Optical connection structure

Abstract

A purpose of the present invention is to provide an optical connection structure and a ferrule capable of stabilizing optical connection quality when performing positioning without using pins.　A ferrule (50) according to the present invention comprises: a fiber pore (51) into which an optical fiber (F) is to be inserted; a light emission face from which light having passed through the optical fiber (F) is to be emitted; and a longitudinal reference face (50a) which positions the ferrule (50) in the longitudinal direction with respect to a receptacle (30). The longitudinal reference face (50a) is located between the center line (O) passing through the center position of the ferrule (50) in the longitudinal direction and the light emission face.

Description

[Technical Field]

[0001] The present invention ,light Regarding the connection structure. This application claims priority to Japanese Patent Application No. 2022-036444, filed on March 9, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] Patent Document 1 discloses an optical connection structure for connecting a photonic element and an optical fiber. In Patent Document 1, the positioning of the optical connector in a direction perpendicular to the longitudinal direction of the optical fiber is performed by a positioning pin. In addition, the positioning of the optical connector in the longitudinal direction is performed by abutting the ferrule of the optical connector against an adapter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent Application Publication No. 2021 / 0055489 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the outer dimensions of the ferrule are increased by the thickness of the pin. If positioning is performed using the outer shape of the ferrule without using the pin, the ferrule can be made smaller. Here, the inventors of the present application have conducted research and found that when positioning a ferrule without using a pin, the placement of the reference surface that serves as the basis for the ferrule position in the longitudinal direction affects the quality of the optical connection using an optical connector.

[0005] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a ferrule and an optical connection structure that can stabilize the quality of optical connection when positioning is performed without using pins. [Means for solving the problem]

[0006] In order to solve the above problem, a ferrule according to one aspect of the present invention is a ferrule that is connected to a receptacle fixed to an optical integrated circuit, and has a fiber hole into which an optical fiber is inserted, a light emission surface from which light that has passed through the optical fiber is emitted, and a longitudinal reference surface that determines the position of the ferrule relative to the receptacle in the longitudinal direction of the optical fiber, and the longitudinal reference surface is located between a center line that passes through the center position of the ferrule in the longitudinal direction and the light emission surface.

[0007] Moreover, an optical connection structure according to one aspect of the present invention comprises the ferrule, the receptacle, and a holding member that holds the ferrule and the receptacle in a positioned state, wherein the ferrule has a pressure-receiving surface that receives a biasing force in a direction intersecting the longitudinal direction, and a sliding surface that is positioned away from the pressure-receiving surface and slides against the receptacle, the holding member has a biasing portion that applies the biasing force to the pressure-receiving surface, the receptacle has a receptacle-side sliding surface that slides against the sliding surface, and the receptacle-side sliding surface has a recess formed therein into which a portion of the ferrule can enter, and when the direction in which light is emitted from the light emitting surface in the longitudinal direction is forward, an inclined surface is formed inside the recess that slopes toward the receptacle-side sliding surface as it moves forward. [Effects of the Invention]

[0008] According to the above aspects of the present invention, it is possible to provide a ferrule and an optical connection structure that can stabilize the quality of optical connection when positioning is performed without using pins. [Brief explanation of the drawings]

[0009] [Figure 1]1A and 1B are diagrams illustrating an optical connection structure according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing the vicinity of one optical connection unit in FIG. [Figure 3A] FIG. 3 is an exploded perspective view of FIG. 2. [Figure 3B] 3B is a perspective view of the vicinity of the receptacle in FIG. 3A as viewed from below. FIG. [Figure 3C] 3B is a front perspective view of the optical connector of FIG. 3A. FIG. [Figure 4] 2 is a schematic diagram illustrating the transfer of light between an optical fiber and an optical integrated circuit in the present embodiment. FIG. [Figure 5] FIG. 3 is a cross-sectional view taken along the arrows VV in FIG. 2. [Figure 6] FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 2. [Figure 7A] 1A to 1C are diagrams illustrating a method for connecting a ferrule and a receptacle in this embodiment. [Figure 7B] FIG. 7B is a diagram showing a state subsequent to FIG. 7A. [Figure 7C] FIG. 7B shows a state following FIG. 7B. DETAILED DESCRIPTION OF THE INVENTION

