JP2008083155A - Method of processing terminal of multicore optical fibre and terminal structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of processing the terminal of a multicore optical fiber taking the improvement in workability into account and to provide a terminal structure. <P>SOLUTION: The method of processing the terminal includes: a first process which includes a process in which a coating film 25 of the terminal of the multicore optical fiber 21 having the coating film 25 formed on the outer side in a state of bundling a lot of optical fibers 24, is removed and a process in which a metal sleeve 23 is fixed to the terminal part where the coating film is removed; and a second process in which the metal sleeve 23 of the terminal of the multicore optical fiber 21 is inserted into a through hole 34 formed at the optical splicing end face 35 of a ferrule 22 and the metal sleeve 23 and the ferrule 22 are fixed. When the ferrule 22 used in the second process has a female shape, the first process further includes a terminal processing such as grinding after the metal sleeve 23 is fixed to the end of the multicore optical fiber 21. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of processing a terminal of a multi-core optical fiber and a structure of the terminal.

  In recent years, a system has been adopted in which a part of the wire harness is replaced with an optical fiber, for example, each node is connected with an optical fiber. As such a system, for example, an optical module disclosed in Patent Document 1 below is known. In FIG. 3, reference numeral 1 denotes an optical module disclosed in Patent Document 1 below. The optical module 1 is a pigtail type optical module, and includes a circuit board 2, a light emitting / receiving unit (optical transceiver) 3 mounted on the circuit board 2, and a pair of connectors provided at the end of the circuit board 2. 4 and 4 and optical fiber cables 5 and 5 for relay that optically connect the light emitting / receiving unit 3 and the connector units 4 and 4.

  Ferrules 6 and 6 (see FIG. 4) are fixed to the terminals of the optical fiber cables 5 and 5, respectively. The ferrules 6 and 6 are accommodated in the connector portions 4 and 4. The connector parts 4 and 4 are formed in a receptacle shape. Optical connectors 7 and 7 as connection partners are fitted and connected to such connector portions 4 and 4. The optical connectors 7 are formed in a plug shape. The optical connectors 7 and 7 are provided at the ends of the optical fiber cables 8 and 8. Ferrules 9 and 9 (see FIG. 4) housed inside the optical connectors 7 and 7 are provided at the ends of the optical fiber cables 8 and 8, respectively.

  The ferrules 6 and 6 of each end of the optical fiber cables 5 and 5 and the ferrules 9 and 9 of each end of the optical fiber cables 8 and 8 are formed in the same shape, and the connector portions 4, 4 and Inside the optical connectors 7, the front end faces face each other so that the optical axes coincide with each other.

  The optical fiber cables 5 and 8 and the ferrules 6 and 9 will be described with reference to FIG. The optical fiber cables 5 and 8 include an optical fiber 10 composed of a core and a clad, and a primary sheath 11 and a secondary sheath 12 that cover the optical fiber 10. The ends of the optical fiber cables 5 and 8 are processed so that the primary sheath 11 and the secondary sheath 12 are removed and the optical fiber 10 is exposed to a predetermined length in order to fix the ferrules 6 and 9.

  The ferrules 6 and 9 are formed in a substantially cylindrical shape having a small diameter portion 13 and a large diameter portion 14. The ferrules 6 and 9 are formed so that the front end face 15 and the rear end face 16 pass straight through. The inner diameter of the small diameter portion 13 is formed in accordance with the outer diameter of the optical fiber 10. Further, the inner diameter of the large diameter portion 14 is formed in accordance with the outer diameter of the primary sheath 11. The end portion of the secondary sheath 12 abuts against the rear end surface 16.

Regarding the terminal processing, an epoxy adhesive is applied to the ends of the optical fiber cables 5 and 8, the ends are inserted into the ferrules 6 and 9, the adhesive is dried, and the light protruding from the front end face 15 after the fixing is applied. The process is such that the fiber 10 is cut or polished.
JP 2003-149515 A

  A multi-core optical fiber is known in which a large number of optical fibers are bundled and a coating is provided on the outside thereof. This multi-core optical fiber has a structure in which a large number of optical fibers are scattered when the terminal coating is removed. Accordingly, when such a multi-core optical fiber having such a variation is used instead of the optical fiber cable 5, there is a problem that workability when fixing the ferrules 6 and 9 to the terminal is lowered. Yes.

