along the first optical axis,
The waveguide section includes a transmission optical fiber that receives the transmission light at the second optical axis,
The transmission lens condenses the transmission light so that a spot diameter is smaller than a core diameter of the transmission optical fiber and a numerical aperture is smaller than a numerical aperture of the transmission optical fiber. Item 8. The optical module according to any one of Items 1 to 7. A receiving lens formed on the first optical axis;
The input / output unit includes a light receiving element that receives received light on the first optical axis,
The waveguide section includes a receiving optical fiber that emits the received light along the second optical axis,
The optical module according to claim 1, wherein the reception lens condenses the reception light so that a spot diameter is smaller than a light reception diameter of the light receiving element. In a first surface intersecting with a plurality of the second optical axes and a first surface extended by the second optical axes, an angle formed by the first reflecting portion with a direction along the second optical axes ( X), an angle (Y) between the second reflecting portion and the direction along the second optical axis, and a medium through which the first optical axis, the second optical axis, and the third optical axis propagate. The refractive index (n1) of the following satisfies the following formulas (1) to (3):
-90 ° <X <+ 90 ° (1)
Y = −X / 2 (2)
45 ° + X / 2 ≧ arcsin (1 / n1) × (180 / π) (3)
The optical module according to claim 2.

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