Optical connector manufacturing method

Abstract

To provide a manufacturing method of an optical connector in which a change in a core position of an optical fiber on an end face of an optical connector is small, and connection loss is little, between thermosetting and bonding, and after polishing.SOLUTION: An optical connector includes an optical fiber which contains a glass fiber and a resin coating covering the glass fiber, where the end of the glass fiber is exposed from the resin coating, and a ferrule which has a through hole and holds the optical fiber. A manufacturing method includes the steps of: coating a thermosetting resin onto an inner wall of the through hole; inserting a glass fiber exposed from a coating resin into the through hole; adjusting a mutual positional relation between the optical fiber and the ferrule so that a distance between end faces between the top of the glass fiber and the tip of the ferrule is 1 mm or less; rotationally aligning the glass fiber to the ferrule; curing the thermosetting resin; and polishing the tip of the glass fiber and the tip of the ferrule.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing an optical connector. This application claims priority based on a Japanese patent application (Patent Application No. 2019-001154) filed on January 8, 2019, and incorporates by reference all of the contents of said Japanese application. [Background technology]

[0002] In addition to the increased speed and volume of information due to the spread of information communications such as the Internet, the construction of optical networks is progressing to accommodate bidirectional and large-capacity communications. Multicore fibers (hereinafter referred to as "MCF"), which have multiple cores, have been proposed as a means of increasing the transmission capacity of optical fibers. When constructing an optical network using MCF, optical connectors are required to easily connect the MCF. To connect all cores of the MCF, the MCF must be rotated around its center axis and its rotational position must be aligned (rotational alignment).

[0003] Patent Document 1 discloses a manufacturing method that includes rotational alignment of an optical connector for connecting MCFs. In this manufacturing method, first, an MCF fixed to a ferrule is positioned so that it faces a master MCF connector to which the master MCF is fixed, and the centers of the MCF fixed to the ferrule and the master MCF are aligned. Next, light is introduced into one core of the master MCF or the MCF, and the ferrule is rotated relative to the master MCF connector to detect light from the other core of the master MCF or the MCF, and the ferrule is held at a position where the light intensity is maximized. After that, a flange with a positioning mechanism is fixed to the ferrule of the rotationally aligned MCF. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2013-238692 Summary of the Invention [Means for solving the problem]

