JP7198155B2 - Ferrule, ferrule with fiber, and method for manufacturing ferrule with fiber - Google Patents

Description

TECHNICAL FIELD The present invention relates to a ferrule, a ferrule with fiber, and a method of manufacturing a ferrule with fiber.

2. Description of the Related Art A so-called lens connector technology is known, in which ferrules having lenses on their end faces face each other to optically connect optical fibers held by the respective ferrules. As such a lens connector, for example, Patent Document 1 discloses a lens connector having a ferrule for holding the ends of two optical fibers.

The lens connector described in Patent Document 1 is provided with an abutment surface for abutting the end faces of two optical fibers. Here, the optical signal transmitted through the optical fiber may be reflected by this abutment surface and return to the optical fiber again. For this reason, in the lens connector described in Patent Document 1, the abutment surface is inclined with respect to the plane perpendicular to the optical axis of the optical fiber, and the optical signal is reflected at a predetermined angle on the abutment surface (Patent Document 1). See FIG. 9B in Document 1).

JP 2018-92152 A

If the end faces of two optical fibers are abutted against the inclined abutment surface shown in FIG. 9B of Patent Document 1, the position of the end face of one optical fiber in the optical axis direction and the position of the other optical fiber The position of the end face in the optical axis direction will be different. As a result, the optical path length from the end face of the optical fiber to the lens for the optical signal entering and exiting one optical fiber differs from the optical path length from the end face of the optical fiber to the lens for the optical signal entering and exiting the other optical fiber. end up Therefore, as described in FIG. 9C of Patent Document 1, by providing a step on the abutment surface, the optical path length from the end surface of the optical fiber to the lens of the optical signal entering and exiting both optical fibers can be made uniform. can be done. However, there has been a problem that this complicates the structure of the ferrule.

The present invention aims to simplify the structure of a ferrule in a lens connector for holding the ends of two optical fibers while suppressing the optical path length difference from the end faces of the two optical fibers to the lens. With the goal.

Some embodiments of the present invention are a ferrule for holding an end of a first optical fiber and an end of a second optical fiber arranged side-by-side with respect to said first optical fiber. , a first abutment surface for abutting the end surface of the first optical fiber; a second abutment surface for abutting the end surface of the second optical fiber; a first lens portion arranged corresponding to the end face; and a second lens portion arranged corresponding to the end face of the second optical fiber; inclined with respect to a plane perpendicular to the optical axis of the first optical fiber, the second abutting surface is inclined with respect to a plane perpendicular to the optical axis of the second optical fiber, and the first and the plane perpendicular to the optical axis of the first optical fiber is equal to the angle between the second abutment plane and the plane perpendicular to the optical axis of the second optical fiber and the inclination direction of the first abutment surface with respect to the plane perpendicular to the optical axis of the first optical fiber is the second abutment surface with respect to the plane perpendicular to the optical axis of the second optical fiber. The ferrule is characterized in that it is opposite to the direction of inclination of the contact surface .

Other features of the present invention will be clarified by the description of the specification and drawings described later.

According to some embodiments of the present invention, in a lens connector that holds the ends of two optical fibers, while suppressing the difference in optical path length from the end face of the optical fiber to the lens for the two optical fibers, The ferrule structure can be simplified.

FIG. 1A is an overall perspective view of a ferrule structure 10 of this embodiment. FIG. 1B is an exploded perspective view of the ferrule structure 10 of this embodiment. FIG. 2A is an exploded perspective view of the ferrule structure 10 of this embodiment viewed from below. FIG. 2B is a cross-sectional view of the fiber-attached ferrule structure 10 of this embodiment. FIG. 3A is an explanatory diagram showing a state around the abutment surface 36. FIG. FIG. 3B is an explanatory diagram showing how optical connectors having the ferrule structure 10 of this embodiment are connected to each other. FIG. 4 is an explanatory diagram showing how optical signals are transmitted between ferrule structures 10 facing each other. FIG. 5 is a flow chart of a manufacturing method (assembling procedure) of the fiber-attached ferrule structure 10 of this embodiment. FIG. 6A is an explanatory view showing the surroundings of the abutment surface 36 of the fiber-attached ferrule structure 10 of the first comparative example. FIG. 6B is an explanatory view showing the surroundings of the abutment surface 36 of the fiber-attached ferrule structure 10 of the second comparative example. FIG. 7 is an explanatory diagram showing another example of the ferrule structure 10 with fiber.

At least the following matters will become clear from the description of the specification and drawings described later.

A ferrule for holding an end of a first optical fiber and an end of a second optical fiber arranged side by side with respect to the first optical fiber, wherein the end face of the first optical fiber is a first abutting surface for abutting; a second abutting surface for abutting the end face of the second optical fiber; and a second lens portion arranged corresponding to the end surface of the second optical fiber, wherein the first abutting surface is perpendicular to the optical axis of the first optical fiber the second abutting surface is inclined with respect to a plane perpendicular to the optical axis of the second optical fiber, and is inclined with respect to a certain surface with respect to the optical axis of the first optical fiber and the first abutting surface and the second abutting surface are symmetrical when the certain plane on which the optical axis of the second optical fiber is arranged symmetrically is taken as a plane of symmetry. A ferrule is revealed that is characterized by symmetry in the plane. According to such a ferrule, in a lens connector that holds the ends of two optical fibers, the structure of the ferrule is improved while suppressing the optical path length difference from the end face of the optical fiber to the lens for the two optical fibers. can be simplified.