[0010] The ferrule and optical connection structure of this embodiment will be described below with reference to the drawings. As shown in Fig. 1, the optical connection structure 1 includes a substrate 10 and a plurality of optical connection units U. As shown in Figs. 2, 3A, and 3B, each optical connection unit U includes an optical integrated circuit 20, a receptacle 30, a microlens array 40, an optical connector C, and a holding member 80. The optical connector C includes a ferrule 50, a boot 60, and a ribbon fiber 70. The ferrule 50 has a plurality of fiber holes 51 (see Figs. 4 and 6) formed therein, into which a plurality of optical fibers F can be inserted. The plurality of fiber holes 51 are arranged in one direction perpendicular to the longitudinal direction of each fiber hole 51.

[0011] (direction definition) In this embodiment, the positional relationship of each component will be described using an XYZ Cartesian coordinate system. The X-axis direction is the longitudinal direction of each fiber hole 51. The Y-axis direction is the direction in which the multiple fiber holes 51 are arranged. The Z-axis direction is a direction perpendicular to both the X-axis and the Y-axis. In this specification, the X-axis direction may be referred to as the longitudinal direction X, the Y-axis direction may be referred to as the first direction Y, and the Z-axis direction may be referred to as the second direction Z. The direction from the ferrule 50 toward the optical integrated circuit 20 along the longitudinal direction X is referred to as the +X side or forward. The direction opposite the +X side is referred to as the -X side or rear. A direction along the first direction Y is referred to as the +Y side or left. The direction opposite the +Y side is referred to as the -Y side or right. The direction from the substrate 10 toward the optical integrated circuit 20 along the second direction Z is referred to as the +Z side or upward. The direction opposite the +Z side is referred to as the -Z side or downward.

[0012] In this embodiment, a ribbon fiber 70 is formed by coating a plurality of optical fibers F collectively or by intermittently fixing the optical fibers F to each other. Note that a plurality of optical fibers F may not form the ribbon fiber 70, and each optical fiber F may be coated individually. The boot 60 is tubular and extends in the longitudinal direction X, and the ribbon fiber 70 is inserted into the boot 60. The boot 60 is made of an elastic material and extends from the ferrule 50 toward the -X side. The boot 60 serves to relieve bending and stress applied to the optical fibers F.

[0013] 1, an electronic component 11 is mounted on the upper surface of a substrate 10. A circuit pattern (not shown) electrically connected to the electronic component 11 is also formed on the substrate 10. The electronic component 11 may be, for example, a switch circuit. A plurality of optical connection units U are arranged to surround the electronic component 11.

[0014] The optical integrated circuit 20 is mounted on the upper surface of the substrate 10. The optical integrated circuit 20 is formed in a rectangular parallelepiped shape. The optical integrated circuit 20 has a light-receiving element (not shown) that converts an optical signal into an electrical signal, and a light-emitting element (not shown) that converts an electrical signal into an optical signal. As the light-receiving element, for example, a photodetector such as a photodiode can be used. As the light-emitting element, for example, a semiconductor laser, a light-emitting diode, etc. can be used.

[0015] 3B, the optical integrated circuit 20, the microlens array 40, and the receptacle 30 are fixed to one another with an adhesive. For example, the front surface (the end surface on the +X side) of the microlens array 40 may be adhesively fixed to the rear surface (the end surface on the -X side) of the optical integrated circuit 20. In this case, since optical signals pass through the adhesive layer, it is preferable that the adhesive be made of a material that transmits light. However, the method of fixing the optical integrated circuit 20, the receptacle 30, and the microlens array 40 is not limited to the above and may be changed as appropriate.

[0016] As shown in FIG. 4, the optical integrated circuit 20 has a plurality of waveguides 21. Note that the waveguides 21 are not shown in figures other than FIG. 4. Each waveguide 21 is optically connected to the above-described light-receiving element and light-emitting element. In this embodiment, each waveguide 21 extends along the longitudinal direction X. Each waveguide 21 is formed of, for example, silicon. The refractive index of the waveguide 21 is higher than the refractive index of portions of the optical integrated circuit 20 other than the waveguide 21. This confines the optical signal inside the waveguide 21, and the optical signal propagates in the longitudinal direction X. The waveguide 21 may be provided on the surface (top surface) of the optical integrated circuit 20, or may be provided inside the optical integrated circuit 20. An input / output portion 21a is provided at the rear end (the end on the -X side) of each waveguide 21. The input / output portion 21a is a part of the waveguide 21 and receives and emits optical signals.

