Optical connector and method for connecting optical fiber

Abstract

The present invention addresses the problem of providing an optical connector and an optical fiber connection method capable of appropriately and quickly connecting optical fibers to each other even when the optical fibers have deteriorated or suffered damage. Said problem is solved by an optical connector (1) for optically connecting optical fibers (3), said optical connector (1) comprising: a guide part (5) that accommodates the optical fibers (3) so as to be movable in the axial direction of said optical fibers (3); a coating removal part (9) for removing a coating part (7) of the optical fibers (3); and a cleaving part (13) for cleaving the optical fibers (3) from which the coating part (7) has been removed by the coating removal part (9). Using this optical connector (1) makes it possible to modify the optical fibers (3) so as to have an end face suitable for connection, by moving the optical fibers (3) in the axial direction, removing the coating part therefrom, and then cleaving the optical fibers (3). When connecting optical fibers (3) which have a modified end face, the optical fibers (3) can be appropriately and quickly connected to each other.

Description

Optical Connector and Method for Connecting Optical Fibers

[0001] This invention relates to a method for connecting optical fibers. More specifically, this invention relates to an optical connector that, after removing the coating of an optical fiber, cleaves the optical fiber to expose a new end face without using flat glass, making it easier to connect optical fibers to each other, and a method for connecting optical fibers using such an optical connector.

[0002] International Publication WO2022 - 044891 pamphlet describes an optical connection component for connecting optical fibers. FIG. 6 is a conceptual diagram showing the end structure of the optical fiber of this application. In this example, a flat glass subjected to an antireflection film treatment is obliquely attached to the end structure of an optical fiber obtained by obliquely cleaving a hollow core optical fiber (HCF).

[0003] Since the end of the above optical fiber has a flat glass attached, Fresnel reflection always occurs, which affects the reflection attenuation amount. In this regard, although the end of the above optical fiber uses a flat glass subjected to an antireflection film treatment, it cannot completely suppress Fresnel reflection. Also, since the end of the above optical fiber obliquely attaches the flat glass, when connecting the optical fibers, a gap occurs between the end faces of the optical fibers, which is a factor causing connection loss.

[0004] Also, the end faces of optical fibers such as HCF may deteriorate or be damaged by being continuously exposed to the outside air. Even in such a case, it is desirable to quickly restore the optical connection between the optical fibers.

[0005] International Publication WO2022 - 044891 pamphlet

[0006] An object of this invention is to provide an optical connector that can connect optical fibers such as HCF without using flat glass, and a method for connecting optical fibers using such an optical connector. Another object of this invention is to provide an optical connector that can quickly restore the optical connection between optical fibers, and a method for connecting optical fibers using such an optical connector.

[0007] The above invention is basically based on the realization that by moving an optical fiber, removing a portion of its coating, and then cutting the portion of the optical fiber from which the coating has been removed, an optical fiber having an end face suitable for connection can be used for connecting with other optical fibers.

[0008] The first invention relates to an optical connector 1. The optical connector 1 is a device for optically connecting optical fibers. The optical connector 1 has a guide portion 5, a coating removal portion 9, and a cleaving portion 13. The guide portion 5 is an element for housing the optical fiber 3 so that it can move in the axial direction of the optical fiber 3. The coating removal portion 9 is an element for removing the coating portion 7 of the optical fiber 3. The cleaving portion 13 is an element for cleaving the optical fiber 3 from which the coating portion 7 has been removed by the coating removal portion 9.

[0009] Using the optical connector 1 described above, the optical fiber 3 can be moved in the axial direction, the coating 7 of the optical fiber 3 can be removed, and the portion of the optical fiber 3 from which the coating 7 was removed can be cleaved to adjust the optical fiber to have an end face suitable for connection. In addition, this method exposes the end face of the optical fiber that is not deteriorated or damaged. Then, by connecting the optical fibers with adjusted end faces, the optical fibers can be connected appropriately and quickly.

[0010] Figure 1 is a conceptual diagram illustrating the optical connector of this invention. Figure 2 is a conceptual diagram illustrating an example of a gripping portion. Figure 3 is a conceptual diagram illustrating a cleaving mechanism. Figure 4 is a conceptual diagram showing an example of an optical fiber fixing portion. Figure 5 shows an example of a flow chart illustrating a method for connecting optical fibers. Figure 6 is a conceptual diagram showing a conventional optical fiber termination structure. Figure 7 is the first diagram showing an example of an optical connector according to the first modification. Figure 8 is the second diagram showing an example of an optical connector according to the first modification. Figure 9 is a diagram illustrating the fixing and release of an optical fiber by a fiber chuck according to the first modification. Figure 10 is a diagram showing an example of a connector adapter according to the first modification. Figure 11 is a diagram showing an example of how the connector adapter is used in the first modification. Figure 12 is a diagram showing an example of the state in the first modification where the core portion is cut by the cutting blade of the connector adapter. Figure 13 is a diagram showing an example of how optical fibers with end faces for connecting optical fibers are connected by the connector adapter in the first modification. Figure 14 is a diagram showing an example of the end face of the cleaved core portion in the first modification. Figure 15 is a diagram illustrating an example of a flow chart for explaining the method of connecting optical fibers in the first modified example.