The distance between the optical axis of the first optical fiber and the optical axis of the second optical fiber, and the distance between the center of the first lens section and the center of the second lens section preferably equal. As a result, in a lens connector that holds the ends of two optical fibers, it is possible to simplify the structure of the ferrule while suppressing the optical path length difference between the end faces of the two optical fibers and the lens. can.

a first optical fiber, a second optical fiber arranged side by side with respect to the first optical fiber, and a ferrule holding ends of the first optical fiber and the second optical fiber A ferrule with fiber having a first abutment surface for abutting the end surface of the first optical fiber and a second abutment surface for abutting the end surface of the second optical fiber A contact surface, a first lens portion arranged corresponding to the end surface of the first optical fiber, and a second lens portion arranged corresponding to the end surface of the second optical fiber, The first abutment surface is inclined with respect to a plane perpendicular to the optical axis of the first optical fiber, and the second abutment surface is a plane perpendicular to the optical axis of the second optical fiber. , and the optical axis of the first optical fiber and the optical axis of the second optical fiber are arranged symmetrically with respect to a certain plane. A ferrule with fiber is revealed, characterized in that the first abutment surface and the second abutment surface are symmetrical in the plane of symmetry. According to such a ferrule with fiber, in a lens connector that holds the ends of two optical fibers, the difference in optical path length from the end face of the optical fiber to the lens of the two optical fibers can be suppressed, and the ferrule The structure can be simplified.

It is preferable that the distance from the end surface of the first optical fiber to the first lens section and the distance from the end surface of the second optical fiber to the second lens section are equal. As a result, the optical path length from the end surface of the first optical fiber to the lens surface of the first lens unit of the optical signal entering and exiting the first optical fiber and the optical path length of the optical signal entering and exiting the second optical fiber are determined. It is possible to prevent the optical path length from the end surface of the second optical fiber to the lens surface of the second lens unit from being different.

The end surface of the first optical fiber is formed so as to be inclined with respect to a plane perpendicular to the optical axis of the first optical fiber, is in contact with the first abutment surface, and receives the second light beam. It is desirable that the end face of the fiber be inclined with respect to a plane perpendicular to the optical axis of the second optical fiber and be in contact with the second abutting surface. Thereby, the gap between the end surface of the optical fiber and the abutting surface can be reduced.

a first optical fiber, a second optical fiber arranged side by side with respect to the first optical fiber, and a ferrule holding ends of the first optical fiber and the second optical fiber A method for manufacturing a ferrule with fibers comprising: a first abutment surface for abutting the end surface of the first optical fiber; and a second abutment surface for abutting the end surface of the second optical fiber a surface, a first lens portion arranged corresponding to the end surface of the first optical fiber, and a second lens portion arranged corresponding to the end surface of the second optical fiber, The first abutment surface is inclined with respect to a plane perpendicular to the optical axis of the first optical fiber, and the second abutment surface is inclined with respect to a plane perpendicular to the optical axis of the second optical fiber. and the optical axis of the first optical fiber and the optical axis of the second optical fiber are arranged symmetrically with respect to a certain plane. Preparing a ferrule in which the first abutment surface and the second abutment surface are symmetrical with respect to the plane of symmetry, and abutting the end surface of the first optical fiber against the first abutment surface. , a method of manufacturing a ferrule with fiber, characterized in that the end surface of the second optical fiber is abutted against the second abutment surface. According to such a method for manufacturing a ferrule with fibers, in a lens connector that holds the ends of two optical fibers, the optical path length difference from the end face of the optical fiber to the lens is suppressed for the two optical fibers. , the structure of the ferrule can be simplified.

cutting the end face of the first optical fiber so as to be inclined with respect to a plane perpendicular to the optical axis of the first optical fiber; It is desirable to cut the end face so as to be inclined with respect to a plane perpendicular to the optical axis of the optical fiber. Thereby, the gap between the end surface of the optical fiber and the abutting surface can be reduced.

A ferrule for holding an end of a first optical fiber and an end of a second optical fiber arranged side by side with respect to the first optical fiber, wherein the end face of the first optical fiber is a first abutting surface for abutting; a second abutting surface for abutting the end face of the second optical fiber; and a second lens portion arranged corresponding to the end surface of the second optical fiber, wherein the first abutting surface is perpendicular to the optical axis of the first optical fiber and the second abutment surface is inclined with respect to a plane perpendicular to the optical axis of the second optical fiber, and the first abutment surface and the second abutment surface are inclined with respect to a plane perpendicular to the optical axis of the second optical fiber. A ferrule characterized by being formed so as to be symmetrical with respect to the plane becomes clear. According to such a ferrule, in a lens connector that holds the ends of two optical fibers, the structure of the ferrule is improved while suppressing the optical path length difference from the end face of the optical fiber to the lens for the two optical fibers. can be simplified.

a first optical fiber, a second optical fiber arranged side by side with respect to the first optical fiber, and a ferrule holding ends of the first optical fiber and the second optical fiber A ferrule with fiber having a first abutment surface for abutting the end surface of the first optical fiber and a second abutment surface for abutting the end surface of the second optical fiber A contact surface, a first lens portion arranged corresponding to the end surface of the first optical fiber, and a second lens portion arranged corresponding to the end surface of the second optical fiber, The first abutment surface is inclined with respect to a plane perpendicular to the optical axis of the first optical fiber, and the second abutment surface is a plane perpendicular to the optical axis of the second optical fiber. , and the first abutment surface and the second abutment surface are formed symmetrically. According to such a ferrule with fiber, in a lens connector that holds the ends of two optical fibers, the difference in optical path length from the end face of the optical fiber to the lens of the two optical fibers can be suppressed, and the ferrule The structure can be simplified.

a first optical fiber, a second optical fiber arranged side by side with respect to the first optical fiber, and a ferrule holding ends of the first optical fiber and the second optical fiber A method for manufacturing a ferrule with fibers comprising: a first abutment surface for abutting the end surface of the first optical fiber; and a second abutment surface for abutting the end surface of the second optical fiber a surface, a first lens portion arranged corresponding to the end surface of the first optical fiber, and a second lens portion arranged corresponding to the end surface of the second optical fiber, The first abutment surface is inclined with respect to a plane perpendicular to the optical axis of the first optical fiber, and the second abutment surface is inclined with respect to a plane perpendicular to the optical axis of the second optical fiber. preparing a ferrule that is inclined with respect to the first abutment surface and that is formed such that the second abutment surface is symmetrical; A method of manufacturing a ferrule with fibers is disclosed, which comprises abutting an end face of an optical fiber, and abutting an end face of the second optical fiber against the second abutment surface. According to such a method for manufacturing a ferrule with fibers, in a lens connector that holds the ends of two optical fibers, the optical path length difference from the end face of the optical fiber to the lens is suppressed for the two optical fibers. , the structure of the ferrule can be simplified.

