WO2004090596A1

WO2004090596A1 - Optical fiber connector

Info

Publication number: WO2004090596A1
Application number: PCT/JP2003/004242
Authority: WO
Inventors: Tomohiro Hikosaka
Original assignee: Suncall Corporation
Priority date: 2003-04-02
Filing date: 2003-04-02
Publication date: 2004-10-21
Also published as: AU2003220833A1

Abstract

An optical fiber connector used for connecting polarization storage type optical fibers, comprising a housing (4) having a housing body (5) and an auxiliary housing (6), a ferrule (7), a compression spring (8), and a rotation restricting and sliding mechanism having a stop key member, wherein the ferrule (7) and the optical fibers are fitted, slidably in axial direction, to the auxiliary housing (6) through the rotation restricting and sliding mechanism, a slit (21) is formed in the tubular part (15) of the housing body (5), a rotation restricting projection (25) engaged with the slit (21) is formed on the insert tube part (22) of the auxiliary housing (6) and engaged with the slit (21) to prevent the auxiliary housing (6) from being rotated relative to the housing body (5), and at the time of assembly, the adhesive part of the rotation restricting and sliding mechanism is fixed after the ferrule (7) is rotated to adjust the rotational phases of the ferrule and the optical fibers so that the major axis of the optical fibers faces a reference direction.

Description

Description Optical fiber connector Technical field

The present invention relates to an optical fiber connector used for optically connecting the ends of optical fibers via an adapter, and in particular, to a light such as a polarization-maintaining optical fiber in which a rotation angle deviation greatly affects light transmission characteristics when a connector is connected. The present invention relates to an optical fiber connector suitable for optically connecting a fiber.

Background art

Conventionally, an optical fiber connector has a housing that can be attached to and detached from an adapter, a ferrule that is mounted on the housing so as to be movable in the axial direction, and that holds an end of the optical fiber. It has a compression coil spring that urges it to the side. A fiber through-hole (for example, 127 μm in diameter) is formed at the tip of the ferrule, and a bare fiber of an optical fiber (for example, 125 μm in diameter) is passed through and held by the fiber through-hole. When the two optical fiber connectors are connected via the adapter, the ends of the pair of ferrules and the ends of the pair of optical fibers are abutted and connected by the urging force of the compression coil spring.

A wide variety of optical fiber connectors have been put into practical use, such as LC connectors, MU connectors, and SC connectors. As optical fibers, there are ordinary non-polarization-maintaining optical fibers and polarization-maintaining optical fibers. In recent optical multiplex communication, polarization-maintaining optical fibers have been adopted.

In an optical fiber connector for connecting an ordinary optical fiber, the light transmission efficiency is reduced depending on the rotational phase when connecting the optical fiber due to a manufacturing error of the ferrule. After adjustment, set the rotation phase of ferrule and optical fiber for paging.

In a conventional LC type optical fiber connector for connecting a normal optical fiber, Usually, a hexagonal flange is formed in the ferrule, a hexagonal hole is formed in the housing, and the rotational phase of the ferrule and the optical fiber is set at a position where the optical transmission loss is minimized during the connector assembly stage. After adjusting so that the phase becomes the maximum, fit the hexagonal flange of the ferrule into the hexagonal hole to regulate the rotation of the ferrule with respect to the housing. In the case of this optical fiber connector, the rotational phase of the ferrule and the optical fiber with respect to the housing cannot be adjusted at an angle smaller than 60 degrees, so that the rotational phase of the optical fiber cannot be precisely adjusted. .

The three types of polarization-maintaining optical fibers shown in Figs. 12 to 14 are in practical use. In these polarization-maintaining optical fibers 100 to 102, stress applying portions 100b to 102b made of, for example, B203 are formed in the vicinity of the core portions 100a to 102a. In addition, birefringence is realized in the core by stress applying portions having different refractive indices, and a polarization maintaining function is provided. Therefore, it is necessary to connect the polarization-maintaining optical fiber connector while maintaining the phase of the main axis of the optical fiber.