[0011] The following describes embodiments for carrying out the present invention with reference to the drawings. The present invention is not limited to the embodiments described below, but also includes modifications made to the following embodiments to the extent that is obvious to those skilled in the art.

[0012] Figure 1 is a conceptual diagram illustrating the optical connector of the present invention. As shown in Figure 1, the optical connector 1 of the present invention has a guide portion 5, a coating removal portion 9, and a cleave portion 13. As shown in Figure 1, the guide portion 5 of the optical connector 1 of the present invention may have a gripping portion 15. Furthermore, the optical connector 1 of the present invention may further have an optical fiber fixing portion 17 and a biasing portion 19. In addition, the optical connector 1 of the present invention may appropriately include elements of already known optical connectors.

[0013] In the example shown in Figure 1, the guide portion 5 is housed in the plug housing 21. The guide portion 5 is biased by a biasing portion 19, which is supported by a stop ring 23. A removable boot 25 is attached to the stop ring 23. In the example shown in Figure 1, a flange 24 is present at the end of the ferrule 31. Also in the example shown in Figure 1, the plug housing 21 has a knob 27. Each element will be described below.

[0014] Optical Connector 1: Optical connector 1 is a device for optically connecting (and disconnecting) optical fibers. For example, when two optical fibers are connected using an optical connector, light propagating through one optical fiber can then propagate through the other optical fiber. Optical connectors are also called optical fiber connectors or optical connection components.

[0015] Optical fiber 3 Optical fiber 3 is a transmission path for transmitting light to distant locations. Optical fiber 3 can be of various types, and the optical connector of this invention can utilize various types of optical fibers. The optical fiber 3 that can be used in this invention is, for example, a type in which a core portion 11 is located in the center, and the core portion 11 is covered by a cladding portion 7. The core portion 11 may have a core and a cladding. The cladding portion 7 is the cladding in a cladded optical fiber as described in Japanese Patent Publication No. 5116103. Therefore, the core portion 11 corresponds to the bare optical fiber strand in the same publication. The optical connector of this invention can be used particularly preferably when connecting hollow core optical fibers (HCFs). HCFs are already known optical fibers as described in Japanese Patent Publication No. 7107840. This publication describes a hollow core photonic crystal fiber (PCF) comprising an outer cladding region and a plurality of hollow tubes surrounded by the outer cladding region. The number of hollow tubes included in each HCF is arbitrary. The optical connector 1 of this invention can also connect both different fibers. For example, it can be used to connect both single-mode fibers (SMF) or to connect HCF and SMF.

[0016] Guide section 5 The guide section 5 is an element for housing the optical fiber 3 so that it can move in the axial direction of the optical fiber 3. The axis of the optical fiber 3 refers to the central axis of the optical fiber. "Movable in the axial direction of the optical fiber 3" means that the optical fiber 3 can be moved along its central axis.

[0017] In the example shown in Figure 1, the guide portion 5 includes a gripping portion 15 and a ferrule 31. The gripping portion 15 is an element for gripping the optical fiber 3 in a releasable manner. The ferrule is a member for holding the optical fiber. In this invention, the optical fiber 3 may be brought out from the end face side of the ferrule 31. Therefore, unlike a normal optical connector, the optical fiber 3 is not permanently fixed to the ferrule 31 and may have a free-floating relationship. However, when connecting two optical fibers 3 together, the optical fiber 3 needs to be fixed. For this reason, the optical fiber 3 is fixed by the gripping portion 15.

[0018] Figure 2 is a conceptual diagram illustrating an example of a gripping section. The gripping section 15 shown in Figure 2 includes a lid 33, a clamp spring 35, a V-groove substrate 37, and a wedge 39. This configuration is merely illustrative, and the gripping section may be composed of elements other than those shown. In the example shown in Figure 2, the optical fiber 3 is housed in the V-groove of the V-groove substrate 37 and is sandwiched between the lid 33 and the V-groove substrate 37. The lid 33 and the V-groove substrate 37 are subjected to pressure from the surrounding clamp spring 35, which moves them closer together. The gripping section 15 in Figure 2 has notches on the end faces of the lid 33 and the V-groove substrate 37 for accommodating the wedge 39. When the wedge 39 is inserted into these notches, the pressure of the clamp spring 35 is relieved, and the optical fiber 3 is released. On the other hand, when the wedge 39 is removed, the pressure of the clamp spring 35 is applied in a direction that moves the lid 33 and the V-groove substrate 37 closer together. In this way, the gripping portion 15 fixes the optical fiber 3. However, when the wedge 39 is inserted into the notch again, the optical fiber 3 is released from the gripping portion 15. The gripping portion 15 may use a substrate with a semicircular groove instead of the V-groove substrate 37. Alternatively, multiple irregularities may be provided inside the groove to allow for easier holding of the optical fiber 3 by friction.