===this embodiment===
<Overview of ferrule structure 10>
FIG. 1A is an overall perspective view of a ferrule structure 10 of this embodiment. FIG. 1B is an exploded perspective view of the ferrule structure 10 of this embodiment. FIG. 2A is an exploded perspective view of the ferrule structure 10 of this embodiment viewed from below. FIG. 2B is a cross-sectional view of the fiber-attached ferrule structure 10 of this embodiment.

In the following description, each direction is defined as shown in the figure. That is, the direction of the fiber hole 22 (the fiber hole 22A and the fiber hole 22B) is defined as the "front-rear direction", and the end face side of the optical fiber 1 (the optical fiber 1A and the optical fiber 1B) inserted into the fiber hole 22 or the ferrule The side of the lens plate 12 as viewed from the main body 11 is defined as "front", and the opposite side is defined as "rear". Also, the direction in which the two main body side guide holes 21 are aligned or the direction in which the two plate side guide holes 32 are aligned is defined as the "left and right direction", and the right side when viewed from the rear side to the front side is defined as the "right direction". is "left". A direction perpendicular to the front-rear direction and the left-right direction is defined as the "vertical direction". In the case of the optical connector having the ferrule structure 10, the side on which the key 5 (see FIG. 3B, which will be described later) is provided is defined as "top", and the opposite side is defined as "bottom".

The ferrule structure 10 is a member for holding the ends of the optical fibers 1 (the optical fibers 1A and 1B) and optically connecting the optical fibers 1 to other optical components. The ferrule structure 10 is sometimes simply called "ferrule". The ferrule structure 10 has a ferrule body 11 and a lens plate 12 .

The ferrule body 11 is a member that holds the end of the optical fiber 1 . The ferrule body 11 has two body side guide holes 21 , a fiber hole 22 (fiber hole 22A and fiber hole 22B), a fiber insertion port 23 and an adhesive filling portion 24 .

The ferrule body 11 has substantially the same structure as, for example, an MT type optical connector (F12 type optical connector established by JIS C5981; MT: Mechanically Transferable). However, in a normal MT type optical connector, the end face of the ferrule and the end face of the optical fiber are polished. The end face 3 (end face 3A and end face 3B) protrudes from the front end face 20 (open face of the fiber hole 22) of the ferrule body 11, and the end face of the ferrule and the end face of the optical fiber are not polished. In addition, in a normal MT type optical connector, the end face of the fiber is exposed at the end face of the ferrule. Since the end face of the optical fiber is abutted against the lens plate 12, the end face of the optical fiber is not exposed to the outside.

The two body-side guide holes 21 are holes for inserting guide pins (not shown). As will be described later, the body-side guide hole 21 is also used for alignment between the ferrule body 11 and the lens plate 12 . The body-side guide holes 21 pass through the ferrule body 11 along the front-rear direction, and the two body-side guide holes 21 are opened in the front end surface 20 of the ferrule body 11 . The two main-body-side guide holes 21 are spaced apart in the left-right direction so as to sandwich the plurality of fiber holes 22 (fiber holes 22A and 22B) in the left-right direction.

A fiber hole 22 is a hole for inserting the optical fiber 1 . Also, the fiber hole 22 is a hole for positioning the optical fiber 1 . Therefore, the fiber hole 22 is formed with high precision with respect to the body-side guide hole 21 . The fiber hole 22 penetrates between the front end face 20 and the adhesive filling portion 24 , and the fiber hole 22 opens in the front end face 20 of the ferrule body 11 . A bare optical fiber obtained by removing the coating from the optical fiber core wire is inserted into the fiber hole 22 . The fiber hole 22 is formed along the front-rear direction.

A plurality of fiber holes 22 (fiber hole 22A and fiber hole 22B) are formed in the ferrule body 11 of this embodiment. Furthermore, in the present embodiment, two rows of fiber holes 22 arranged in the horizontal direction are formed in the vertical direction. As shown in FIGS. 1B-2B, the upper row of fiber holes 22 may be referred to as fiber holes 22A and the lower row of fiber holes 22 may be referred to as fiber holes 22B. Optical fibers 1 (optical fibers 1A and 1B) constituting an optical fiber tape (optical fiber ribbon) are respectively inserted into rows of fiber holes 22 (fiber holes 22A and fiber holes 22B) aligned in the horizontal direction. It will be. In this embodiment, an optical fiber tape (optical fiber ribbon) composed of the optical fibers 1A is inserted into the fiber hole 22A, and an optical fiber tape (optical fiber ribbon) composed of the optical fibers 1B is inserted into the fiber hole 22B. will be However, the fiber holes 22A and the fiber holes 22B do not have to be rows of fiber holes arranged side by side in the left-right direction. For example, only one fiber hole 22A may be formed on the upper side and one fiber hole 22B may be formed on the lower side. In this case, the optical fibers 1 inserted into the fiber holes 22A and 22B are not optical fiber tapes (optical fiber ribbons) but single optical fibers.

The fiber insertion port 23 is an opening formed in the rear end face of the ferrule body 11 . The optical fiber 1 (optical fiber 1A and optical fiber 1B) is inserted into the ferrule body 11 through the fiber insertion port 23 . A boot (not shown) may be inserted into the ferrule body 11, so the fiber insertion port 23 is sometimes called a "boot hole".

The adhesive filling portion 24 is a hollow portion for filling with an adhesive. The adhesive-filled portion 24 is filled with an adhesive for holding the optical fiber 1 to the ferrule body 11 . By filling the adhesive-filled portion 24 with the adhesive, the adhesive is applied between the adhesive-filled portion 24 and the inner wall surface of the fiber hole 22 and the optical fiber 1, and the adhesive hardens to harden the optical fiber. 1 will be fixed to the ferrule body 11 .