[0017] 4, an abutting surface 51a against which the +X side end of the optical fiber F abuts is formed inside the fiber hole 51 of the ferrule 50. The abutting surface 51a faces the -X side. When the optical connector C is assembled, the multiple optical fibers F are inserted into the multiple fiber holes 51, respectively, and abut against each abutting surface 51a of the fiber hole 51. The ferrule 50 has a lens forming surface 52 that faces the microlens array 40 in the longitudinal direction X. On the lens forming surface 52, a plurality of lenses L2 arranged in the first direction Y are formed.

[0018] The microlens array 40 is made of a material that can transmit light. The microlens array 40 may be made of, for example, quartz glass or a silicon substrate. In this embodiment, the microlens array 40 has a rectangular plate shape. As shown in FIG. 3B, the microlens array 40 has a plurality of lenses L1 formed therein.

[0019] When the optical connector C is connected to the receptacle 30, the ferrule 50 and the microlens array 40 face each other in the longitudinal direction X, as shown in FIG. 4. More specifically, the plurality of lenses L2 formed on the ferrule 50 face the plurality of lenses L1 of the microlens array 40. An optical signal traveling in the +X direction through the optical fiber F enters the ferrule 50 from the abutting surface 51a of the fiber hole 51. The optical signal also exits from the lens L2 of the ferrule 50 in the +X direction. In other words, the surface of the lens L2 is the light exit surface from which light exits the ferrule 50.

[0020] Light emitted from the ferrule 50 enters the microlens array 40 through the lens L1. The light that has passed through the microlens array 40 is received by the input / output portion 21a of the optical integrated circuit 20 and propagates through the waveguide 21. The optical signal is then converted into an electrical signal by a light-receiving element provided in the optical integrated circuit 20 and passed to the substrate 10. Conversely, the electrical signal transmitted from the substrate 10 to the optical integrated circuit 20 is converted into an optical signal by a light-emitting element provided in the optical integrated circuit 20. The optical signal then propagates through the waveguide 21 and is emitted from the input / output portion 21a toward the optical fiber F. In this way, the optical connection structure 1 performs optical connection between the optical fiber F and the optical integrated circuit 20.

[0021] The optical connector C can be attached to and detached from the receptacle 30 (details will be described later). The receptacle 30 serves to position the ferrule 50 of the optical connector C relative to the optical integrated circuit 20. As shown in FIG. 3B , the receptacle 30 has a top wall 31, a first side wall 32, and a second side wall 33. The top wall 31 is plate-shaped and extends in the first direction Y and the longitudinal direction X. The first side wall 32 extends from the +Y side end of the top wall 31 toward the -Z side. The second side wall 33 extends from the -Y side end of the top wall 31 toward the -Z side. Comparing the dimensions in the longitudinal direction X, the dimension of the second side wall 33 is shorter than the dimension of the first side wall 32. The first side wall 32 and the second side wall 33 are spaced apart in the first direction Y. When the optical connector C is connected to the receptacle 30, the ferrule 50 enters between the first side wall 32 and the second side wall 33.

[0022] 3A, a protrusion 31a that protrudes toward the +Z side is formed on the upper wall 31. A locking portion 86 (described later) of the holding member 80 is locked onto the protrusion 31a. 3B, first side wall 32 has receptacle-side sliding surface 34 facing the -Y side. Receptacle-side sliding surface 34 has recessed portion 34a recessed toward the +Y side. Receptacle-side sliding surface 34 is divided into two separate portions in longitudinal direction X by recessed portion 34a. 5, an inclined surface 34b is formed on the inside of the recess 34a. The inclined surface 34b is inclined toward the -Y side as it approaches the +X side. In other words, the inclined surface 34b is inclined so as to approach the receptacle-side sliding surface 34 as it approaches the +X side.

[0023] The first side wall 32 is formed with a positioning surface 35 facing the -X side. The positioning surface 35 is located on the +X side of the receptacle-side sliding surface 34. The positioning surface 35 serves to determine the relative positions of the receptacle 30 and the ferrule 50 in the longitudinal direction X. The second side wall 33 also has a positioning surface located in the same plane as the positioning surface 35 of the first side wall 32. The ferrule 50 abuts against these two positioning surfaces.