Fig. 15 shows the deviation angle 0 (-) of the main axis 104 with respect to the reference line 103 (reference direction) of the scope section of a predetermined optical fiber phase adjusting device in the stage of assembling the polarization maintaining optical fiber connector. FIG. 4 is a diagram showing a deviation angle of a main axis of another optical fiber with respect to a main axis of one optical fiber. FIG. 16 is an example of a graph showing the relationship of the extinction ratio (ER) with the aforementioned deviation angle 角 as a parameter.In order to secure an extinction ratio (ER) of 20 d′ B or more, the deviation angle Θ is 5. Must be less than 71 degrees. Japanese Patent Application Laid-Open No. 8-160255 discloses an SC type optical fiber connector for connecting a polarization maintaining optical fiber. The optical fiber connector has a housing, a ferrule, a stop ring, and a compression coil spring. A stop ring is screwed into the housing so as to be fitted inside, and a pair of keys of the stop ring is slidably engaged with a pair of key grooves of a flange portion of the ferrule. When assembling this connector, adjust the rotation phase by turning the ferrule and stop ring around the axis with respect to the housing, and then fix the housing and the stop ring with adhesive.

Problems to be solved by the present invention will be described.

For example, an LC fiber to connect a normal optical fiber polarization maintaining optical fiber The Aiva connector includes a housing composed of a housing body and an auxiliary housing (extender cap) partially inserted into the housing body, a ferrule, a compression coil spring, and a shaft that regulates rotation of a ferrule with respect to the housing. It has a rotation restricting mechanism and the like for holding it movably in the center direction. In this connector, the causes of the deviation in the rotational phase angle of the optical fiber include the angular deviation caused by the clearance between the housing and the auxiliary housing, the angular deviation caused by the clearance between the housing and the adapter, and the ferrule and the optical fiber. Angle shift when rotating and adjusting the phase.

Here, when a conventional LC-type optical fiber connector was actually measured, the angle deviation caused by the clearance between the housing body and the capture housing was a value of about 3.2 degrees or more. In this connector, the insertion cylinder of the auxiliary housing is inserted into the cylinder of the housing body, and a pair of engaging claws of the insertion cylinder is engaged with a pair of engagement holes of the cylinder to engage. However, since the width of the engagement hole is larger than the width of the locking claw, the angle shift of about 3.2 degrees or more occurs as described above. Due to this large angular deviation, the extinction ratio (E R) of the polarization-maintaining optical fiber connection part using the LC fiber-optic connector is significantly reduced. The conventional MU-type optical fiber connector is somewhat different from the above connector in the structure of the housing body and the auxiliary housing. However, the structure in which the auxiliary housing is partially fitted into the housing body and locked by a pair of rectangular holes and a pair of locking claws is almost the same as the connector described above.

Even in the case of an APC (Angled-Physical Contact) type optical fiber connector in which the tip of the bare fiber is inclined several degrees with respect to the direction perpendicular to the fiber axis, the rotation phase angle of the optical fiber with respect to the housing is set precisely. There must be.

In addition, even in a connector for connecting an ordinary optical fiber, the rotational phase of the ferrule and the optical fiber with respect to the housing is adjusted so that the rotational phase at which the light transmission efficiency is maximized, in consideration of a manufacturing error of the ferrule. However, the angular deviation between the housing main body and the auxiliary housing causes a deviation in the rotation phase of the optical fiber, which causes a reduction in light transmission efficiency.

An object of the present invention is to prevent an angular displacement between the housing body and the auxiliary housing. To provide an optical fiber connector having such a simple structure as to provide an optical fiber connector having a mechanism capable of continuously adjusting the rotational phase of a ferrule and an optical fiber with respect to a housing and fixing the same. That is. Disclosure of the invention

An optical fiber connector according to the present invention is an optical fiber connector to which an end of an optical fiber is attached, and which is used for optically connecting the ends of the optical fiber via an adapter. A housing having an auxiliary housing with an insertion tube portion partially inserted into the base end portion of the housing body and connected so as not to be detached in the axial direction of the optical fiber; the housing body and the insertion tube portion A slit or groove formed on one of the peripheral walls in parallel to the axial direction and open at the base end; and a rotation restricting projection formed on the other peripheral wall of the housing body and the insertion tube. A rotation restricting projection for restricting rotation of the auxiliary housing relative to the housing around the axis of the housing in such a manner that the slit or the groove cannot move in the width direction thereof. It is characterized by having.

At the time of assembling the connector, if the insertion cylinder part of the auxiliary housing is inserted into the housing from the base end side, the rotation regulating projection will engage with the slit or groove in the width direction so that it cannot move. The auxiliary housing cannot rotate. As a result, there is no angular displacement (rattle) between the housing body and the auxiliary housing. Here, in addition to the above configuration, the following various configurations can also be adopted.