The lens plate 12 is an optical member provided with a plurality of lenses (upper lens portion 33A and lower lens portion 33B). The lens plate 12 is molded from a transparent resin that allows optical signals to pass therethrough. The lens plate 12 is arranged on the front side of the ferrule body 1 with its rear end face 31 in contact with the front end face 20 of the ferrule body 11 . The lens plate 12 has two plate-side guide holes 32, a lens portion 33 (an upper lens portion 33A and a lower lens portion 33B), and an abutting surface 36 (an upper abutting surface 36A and a lower abutting surface 36B). have

The two plate-side guide holes 32 are holes for inserting guide pins (not shown). By inserting the guide pin into the plate-side guide hole 32, the ferrule structures 10 are aligned with each other. The plate-side guide hole 32 is also used for alignment between the ferrule body 11 and the lens plate 12 . Therefore, the interval between the two plate-side guide holes 32 is the same as the interval between the two body-side guide holes 21 of the ferrule body 10 . That is, the distance between the central axes of the two plate-side guide holes 32 is the same as the distance between the central axes of the two body-side guide holes 21 of the ferrule body 10 . The plate-side guide holes 32 pass through the lens plate 12 along the front-rear direction, and two plate-side guide holes 32 are opened in the front end surface 30 and the rear end surface 31 of the lens plate 12, respectively.

The lens portion 33 (upper lens portion 33A and lower lens portion 33B) has a plurality of optical fibers 1 (optical fiber 1A and optical fiber 1B) respectively inserted into a plurality of fiber holes 22 (fiber hole 22A and fiber hole 22B). , and an optical signal is incident on and emitted from the end face of the optical fiber 1 via the lens portion 33 . As described above, in this embodiment, the row of fiber holes 22A aligned in the horizontal direction is arranged above the ferrule body 11, and the row of fiber holes 22B aligned in the horizontal direction is arranged below the ferrule body 11. ing. As for the lens portions 33, two rows of the lens portions 33 arranged in the horizontal direction are arranged in the vertical direction. That is, by arranging the rows of the upper lens portions 33A arranged in the horizontal direction above the lens plate 12, they are arranged corresponding to the end surfaces of the optical fibers 1A inserted into the rows of the fiber holes 22A. Become. Further, by arranging the rows of the lower lens portions 33B arranged in the left-right direction on the lower side of the lens plate 12, they are arranged corresponding to the end surfaces of the optical fibers 1B inserted into the rows of the fiber holes 22B. It will be. Therefore, the lens portion 33 is formed with high accuracy with respect to the plate-side guide hole 32 . The lens portion 33 is formed to function as, for example, a collimating lens. By inputting and outputting the optical signal whose diameter has been enlarged by the lens portion 33, the optical signal propagates as collimated light. Therefore, even if dust enters between the connectors, stable connection is possible, and the optical signal is transmitted. transmission loss can be suppressed. In addition, since the optical signal whose diameter is enlarged by the lens portion 33 is incident and emitted, the optical signal propagates as collimated light. can be suppressed. The lens portion 33 is formed on the front end surface 30 side of the lens plate 12 and formed on the front end surface of the ferrule structure 10 . In order to prevent the convex lens portions 33 from coming into contact with each other when the ferrule structures 10 face each other and butt against each other, the lens portions 33 are provided in recesses (lens placement portions 34) formed in the lens plate 12. is formed at the bottom of the However, when one fiber hole 22A is formed on the upper side of the ferrule body 11 and one fiber hole 22B is formed on the lower side of the ferrule body 11, the corresponding upper lens portion 33A and lower lens portion 33B are They will be placed one by one.

The abutment surface 36 is an abutment surface against which the end surface of the optical fiber 1 is abutted. The abutment surface 36 is formed at the bottom of an abutment surface arrangement portion 35 which is a portion recessed from the rear end surface 31 of the lens plate 12 . Therefore, when the lens plate 12 is attached to the ferrule body 11 via a guide pin (not shown) (described later), the abutment surface 36 faces the opening of the fiber hole 22 of the ferrule body 11 . The width of the bottom surface of the abutting surface arrangement portion 35 (abutting surface 36) in the horizontal direction is longer than the width of the row of the fiber holes 22 (fiber holes 22A and 22B) aligned in the horizontal direction (optical fiber tape width). A gap is formed between the opening surface of the fiber hole 22 of the ferrule body 11 and the abutment surface 36 of the lens plate 12 by forming the abutment surface arrangement portion 35 . That is, a gap is formed between the lens plate 12 and the ferrule body 11 by forming the abutment surface arrangement portion 35 on the lens plate 12, and this gap serves as an adhesive that functions as a refractive index matching agent. It becomes a matching agent filling portion for filling. In this embodiment, the abutment surface arrangement portion 35 is formed from the upper surface to the lower surface of the lens plate 12 . Therefore, the abutting surface arrangement portion 35 (matching agent filled portion) is open on the upper and lower surfaces of the ferrule structure 10 . However, the gap between the lens plate 12 and the ferrule body 11 may not be filled with the refractive index matching agent.

<Detailed configuration of abutment surface 36>
FIG. 3A is an explanatory diagram showing a state around the abutment surface 36. FIG.

The abutment surface 36 has an upper abutment surface 36A and a lower abutment surface 36B. The upper abutment surface 36A is an abutment surface for abutting the end surface of the optical fiber 1A inserted into the upper lens portion 33A. Further, the lower abutment surface 36B is a abutment surface for abutting the end face of the optical fiber 1B inserted into the lower lens portion 33B. As shown in FIG. 3A, the upper abutment surface 36A is inclined with respect to a plane perpendicular to the optical axis 2A of the optical fiber 1A (a plane perpendicular to the front-rear direction). The lower abutment surface 36B is also inclined with respect to a plane perpendicular to the optical axis 2B of the optical fiber 1B (a plane perpendicular to the front-rear direction). Furthermore, the inclination angle of the upper abutment surface 36A and the inclination angle of the lower abutment surface 36B are symmetrical with respect to the plane of symmetry 4 shown in FIG. 3A. That is, the upper abutment surface 36A and the lower abutment surface 36B are formed vertically symmetrically.