[0019] Coating Removal Section 9 The coating removal section 9 is an element for removing the coating 7 of the optical fiber 3. For example, the coating removal section 9 can remove the coating from one end of the optical fiber 3 by inserting one end of the coated optical fiber 3 into the coating removal section 9. The coating removal section 9 is a known technology, as described in, for example, Japanese Patent Publication No. 5116103. The coating removal section 9 may also have a centering section having a smaller diameter than the optical fiber 3 on which the coating exists, and when the optical fiber 3 is pressed against the centering section, the coating 7 of the optical fiber 3 is removed. In this case, the centering section may be provided with a blade for cutting the coating 7. In the example shown in Figure 1, the coating housing section 41 houses the coating 7 of the optical fiber 3 removed by the coating removal section 9. The coating removal section 9 may be provided on the tip side of the ferrule 31 as shown in Figure 1, or on the gripping section 15 side. In the latter case, the optical fiber 3 with a portion of the coating 7 removed may travel inside the ferrule. Furthermore, the removed coating portion 7 may be discharged to the outside of the optical connector 1.

[0020] Cleave section 13 The cleave section 13 is an element for cleaving the optical fiber 3 from which the coating 7 has been removed by the coating removal section 9. Figure 3 is a conceptual diagram illustrating the cleaving mechanism. The cleave section 13 is also called a cleaver. The cleave section 13 has an optical fiber fixing section 17, a wedge section 51 having a wedge 39, a fiber feeding section 53, and a cutting blade section 55. Cleave means cutting. It is already known to cleave the end of an optical fiber to obtain a cleave end, as described in, for example, Japanese Patent Publication No. 5810268 and Japanese Patent Publication No. 4874115. The wedge section 51 is an element for moving the wedge 39. The fiber feeding section 53 is an element for advancing the optical fiber 3 in the axial direction. The wedge section 51 may have a structure to support the wedge 39, such as a locking mechanism, in order to firmly fix the wedge 39. The fiber feeding section 53 includes, for example, two rollers that hold the optical fiber 3 between them. The fiber feeding section 53 has a structure that, for example, clamps the optical fiber 3 at the rear end of the connector with an arbitrary number of cylindrical parts and pushes the optical fiber 3 toward the ferrule end face by rotating the cylindrical parts in the axial direction. At this time, to prevent the fiber from bending, the fiber feeding section 53 may have a structure that allows the boot 25 to be removed and the fiber to be pushed out from the base of the stop ring 23. The optical fiber fixing section 17 and the cutting blade section 55 may be housed in, for example, a connector (not shown). In this case, two optical connectors 1 can be inserted into the connector to connect two optical fibers 3. Furthermore, such a connector may have an opening window in part thereof for viewing the end face of the optical fiber 3 cut by the cleave section 13.

[0021] Optical fiber fixing part 17 The optical fiber fixing part 17 is an element for fixing the optical fiber 3 from which the coating part 7 has been removed by the coating removal part 9. For example, the optical fiber 3 from which the coating part 7 has been removed by the coating removal part 9 advances further in the axial direction of the optical fiber 3 on the ferrule 31 and is gripped and fixed by the optical fiber fixing part 17. Typically, the optical fiber fixing part 17 fixes the optical fiber 3 by gripping the portion of the optical fiber 3 from which the coating part 7 has been removed (core part 11 including the core and cladding).

[0022] Figure 4 is a conceptual diagram showing an example of an optical fiber fixing part. The optical fiber fixing part 17 shown in Figure 4 grips the portion of the optical fiber 3 from which the coating 7 has been removed, and has a mechanism for pulling the optical fiber 3 to the left of the plane of the paper. In the example in Figure 4, the optical fiber fixing part 17 has an elastic part at its tip, and when the optical fiber 3 from which the coating 7 has been removed is inserted, tension is generated that pulls the optical fiber 3 to the left of the plane of the paper. In this way, in order to perform cleaving of the optical fiber 3 with precision, it is preferable that the optical fiber fixing part 17 not only fixes the optical fiber 3 (the portion from which the coating 7 has been removed), but also has a structure that applies force in the direction of pulling the optical fiber 3 against the ferrule end face.

[0023] The biasing part 19 is, for example, an element for biasing the gripping part 15 toward the tip of the optical fiber 3. The biasing part 19 is also used to press and hold the ferrules of the two optical fibers 3 to be connected with a constant force. An example of the biasing part 19 is a spring.

[0024] Next, a method for connecting optical fibers will be described. Figure 5 shows an example of a flow chart illustrating a method for connecting optical fibers. As shown in Figure 5, the method for connecting optical fibers includes a moving step (S101), a coating removal step (S102), and a cleaving step (S104). In the example in Figure 5, an optical fiber fixing step (S103) is further included before the cleaving step. Also, in the example in Figure 5, a fiber connection step (S105) is further included.