[0005] The present disclosure provides a method for manufacturing an optical connector including an optical fiber that includes a glass fiber and a resin coating that covers the glass fiber, with an end of the glass fiber exposed from the resin coating, and a ferrule that has a through hole and holds the optical fiber, wherein the optical fiber is an optical fiber that requires adjustment of a rotation angle around a central axis when optically connecting, and the manufacturing method includes a first step of applying a thermosetting resin to an inner wall of the through hole; Resin coating a second step of inserting the glass fiber exposed from the ferrule into the through-hole; and a second step of inserting the glass fiber so that the tip of the glass fiber is positioned within the ferrule. Between the tip of the glass fiber and the tip of the ferrule a third step of adjusting the relative positional relationship between the optical fiber and the ferrule so that the distance between the end faces is 0.5 mm or less; a fourth step of rotationally aligning the glass fiber with respect to the ferrule; a fifth step of curing the thermosetting resin; and a sixth step of polishing the tip of the glass fiber and the tip of the ferrule, wherein the first step, the second step, the third step, the fourth step, the fifth step, and the sixth step are carried out in this order, Recording end A step of measuring the inter-surface distance is included between the second step and the third step. The present disclosure also provides a method for manufacturing an optical connector including an optical fiber that includes a glass fiber and a resin coating that covers the glass fiber, with an end of the glass fiber exposed from the resin coating, and a ferrule that has a through hole and holds the optical fiber, wherein the optical fiber is a multi-core fiber or a bundle fiber, and the manufacturing method includes a first step of applying a thermosetting resin to an inner wall of the through hole; Resin coating a second step of inserting the glass fiber exposed from the ferrule into the through-hole; and a second step of inserting the glass fiber so that the tip of the glass fiber is positioned within the ferrule. Between the tip of the glass fiber and the tip of the ferrulea third step of adjusting the relative positional relationship between the optical fiber and the ferrule so that the distance between the end faces is 0.5 mm or less; a fourth step of rotationally aligning the glass fiber with respect to the ferrule; a fifth step of curing the thermosetting resin; and a sixth step of polishing the tip of the glass fiber and the tip of the ferrule, wherein the first step, the second step, the third step, the fourth step, the fifth step, and the sixth step are carried out in this order, Recording end A step of measuring the inter-surface distance is included between the second step and the third step. The present disclosure also provides a method for manufacturing an optical connector including an optical fiber that includes a glass fiber and a resin coating that covers the glass fiber, with an end of the glass fiber exposed from the resin coating, and a ferrule that has a through hole and holds the optical fiber, wherein the optical fiber is an optical fiber whose core position needs to be controlled in a rotational direction of an axis, the manufacturing method comprising: a first step of applying a thermosetting resin to an inner wall of the through hole; Resin coating a second step of inserting the glass fiber exposed from the ferrule into the through-hole; and a second step of inserting the glass fiber so that the tip of the glass fiber is positioned within the ferrule. Between the tip of the glass fiber and the tip of the ferrule a third step of adjusting the relative positional relationship between the optical fiber and the ferrule so that the distance between the end faces is 0.5 mm or less; a fourth step of rotationally aligning the glass fiber with respect to the ferrule; a fifth step of curing the thermosetting resin; and a sixth step of polishing the tip of the glass fiber and the tip of the ferrule, wherein the first step, the second step, the third step, the fourth step, the fifth step, and the sixth step are carried out in this order, Recording end A step of measuring the inter-surface distance is included between the second step and the third step. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is an external perspective view of an optical connector according to the present disclosure. [Figure 2] FIG. 2 is a perspective view of a ferrule included in the optical connector of FIG. 1. [Figure 3]3 is a cross-sectional view showing a state after the ferrule of FIG. 2 is accommodated in a plug frame. FIG. [Figure 4] FIG. 2 is a flow diagram showing a method for manufacturing an optical connector according to the present disclosure. [Figure 5A] 10A to 10C are diagrams for explaining a step up to a thermosetting resin curing step in a method for manufacturing an optical connector according to the present disclosure. [Figure 5B] 10A and 10B are diagrams showing the state after a polishing process in one manufacturing method of an optical connector of the present disclosure. [Figure 6] 1 is a diagram showing the relationship between the amount of core position deviation and splice loss in an optical fiber according to the present disclosure. [Figure 7] FIG. 2 is a diagram for explaining a bundle fiber. [Figure 8] 1A and 1B are diagrams showing the state of the optical fiber end face during thermal curing and after polishing. DETAILED DESCRIPTION OF THE INVENTION

[0007] [Description of the embodiments disclosed herein] First, embodiments of the present disclosure will be listed and described. (1) A method for manufacturing an optical connector including an optical fiber including a glass fiber and a resin coating covering the glass fiber, the end of the glass fiber being exposed from the resin coating, and a ferrule having a through hole and holding the optical fiber, wherein the optical fiber is an optical fiber that requires adjustment of a rotation angle around a central axis when optically connecting, and the manufacturing method includes a first step of applying a thermosetting resin to an inner wall of the through hole; Resin coating a second step of inserting the glass fiber exposed from the ferrule into the through-hole; and a second step of inserting the glass fiber so that the tip of the glass fiber is positioned within the ferrule. Between the tip of the glass fiber and the tip of the ferrulea third step of adjusting the relative positional relationship between the optical fiber and the ferrule so that the distance between the end faces is 0.5 mm or less; a fourth step of rotationally aligning the glass fiber with respect to the ferrule; a fifth step of curing the thermosetting resin; and a sixth step of polishing the tip of the glass fiber and the tip of the ferrule, wherein the first step, the second step, the third step, the fourth step, the fifth step, and the sixth step are carried out in this order, Recording end A step of measuring the inter-surface distance is included between the second step and the third step. This makes it possible to obtain an optical connector with little change in the core position of the optical fiber at the end face of the optical connector between the time of thermal curing bonding and after polishing, and with little connection loss. Furthermore, since the amount of glass fiber to be polished can be reduced, it is possible to reliably reduce the change in the core position of the optical fiber at the end face of the optical connector between when the glass fiber is thermally cured and after polishing.