Here, the plane of symmetry 4 is a plane on which the optical axis 2A of the optical fiber 1A and the optical axis 2B of the optical fiber 1B are arranged symmetrically. As shown in FIG. 3A, the plane of symmetry 4 is a plane at the same distance from the optical axis 2A of the optical fiber 1A and the optical axis 2B of the optical fiber 1B arranged side by side (in parallel) with respect to the optical fiber 1A. is. However, in reality, the optical fibers 1A and the optical fibers 1B are arranged side by side in the left-right direction (the direction perpendicular to the paper surface of FIG. 3A), and the plane of symmetry 4 is the light of each optical fiber 1A. This plane is at the same distance from the axis 2A and each optical fiber 1B. Thereby, the plane of symmetry 4 becomes a plane in which the optical axis 2A of the optical fiber 1A and the optical axis 2B of the optical fiber 1B are arranged symmetrically. With the plane of symmetry 4 as a boundary, the upper abutment surface 36A is inclined forward toward the upper side, and the lower abutment surface 36B is inclined forward toward the lower side. The angle between the surface perpendicular to the optical axis 2A of the optical fiber 1A (the surface perpendicular to the front-rear direction) and the upper abutment surface 36A and the surface perpendicular to the optical axis 2B of the optical fiber 1B (the surface perpendicular to the front-rear direction) surface) and the lower abutting surface 36B are the same. Accordingly, the inclination angle of the upper abutment surface 36A and the inclination angle of the lower abutment surface 36B are symmetrical with respect to the plane of symmetry 4. As shown in FIG.

In this embodiment, as shown in FIG. 3A, the inclination angle of the upper abutment surface 36A and the inclination angle of the lower abutment surface 36B are symmetrical with respect to the plane of symmetry 4, thereby The optical path length from the end face 3A of the optical fiber 1A to be emitted to the lens surface of the upper lens portion 33A (the surface of the lens portion 33A), and the optical path length from the end face 3B of the optical fiber 1B to be emitted to and emitted from the optical fiber 1B. It is possible to suppress the difference in the optical path length to the lens surface of the side lens portion 33B (the surface of the lens portion 33B). Further, the abutment surface 36 is shaped to be convex rearward, that is, the upper abutment surface 36A is slanted forward as it goes upward, and the lower abutment surface 36B is slanted forward as it goes downward. can be easily molded. As a result, in the lens connector that holds the ends of two optical fibers 1 (the optical fiber 1A and the optical fiber 1B), the optical signal entering and exiting the optical fiber 1A is transferred from the end face 3A of the optical fiber 1A to the upper lens portion 33A. Simplifying the structure of the ferrule while suppressing the difference between the optical path length to the lens surface and the optical path length from the end surface 3B of the optical fiber 1B to the lens surface of the lower lens part 33B of the optical signal entering and exiting the optical fiber 1B. can be However, the abutment surface 36 may be recessed forward, that is, the upper abutment surface 36A may be inclined forward as it goes downward, and the lower abutment surface 36B may be inclined forward as it goes upward. good. Even in such a shape, the inclination angle of the upper abutment surface 36A and the inclination angle of the lower abutment surface 36B are symmetrical with respect to the plane of symmetry 4. Suppressing the difference between the optical path length to the lens surface of the upper lens part 33A and the optical path length from the end face 3B of the optical fiber 1B to the lens surface of the lower lens part 33B of the optical signal entering and exiting the optical fiber 1B. can do.

FIG. 3B is an explanatory diagram showing how optical connectors having the ferrule structure 10 of this embodiment are connected to each other.

In this embodiment, when connecting the optical connectors having the ferrule structure 10 to each other, one optical connector is opposed to the other optical connector while reversing the vertical direction. That is, the ferrule structure 10 of one optical connector and the ferrule structure 10 of the other optical connector face each other while being vertically inverted. As shown in FIG. 3B, the key 5 serving as a key for rotating the optical connectors with respect to the connecting direction is reversed in the vertical direction between the left and right optical connectors. As a result, as shown in FIG. 3B, in each ferrule structure 10, the upper lens portion 33A of one (for example, the ferrule structure 10 on the left side in FIG. 3B) It will face the lower lens portion 33B of the body 10). Similarly, the lower lens portion 33B on one side (eg, the left ferrule structure 10 in FIG. 3B) will face the upper lens portion 33A on the other side (eg, the right ferrule structure 10 in FIG. 3B). . As described above, the inclination angle of the upper abutment surface 36A and the inclination angle of the lower abutment surface 36B are arranged symmetrically with respect to the plane of symmetry 4, so that one ferrule structure is shown in FIG. 3B. Even when the other ferrule structure 10 is opposed to the body 10 while being vertically inverted, it is possible to prevent the optical path lengths of the upper and lower optical fibers 1 from being different.

FIG. 4 is an explanatory diagram showing how optical signals are transmitted between ferrule structures 10 facing each other.

In this embodiment, as shown in FIG. 4, the optical axis 2A of the optical fiber 1A held by one ferrule structure 10 (for example, the ferrule structure 10 on the left side in FIG. 4) and the other ferrule structure 10 ( For example, the ferrule structures 10 face each other so that the optical axis 2B of the optical fiber 1B held by the ferrule structure 10) on the right side of FIG. 4 is positioned on the same straight line. Similarly, the optical axis 2B of the optical fiber 1B held by one ferrule structure 10 (for example, the left ferrule structure 10 in FIG. 4) and the other ferrule structure 10 (for example, the right ferrule structure in FIG. 4) The ferrule structures 10 face each other so that the optical axis 2A of the optical fiber 1A held by the body 10) is aligned with the optical axis 2A.

Further, in this embodiment, as shown in FIG. 4, the distance between the optical axis 2A of the optical fiber 1A and the optical axis 2B of the optical fiber 1B, and the distance between the center 37A of the upper lens portion 33A and the lower lens portion 33B. is equal to the distance to the center 37B. In other words, the center 37A of the upper lens portion 33A is located on the optical axis 2A of the optical fiber 1A, and the center 37B of the lower lens portion 33B is located on the optical axis 2B of the optical fiber 1B. In this embodiment, the optical signal is refracted by the abutment surface 36, but the ferrule structure 10 does not need to be molded by shifting the lens portion 33 from the optical axis 2 of the optical fiber 1. FIG. Therefore, the structure of the ferrule of the lens connector that holds the ends of the two optical fibers 1 (optical fiber 1A and optical fiber 1B) can be simplified. However, the ferrule structure 10 may be molded with the lens portion 33 shifted from the optical axis 2 of the optical fiber 1 .