(a) The optical fiber is a polarization-maintaining optical fiber.

(b) The slit is formed in a peripheral wall portion of the housing main body, and the rotation restricting projection is formed in the insertion tube portion.

(c) Further, a ferrule which holds the optical fiber at the distal end thereof and is movably mounted in the housing in the axial direction, and which is externally fitted to the ferrule in the housing and the ferrule is directed toward the distal end. A biasing compression coil spring; and a rotation regulating / sliding mechanism that regulates relative rotation of the ferrule with respect to the housing and allows sliding movement of the ferrule in the axial direction at a base end side of the housing. (d) The optical fiber connector is an LC type connector, and the catching housing is an extender cap.

(e) The optical fiber connector is an MU type connector, and the auxiliary housing is a stopping ring.

(f) The rotation restricting and sliding mechanism includes a base side slit formed in the base end of the auxiliary housing in parallel with the axial direction, and a base formed in the base end portion of the flue. A stop key having a base screw part at least partially protruding toward the end, a key part slidably engaged with the base slit, and externally screwed to the base screw. And a bonding part for fixing the ferrule and the stop key member.

(g) A rotation operation unit is provided at the base end of the ferrule to rotate the ferrule with respect to the housing at the stage of assembling the optical fiber connector.

(h) At the stage of assembling the optical fiber connector, the optical fiber connector is fixed to the housing by adjusting the rotational phase of the ferrule with respect to the housing so that the rotational phase is maximized.

(i) The optical fiber is a polarization-maintaining optical fiber, and in the assembling step of the optical fiber connector, the main axis of the polarization-maintaining optical fiber is in a rotational phase facing a reference direction. With the rotational phase of the ferrule adjusted with respect to the housing, the fixing is performed by the adhesive portion. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a configuration diagram of an adapter and an LC-type optical fiber connector according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the optical fiber connector, FIG. 3 is a plan view of the optical fiber connector, and FIG. 4 is a front view of the optical fiber connector, FIG. 5 is an exploded view of the optical fiber connector, FIG. 6 is an enlarged sectional view of the ferrule, and FIG. 7 is a housing body including an auxiliary housing, a ferrule, and a compression coil spring. FIG. 8 is a sectional view of an MU-type optical fiber connector according to another embodiment, FIG. 9 is a view showing a housing main body, and FIG. 10 is a view showing an auxiliary housing. , FIG. 11 is a sectional view of the housing body and the catching housing. Fig. 12 to Fig. 14 are explanatory diagrams of three types of polarization-maintaining optical fibers according to the prior art, and Fig. 15 illustrates the deviation angle of the polarization-maintaining optical fiber according to the prior art. FIG. 16 is a diagram showing the relationship between the shift angle and the extinction ratio according to the conventional technique. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. As shown in FIG. 1, an optical fiber connector 1 according to this embodiment has an optical connection between polarization-maintaining optical fibers 2 via an adapter 3 to which a distal end of a polarization-maintaining optical fiber 2 is attached. LC type optical fiber connector used for

As shown in FIGS. 2 to 5, an optical fiber connector 1 (hereinafter, referred to as a connector 1) passes through a housing 4 detachable from an adapter 3 and a bare fiber 2a at an end of the optical fiber 2. A ferrule 7 for holding the ferrule 7, a compression coil spring 8 for urging the ferrule 7 toward the distal end in the axial direction of the optical fiber 2, and a stop key member 9 for locking the base end of the ferrule 7 to the housing 4. And a rotation restricting and sliding mechanism 10 including the stop key member 9, a cap 11 for protecting the distal end of the optical fiber 2, and a boot 12 on the proximal end side of the connector 1.

As shown in FIGS. 2 to 5, the housing 4 includes a housing body 5 made of synthetic resin detachable from the adapter 3, and partially inserted into the housing body 5 so as to extend in the axial direction of the optical fiber 2. And a synthetic resin auxiliary housing 6 (referred to as an extender cap) connected so as not to be detached. The housing body 5 has a tubular portion 5 having a rectangular outer peripheral shape, and a lever portion 16 extending obliquely upward from an upper end of the tubular portion 15.