[0008] (2) A method for manufacturing an optical connector including an optical fiber including a glass fiber and a resin coating covering the glass fiber, the end of the glass fiber being exposed from the resin coating, and a ferrule having a through hole and holding the optical fiber, wherein the optical fiber is a multi-core fiber or a bundle fiber, and the manufacturing method includes a first step of applying a thermosetting resin to an inner wall of the through hole; Resin coating a second step of inserting the glass fiber exposed from the ferrule into the through-hole; and a second step of inserting the glass fiber so that the tip of the glass fiber is positioned within the ferrule. Between the tip of the glass fiber and the tip of the ferrule a third step of adjusting the relative positional relationship between the optical fiber and the ferrule so that the distance between the end faces is 0.5 mm or less; a fourth step of rotationally aligning the glass fiber with respect to the ferrule; a fifth step of curing the thermosetting resin; and a sixth step of polishing the tip of the glass fiber and the tip of the ferrule, wherein the first step, the second step, the third step, the fourth step, the fifth step, and the sixth step are carried out in this order, Recording end A step of measuring the inter-surface distance is included between the second step and the third step. This makes it possible to obtain an optical connector with little change in the core position of the optical fiber at the end face of the optical connector between the time of thermal curing bonding and after polishing, and with little connection loss. Furthermore, since the amount of glass fiber to be polished can be reduced, it is possible to reliably reduce the change in the core position of the optical fiber at the end face of the optical connector between when the glass fiber is thermally cured and after polishing. (3) A method for manufacturing an optical connector including an optical fiber including a glass fiber and a resin coating covering the glass fiber, the end of the glass fiber being exposed from the resin coating, and a ferrule having a through hole and holding the optical fiber, wherein the optical fiber is an optical fiber whose core position needs to be controlled in a rotational direction of an axis, the manufacturing method comprising: a first step of applying a thermosetting resin to an inner wall of the through hole; Resin coating a second step of inserting the glass fiber exposed from the ferrule into the through-hole; and a second step of inserting the glass fiber so that the tip of the glass fiber is positioned within the ferrule. Between the tip of the glass fiber and the tip of the ferrule a third step of adjusting the relative positional relationship between the optical fiber and the ferrule so that the distance between the end faces is 0.5 mm or less; a fourth step of rotationally aligning the glass fiber with respect to the ferrule; a fifth step of curing the thermosetting resin; and a sixth step of polishing the tip of the glass fiber and the tip of the ferrule, wherein the first step, the second step, the third step, the fourth step, the fifth step, and the sixth step are carried out in this order, Recording end A step of measuring the inter-surface distance is included between the second step and the third step. This makes it possible to obtain an optical connector with little change in the core position of the optical fiber at the end face of the optical connector between the time of thermal curing bonding and after polishing, and with little connection loss. Furthermore, since the amount of glass fiber to be polished can be reduced, it is possible to reliably reduce the change in the core position of the optical fiber at the end face of the optical connector between when the glass fiber is thermally cured and after polishing.

[0009] [Details of the embodiments disclosed herein] Embodiments of a manufacturing method for an optical connector according to the present disclosure will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiments, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. Furthermore, as long as multiple embodiments can be combined, the present invention includes any combination of embodiments. Note that in the following description, configurations with the same reference numerals in different drawings are considered to be similar, and their description may be omitted.

[0010] In the manufacturing method disclosed in Patent Document 1, an MCF is fixed to a ferrule, rotational alignment is performed, and then a flange is fixed. However, there is also a method in which an MCF is inserted into a flanged ferrule, the MCF is rotated to perform rotational alignment, and then the MCF is fixed to the ferrule. In this case, it is necessary to perform rotational alignment so that the MCF is at a predetermined angle in the axial rotation direction with respect to the flange, and then the MCF is thermally cured and bonded to the ferrule. One possible method for rotational alignment is to insert the MCF into a flanged ferrule, rotate it while observing the end face, and then thermally cure it.