[0024] As shown in FIG. 3C, the ferrule 50 is formed in a substantially rectangular parallelepiped shape. The ferrule 50 is a molded product made of, for example, a permeable resin. The ferrule 50 has a longitudinal reference surface 50a, a plurality of fiber holes 51 (see FIG. 4), a lens-forming surface 52, a pressure-receiving surface 53, a sliding surface 54, a filling hole 55, and a dustproof wall 56. The plurality of fiber holes 51 are aligned in the first direction Y. A plurality of lenses L2 are formed on the lens-forming surface 52 so as to protrude toward the +X side. The lens-forming surface 52 is the surface of the ferrule 50 located closest to the +X side, excluding the dustproof wall 56 and the lenses L2.

[0025] The position of each lens L2 corresponds to the position of each fiber hole 51. More specifically, when viewed from the longitudinal direction X, each lens L2 is disposed at a position overlapping with each fiber hole 51. The dustproof wall 56 protrudes from the longitudinal reference plane 50a toward the +X side. The dustproof wall 56 has a rectangular frame shape when viewed from the longitudinal direction X, and surrounds the lens forming surface 52 and the lens L2. The dustproof wall 56 serves to prevent dust and the like from adhering to the lens forming surface 52 and the lens L2. However, the dustproof wall 56 is not essential.

[0026] The filling hole 55 penetrates the ferrule 50 in the second direction Z. When assembling the optical connector C, after the optical fiber F is inserted into the fiber hole 51, adhesive is injected through the filling hole 55. This allows the optical fiber F to be fixed to the ferrule 50.

[0027] The pressure-receiving surface 53 and the sliding surface 54 are both end surfaces of the ferrule 50 in the first direction Y. In this embodiment, the pressure-receiving surface 53 is the end surface on the -Y side, and the sliding surface 54 is the end surface on the +Y side. However, the positional relationship between the pressure-receiving surface 53 and the sliding surface 54 may be reversed. The pressure-receiving surface 53 is a portion that receives a biasing force from a biasing portion 82a (described later) of the holding member 80. The sliding surface 54 is a portion that slides against the receptacle 30. In other words, when the optical connector C is connected to the receptacle 30, the ferrule 50 slides against the receptacle 30 at the sliding surface 54.

[0028] The holding member 80 serves to maintain the ferrule 50 positioned in the receptacle 30. As shown in FIG. 3A , the holding member 80 has an upper plate 81, a first side plate 82, a second side plate 83, a first support plate 84, a second support plate 85, and a locking portion 86. The holding member 80 of this embodiment is formed by molding a metal plate. However, the material, shape, and manufacturing method of the holding member 80 may be changed as appropriate.

[0029] 2, when holding member 80 holds the relative positions of optical connector C and receptacle 30, upper plate 81 is located on the +Z side of receptacle 30, and first support plate 84 and second support plate 85 are located on the -Z side of receptacle 30. In addition, receptacle 30 and ferrule 50 are disposed between first side plate 82 and second side plate 83.

[0030] As shown in FIG. 3A, the upper plate 81 extends in the first direction Y and the longitudinal direction X. The first side plate 82 extends from the -Y side end of the upper plate 81 toward the -Z side. The second side plate 83 extends from the +Y side end of the upper plate 81 toward the -Z side. The second side plate 83 and the first side plate 82 face each other in the first direction Y. The first support plate 84 protrudes toward the +Y side from the -Z side end of the first side plate 82. The second support plate 85 protrudes toward the -Y side from the -Z side end of the second side plate 83.

[0031] The locking portion 86 protrudes from the upper plate 81 toward the +X side. A through hole 86a is formed in the locking portion 86. When the holding member 80 holds the relative positions of the optical connector C and the receptacle 30, the protrusion 31a of the receptacle 30 is positioned inside the through hole 86a (see FIG. 2).

[0032] 2, the holding member 80 has a biasing portion 82a that generates a biasing force in the first direction Y, two second biasing portions 81a that generate a biasing force in the second direction Z, and a third biasing portion 87 that generates a biasing force in the longitudinal direction X. In this embodiment, the biasing portion 82a, the second biasing portion 81a, and the third biasing portion 87 are elastic portions (leaf springs) formed in part of the holding member 80. However, some or all of the biasing portions 82a, the second biasing portions 81a, and the third biasing portion 87 do not have to be leaf springs, and may be formed as separate members from the holding member 80.