An inner flange 17 is formed on the inner distal end side of the cylindrical portion 15, an insertion hole 18 is formed on the distal end side of the inner flange 17, and one pair is formed on the proximal end portion of the cylindrical portion 15. The engagement hole 19 is formed. The lever portion 16 has appropriate elasticity in the vertical direction, and the lever portion 16 is formed with a pair of engagement projections 20.

As shown in FIGS. 2 to 5, the auxiliary housing 6 is inserted into the housing body 5. Insertion cylinder 22, a flange 23 extending from the insertion cylinder 22 to the base end side, and a rotation restricting part 24. As shown in FIG. 7, the peripheral wall on the upper surface side of the cylindrical portion 15 of the housing main body 5 is parallel to the axial direction of the optical fiber 2 in order to impart elasticity to the cylindrical portion 15. A slit 21 having an open base end (for example, a width of about 0.7 to 1.0 mm) is formed. The peripheral wall on the upper surface side of the insertion cylindrical portion 22 of the auxiliary housing 6 is engaged with the slit 21 so as to be immovable in the slit width direction and rotates around the axis of the capture housing 6 with respect to the housing body 5. The rotation regulating protrusion 25 for regulating the pressure is formed physically. The rotation restricting projection 25 is a linear projection that extends linearly in parallel with the axial direction.

The catch housing 6 is formed with a flange portion 23 having the same outer peripheral shape as the cylindrical portion 15 of the housing body 5, and a pair of engaging claws 2 is formed on the outer peripheral surface of the distal end portion of the input cylindrical portion 22. It is formed so as to correspond to a pair of engagement holes 19 of six forces. The rotation restricting portion 24 has a pair of semi-cylindrical portions 24a and a pair of base-side slits 24b between the semi-cylindrical portions 24a, and the base end of each semi-cylindrical portion 24a. The large diameter portion 24c of the portion is formed in a tapered shape.

The insertion cylindrical portion 22 of the auxiliary housing 6 is fitted into the cylindrical portion 15 with little play, and the rotation restricting projection 25 is engaged with the slit 21 immovably in the slit width direction. In the state where 23 is in contact with the base end face of the cylindrical portion 15, a pair of engaging claws 26 force S engages a pair of engaging holes 19, and the auxiliary housing 6 is loosely fitted to the housing body 5. They are connected without any connection.

As shown in FIGS. 5 and 6, the ferrule 7 holds the bare fiber 2a at the end of the optical fiber 2 through the optical fiber 2 and is mounted on the housing 4 so as to be movable in the axial direction of the optical fiber 2. Is done. The ferrule 7 has a ferrule body 30 (for example, about 18 mm in length) made of phosphor bronze and plated with nickel, and a cylindrical body 31 (for example, about 1.3 mm in diameter and about 5 mm in length) made of zirconia. ).

A fiber through hole 32 (for example, 1 mm in diameter) and a flange portion 33 are formed in the ferrule body 30, and the tip of the ferrule body 30 has a larger diameter than the fiber through hole 32. A mating hole 33a is formed. The base end portion of the cylindrical body 31 is fixed in the fitting hole 33 a in an inner fitting manner, and the cylindrical body 31 has a fiber through hole 3 4 (for example, a fiber through hole 34 communicating with the fiber through hole 32). , With a diameter of 127 ^ 111). Flange 3 3 The outer peripheral shape is circular, and the flange portion 33 is formed to have a larger diameter than the inner flange 17 of the housing body 5.

At the distal end of the optical fiber 2, the skin is peeled to expose the bare fiber 2a, and the bare fiber 2a is inserted into the fiber through hole 34 of the cylindrical body 31 and the proximal end of the bare fiber 2a The core wire 2 b including the skin on the side is passed through the fiber through hole 32 of the ferrule body 30, and is held in a state where the tip of the skin is in contact with the cylindrical body 31. The core wire 2 b of the optical fiber 2 is fixed to the inner surface of the ferrule main body 30 by an adhesive.

In this state, the cylindrical body 31 of the ferrule 7 and the distal end face of the bare fiber 2a are polished so as to be flush. With the ferrule 7 housed in the housing 4, the distal end portion of the cylindrical body 31 projects slightly forward from the housing 4. The body 30 of the fuel rod projects through the auxiliary housing 6 to the base end side, and a base end portion 35 of the ferrule 7 is formed at the base end portion. It protrudes more proximally than part 24.