[0011] However, if rotational alignment is performed without controlling the end-to-end distance between the end face of the glass fiber and the end face of the ferrule, and then the MCF is heat-cured and bonded to the ferrule and then subjected to subsequent processes such as polishing, the core position at the connector end face after polishing may deviate from the core position at the end face of the glass fiber during rotational alignment. Figure 8 shows the state of the optical fiber end face during heat-curing and polishing. In Figure 8, the position of the core 4 at the end face of the glass fiber 2 of the optical fiber F during heat-curing and polishing after rotational alignment is deviated by an amount r from the position of the core 4 at the end face of the glass fiber 2 before polishing to the position of the core 4 at the end face of the optical fiber F after the glass fiber 2 protruding from the ferrule body 11 has been removed and polished together with the ferrule body 11. In other words, the core at a position length d from the tip of the glass fiber 2 is deviated by an amount r compared to the tip.

[0012] There are two reasons for this misalignment: First, the MCF is twisted inside the ferrule due to the small clearance of less than 1 μm between the fiber through-hole in the ferrule and the MCF. Second, the core position inside the MCF fluctuates due to the constant twisting applied during drawing.

[0013] The present disclosure relates to an optical fiber that requires the core position to be controlled in the rotation direction of the axis. Ba The present invention aims to provide a method for manufacturing an optical connector having a low connection loss.

[0014] Fig. 1 is an external perspective view of an optical connector 1 according to one embodiment of the present disclosure, Fig. 2 is a perspective view of a ferrule 10 included in the optical connector 1, and Fig. 3 is a cross-sectional view showing the state after the ferrule 10 has been accommodated in a plug frame 20. Note that in the following embodiments, an LC connector will be used as an example of the optical connector 1, but the present invention can also be applied to other types of optical connectors, including, for example, an SC connector or an MU connector.

[0015] The optical connector 1 includes a plug frame 20 that houses a ferrule 10, and a boot 34 that protects an optical fiber F is provided at the rear end of the plug frame 20. The ferrule 10 has a ferrule body 11 that extends in the X-axis direction shown in the figure. The ferrule body 11 is a cylindrical component made of, for example, zirconia, and has a through-hole in the X-axis direction inside the ferrule body 11 that holds a glass fiber exposed from a resin coating at the tip end of the optical fiber F. The optical fiber F is, for example, an MCF having multiple cores, and is inserted from the rear end 13 side of the ferrule 10, with its tip end face exposed at the front end 12 and fixed to the ferrule 10 with the multiple cores arranged at predetermined positions around the central axis of the ferrule 10. The X-axis direction shown in the figure corresponds to the optical axis direction of the optical fiber F.

[0016] A metal flange 14 is provided on the outer side of the approximate center of the ferrule body 11. In this embodiment, the flange 14 has a generally rectangular cross section, with the boundaries of each face being chamfered. The flange 14 has the function of positioning and fixing the ferrule 10 to the plug frame 20 using one of the faces of the flange 14 as a reference.

[0017] The plug frame 20 has a square cylindrical front housing 21 that extends in the X-axis direction shown in the figure. The front housing 21 is made of, for example, resin, and has a rear-end opening that can accept a ferrule 10 with a flange 14, and an opening 24 through which the front end 12 of the ferrule body 11 protrudes. The front housing 21 has a generally square cylindrical shape in cross section, and is designed to position the flange 14 of the ferrule 10 inserted into the front housing 21 in the YZ directions. In addition, a positioning protrusion 23 that abuts against the front end surface of the flange 14 is provided. Furthermore, a flexible latch arm 22 is provided on the outer peripheral surface of the front housing 21.