In the following, for example, a case in which an optical signal is transmitted from the optical fiber 1A held by the ferrule structure 10 on the right side of FIG. 4 toward the optical fiber 1B held by the ferrule structure 10 on the left side will be described. An optical signal transmitted through the optical fiber 1A enters the lens plate 12 from the end surface of the optical fiber 1A through the upper abutment surface 36A. As described above, the upper abutment surface 36A is inclined forward toward the upper side with respect to the plane perpendicular to the optical axis 2A of the optical fiber 1A (the plane perpendicular to the front-rear direction). Therefore, as shown in FIG. 4, after being incident on the upper abutment surface 36A, it is transmitted as an optical signal (lens incident/emitted light 6) refracted downward. The angle of the refracted light (lens incident/emitted light 6) on the upper abutting surface 36A depends on Snell's law. Then, the lens incident/emitted light 6 is collimated as collimated light 7 via the upper lens portion 33A. In this embodiment, the center 37A of the upper lens portion 33A is located on the optical axis 2A of the optical fiber 1A. That is, the axis of the lens incident/emitted light 6 is deviated from the center 37A of the upper lens portion 33A. However, by forming the upper lens portion 33A (lens portion 33) large in consideration of such a deviation, the optical path of the lens incident/emitted light 6 can be incident without protruding from the lens surface of the upper lens portion 33A. can.

<Comparative example>
FIG. 6A is an explanatory view showing the surroundings of the abutment surface 36 of the fiber-attached ferrule structure 10 of the first comparative example.

In this embodiment described above, the abutment surface 36 is formed by the upper abutment surface 36A inclined forward with respect to the plane perpendicular to the optical axis 2A of the optical fiber 1A and the optical axis 2B of the optical fiber 1B. It has a lower abutment surface 36B which is inclined forward toward the lower side with respect to the vertical surface. In the first comparative example shown in FIG. 6A, the abutment surface 36 is inclined forward with respect to a plane perpendicular to the optical axis 2A of the optical fiber 1A (or the optical axis 2B of the optical fiber 1B). formed on one side.

In the first comparative example, the end surfaces of the two optical fibers 1 (the optical fiber 1A and the optical fiber 1B) are abutted against the abutting surface 36 formed of one inclined surface. . Therefore, for example, the position of the end surface of the optical fiber 1A in the optical axis direction (front-back direction) differs from the position of the end surface of the optical fiber 1B in the optical axis direction (front-back direction). Therefore, the optical path length from the end face of the optical fiber 1A to the lens for the optical signal entering and exiting the optical fiber 1A is different from the optical path length from the end face of the optical fiber 1B to the lens for the optical signal entering and exiting the optical fiber 1B. put away.

FIG. 6B is an explanatory view showing the surroundings of the abutment surface 36 of the fiber-attached ferrule structure 10 of the second comparative example.

In the second comparative example, a step is provided so that the end faces of two optical fibers 1 (optical fiber 1A and optical fiber 1B) arranged vertically are aligned in the optical axis direction (front-rear direction). The abutment surface 36 is formed in multiple steps. As a result, the optical path length from the end face of the optical fiber 1A to the lens for the optical signal entering and exiting the optical fiber 1A differs from the optical path length from the end face of the optical fiber 1B to the lens for the optical signal entering and exiting the optical fiber 1B. can be suppressed. However, the provision of the step complicates the structure of the ferrule structure 10 .

Compared with the first comparative example, in the present embodiment described above, the inclination angle of the upper abutment surface 36A and the inclination angle of the lower abutment surface 36B are made symmetrical with respect to the plane of symmetry 4, so that light The optical path length from the end surface 3A of the optical fiber 1A to the lens surface of the upper lens portion 33A of the optical signal entering and exiting the fiber 1A, and the optical path length from the end surface 3B of the optical fiber 1B to the lower lens portion of the optical signal entering and exiting the optical fiber 1B It is possible to suppress the difference in optical path length to the lens surface of 33B. In addition, the abutment surface 36 has a rearward convex shape, that is, a shape in which the upper abutment surface 36A is inclined forward as it goes upward, and the lower abutment surface 36B is inclined forward as it goes downward. can be easily molded as compared with the shape provided with a step like the fiber-attached ferrule structure 10 of the second comparative example.

<Manufacturing method of fiber-attached ferrule structure 10>
FIG. 5 is a flow chart of a manufacturing method (assembling procedure) of the fiber-attached ferrule structure 10 of this embodiment.

First, an operator prepares the ferrule body 11 and the lens plate 12 (S101). The operator also prepares a guide pin (not shown) for the next step. The operator also prepares a jig or the like for assembling the ferrule body 11 and the lens plate 12 as necessary.

Next, the operator aligns the ferrule body 11 and the lens plate 12 with guide pins (S102). At this time, the operator inserts guide pins (not shown) into both the body-side guide hole 21 of the ferrule body 11 and the plate-side guide hole 32 of the lens plate 12 . As a result, the ferrule body 11 and the lens plate 12 are aligned vertically and horizontally. Further, the operator brings the front end surface 20 of the ferrule body 11 and the rear end surface 31 of the lens plate 12 into contact with each other while inserting the guide pin. As a result, the ferrule body 11 and the lens plate 12 are aligned in the front-rear direction. By setting the ferrule structure 10 to which the ferrule body 11 and the lens plate 12 are attached via a guide pin (not shown) on a jig, the front end face 20 of the ferrule body 11 and the rear end face 31 of the lens plate 12 can be separated. may be kept in contact with each other.

In S102, when the ferrule body 11 and the lens plate 12 are aligned, the positional relationship between the ferrule body 11 and the lens plate 12 is as shown in FIGS. 1A and 2B (guide pins are not shown). At this time, a gap is formed between the lens plate 12 and the ferrule body 11 by the abutment surface arrangement portion 35 of the lens plate 12 . Also, the abutment surface 36 of the lens plate 12 faces the opening of the fiber hole 22 of the ferrule body 11 .