[0025] The moving step (S101) is a step in which the optical fiber 3 is moved in the axial direction of the optical fiber 3. The wedge portion 51 is used to insert the wedge 39 into the V-groove substrate 37 and the notch portion of the lid 33. This releases the optical fiber 3 (e.g., HCF) and makes it movable. Next, the fiber feeding portion 53 pushes the optical fiber 3 toward the ferrule end face.

[0026] The coating removal step (S102) is a step for removing the coating portion 7 of the optical fiber 3. The coating portion 7 of the optical fiber 3 is removed as the optical fiber 3 passes through the coating removal section 9. Only the portion of the coating portion 7 of the optical fiber 3 that passes through a predetermined part of the coating removal section 9 is removed. In this way, the tip region portion of the coating portion 7 of the optical fiber 3 (for example, the portion that passes through the coating removal section 9) is removed.

[0027] The optical fiber fixing step (S103) is a step in which the optical fiber 3 from which the coating has been removed is fixed. When the optical fiber 3 is pushed out toward the ferrule end face, the optical fiber fixing part 17 fixes the pushed-out optical fiber 3. In order to perform the cleaving of the optical fiber 3 with precision, the optical fiber fixing part 17 may not only fix the optical fiber 3 but also apply force in the direction of pulling the optical fiber 3 toward the ferrule end face. Furthermore, when force is applied in the direction of pulling the optical fiber 3, in order to maintain the tension applied to the optical fiber 3, the wedge part 51 may be used to remove the wedge 39 from the cover 33 and the V-groove substrate 37, and the optical fiber 3 may be fixed by the pressure of the clamp spring 35.

[0028] The cleaving step (S104) is a step in which the optical fiber 3, from which the coating portion 7 has been removed in the coating removal step, is cleaved. For example, the cutting blade portion 55 cleaves the portion of the optical fiber 3 from which the coating portion 7 has been removed (for example, the core portion 11 or the bare optical fiber strand) along the end face of the ferrule 31. After cleaving, the optical fiber 3 is released from the tension applied to the optical fiber 3 by the optical fiber fixing portion 17. As a result, the cleaved portion of the optical fiber 3 is positioned so as to be pulled in by several tens of nanometers relative to the end face of the ferrule 31.

[0029] The fiber connection process (S105) is a process of joining the cleaved optical fibers 3 together to optically connect the optical fibers. The gripping portion 15 is biased toward the tip of the optical fiber 3 using the spring that constitutes the biasing portion 19. Alternatively, the biasing portion 19 may connect the two optical fibers 3 by pressing the ferrules of the two optical fibers 3 to be connected with a constant force.

[0030] <First Modification> In the embodiments described above, the wedge portion 51 and the fiber feeding portion 53 were used for moving and fixing the optical fiber 3. In the first modification, a configuration in which a fiber chuck is used for moving and fixing the optical fiber 3 will be described. The first modification will be described below with reference to the drawings.

[0031] Figures 7 and 8 show an example of an optical connector 100 according to the first modified example. In Figure 7, the direction from the boot 101 toward the coating removal portion 119 is defined as the +X direction. The X direction coincides with the axial direction of the optical fiber 3. In the optical connector 100, the coating portion 7 of the optical fiber 3 is removed by the coating removal portion 119 when the first stop ring 103 is pushed in the +X direction. Figure 7 illustrates a state in which the first stop ring 103 is not pushed in the +X direction. Figure 8 illustrates a state in which the first stop ring 103 is pushed in the +X direction. Hereinafter, in this specification, the state in which the first stop ring 103 is not pushed in the +X direction will also be referred to as the "first state". The state in which the first stop ring 103 is pushed in the +X direction will also be referred to as the "second state".

[0032] The optical connector 100 is a cylindrical component formed in an overall view, into which the optical fiber 3 is inserted in the +X direction from the boot 101. In the optical connector 100, the boot 101, first stop ring 103, fiber chuck 106, cylindrical member 114, and ferrule 118 are arranged in a line in the X direction from the +X side to the -X side. The boot 101, first stop ring 103, fiber chuck 106, cylindrical member 114, and ferrule 118 each have a first fiber passage 131, second fiber passage 132, third fiber passage 133, fourth fiber passage 134, and fifth fiber passage 135, which are formed in a cylindrical shape with their longitudinal direction in the X direction. The boot 101, first stop ring 103, fiber chuck 106, cylindrical member 114, and ferrule 118 are arranged so that the central axes of the first fiber passage 131, second fiber passage 132, third fiber passage 133, fourth fiber passage 134, and fifth fiber passage 135 coincide. The first fiber passage 131, second fiber passage 132, third fiber passage 133, fourth fiber passage 134, and fifth fiber passage 135 form the fiber passage 130, which is the path for the optical fiber 3 within the optical connector 100.

[0033] The boot 101 is a component that protects the optical fiber 3 inserted into the optical connector 100. As described above, the boot 101 is provided with a first fiber passage 131 into which the optical fiber 3 is inserted. The boot 101 can also be described as an insertion opening that receives the optical fiber 3 into the optical connector 100. The boot 101 is formed of a flexible material (for example, an elastic material).