  By the way, the inventor of the present application considers the following. That is, a cylindrical portion in which the small diameter portion 13 of the ferrule 9 can be inserted into the front end surface 15 of the ferrule 6 so that the front end surfaces 15 of the ferrules 6 and 9 face each other so that there is no deviation of the optical axis. Is considered to be formed integrally.

  However, if a cylindrical portion is integrally formed on the front end surface 15 of the ferrule 6, particularly in the case of the multi-core optical fiber described above, a large number of optical fibers protruding from the front end surface 15 are cut and polished in the terminal processing. There is a problem that the work becomes very difficult (cutting and polishing may not be possible, even with the optical fiber cable 5).

  This invention is made | formed in view of the situation mentioned above, and makes it a subject to provide the terminal processing method and terminal structure of a multi-core optical fiber in consideration of the improvement of workability | operativity.

  In order to solve the above-mentioned problem, the multicore optical fiber terminal processing method of the present invention according to claim 1 is characterized in that the coating of the multicore optical fiber terminal is formed by providing a coating on the outside in a state where a number of optical fibers are bundled. A first step including a step of removing, and a step of fixing a metal sleeve to the terminal covering removal portion; and inserting the metal sleeve of the terminal into a through hole formed in an optical connection end surface of the ferrule; And a second step of fixing with the ferrule.

  According to the present invention having such a feature, the ferrule is attached to the terminal in this state after being fixed with the metal sleeve so that the multiple optical fibers of the multi-core optical fiber terminal are not scattered. By adopting such a method, it is possible to attach the ferrule to the terminal with good workability even with a multi-core optical fiber. Regarding the fixing of the metal sleeve, a thermocompression bonding method is mentioned as a preferred example.

  A multicore optical fiber terminal processing method according to a second aspect of the present invention is the multicore optical fiber terminal processing method according to the first aspect, wherein the ferrule used in the second step has a female shape. The first step further includes a step of performing an end face treatment of the optical fiber after the metal sleeve is fixed to the end of the multi-core optical fiber.

  According to the present invention having such characteristics, the end face treatment of the optical fiber is performed before the ferrule is mounted. Since the end face processing of the optical fiber is performed first, it is possible to avoid the workability from affecting the shape of the ferrule. According to the present invention, it is possible to give a degree of freedom to the shape of the ferrule by processing the end face of the optical fiber first. This is particularly useful when a female ferrule is attached to the terminal.

  The terminal processing method for a multi-core optical fiber according to claim 3 of the present invention is the terminal processing method for a multi-core optical fiber according to claim 1 or 2, wherein the ferrule and the coating are provided after the second step. It is characterized by further including a third step of performing a fixing process.

  According to the present invention having such characteristics, the ferrule is fixed at two locations, that is, the metal sleeve portion and the covering portion. According to the present invention, it is possible to fix different means, and a reliable fixed state with the ferrule is formed. Regarding the fixing, for example, the metal sleeve portion can be temporarily fixed by press-fitting, and in this state, the main fixing can be performed on the covering portion.

  The multi-core optical fiber terminal structure of the present invention according to claim 4 is provided with a metal sleeve at a coating removal portion of a multi-core optical fiber terminal in which a large number of optical fibers are bundled and a coating is provided on the outside thereof, and the metal sleeve It is characterized in that a ferrule is attached to the outside of.

  According to the present invention having such a feature, a ferrule can be attached to a terminal with good workability even with a multi-core optical fiber.

  The terminal structure of the multi-core optical fiber according to claim 5 of the present invention is the terminal structure of multi-core optical fiber according to claim 4, wherein the metal sleeve and the ferrule are fixed by press fitting, and the ferrule and the coating are fixed. Are fixed by caulking or welding.

  According to the present invention having such characteristics, the ferrule can be securely fixed to the end of the multi-core optical fiber.