Next, the operator cuts the end face of each optical fiber 1 of the optical fiber tape (S103). The end face of the optical fiber 1 may be cut by laser cutting, mechanical cutting by a blade, or polishing. As described above, the inclination angle of the upper abutment surface 36A and the inclination angle of the lower abutment surface 36B are arranged symmetrically with respect to the plane of symmetry 4. The inclination angle of the end surface of the optical fiber 1 to be applied is also cut so as to be symmetrical with respect to the plane of symmetry 4 .

Next, the operator inserts each optical fiber 1 of the optical fiber tape into the fiber hole 22 of the ferrule body 11 (S104). Then, the optical fiber 1 is protruded from the front end face 20 of the ferrule body 11 (open face of the fiber hole 22). However, at this stage, the end surface of the optical fiber 1 is not abutted against the abutment surface 36 of the lens plate 12 (the bottom surface of the abutment surface arrangement portion 35). This is because when the optical fiber 1 is passed through the fiber hole 22, dust or the like may adhere to the end surface of the optical fiber 1. FIG.

Note that the end face of the optical fiber 1 may be washed (not shown) before S105 (butting process) and S106 (optical fiber retaining process), which will be described later. For example, the operator blows air to blow off dust adhering to the end face of the optical fiber 1 protruding from the front end face 20 of the ferrule body 11 . As a result, dust on the end face of the optical fiber 1 attached when the optical fiber 1 was inserted into the fiber hole 22 (S104) can be removed.

Next, the operator further inserts the optical fiber 1 and abuts the end surface of the optical fiber 1 against the abutment surface 36 of the lens plate 12 (105). As described above, the end face of the optical fiber 1 is formed so as to be inclined with respect to the plane perpendicular to the front-rear direction (the plane perpendicular to the optical axis of the optical fiber 1). Further, the optical fiber 1 is inserted into the fiber hole 22 so that the inclined end surface of the optical fiber 1 is in contact with the abutting surface 36 . Thereby, it is possible to suppress the formation of an air layer between the end surface of the optical fiber 1 and the abutment surface 36 . Incidentally, in this embodiment, the operator inserts the boot into the fiber insertion port 23 . However, it is not necessary to insert the boot into the fiber insertion port 23 .

Next, the operator holds the optical fiber 1 to the ferrule body 11 (S106). In the optical fiber retaining process of S106, the operator first fills the adhesive filling portion 24 of the ferrule body 11 with the adhesive. Thereby, the adhesive is applied between the inner wall surface of the adhesive filling portion 24 and the optical fiber 1 . When the adhesive filling portion 24 is filled with adhesive, the adhesive permeates between the inner wall surface of the fiber hole 22 and the optical fiber 1 . Then, the operator fills the opening above the abutting surface arrangement portion 35 with an adhesive that serves as a refractive index matching agent. When the abutment surface arrangement portion 35 is filled with an adhesive that serves as a refractive index matching agent in S106, the adhesive permeates into minute gaps between the contact surfaces of the ferrule main body 11 and the lens plate 12 . As a result, when the adhesive is cured, the ferrule body 11 and the lens plate 12 can be adhered and fixed. Therefore, the work of bonding and fixing the ferrule body 11 and the lens plate 12 is facilitated. Finally, the operator cures the adhesive. If an ultraviolet curable resin is used as the adhesive, the operator will irradiate the adhesive with ultraviolet rays. Moreover, when an ultraviolet curable resin is used as the adhesive, the operator will perform heating.

===Others===
As shown in FIG. 3A, the end face 3A of the optical fiber 1A is formed so as to be inclined with respect to a plane perpendicular to the optical axis 2A of the optical fiber 1A and is formed so as to be in contact with the upper abutting face 36A. there is Similarly, the end surface 3B of the optical fiber 1B is formed so as to be inclined with respect to the plane perpendicular to the optical axis 2B of the optical fiber 1B and is formed so as to be in contact with the lower abutting surface 36B. The inclined end face 3A of the optical fiber 1A and the inclined end face 3B of the optical fiber 1B are formed by polishing. When cutting the end face of the optical fiber 1 (S103 of the manufacturing method of the fiber-attached ferrule structure 10), the inclined end face may be formed by laser cutting or mechanical cutting with a blade. Thereby, the gap between the end surface of the optical fiber and the abutment surface can be reduced. However, the end face 3A of the optical fiber 1A is not formed to be inclined with respect to the plane perpendicular to the optical axis 2A of the optical fiber 1A. It may be a vertical plane. As a result, it does not have to be formed in contact with the upper abutment surface 36A. Further, the end surface 3B of the optical fiber 1B is not formed so as to be inclined with respect to the plane perpendicular to the optical axis 2B of the optical fiber 1B. It may be a vertical plane. Thereby, it does not have to be formed so as to be in contact with the lower abutment surface 36B.

FIG. 7 is an explanatory diagram showing another example of the ferrule structure 10 with fiber.

In the fiber-attached ferrule structure 10 shown in FIG. 7, the end face 3A of the optical fiber 1A is a plane perpendicular to the optical axis 2A. Similarly, in the fiber-attached ferrule structure 10 shown in FIG. 7, the end surface 3B is a surface perpendicular to the optical axis 2B. Note that the abutting surface arrangement portion 35 between the lens plate 12 and the ferrule body 11 is filled with a refractive index matching agent. Other configurations are the same as those of the fiber-attached ferrule structure 10 shown in FIG. 3A.