[0034] The first stop ring 103 is provided such that, for example, its end in the -X direction is connected to the boot 101. The first stop ring 103 is movable in the +X direction when a force is applied to the boot 101 in the +X direction. When the first stop ring 103 moves in the +X direction, the first spring 105 is compressed by elastic deformation. When the force applied to the boot 101 in the +X direction is released, the elastic force of the first spring 105 causes the first stop ring 103 to return to its original position (the position illustrated in Figure 7).

[0035] The interior of the second stop ring 104 is formed in a cylindrical shape so that the first stop ring 103 can move along the X direction. The first stop ring 103, the first spring 105, and the fiber chuck 106 are housed inside the cylindrical interior of the second stop ring 104. The end of the first spring 105 in the +X direction is fixed, for example, inside the second stop ring 104. The end of the first spring 105 in the -X direction is fixed, for example, to the first stop ring 103. Therefore, when the first stop ring 103 moves in the +X direction, the first spring 105 elastically deforms and compresses.

[0036] The fiber chuck 106 is a component used to fix and release the optical fiber 3. The -X end of the fiber chuck 106 is fixed to, for example, the first stop ring 103. Therefore, when the first stop ring 103 moves in the X direction, the fiber chuck 106 also moves in the X direction. The optical fiber 3 is released when the fiber chuck 106 opens, and the optical fiber 3 is fixed when the fiber chuck 106 closes. When the fiber chuck 106 is closed, the surface that contacts the optical fiber 3 is also called the gripping portion 109. The fiber chuck 106 is an example of a "gripping portion".

[0037] The fiber chuck 106 has a small diameter cylindrical portion 107 and a large diameter cylindrical portion 108. The large diameter cylindrical portion 108 has a larger outer diameter than the small diameter cylindrical portion 107. The large diameter cylindrical portion 108 is also located on the +X side of the small diameter cylindrical portion 107. The gripping portion 109 is formed on the large diameter cylindrical portion 108. In the first state, the large diameter cylindrical portion 108 is housed in a ring-shaped chuck ring 110. The inner diameter of the chuck ring 110 is set to be approximately equal to the outer diameter of the large diameter cylindrical portion 108. The chuck ring 110 is movable in the X direction relative to the fiber chuck 106. The opening and closing of the fiber chuck 106 is controlled by the chuck ring 110. The chuck ring 110 is an example of a "switching portion".

[0038] When the large-diameter cylindrical portion 108 is housed within the chuck ring 110, the inner diameter of the chuck ring 110 is approximately equal to the outer diameter of the large-diameter cylindrical portion 108, causing the large-diameter cylindrical portion 108 to close. As a result, the optical fiber 3 is fixed by being gripped by the gripping portion 109. Furthermore, when the chuck ring 110 moves in the -X direction relative to the large-diameter cylindrical portion 108, the large-diameter cylindrical portion 108 moves out of the chuck ring 110. When the large-diameter cylindrical portion 108 moves out of the chuck ring 110, the space between the gripping portions 109 of the large-diameter cylindrical portion 108 opens, and the fixing of the optical fiber 3 by the gripping portion 109 is released. Details of fixing and releasing the optical fiber 3 by the fiber chuck 106 will be described later with reference to the drawings.

[0039] The third stop ring 111 restricts the range of movement of the chuck ring 110 in the +X direction. The third stop ring 111 is provided with a projection 112 that protrudes inward from the inner wall of the third stop ring 111. The inner diameter of the fiber chuck insertion portion 113 formed by the projection 112 is set to be approximately equal to or larger than the outer diameter of the large diameter cylindrical portion 108 of the fiber chuck 106. Furthermore, the inner diameter of the fiber chuck insertion portion 113 is formed to be smaller than the outer diameter of the chuck ring 110. Therefore, when the large diameter cylindrical portion 108 is inserted into the fiber chuck insertion portion 113, the chuck ring 110, which is positioned outside the large diameter cylindrical portion 108, comes into contact with the projection 112, restricting its movement in the +X direction. As a result, the large diameter cylindrical portion 108 inserted into the fiber chuck insertion portion 113 comes out of the chuck ring 110.

[0040] A cylindrical member 114 is positioned between the third stop ring 111 and the ferrule 118. A fourth fiber passage 134 is formed in the cylindrical member 114, supporting the optical fiber 3 between the third stop ring 111 and the ferrule 118. The length of the cylindrical member 114 can be appropriately determined according to the distance between the third stop ring 111 and the ferrule 118. Furthermore, if the distance between the third stop ring 111 and the ferrule 118 is short, the cylindrical member 114 may be omitted.

[0041] The ferrule 118 holds the optical fiber 3. A projection 118A is provided at the -X end of the ferrule 118 so as to protrude outward from the ferrule 118. A coating removal section 119 is provided at the +X end of the ferrule 118. The coating removal section 119 has a removal opening 120. The removal opening 120 has an inner diameter approximately equal to the outer diameter of the core section 11. The removal opening 120 is also provided so as to be aligned with the central axis direction of the fiber passage 130. When the optical fiber 3 is inserted into the removal opening 120 from the -X direction to the +X direction, the coating section 7 is removed and the core section 11 is exposed. The coating 71 removed from the optical fiber 3 is discharged to the outside through the discharge opening 121. In addition, the discharge opening 121 may be omitted in the ferrule 118 so that the removed coating 71 accumulates inside the ferrule 118.