[0033] The biasing portion 82a is formed on the first side plate 82 and biases the pressure-receiving surface 53 of the ferrule 50 toward the +Y side. As shown in Fig. 5, when the ferrule 50 is biased by the biasing portion 82a, the sliding surface 54 comes into contact with the receptacle-side sliding surface 34. This determines the relative positions of the ferrule 50 and the receptacle 30 in the first direction Y. The receptacle-side sliding surface 34 and the sliding surface 54 are parts that serve as references for the positions in the first direction Y.

[0034] Two second urging portions 81a are formed on the upper plate 81. The number of second urging portions 81a may be one. As shown in FIG. 6, the second urging portion 81a presses the upper wall 31 of the receptacle 30 toward the -Z side. At this time, the first support plate 84 and the second support plate 85 contact the lower surface (the end surface on the -Z side) of the ferrule 50 and support the ferrule 50 from the -Z side. In other words, the upper wall 31 of the receptacle 30 and the ferrule 50 are sandwiched in the second direction Z between the first support plate 84, the second support plate 85, and the second urging portion 81a. This determines the relative positions of the ferrule 50 and the receptacle 30 in the second direction Z. The lower surface (the end surface on the -Z side) of the upper wall 31 and the upper surface (the end surface on the +Z side) of the ferrule 50 are reference points for the positions in the second direction Z.

[0035] As shown in FIG. 2, the third biasing portion 87 protrudes toward the -Z side from the -X side end of the upper plate 81. The third biasing portion 87 biases the ferrule 50 toward the +X side. As shown in FIG. 5, when the ferrule 50 is biased by the third biasing portion 87, the longitudinal reference surface 50a abuts against the positioning surface 35. This determines the relative positions of the ferrule 50 and the receptacle 30 in the longitudinal direction X. The longitudinal reference surface 50a and the positioning surface 35 are reference surfaces that determine the position of the ferrule 50 relative to the receptacle 30 in the longitudinal direction X. A reaction force toward the -X side resulting from the biasing force of the third biasing portion 87 acts on the holding member 80. This reaction force is supported by the protrusion 31a of the receptacle 30 via the locking portion 86.

[0036] As described above, in this embodiment, positioning is performed by butting the ferrule 50 and the receptacle 30 together in three directions (X, Y, and Z) without using positioning pins. In this way, by not using positioning pins, it is possible to reduce the external dimensions of the ferrule 50 (particularly the dimensions in the first direction Y). Therefore, more optical connection units U can be arranged on the substrate 10, and the arrangement density of optical fibers F in a data center or the like can be increased.

[0037] 5 shows a center line O that passes through the center of the ferrule 50 in the longitudinal direction X. The longitudinal reference surface 50a is located between this center line O and the lens forming surface 52 in the longitudinal direction X. This arrangement provides the following effects. If the longitudinal reference surface 50a were to be located at the tip (the end on the +X side) of the ferrule 50, the distance between the longitudinal reference surface 50a and the lens forming surface 52 would be too close. This would make it easier for dust and other particles to adhere to the lens L2 when the longitudinal reference surface 50a abuts against the positioning surface 35. If dust and other particles adhere to the lens L2, this would lead to an increase in the optical connection loss between the optical integrated circuit 20 and the optical fiber F.

[0038] Alternatively, if the longitudinal reference surface 50a were located at the base end (the end on the -X side) of the ferrule 50, the distance between the longitudinal reference surface 50a and the lens L2 would be too great. Therefore, when the ferrule 50 is held with the longitudinal reference surface 50a tilted relative to the positioning surface 35, the positional deviation of the lens L2 from the lens L1 would increase. This also leads to an increase in the optical connection loss between the optical integrated circuit 20 and the optical fiber F.

[0039] In contrast, in this embodiment, by arranging the longitudinal reference surface 50a between the center line O and the lens forming surface 52, it is possible to suppress the adhesion of dust to the lens L2 and also to suppress the misalignment of the lens L2 with respect to the lens L1. Therefore, when positioning the ferrule 50 without using a pin, it is possible to stabilize the quality of the optical connection.