At the base end of the ferrule 7, a rotation operation part 36 for rotating the ferrule 7 with a manual rotation tool is chamfered. With the ferrule 7 accommodated in the housing 4, the flange portion 33 can be engaged with the inner flange 17, so that the ferrule 7 does not come out of the housing 4 toward the distal end. As shown in FIG. 2, the compression coil spring 8 is mounted on the outer peripheral side of the ferrule body 30 and is provided between the flange portion 33 of the ferrule 7 and the auxiliary housing 6.

As shown in FIGS. 2, 5, and 8, the rotation regulating and sliding mechanism 10 regulates the relative rotation of the ferrule 7 with respect to the housing 4 at the base end side of the housing 4 and slides in the axial direction. It is acceptable. The rotation restricting / sliding mechanism 10 includes a pair of axially-oriented base-side slits 24 b formed in the rotation restricting portion 24 and an auxiliary formed at the base end of the ferrule 7. It has a base screw part 35 at least partially protruding toward the base end of the housing 6, and a pair of key parts 9a slidably engaged with these base slits 24b. And a stop key member 9 (for example, made of phosphor bronze) which is externally fitted to the base screw portion 35 of the ferrule 7 and screwed thereto, and a ferrule 7 and a base end of the key member 9. Adhesive part 10 a Have. As in the case of the pair of slits 24b, the pair of key portions 9a are formed opposite to each other at axially symmetric positions.

As shown in FIGS. 2 and 5, the key member 9 has a pair of key portions 9a and a ring portion 9b, and the pair of key portions 9a protrudes from the outer peripheral surface of the ring portion 9b. Most of the ring portion 9 b is fitted in the rotation restricting portion 24 of the auxiliary housing 6. At the final stage of assembling the connector 1, a rotation control and slide mechanism 10 and a synthetic resin boot 12 that partially covers the optical fiber 2 are mounted. When the connector 1 is not used, the synthetic resin cap 11 covering the tip of the ferrule 7 is inserted into the cylinder insertion hole 18 of the housing body 5 (see FIG. 2, See Figure 5).

As shown in FIG. 1, the adapter 3 is formed by fixing a pair of adapter dividing members 40 so as to face each other. Each of the adapter dividing members 40 includes a housing accommodating portion 41, a cylindrical portion 42 formed at a rear end of the housing accommodating portion 41 and fitted with a sleeve, and an upper portion of the housing accommodating portion 41. And a pair of formed slide portions 43. When connecting the connector 1 to the adapter 3 and inserting the housing body 5 into the housing 41, a pair of engaging projections 20 on the lever part 16 0 force S 1 pair of sliding parts 4 3, the lever 16 is elastically deformed downward. When the housing body 5 is completely inserted into the housing accommodating portion 41, the lever portion 16 returns, and the pair of engaging projections 20 engage with the pair of sliding portions 43 to be prevented from being removed. .

As described above, when the two connectors 1 are connected to the adapter 3 from both sides, the tip surfaces of the two ferrules 7 abut against each other while being pressed by the compression coil springs 8 of the connectors 1 on both sides. The end surfaces of the bare fibers 2a of the optical fiber 2 are in contact with each other so as to be able to transmit light, and the optical connection state is maintained. When disconnecting the connector 1 from the adapter 3, the lever 16 is operated downward to release the engagement between the engagement projection 20 and the slide portion 43, and then pull it out.

A method of assembling the connector 1 will be briefly described.

First, the compression coil spring 8 is attached to the ferrule 7, the auxiliary housing 6 and the key member 9 are attached to the ferrule 7, and the ferrule 7 is attached to the auxiliary housing 6 against the urging force of the compression coil spring 8. In the state pushed relatively to the proximal end, The key member 9 is screwed to the base screw portion 35, and the pair of key portions 9a of the key member 9 is engaged with the pair of slits 24b of the rotation restricting portion 24 by the urging force of the compression coil spring 8. Make them match. Next, the bare fiber 2a of the polarization-maintaining optical fiber 2 and the core wire 2b are inserted from the base end side of the ferrule 7, and the bare fiber 2a is inserted into the fiber through hole 34, including the skin. The core wires 2 b are inserted into the fiber through holes 32, respectively, and fixed with an adhesive. Next, as shown in FIG. 7, the ferrule 7, the compression coil spring 8, and the catching housing 6 are inserted into the cylindrical portion 15 of the housing body 5, and the rotation regulating protrusion 25 is engaged with the slit 21. And a pair of engaging claws 26 are engaged with a pair of engaging holes 19. Next, the bare fiber 2a and the end face of the ferrule 7 are polished. Next, the assembly of the connector 1 is set on an optical fiber phase adjusting device (not shown) such as a microscope, and the rotation operation section 36 of the ferrule 7 is observed while observing the end of the bare fiber 2 a of the optical fiber 2. Is gripped with a tool and turned, so that the main axis of the bare fiber 2a (the direction of the stress applying part) matches the reference line of the scope part of the inspection device. In this state, an adhesive is applied to the bonding portion 10a for bonding the base end of the key member 9 and the base screw portion 35 of the ferrule 7, so that the ferrule 7 and the key member 9 do not rotate relative to each other. Fixed to.