  The terminal structure of the multi-core optical fiber according to claim 6 of the present invention is the terminal structure of the multi-core optical fiber according to claim 4 or 5, wherein the terminal is inserted into the mating ferrule before the optical connection end face of the ferrule. A connection portion is formed to make the ferrule female.

  According to the present invention having such a feature, it is possible to easily cope with a female ferrule by providing a metal sleeve at the coating removal portion of the multi-core optical fiber terminal.

  According to the first aspect of the present invention, there is an effect that it is possible to provide a terminal processing method for a multi-core optical fiber in consideration of improvement in workability. Moreover, according to the second aspect of the present invention, there is an effect that the shape of the ferrule can have a degree of freedom. Further, according to the present invention described in claim 3, there is an effect that the fixation with the ferrule can be ensured.

  According to the present invention described in claim 4, there is an effect that it is possible to provide a terminal structure of a multi-core optical fiber in consideration of improvement in workability. Further, according to the present invention described in claim 5, there is an effect that the ferrule can be reliably fixed. Further, according to the present invention described in claim 6, there is an effect that a structure corresponding to a female ferrule can be provided.

  Hereinafter, description will be given with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a terminal processing method and a terminal structure of a multi-core optical fiber according to the present invention, wherein (a) is a perspective view showing a state during terminal processing (a ferrule is a female type), and (b). These are sectional drawings of a terminal structure (a ferrule is a female type).

  First, the configuration related to the terminal structure of the present invention by fixing a female ferrule 22 to the terminal of the multi-core optical fiber 21 will be described with reference to FIG.

  A metal sleeve 23 is provided at the end of the multi-core optical fiber 21. A ferrule 22 is attached and fixed to the outside of the metal sleeve 23. The ferrule 22 is attached and fixed so as to straddle the multi-core optical fiber 21 and the metal sleeve 23.

  The multi-core optical fiber 21 includes an optical fiber 24 having a core and a clad, and a coating (sheath) 25 provided on the outside in a state where a large number of optical fibers 24 are bundled. In the multi-core optical fiber 21, the covering 25 is removed by a predetermined length (a covering removal portion is formed) in order to attach the metal sleeve 23 to this end.

  The multi-core optical fiber 21 is not particularly limited, but an optical fiber made of glass (for example, MC-GOF) is used. In this case, the optical fiber 24 is a glass fiber having a diameter of several tens of microns. 200 to 300 optical fibers 24 are bundled to form a bundle of many optical fibers 26 (a glass fiber may be used instead of a glass fiber. In this embodiment, a glass fiber is used to reduce the melting point. It is 125 ° C. to 150 ° C., which is higher than that of plastic at 95 ° C. When considering heat resistance, glass fiber is preferable.

  The ferrule 22 is made of metal or synthetic resin, and has an insertion connecting portion 27, a first small diameter cylindrical portion 28, a large diameter cylindrical portion 29, and a second small diameter cylindrical portion 30 in order from the front ( An example). Moreover, the ferrule 22 has the 1st flange 31, the 2nd flange 32, and the 3rd flange 33 in order from the front on this outer side (it shall be an example). The ferrule 22 also has a through hole 34 inside thereof.

  The plug-in connection part 27 is formed as a guide part for the male ferrule as a connection partner. The insertion connection part 27 is formed in a cylindrical shape. An optical connection end face 35 is formed in a continuous portion of the insertion connection portion 27 and the first small diameter cylindrical portion 28 inside the insertion connection portion 27. The optical connection end surface 35 is formed as a surface orthogonal to the axis of the ferrule 22. The insertion connecting portion 27 is formed in a dimensional relationship such that the front end of the male ferrule to be connected is spaced apart from the optical connection end surface 35 or abutted against the optical connection end surface 35.

  A through hole 34 is formed in the center of the optical connection end face 35. The through hole 34 is formed in accordance with the outer diameter of the coating 25 of the multicore optical fiber 21. The through hole 34 is formed to have a diameter slightly smaller than the outer diameter of the metal sleeve 23. The through hole 34 is formed so as to penetrate straight along the axis of the ferrule 22.