[0042] Furthermore, a second spring 115 is provided on the ferrule 118. When the ferrule 118 is pressed in the -X direction, the second spring 115 biases the ferrule 118 in the +X direction by its elastic force. This allows the optical fiber 3 inserted through another ferrule 118 to be pressed against the optical fiber 3 to be connected.

[0043] The flag frame 116 is a cylindrical member that houses the cylindrical member 114. A projection 112 is provided at the -X end of the flag frame 116. The projection 118A of the ferrule 118 is housed at the +X end of the flag frame 116. At the -X end of the flag frame 116, the projection 116A is provided so as to protrude from the inner wall into the inside of the flag frame 116. Even when the ferrule 118 is pushed in the +X direction by the elastic force of the second spring 115, the projection 116A and projection 118A come into contact with each other, preventing the ferrule 118 from falling out of the flag frame 116.

[0044] The main body case 117 is a cylindrical member that houses the flag frame 116. At the -X direction end of the main body case 117, a knob 117A that protrudes from the inner wall of the main body case 117 toward the inside of the main body case 117 is provided. By the knob 117A and the protrusion 116A coming into contact, the detachment of the flag frame 116 from the main body case 117 is suppressed.

[0045] Here, the fixing and releasing of the optical fiber 3 by the fiber chuck 106 in the first modification will be described in detail with reference to the drawings. FIG. 9 is a diagram for explaining the fixing and releasing of the optical fiber 3 by the fiber chuck 106 according to the first modification. In the upper part of FIG. 9, the positional relationship between the chuck ring 110 and the large-diameter cylindrical portion 108 in the first state is illustrated. In the first state, the large-diameter cylindrical portion 108 is housed within the chuck ring 110. Since the inner diameter of the chuck ring 110 is substantially equal to the outer diameter of the large-diameter cylindrical portion 108, the large-diameter cylindrical portion 108 is closed by the chuck ring 110. As a result, the optical fiber 3 is gripped by the gripping portion 109, and the optical fiber 3 is fixed. The position of the fiber chuck 106 in the first state is an example of the "first position".

[0046] The lower part of Figure 9 illustrates the positional relationship between the chuck ring 110 and the large-diameter cylindrical portion 108 in the second state. When the first stop ring 103 is pushed in the +X direction, causing the fiber chuck 106 to move in the +X direction, the chuck ring 110, which is located outside the large-diameter cylindrical portion 108, is restricted from moving in the +X direction by contacting the protruding portion 112. If the fiber chuck 106 moves further in the +X direction while the movement of the chuck ring 110 in the +X direction is restricted, the large-diameter cylindrical portion 108 will move outside the chuck ring 110. When the large-diameter cylindrical portion 108 moves outside the chuck ring 110, it is no longer closed by the chuck ring 110, so a gap G1 is formed between the gripping portion 109 and the optical fiber 3, and the gripping portion 109 no longer grips the optical fiber 3. As a result, the optical fiber 3 is released from the gripping portion 109 and becomes slidable in the X direction. For example, the fiber chuck 106 is made of an elastic material, and when the large-diameter cylindrical portion 108 is restrained by the chuck ring 110, the fiber chuck 106 may elastically deform so that the gripping portion 109 closes, thereby transitioning to a state in which the gripping portion 109 grips the optical fiber 3. When the large-diameter cylindrical portion 108 is not restrained by the chuck ring 110, the gripping portion 109 may open due to the elastic force of the fiber chuck 106, thereby transitioning to a state in which the gripping portion 109 does not hold the optical fiber 3. The position of the fiber chuck 106 in the second state is an example of the "second position".

[0047] FIG. 10 is a diagram showing an example of a connector adapter 200 according to the first modification. The connector adapter 200 is a member that forms an end face for connecting the optical fiber 3 by cutting (cleaving) the core portion 11 exposed by the removal port 120 of the ferrule 118. The connector adapter 200 has a cutting blade 201, a main body 202, and a sleeve 203. The cutting blade 201 is used for cleaving the core portion 11. Since the connector adapter 200 is connected to and used with the optical connector 100, the main body 202 is formed in a shape that can be connected to the optical connector 100. And the cutting blade 201 is disposed at a position where it can move along the +X direction end of the ferrule 118, for example, when cleaving the core portion 11. The sleeve 203 is a member that supports the ferrule 118 when the connector adapter 200 is connected to the optical connector 100. The sleeve 203 is provided with a ferrule insertion passage 204 that penetrates the sleeve 203 in the X direction. The inner diameter of the ferrule insertion passage 204 is formed to be substantially equal to the outer diameter of the ferrule 118. Note that the sleeve 203 may be a split sleeve having a notch formed in the X direction. Also, the sleeve 203 may be a precision sleeve having no such notch.