The operation and effect of the optical fiber connector 1 will be described.

In the connector 1 that connects the ends of the polarization-maintaining fiber 2, the polarization-maintaining fiber 2 is rotated at a rotational phase that minimizes the deviation angle of the main axis (that is, the rotational phase at which the main axis of the optical fiber 2 is oriented in the reference direction) Assume that the connector 1 is assembled so that the light is propagated while maintaining the polarization state by adjusting to (2). In this connector 1, if the rotation restricting portion 25 is not provided, the relative rotation angle caused by backlash between the housing body 5 and the capture housing 6 is calculated to be approximately ± 3.9 degrees, The actual measurement was about ± 3.2 degrees.

However, in the connector 1 of the present invention, the rotation restricting portion 25 of the auxiliary housing 6 is engaged with the slit 21 of the housing body 5, and the housing 6 is assisted / removed with respect to the housing body 5, and the housing 6 is connected to the axis of the optical fiber 2. Since it is restricted from rotating around, the relative rotation angle due to rattling between the housing body 5 and the auxiliary housing 6 is about ± 1.5 degrees in calculation, and about ± 1.2 degrees in actual measurement. became. As a result, the misalignment angle of the main shaft in the optical fiber connector 1 is reduced by about 2.0 degrees, which can be seen from the graph in Fig. 16. Thus, the extinction ratio can be improved by about 10 dB.

Further, since a rotation regulating and sliding mechanism 10 is provided to regulate the relative rotation of the ferrule 7 with respect to the housing 4 and to allow the optical fiber 2 to slide in the axial direction, the connector 1 is assembled with the housing 4 at the assembling stage. The rotation phase around the axis of the ferrule 7 can be adjusted in a 360-degree stepless manner. After the rotation phase is adjusted, the key member 9 and the ferrule 7 are fixed to each other by the adhesive portion 10a, and the housing 4 The optical fiber 2 can be fixed so as not to rotate relative to the optical fiber 2. Thus, the deviation angle of the main axis of the polarization-maintaining optical fiber 2 can be improved by about 2.0 degrees. The connector 1 is capable of high-precision optical connection between the ends of the bare fiber 2a of the polarization-maintaining optical fiber 2.

In addition, the slit 21 also serves as a slit for imparting flexibility to the cylindrical portion 15 of the housing body 5, and simply adds a rotation regulating protrusion 25 to the insertion cylindrical portion 22 of the auxiliary housing 6. The goal can be achieved with a very simple configuration. The rotation control and slide mechanism 10 requires only the key member 9 in addition to the base screw portion 35 of the ferrule 7 and the auxiliary / paging 6, so the number of members is small, the structure is simple, and the manufacturing cost is low. Can be reduced. Since the bonding portion 10a is configured to bond the base end of the key member 9 and the base end screw portion 35, the bonding can be performed by applying an adhesive after the phase adjustment between the ferrule 7 and the optical fiber 2 is completed. . However, as the bonding portion 10a, an adhesive may be injected and fixed to the rotation regulating slit 9a.

In this embodiment, an LC type optical fiber connector used for connecting the polarization-maintaining optical fiber 2 has been described as an example, but the optical fiber 2 is not necessarily a polarization-maintaining optical fiber. Instead, the optical fiber connector of the present invention can be similarly applied to an APC (Angled-Physical Contact) type optical fiber or an optical fiber connector for a normal optical fiber.