  The metal sleeve 23 is made of metal and has a cylindrical shape. The metal sleeve 23 is attached to the coating removal portion at the end of the multi-core optical fiber 21. The attachment is not particularly limited, but the attachment is performed by a thermocompression bonding method in which a large number of bundled optical fibers 26 are heated and pressurized. The metal sleeve 23 does not easily fall off after being attached. The metal sleeve 23 is attached to the coating removal portion and can suppress the dispersion of the optical fiber 24.

  Next, the multicore optical fiber terminal processing method of the present invention will be described based on the above configuration. In other words, the terminal processing method of the present invention is a work method for fixing the female ferrule 22 to the terminal of the multi-core optical fiber 21 and includes the following first to third steps.

  In the first step, first, an operation of inserting the ferrule 22 into the terminal of the multi-core optical fiber 21 is performed. At this time, the insertion is performed so that the end surface of the multi-core optical fiber 21 is positioned in front of the insertion connection portion 27 of the ferrule 22. Next, an operation of removing the coating 25 of the multi-core optical fiber 21 by a predetermined length is performed in front of the insertion connection portion 27. Here, the predetermined length is a length that is slightly longer than the entire length of the metal sleeve 23. When the coating 25 is removed by a predetermined length, a terminal coating removal portion composed of a large number of bundled optical fibers 26 is formed at the end of the multi-core optical fiber 21.

  In the first step, when the terminal coating removal portion is formed, the work of fixing the metal sleeve 23 to the terminal coating removal portion is performed next. The metal sleeve 23 is attached and fixed by a thermocompression bonding method. Then, when the metal sleeve 23 is fixed to the terminal coating removal portion, the end face processing of the optical fiber (the optical fibers 26 in a bundled state) is performed on the front end face side of the metal sleeve 23. The end surface treatment is a conventional treatment for cutting or polishing the protruding portion. When the first step is completed, the state shown in FIG.

  In the second step, for example, the operation of sliding the multi-core optical fiber 21 as shown by an arrow is performed without changing the position of the ferrule 22. Then, while sliding, the metal sleeve 23 at the end of the multi-core optical fiber 21 is inserted into the through hole 34 of the ferrule 22 so as to be in a press-fitted state. At this time, the metal sleeve 23 is pressed into the through hole 34 and is fixed to the ferrule 22.

  Regarding the positioning of the metal sleeve 23, for example, the front end surface of the metal sleeve 23 is pushed in with a jig and the jig is brought into contact with the optical connection end surface 35, whereby the positioning can be easily performed. That is, if the pressing is performed until it abuts on the optical connection end surface 35, the front end surface of the metal sleeve 23 and the optical connection end surface 35 are flush with each other (see FIG. 1B). The above-mentioned slide can be generated by pushing with a jig.

  In the third step, an operation for fixing the coating 25 and the ferrule 22 of the multi-core optical fiber 21 is performed. The fixing process here is not particularly illustrated, but the cover 25 is fixed by caulking the second small-diameter cylindrical part 30 of the ferrule 22, or the inner surface of the second small-diameter cylindrical part 30 and the outer surface of the cover 25 by laser welding. In the case of laser welding, at least the second small-diameter cylindrical portion 30 is light-transmitted. To form sex). Note that the third step can be omitted when the fixing by the press-fitting of the metal sleeve 23 in the second step is sufficient.

  When the fixing process is performed and the coating 25 of the multi-core optical fiber 21 and the ferrule 22 are in a fixed state, a series of operations based on the terminal processing method of the present invention is completed, and the terminal structure of the present invention is formed.

  Next, another embodiment of the multicore optical fiber terminal processing method and terminal structure of the present invention will be described with reference to FIG. 2A and 2B are diagrams showing another embodiment, in which FIG. 2A is a perspective view showing a state during terminal processing (a ferrule is a male type), and FIG. 2B is a sectional view of a terminal structure (a ferrule is a male type). It is. In addition, about the same structure as the above-mentioned form, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In FIG. 2, a metal sleeve 23 is provided at the end of the multi-core optical fiber 21. A male ferrule 41 is attached and fixed to the outside of the metal sleeve 23. The male ferrule 41 is attached and fixed so as to straddle the multi-core optical fiber 21 and the metal sleeve 23 (having a terminal structure formed by fixing the male ferrule 41 to the end of the multi-core optical fiber 21).