[0018] The plug frame 20 also has a rear housing 31 behind the front housing 21. The rear housing 31 is made of, for example, resin and has a cylindrical spring accommodating portion 33 that can accommodate the rear end portion of the ferrule 10 and a connector pressing spring 35. The connector pressing spring 35 is disposed behind the ferrule 10 and can urge the ferrule 10 forward (in the positive direction of the X-axis shown in the figure; the same applies below) by abutting against the rear end surface of the flange 14. In addition, a clip 32 that can engage with the latch arm 22 is provided on the outer circumferential surface of the rear housing 31.

[0019] To assemble the optical connector 1, the rear end portion of the ferrule 10 and the connector pressing spring 35 are housed in the rear housing 31, and the front end portion of the ferrule 10 is inserted into the front housing 21. Next, when the clip 32 rides up onto the latch arm 22, the front housing 21 is latched to the rear housing 31. At the same time, the flange 14 is pressed forward by the biasing force of the connector pressing spring 35. As a result, the front end face of the flange 14 abuts against the positioning protrusion 23 of the front housing 21, thereby positioning the ferrule 10 in the X-axis direction. In this state, the flange 14 moves forward, and the front end portion of the ferrule 10 protrudes from the front housing 21.

[0020] Next, a method for attaching the optical fiber F to the ferrule 10 will be described. Fig. 4 is a flow chart showing a method for manufacturing the optical connector 1. Fig. 5A is a diagram for explaining up to the thermosetting resin curing step in one method for manufacturing the optical connector 1, and Fig. 5B is a diagram showing the optical connector 1 after the polishing step in one method for manufacturing the optical connector 1.

[0021] First, a ferrule 10 with a flange 14 is prepared, and a thermosetting resin 41 is applied to the inner wall of the through-hole 15 of the ferrule body 11 (step S1, thermosetting resin application step). Next, a portion of the resin coating 3 is removed to expose the tip of the glass fiber 2, and the glass fiber 2 exposed from the resin coating 3 is inserted into the through-hole 15 of the ferrule 10 from the rear end (the negative side in the X-axis direction) (step S2, optical fiber insertion step). Here, the clearance (gap) between the glass fiber 2 and the inner wall of the through-hole 15 of the ferrule body 11 is approximately less than 1 μm.

[0022] Next, the distance between the end face of the glass fiber 2 and the end face of the ferrule 10 (hereinafter referred to as the "protrusion length"; it is expressed as a positive value when the end face of the glass fiber 2 protrudes from the end face of the ferrule 10 and as a negative value when the tip of the glass fiber 2 is located within the through-hole 15) is measured (protrusion length measurement process in step S3), and the relative positions of the optical fiber F and the ferrule 10 are adjusted so that the protrusion length is 1 mm or less (protrusion length adjustment process in step S4). Figure 6 shows the relationship between the amount of core position deviation of the optical fiber 1 and the connection loss. It is desirable to keep the connection loss to 0.5 dB or less, which is the allowable value for the product. In this case, the core position deviation needs to be kept to 1.6 μm or less, as can be seen from the graph in Figure 6. A 2 mm change in the longitudinal position of the end face of the optical fiber F could result in a 1.6 μm deviation in the core position. Therefore, the amount of removal and polishing of the tip of the optical fiber 1 needs to be 2 mm or less, and preferably 1.5 mm or less.

[0023] The polishing allowance B of the ferrule 10, which is polished together with the tip of the optical fiber, is preferably 0.5 mm or less in order to maintain the product dimensions of the ferrule 10. Therefore, as shown in FIG. 5A, the protruding length A of the glass fiber 2 protruding from the front end (tip end face) 12 of the ferrule 10 is preferably 1 mm or less. The tip of the glass fiber 2 may be adjusted so as to be retracted beyond the front end 12 of the ferrule 10. In this case, the protruding length is preferably set to be greater than 0.5 mm, taking into account the polishing allowance B of the ferrule 10.