Also when connecting the APC type optical fiber, it is necessary to connect the two optical fibers to be connected with the directions of the reference lines precisely matched. It is also suitable for a connector used for connecting an optical fiber. Even with ordinary optical fiber connectors, optical transmission due to manufacturing errors in ferrules etc. In order to minimize the decrease in the transmission efficiency, in the connector assembling stage, the ferrule 7 and the optical fiber 2 are rotated steplessly 360 degrees around the axis with respect to the housing 4 to maximize the light transmission efficiency. And then fix it with the adhesive portion 10a.

The slit 21 and the rotation restricting protrusion 25 may be changed as follows.

Instead of the slit 21 formed in the housing body 5, a concave groove having the same function as the slit 21 may be formed.

Alternatively, the slit 21 is left as it is in order to impart elasticity to the cylindrical portion 15, and the rotation restricting projection 25 is placed on the peripheral wall portion of the insertion cylindrical portion 22 different from the above-described embodiment in a circumferential position. Alternatively, a concave groove with which the rotation restricting projection engages may be formed on the peripheral wall of the housing body 5.

Alternatively, a rotation restricting projection functioning as the rotation restricting projection 25 is formed on the inner surface side of the cylindrical portion 15 of the housing main body 5, and a slit or a concave groove with which the rotation restricting projection engages is formed by the auxiliary housing 6. It may be formed on the peripheral wall portion of the insertion tube portion 22.

Next, an example in which the present invention is applied to an MU-type optical fiber connector 51 for optically connecting the tip of a polarization-maintaining optical fiber will be briefly described.

As shown in FIGS. 8 to 11, the optical fiber connector 51 includes a housing 54 made of synthetic resin, a ferrule 57 for holding the distal end of the polarization maintaining optical fiber 50, It has a compression coil spring 58, a rotation restricting mechanism 60 including a stop key member 59, a boot 61, a cover 62, and a cap (not shown) similar to the above-mentioned cap.

The housing 54 is connected to a housing body 55 detachable from the adapter and partially inserted into a base end portion of the housing body 55 so as not to be detached in the axial direction of the optical fiber 50. Auxiliary housing 56 (this is called a stop ring). A pair of slits 66 formed in the peripheral wall of the cylindrical portion 65 of the housing body 55 in parallel with the axial direction of the optical fiber 50 and open at the base end, and a pair of engagements Holes 6 and 7 are formed.

The auxiliary housing 56 is formed by integrally forming an insertion tube portion 68 inserted into the cylindrical portion 65 and a rotation restricting portion 69 extending toward the base end of the insertion tube portion 68. Insert tube 68, one rotation restricting protrusion 70 that engages one of the pair of slits 66 immovably in the width direction of the slit, and a pair of engaging holes 67. A pair of engaging claws 71 to be engaged are formed. Insert the cylindrical part 68 into the cylindrical part 65 of the housing body 55.When the cylinder part 68 is assembled, the rotation restricting projection 70 engages the slit 66 so that it cannot move in the slit width direction. Thus, the rotation of the auxiliary housing 56 around the axis with respect to the housing body 55 is restricted. The rotation restricting portion 69 of the auxiliary housing 56 has a pair of semi-cylindrical portions 69a and a pair of rotation restricting slits 69b.

The ferrule 57 has substantially the same structure as the ferrule 7 described above. The ferrule 57 includes a ferrule body 72 made of phosphor bronze, a cylindrical body 73 made of zirconia, and a flange portion 74. A base screw portion 75 and a rotation operation portion 76 are formed on a base end portion of the ferrule body 72.

The rotation restricting and sliding mechanism 60 is formed in a pair of base-side slits 69 b formed in the base end of the auxiliary housing 56 in parallel with the axial direction, and in the base end of the ferrule 57. And a stop key member 59 fitted externally to the base screw portion 75 (this is a stop adjusting ring member). A stop key member 59 having a pair of key portions 59b slidably engaged with a pair of proximal slits 69b, and a ferrule 57. And a bonding portion 77 for fixing the key member 59 to the key member 59. The bonding portion 77 is configured to bond the base end of the key member 59 to the ferrule 57, but may be configured to bond the inner periphery of the key member 59 to the base screw portion 75.

The stop key member 59 includes a ring portion 59 a that is externally fitted to the proximal screw portion 75 and screwed thereto, and a pair of integrally formed extending from the ring portion 59 a toward the distal end side. And a pair of key portions 59b to be engaged with the pair of rotation restricting slits 69b.