[0048] FIG. 11 is a diagram showing an example of the usage mode of the connector adapter 200 in the first modification. In the optical connector 100, when the coating portion 7 of the optical fiber 3 is removed and the core portion 11 is exposed in the second state, it transitions to the first state. By transitioning to the first state, the optical fiber 3 is fixed by the fiber chuck 106 in a state where the core portion 11 is pulled out from the ferrule 118 to the +X side. Then, the connector adapter 200 is connected to the +X side end of the optical connector 100. When the connector adapter 200 is connected to the +X side end of the optical connector 100, the ferrule 118 is supported by the ferrule insertion passage 204 of the sleeve 203.

[0049] Figure 12 shows an example of the state in which the core portion 11 of the connector adapter 200 is cleaved by the cutting blade 201 in the first modified example. When the cutting blade 201 is extended toward the core portion 11 along the +X end of the ferrule 118, the core portion 11 is cleaved by the cutting blade 201. The cleaving of the core portion 11 by the cutting blade 201 forms an end face used for connecting the optical fiber 3.

[0050] Figure 13 shows an example of a configuration in which two optical fibers 3, each having an end face formed for connecting the optical fibers 3 by a connector adapter 200, are connected in the first modified configuration. For simplicity, Figure 13 shows only the area around the connection portion of the optical fiber 3 from the optical connector 100. When connecting the optical fibers 3, the two optical connectors 100 (optical connectors 100A and 100B) are positioned so that the removal openings 120 of the ferrules 118 abut each other. As a result, the end faces formed on the core portions 11 can be brought together by being connected by the cutting blade 201. When connecting, the end faces of the core portions 11 of optical connector 100A and optical connector 100B may be connected by pressing in both the first stop ring 103 of optical connector 100A and the first stop ring 103 of optical connector 100B. When this operation is performed, the core portion 11 is released from the fiber chuck 106 when the optical fiber 3 is connected, and the ferrule 118 is pushed out by the elastic force of the second spring 115, thereby reducing the pressing force between the end face of the core portion 11 of optical connector 100A and the end face of the core portion 11 of optical connector 100B to an appropriate pressing force.

[0051] Incidentally, a slight angle may occur at the end face of the core portion 11 that has been cleaved by the connector adapter 200. Figure 14 shows an example of the end face of the cleaved core portion 11 in the first modified example. The end face 11A of the core portion 11 that has been cleaved by the connector adapter 200 is, for example, slanted as illustrated in Figure 14. When two core portions 11 having such slanted end faces 11A are connected with their end faces 11A facing each other, a gap may occur between the end faces 11A. In the first modified example, the core portions 11 are connected with a pressing force that does not cause such a gap to collapse (a force that does not cause elastic deformation of the core portion 11). Connecting the core portions 11 with a pressing force that does not cause elastic deformation of the core portion 11 is also called the "weak physical contact method". When the core portions 11 are connected using the "weak physical contact method", light is incident on one optical fiber 3 and emitted from the other optical fiber 3, and the difference (loss) between the incident light and the emitted light was verified. The results of this verification confirmed that the loss when connecting the core units 11 using the weak physical contact method is close to the value when connecting optical fibers with a general optical connector. Therefore, it is considered that connecting the core units 11 using the "weak physical contact method" is suitable for practical use.

[0052] Figure 15 is a diagram illustrating an example of a flowchart for explaining the method of connecting the optical fiber 3 in the first modified example. The method of connecting the optical fiber 3 in the first modified example will be explained below with reference to Figure 15.

[0053] Step S201 is the process of moving the optical fiber 3 in the axial direction of the optical fiber 3 to remove the coating portion 7. For example, by moving the boot 101 in the X direction, the first stop ring 103 moves in the +X direction, and consequently, the optical fiber 3 fixed to the fiber chuck 106 is also fed out in the +X direction. When the fed-out optical fiber 3 is inserted into the removal opening 120 of the coating removal section 119, the coating portion 7 is removed from the optical fiber 3. Note that only the portion of the coating portion 7 of the optical fiber 3 that has passed through a predetermined part of the coating removal section 9 is removed. In this way, the tip region portion of the coating portion 7 of the optical fiber 3 (for example, the portion that has passed through the coating removal section 9) is removed.

[0054] Subsequently, when the first stop ring 103 moves to a position where the chuck ring 110 contacts the protrusion 112, the optical fiber 3 is released from the fiber chuck 106. In this state, when the force applied to the boot 101 is released, the first stop ring 103 returns to its original position due to the elastic force of the first spring 105, and the optical fiber 3, from which the coating 7 has been removed, is fixed in place.

[0055] Step S202 is a step in which the optical fiber 3 from which the coating portion 7 has been removed is cleaved. In step S202, the connector adapter 200 is connected to the optical connector 100. With the connector adapter 200 connected to the optical connector 100, the cutting blade 201 cleaves the optical fiber 3 (core portion 11) from which the coating portion 7 has been removed along the +X end of the ferrule 118.