[0024] When the glass fiber 2 protrudes from the tip of the ferrule 10, the protruding length of the part of the glass fiber 2 protruding from the ferrule 10 corresponds to the distance between the tip of the glass fiber 2 and the tip of the ferrule 10 in the X-axis direction. Thus, the protruding length adjusting step shown in step S4 of FIG. 4 corresponds to the step of adjusting the distance between the tip of the glass fiber 2 and the tip of the ferrule 10 in the X-axis direction. On the other hand, when the tip of the glass fiber 2 is set back from the tip of the ferrule 10 (in other words, when the tip of the glass fiber 2 is located inside the through-hole 15), the retracted length of the glass fiber 2 corresponds to the distance between the tip of the glass fiber 2 and the tip of the ferrule 10 in the X-axis direction. In this case as well, the distance (retracted length) between the tip of the glass fiber 2 and the tip of the ferrule 10 is measured in step S3 of FIG. 4, and the distance is adjusted in step S4.

[0025] Furthermore, in conventional manufacturing methods, when the protruding portion of the glass fiber 2 is cut, the remaining glass fiber 2 remains at the tip of the ferrule 10, and polishing with abrasive paper with coarse abrasive particles is sometimes performed to remove this remaining glass fiber 2. This rough polishing not only removes the glass fiber 2 but also removes excess of the ferrule 10. In contrast, in this embodiment, the protruding length of the glass fiber 2 from the tip of the ferrule 10 is small, so the rough polishing step can be shortened or omitted. Therefore, in this embodiment, it is possible to reduce the amount of the ferrule 10 that needs to be removed.

[0026] After step S4, the process proceeds to step S5, where rotational alignment of the optical fiber F is performed (rotational alignment process of step S5). The rotational alignment is performed by rotating the glass fiber 2 in the direction of arrow R, using a predetermined surface on the outer periphery of the flange 14 as a reference surface, so that the glass fiber 2 at the tip end is rotated at a predetermined angle. The specific method for rotational alignment may be, for example, the method disclosed in Patent Document 1, or any of various existing methods.

[0027] Thereafter, the ferrule 10 with the optical fiber F inserted therein is heated to harden the thermosetting resin 41 in the ferrule body 11 (step S6, the thermosetting resin hardening step). After step S6, as shown in FIG. 5B, the end faces of the tip of the glass fiber 2 and the tip of the ferrule body 11 are polished (step S7, the polishing step). The amount of polishing of the glass fiber 2 in the polishing step is longer than the protrusion length A of the glass fiber 2 protruding from the tip end face of the ferrule 10 but shorter than the sum of the protrusion length A and the polishing allowance B. Note that the polishing step is performed so that the tip of the glass fiber 2 and the tip of the ferrule 10 are flush with each other. Alternatively, the glass fiber 2 may be polished at a predetermined angle relative to the longitudinal direction (X-axis direction) of the glass fiber 2, or may be polished into a convex spherical shape. Note that the polished length in the axial direction of the ferrule body 11 is limited to 0.5 mm or less, as described above. After the polishing step, the tip face of the ferrule body 11 becomes a polished surface 12′, and the ferrule body 11 is shorter than before polishing.

[0028] Next, the ferrule 10 with the optical fiber F mounted thereon is combined with the plug frame 20, the connector pressing spring 35, etc. to obtain the optical connector 1 (connectorization step S8). The connector assembly method is as described above.

[0029] In the above embodiments, the optical connector has been described using an LC connector as an example, but the present invention can also be applied to other types of optical connectors, including an SC connector and an MU connector. Furthermore, the optical fiber F has been described using an MCF as an example, but the optical fiber F of the present disclosure may be, for example, a polarization-maintaining fiber or a bundle fiber. MCF, polarization-maintaining fiber, and bundle fiber are optical fibers that require adjustment of the rotation angle around the central axis when optically connecting.