[0040] Next, the effects obtained by providing the recess 34a and the inclined surface 34b will be described with reference to FIGS. 7A, 7B, and 7C. When connecting optical connector C to receptacle 30, as shown in Fig. 7A, ferrule 50 is pushed in the +X direction while sliding surface 54 of ferrule 50 slides against receptacle-side sliding surface 34. Here, it has been found that if recess 34a were not provided, connection between optical connector C and receptacle 30 would be easily completed with sliding surface 54 tilted relative to receptacle-side sliding surface 34. In particular, a biasing force is applied to ferrule 50 by biasing portion 82a, and once sliding surface 54 tilts relative to receptacle-side sliding surface 34, there is a possibility that the biasing force will act to maintain the tilted state.

[0041] Therefore, in this embodiment, as shown in FIG. 7B, when the corner of the ferrule 50 enters the recess 34a, the ferrule 50 is tilted with respect to the receptacle 30. If the ferrule 50 is further pushed toward the +X side in this state, the ferrule 50 slides along the inclined surface 34b, and the ferrule 50 moves toward the +X side while correcting the tilt. When the corner of the ferrule 50 passes through the recess 34a toward the +X side, as shown in FIG. 7C, the sliding surface 54 abuts against each of the receptacle-side sliding surfaces 34 divided into two by the recess 34a. Here, as shown in FIG. 5, the position where the biasing portion 82a contacts the pressure-receiving surface 53 (hereinafter referred to as the contact point) is near the center line O in the longitudinal direction X. Therefore, the biasing force of the biasing portion 82a toward the +Y side acts near the center of gravity of the ferrule 50, making it difficult for the ferrule 50 to tilt. Furthermore, the position of the contact point in the longitudinal direction X coincides with the position of the recess 34a. Therefore, the biasing force of the biasing portion 82a acts to press the sliding surface 54 against the receptacle-side sliding surface 34, which is divided into two parts, in a balanced manner. This effectively prevents the ferrule 50 from tilting relative to the receptacle 30.

[0042] As described above, this embodiment provides a ferrule 50 to be connected to a receptacle 30 fixed to an optical integrated circuit 20. The ferrule 50 has a fiber hole 51 into which an optical fiber F is inserted, a light emitting surface (the surface of the lens L2 in this embodiment) from which light passing through the optical fiber F is emitted, and a longitudinal reference surface 50a that determines the position of the ferrule 50 in the longitudinal direction X relative to the receptacle 30. The longitudinal reference surface 50a is located between the light emitting surface and a center line O that passes through the center position of the ferrule 50 in the longitudinal direction X. This configuration can suppress an increase in optical connection loss caused by the distance between the light emitting surface and the longitudinal reference surface 50a being too close or too far. Therefore, it is possible to provide a ferrule 50 that can stabilize the quality of optical connection when positioning without using a pin.

[0043] The ferrule 50 also has a lens L2 arranged at a position overlapping the fiber hole 51 when viewed from the longitudinal direction X. The light exit surface is the surface of the lens L2. With this configuration, the light exiting from the optical fiber F can be adjusted by the lens L2 before being incident on the microlens array 40. This can improve the light coupling efficiency.

[0044] Furthermore, variations in the dimension between the longitudinal reference surface 50a and the light emitting surface in the longitudinal direction X affect the optical characteristics of the ferrule 50. Therefore, it is required that the dimension between the longitudinal reference surface 50a and the light emitting surface in the longitudinal direction X has small manufacturing variations. The smaller the dimension between the longitudinal reference surface 50a and the light emitting surface (i.e., the closer the longitudinal reference surface 50a and the light emitting surface in the longitudinal direction X), the easier it is to suppress manufacturing variations. In consideration of this, in this embodiment, as shown in FIG. 6 , the longitudinal reference surface 50a is located between the light emitting surface (the surface of the lens L2) and the abutting surface 51a in the longitudinal direction X. The distance between the abutting surface 51a and the light emitting surface is set small so that the optical signal emitted from the tip of the optical fiber F is not dispersed within the ferrule 50. Therefore, by positioning the longitudinal reference surface 50a between the light emitting surface and the abutting surface 51a, the dimension between the longitudinal reference surface 50a and the light emitting surface also becomes small, and the above-mentioned manufacturing variations can be reduced.