Also in the ferrule structure 10 with fiber shown in FIG. The optical path length from the end surface 3A of the optical fiber 1A to the lens surface of the upper lens portion 33A of the emitted optical signal, and the optical path length from the end surface 3B of the optical fiber 1B to the lens surface of the lower lens portion 33B of the optical signal entering and exiting the optical fiber 1B It is possible to suppress the difference in the optical path length up to. Further, the abutment surface 36 is shaped so as to protrude rearward, that is, the upper abutment surface 36A is inclined forward as it goes upward, and the lower abutment surface 36B is inclined forward as it goes downward. can be easily molded. As a result, in the lens connector holding the ends of the two optical fibers 1 (the optical fiber 1A and the optical fiber 1B), the optical signal entering and exiting the optical fiber 1A is transmitted from the end face 3A of the optical fiber 1A to the upper lens portion 33A. Simplifying the structure of the ferrule while suppressing the difference between the optical path length to the lens surface and the optical path length from the end surface 3B of the optical fiber 1B to the lens surface of the lower lens part 33B of the optical signal entering and exiting the optical fiber 1B. can be

The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit interpretation of the present invention. The present invention can be modified and improved without departing from its spirit, and it goes without saying that the present invention includes equivalents thereof.

1A optical fiber (first optical fiber),
1B optical fiber (second optical fiber),
2A/2B optical axis of optical fiber, 3A/3B end face,
4 symmetry plane, 5 key, 6 lens incident and outgoing light, 7 collimated light,
10 ferrule structure,
11 ferrule body, 12 lens plate, 20 front end face,
21 body side guide hole, 22A/22B fiber hole,
23 fiber insertion port, 24 adhesive filling portion, 30 front end face,
31 rear end face, 32 plate side guide hole,
33A upper lens part (first lens part),
33B lower lens part (second lens part),
34 lens placement portion, 35 abutting surface placement portion,
36A upper abutment surface (first abutment surface),
36B lower abutment surface (second abutment surface), 37A/37B center

Claims (7)

A ferrule for holding an end of a first optical fiber and an end of a second optical fiber arranged side by side with the first optical fiber,
a first abutment surface for abutting the end surface of the first optical fiber;
a second abutment surface for abutting the end surface of the second optical fiber;
a first lens portion arranged corresponding to the end surface of the first optical fiber;
a second lens portion disposed corresponding to the end surface of the second optical fiber;
the first abutment surface is inclined with respect to a plane perpendicular to the optical axis of the first optical fiber;
the second abutment surface is inclined with respect to a plane perpendicular to the optical axis of the second optical fiber ;
The angle between the first abutment surface and the plane perpendicular to the optical axis of the first optical fiber is the angle between the second abutment surface and the plane perpendicular to the optical axis of the second optical fiber. is consistent with the angle of
The direction of inclination of the first abutment surface with respect to the plane perpendicular to the optical axis of the first optical fiber is the direction of inclination of the second abutment surface with respect to the plane perpendicular to the optical axis of the second optical fiber. A ferrule characterized by being opposite to. A ferrule according to claim 1,
The distance between the optical axis of the first optical fiber and the optical axis of the second optical fiber, and the distance between the center of the first lens section and the center of the second lens section A ferrule characterized by being equal to . a first optical fiber;
a second optical fiber arranged side by side with respect to the first optical fiber;
A fiber-equipped ferrule having a ferrule for holding ends of the first optical fiber and the second optical fiber,
The ferrule is
a first abutment surface for abutting the end surface of the first optical fiber;
a second abutment surface for abutting the end surface of the second optical fiber;
a first lens portion arranged corresponding to the end surface of the first optical fiber;
a second lens portion arranged corresponding to the end surface of the second optical fiber,
the first abutment surface is inclined with respect to a plane perpendicular to the optical axis of the first optical fiber;
the second abutment surface is inclined with respect to a plane perpendicular to the optical axis of the second optical fiber ;
The angle between the first abutment surface and the plane perpendicular to the optical axis of the first optical fiber is the angle between the second abutment surface and the plane perpendicular to the optical axis of the second optical fiber. is consistent with the angle of
The direction of inclination of the first abutment surface with respect to the plane perpendicular to the optical axis of the first optical fiber is the direction of inclination of the second abutment surface with respect to the plane perpendicular to the optical axis of the second optical fiber. A ferrule with fiber characterized in that it is opposite to A ferrule with fiber according to claim 3,
A ferrule with fiber, wherein the distance from the end surface of the first optical fiber to the first lens portion is equal to the distance from the end surface of the second optical fiber to the second lens portion. The ferrule with fiber according to claim 3 or 4,
an end surface of the first optical fiber is formed to be inclined with respect to a plane perpendicular to the optical axis of the first optical fiber and is in contact with the first abutting surface;
An end surface of the second optical fiber is formed to be inclined with respect to a plane perpendicular to the optical axis of the second optical fiber, and is in contact with the second abutting surface. ferrule with. a first optical fiber, a second optical fiber arranged side by side with respect to the first optical fiber, and a ferrule holding ends of the first optical fiber and the second optical fiber A method for manufacturing a fiber-equipped ferrule having
a first abutment surface for abutting the end surface of the first optical fiber;
a second abutment surface for abutting the end surface of the second optical fiber;
a first lens portion arranged corresponding to the end surface of the first optical fiber;
a second lens portion arranged corresponding to the end surface of the second optical fiber,
the first abutment surface is inclined with respect to a plane perpendicular to the optical axis of the first optical fiber;
the second abutment surface is inclined with respect to a plane perpendicular to the optical axis of the second optical fiber ;
The angle between the first abutment surface and the plane perpendicular to the optical axis of the first optical fiber is the angle between the second abutment surface and the plane perpendicular to the optical axis of the second optical fiber. is consistent with the angle of
The direction of inclination of the first abutment surface with respect to the plane perpendicular to the optical axis of the first optical fiber is the direction of inclination of the second abutment surface with respect to the plane perpendicular to the optical axis of the second optical fiber. preparing a ferrule that is opposite to
abutting the end surface of the first optical fiber against the first abutting surface;
A method for manufacturing a ferrule with fiber, characterized in that the end surface of the second optical fiber is butted against the second abutment surface. A method for manufacturing a ferrule with fiber according to claim 6,
cutting the end face of the first optical fiber so as to be inclined with respect to a plane perpendicular to the optical axis of the first optical fiber;
A method of manufacturing a ferrule with fiber, wherein the end face of the second optical fiber is cut so as to be inclined with respect to a plane perpendicular to the optical axis of the second optical fiber.

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