[0056] Step S203 is the process of optically connecting the cleaved optical fibers 3. In step S203, the two optical connectors 100 (optical connectors 100A and 100B in Figure 13) are positioned so that the removal openings 120 of the ferrules 118 abut each other, thereby positioning the end faces formed on the core portions 11 facing each other. Then, by pressing in both the first stop ring 103 of optical connector 100A and the first stop ring 103 of optical connector 100B, the end faces of the core portions 11 of the optical connector 100B are connected.

[0057] <Effects of the First Modified Example> In the first modified example, a fiber chuck 106 and a chuck ring 110 are used to fix and release the optical fiber 3. This makes it possible to feed out the optical fiber 3 toward the removal opening 120 of the ferrule 118 simply by moving the first stop ring 103 in the +X direction. Furthermore, when the force moving the first stop ring 103 in the +X direction is released, the elastic force of the first spring 105 returns the first stop ring 103 to its original position, and the optical fiber 3 is fixed in the fed-out state by the fiber chuck 106. In other words, according to the first modified example, the optical fiber 3 can be fixed in the fed-out state by a simple operation of moving the first stop ring 103 in the +X direction and returning the first stop ring 103 to its original position.

[0058] In the first modified example, the first stop ring 103, which has been moved in the +X direction, can be returned to its original position by the elastic force of the first spring 105. Therefore, according to the first modified example, after moving the first stop ring 103 in the +X direction, the first spring 105 can be returned to its original position by a simple operation of releasing the force that moves the first stop ring 103 in the +X direction, thereby fixing the optical fiber 3.

[0059] In the first modified example, the connector adapter 200 is provided with a sleeve 203 for holding the ferrule 118, but the sleeve 203 may be omitted. However, holding the ferrule 118 with the sleeve 203 allows for more precise cleaving of the core portion 11.

[0060] <Other Modifications> In the first modified example described above, a first spring 105 is provided, but the first spring 105 may be omitted. If the first spring 105 is omitted, when returning the first stop ring 103, which has been moved in the +X direction, to its original position, the first stop ring 103 can be moved by hand, for example.

[0061] This invention can be used in the field of optical information communication.

[0062] 1,100 Optical connector 3 Optical fiber 5 Guide section 7 Sheathing section 9 Sheathing removal section 11 Core section 11A End face 13 Cleave section 17 Optical fiber fixing section 19 Biasing section 21 Plug housing 23 Stop ring 24 Flange 25 Boot 27 Knob 31 Ferrule 33 Cover 35 Clamp spring 37 V-groove base plate 39 Wedge 41 Sheathing housing section 51 Wedge section 53 Fiber feeding section 55 Cutting blade section 71 Sheathing 101 Boot 103 First stop ring 104 Second stop ring 105 First spring 106 Fiber chuck 107 Small diameter cylinder section 108 Large diameter cylinder section 109 Gripping section 110 Chuck ring 111 Third stop ring 112 Protruding section 113 Fiber chuck insertion section 114 Cylindrical member 115 Second spring 116 Flag frame 116A Protruding part 117 Main body case 117A Knob 118 Ferrule 118A Protruding part 119 Coating removal section 120 Removal port 121 Discharge port 130 Fiber passage 131 First fiber passage 132 Second fiber passage 133 Third fiber passage 134 Fourth fiber passage 135 Fifth fiber passage 200 Connector adapter 201 Cutting blade 202 Main body 203 Sleeve 204 Ferrule insertion passage

Claims

1. An optical connector for optically connecting optical fibers, comprising: a guide portion for housing an optical fiber so as to be movable in the axial direction of the optical fiber; a coating removal portion for removing the coating portion of the optical fiber; and a cleaving portion for cleaving the optical fiber from which the coating portion has been removed by the coating removal portion.

2. An optical connector according to claim 1, wherein the optical fiber is a hollow-core optical fiber.

3. An optical connector according to claim 1, wherein the guide portion has a gripping portion for releasably gripping the optical fiber.

4. An optical connector according to claim 3, further comprising an optical fiber fixing portion for fixing the optical fiber from which the coating portion has been removed by the coating removal portion.

5. An optical connector according to claim 4, wherein the optical fiber fixing portion further includes a switching portion that causes the gripping portion to grip the optical fiber when the gripping portion is in a first position, and releases the optical fiber from the gripping portion when the gripping portion is in a second position closer to the coating removal portion than the first position.

6. The optical connector according to claim 5, wherein the optical fiber fixing portion further comprises an elastic member that elastically returns the gripping portion, which has been moved to the second position, to the first position.

7. A method for connecting optical fibers, comprising: a moving step, which is a step of moving the optical fiber in the axial direction of the optical fiber; a coating removal step, which is a step of removing the coating of the optical fiber in order to expose the core of the optical fiber; and a cleaving step, which is a step of cleaving the optical fiber exposed by the coating removal step.

8. A method for connecting optical fibers according to claim 7, further comprising, before the cleaving step, an optical fiber fixing step which is a step of fixing the optical fiber exposed by the coating removal step.

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