[0045] The ferrule 50 also has a dustproof wall 56 that protrudes from the longitudinal reference plane 50a and surrounds the light-emitting surface. The dustproof wall 56 more effectively prevents dust and other particles from adhering to the light-emitting surface. If the tip of the dustproof wall 56 (the end face on the +X side) is used as the longitudinal reference plane, the tip of the dustproof wall 56 may come into contact with another structure, and shavings and other particles generated by this contact may enter the dustproof wall 56 and adhere to the light-emitting surface. In contrast, since the dustproof wall 56 protrudes from the longitudinal reference plane 50a, shavings and other particles are even less likely to adhere to the light-emitting surface.

[0046] The optical connection structure 1 of this embodiment also includes a ferrule 50, a receptacle 30, and a holding member 80 that holds the ferrule 50 and the receptacle 30 in a positioned state. The ferrule 50 has a pressure-receiving surface 53 that receives a biasing force in a direction (first direction Y in this embodiment) intersecting the longitudinal direction X of the fiber hole 51, and a sliding surface 54 that is disposed away from the pressure-receiving surface 53 and slides against the receptacle 30. The holding member 80 has a biasing portion 82a that applies a biasing force to the pressure-receiving surface 53, and the receptacle 30 has a receptacle-side sliding surface 34 that slides against the sliding surface 54. A recess 34a is formed in the receptacle-side sliding surface 34 into which a portion of the ferrule 50 can enter. When the direction in which light is emitted from the light emitting surface (surface of lens L2) in the longitudinal direction X is set to the forward (+X side), an inclined surface 34b is formed inside the recess 34a, which is inclined so as to approach the receptacle side sliding surface 34 as it moves forward.

[0047] Such optical connection structure 1 can more reliably prevent the ferrule 50 from tilting relative to the receptacle 30. In particular, when the optical connector C and the receptacle 30 are repeatedly connected and disconnected, the tilt is corrected each time, as shown in Figures 7A to 7C. Therefore, variations in connection loss when repeated connections are made can also be reduced.

[0048] Furthermore, the receptacle-side sliding surface 34 is divided into two parts by the recess 34a in the longitudinal direction X. This allows the sliding surface 54 of the ferrule 50 to be pressed against the receptacle-side sliding surface 34 divided into two parts, thereby more reliably suppressing tilt of the ferrule 50.

[0049] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0050] For example, the light exit surface of the ferrule 50 does not have to be the surface of the lens L2. In the case of a ferrule 50 that does not have the lens L2, the surface 52 may be used as the light exit surface.

[0051] In addition, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate, without departing from the spirit of the present invention. [Explanation of symbols]

[0052] 1...optical connection structure 20...optical integrated circuit 30...receptacle 34...receptacle-side sliding surface 34a...recessed portion 34b...inclined surface 50...ferrule 50a...longitudinal reference surface 51...fiber hole 51a...butting surface 53...pressure receiving surface 54...sliding surface 56...dustproof wall 80...holding member 82a... energizing portion F... optical fiber

Claims

1. A receptacle fixed to an optical integrated circuit; a ferrule to be connected to the receptacle; a holding member that holds the ferrule and the receptacle in a positioned state, The ferrule is a fiber hole into which an optical fiber is inserted; a light exit surface from which light having passed through the optical fiber is emitted; a longitudinal reference plane for determining the position of the ferrule relative to the receptacle in the longitudinal direction of the optical fiber; a pressure-receiving surface that receives a biasing force in a direction intersecting the longitudinal direction; a sliding surface that is disposed apart from the pressure-receiving surface and slides against the receptacle, the longitudinal reference plane is located between a center line passing through a center position of the ferrule in the longitudinal direction and the light exit surface, the holding member has a biasing portion that applies the biasing force to the pressure-receiving surface, the receptacle has a receptacle-side sliding surface that slides on the sliding surface, a recess into which a part of the ferrule can enter is formed on the receptacle-side sliding surface; When the direction in which light is emitted from the light emitting surface in the longitudinal direction is defined as forward, an inclined surface is formed inside the recess so as to approach the receptacle side sliding surface as it moves forward.

2. The optical connection structure according to claim 1 , wherein the receptacle-side sliding surface is divided in the longitudinal direction by the recess.

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