[0030] A bundle fiber is a fiber in which multiple single-core fibers are gathered together to be optically connected to a multicore fiber. More specifically, for example, a multicore fiber with a glass diameter of 125 μm is prepared by chemically etching the tip thereof to reduce the glass diameter to, for example, 45 μm, and multiple fibers (for example, seven fibers) are bundled together with an adhesive and inserted into a ferrule 10 as shown in FIG. 7. In this example, the fibers can be arranged so that the inter-core distance is 45 μm. In this way, in the present disclosure, even when a multicore fiber, a polarization-maintaining fiber, or a bundle fiber is used as the optical fiber F, the optical fiber F can be reliably positioned, thereby preventing a decrease in connection loss of the optical connector 1. [Explanation of symbols]

[0031] 1...optical connector, 2...glass fiber, 3...resin coating, 4...core, 10...ferrule, 11...ferrule body, 12...front end, 12'...polished surface, 13...rear end, 14...flange, 20...plug frame, 21...front housing, 22...latch arm, 23...positioning protrusion, 24...opening, 31...rear housing, 32...clip, 33...spring accommodating portion, 34...boot, 35...connector pressing spring, 41...thermosetting resin

Claims

1. A method for manufacturing an optical connector including an optical fiber including a glass fiber and a resin coating covering the glass fiber, an end of the glass fiber being exposed from the resin coating, and a ferrule having a through hole and holding the optical fiber, the optical fiber is an optical fiber that requires adjustment of a rotation angle around a central axis when optically connecting the optical fiber, The manufacturing method includes: a first step of applying a thermosetting resin to an inner wall of the through hole; a second step of inserting the glass fiber exposed from the resin coating into the through hole; a third step of adjusting the relative positions of the optical fiber and the ferrule so that the tip of the glass fiber is positioned within the ferrule and the end-to-end distance between the tip of the glass fiber and the tip of the ferrule is 0.5 mm or less; a fourth step of rotationally aligning the glass fiber with respect to the ferrule; a fifth step of curing the thermosetting resin; a sixth step of polishing the tip of the glass fiber and the tip of the ferrule; Including, The first step, the second step, the third step, the fourth step, the fifth step, and the sixth step are performed in this order; A method for manufacturing an optical connector, comprising a step of measuring the distance between the end faces between the second step and the third step.

2. A method for manufacturing an optical connector including an optical fiber including a glass fiber and a resin coating covering the glass fiber, an end of the glass fiber being exposed from the resin coating, and a ferrule having a through hole and holding the optical fiber, the optical fiber is a multi-core fiber or a bundle fiber, The manufacturing method includes: a first step of applying a thermosetting resin to an inner wall of the through hole; a second step of inserting the glass fiber exposed from the resin coating into the through hole; a third step of adjusting the relative positions of the optical fiber and the ferrule so that the tip of the glass fiber is positioned within the ferrule and the end-to-end distance between the tip of the glass fiber and the tip of the ferrule is 0.5 mm or less; a fourth step of rotationally aligning the glass fiber with respect to the ferrule; a fifth step of curing the thermosetting resin; a sixth step of polishing the tip of the glass fiber and the tip of the ferrule; Including, The first step, the second step, the third step, the fourth step, the fifth step, and the sixth step are performed in this order; A method for manufacturing an optical connector, comprising a step of measuring the distance between the end faces between the second step and the third step.

3. A method for manufacturing an optical connector including an optical fiber including a glass fiber and a resin coating covering the glass fiber, an end of the glass fiber being exposed from the resin coating, and a ferrule having a through hole and holding the optical fiber, the optical fiber is an optical fiber in which the core position needs to be controlled in the rotation direction of the axis, The manufacturing method includes: a first step of applying a thermosetting resin to an inner wall of the through hole; a second step of inserting the glass fiber exposed from the resin coating into the through hole; a third step of adjusting the relative positional relationship between the optical fiber and the ferrule so that the tip of the glass fiber is positioned within the ferrule and the end-to-end distance between the tip of the glass fiber and the tip of the ferrule is 0.5 mm or less; a fourth step of rotationally aligning the glass fiber with respect to the ferrule; a fifth step of curing the thermosetting resin; a sixth step of polishing the tip of the glass fiber and the tip of the ferrule; Including, The first step, the second step, the third step, the fourth step, the fifth step, and the sixth step are performed in this order; A method for manufacturing an optical connector, comprising a step of measuring the distance between the end faces between the second step and the third step.

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