The method of assembling the connector 51 is almost the same as that of the connector 1 except that the ferrule 57 is provided with the compression coil spring 58 and the base end of the ferrule 57 is attached to the auxiliary housing 5. 6 and screw the stop key member 59 to the base screw part 7 5 of the ferrule 57, and attach the pair of key parts 59b to the base side slit. G 6 9b. In this state, the optical fiber 50 is inserted into the ferrule 57 and fixed with an adhesive. Then, insert the ferrule 57, the compression coil spring 58, and the insertion cylinder 68 of the auxiliary housing 56 into the cylinder 65 of the housing body 55, and engage the rotation regulating projection 70 with the slit 66. Then, the pair of engaging claws 71 are engaged with the pair of engaging holes 67.

Thereafter, the connector 51 is set in the optical fiber phase adjuster, and the rotational phase of the ferrule 57 and the optical fiber 50 with respect to the housing 54 is adjusted in the same manner as in the case of the connector 51. The key member 59 is fixed to the ferrule 57 so that it cannot rotate relative to the ferrule 57.

The same change as in the connector 1 can be applied to the rotation restricting projection 70 and the slit 66 of the connector 51, but the description thereof will be omitted.

Also, in the connector 51, the same operation and effect as those of the connector 1 can be obtained, and thus the description is omitted.

Claims

The scope of the claims

1. In the optical fiber connector to which the tip of the optical fiber is attached and which is used for optical connection of the tip of the optical fiber via an adapter,

A housing having a housing main body detachably attached to the adapter, and an auxiliary housing with an insertion tube portion partially inserted into a base end portion of the housing main body and connected so as not to be detached in the axial direction of the optical fiber. ,

A slit or a groove formed in the housing body and one peripheral wall portion of the insertion cylinder portion in parallel to an axial direction and in a base open shape;

A rotation restricting projection formed on the housing body and the other peripheral wall of the insertion tube portion, the shaft being an auxiliary housing with respect to the housing body, being engaged with the slit or the groove so as to be immovable in the width direction thereof. An optical fiber connector comprising: a rotation restricting projection that restricts rotation around a core.

2. The optical fiber connector according to claim 1, wherein the optical fiber is a polarization-maintaining optical fiber.

3. The optical fiber connector according to claim 1, wherein the slit is formed in a peripheral wall portion of the housing main body, and the rotation restricting projection is formed in the insertion tube portion.

4. A ferrule which holds the tip of the optical fiber so as to pass therethrough and is mounted on the housing so as to be movable in the axial direction.

A compression coil spring attached to the ferrule in the housing so as to be fitted over the ferrule and biasing the ferrule toward the distal end;

A rotation regulating and sliding mechanism that regulates relative rotation of the ferrule with respect to the housing at the base end side of the housing and allows sliding movement of the ferrule in the axial direction;

The optical fiber connector according to any one of claims 1 to 3, further comprising:

5. The optical fiber connector is an LC type connector and the auxiliary housing 5. The optical fiber connector according to claim 4, wherein is an extender cap.

6. The optical fiber connector according to claim 4, wherein the optical fiber connector is an MU type connector, and the auxiliary housing is a stopping ring.

7. The rotation restricting and sliding mechanism includes: a base side slit formed in the base end of the auxiliary housing in parallel with the axial direction; and a base side of the auxiliary housing formed in the base end of the ferrule. And a stop key member having a key portion slidably engaged with the base-side slit, and having a key portion slidably engaged with the base-side slit and externally screwed to the base screw portion. 5. The optical fiber connector according to claim 4, further comprising an adhesive portion for fixing the ferrule and the stop key member.

8. A rotating operation section is provided at a base end of a ferrule for rotating a ferrule with respect to a housing in an assembling step of the optical fiber connector, according to claim 7, wherein: Optical fiber connector.

9. In the assembling step of the optical fiber connector, the fixing by the adhesive portion is performed in a state where the rotation phase of the ferrule with respect to the housing is adjusted so that the rotation phase has the maximum light transmission efficiency. The optical fiber connector according to claim 8, wherein:

10. The optical fiber is a polarization-maintaining optical fiber, and the assembling is performed so that the main axis of the polarization-maintaining optical fiber has a rotational phase oriented in a reference direction in the assembling step of the optical fiber connector. 9. The optical fiber connector according to claim 8, wherein the fixing by the adhesive portion is performed in a state in which the rotation phase of the ferrule with respect to is adjusted.