  The ferrule 41 is made of metal or synthetic resin, and has a first small-diameter cylindrical portion 42, a large-diameter cylindrical portion 43, and a second small-diameter cylindrical portion 44 in order from the front (as an example). To do). In addition, the ferrule 41 has a first flange 45 and a wide second flange 46 in this order from the outside on this outer side (assumed to be an example). The ferrule 41 also has a through hole 34 inside thereof. The first small-diameter cylindrical portion 42 has an optical connection end surface 35 at the tip, and is opposed to the tip of the male ferrule to be connected with a predetermined distance. A through hole 34 is formed in the center of the optical connection end face 35.

  The terminal processing method of the multi-core optical fiber of the present invention will be described based on the above configuration. In other words, the terminal processing method of the present invention in this embodiment is a working method for fixing the male ferrule 41 to the terminal of the multi-core optical fiber 21, and includes the following first to third steps.

  In the first step, first, an operation of inserting the ferrule 41 into the terminal of the multi-core optical fiber 21 is performed. At this time, the insertion is performed so that the end face of the multi-core optical fiber 21 is positioned in front of the optical connection end face 35 of the ferrule 41. Next, an operation of removing the coating 25 of the multi-core optical fiber 21 by a predetermined length is performed in front of the optical connection end face 35. Here, the predetermined length is a length that is slightly longer than the entire length of the metal sleeve 23. When the coating 25 is removed by a predetermined length, a terminal coating removal portion composed of a large number of bundled optical fibers 26 is formed at the end of the multi-core optical fiber 21.

  In the first step, when the terminal coating removal portion is formed, the work of fixing the metal sleeve 23 to the terminal coating removal portion is performed next. The metal sleeve 23 is attached and fixed by a thermocompression bonding method. Then, when the metal sleeve 23 is fixed to the terminal coating removal portion, the end face processing of the optical fiber (the optical fibers 26 in a bundled state) is performed on the front end face side of the metal sleeve 23. The end face treatment is the same as the conventional process of cutting or polishing the protruding portion (in the case of the male ferrule 41, the end face treatment can also be performed after the third step). When the first step is completed, the state shown in FIG.

  In the second step, for example, the operation of sliding the multi-core optical fiber 21 as shown by an arrow is performed without changing the position of the ferrule 41. Then, while sliding, the metal sleeve 23 at the end of the multi-core optical fiber 21 is inserted into the through hole 34 of the ferrule 41 so as to be in a press-fitted state. At this time, the metal sleeve 23 is pressed into the through hole 34 and is fixed to the ferrule 22. The front end surface of the metal sleeve 23 and the optical connection end surface 35 are flush with each other.

  In the third step, an operation for fixing the coating 25 and the ferrule 41 of the multi-core optical fiber 21 is performed. The fixing process here is not particularly shown, but the cover 25 is fixed by caulking the second small diameter cylindrical portion 44 of the ferrule 41, or the inner surface of the second small diameter cylindrical portion 44 and the outer surface of the cover 25 by laser welding. In the case of laser welding, at least the second small-diameter cylindrical portion 44 is allowed to transmit light. To form sex). Note that the third step can be omitted when the fixing by the press-fitting of the metal sleeve 23 in the second step is sufficient.

  When the fixing process is performed and the coating 25 of the multi-core optical fiber 21 and the ferrule 41 are in a fixed state, a series of operations based on the terminal processing method of the present invention is completed, and the terminal structure of the present invention is formed.

  As described above with reference to FIGS. 1 and 2, according to the present invention, even with the multi-core optical fiber 21, the ferrule 22 (41) can be attached to the terminal with good workability. Therefore, it is possible to provide a terminal processing method and a terminal structure in consideration of improvement in workability.

  According to the present invention, there is also an effect that the shape of the ferrule 22 (41) can have a degree of freedom.

  In addition, it goes without saying that the present invention can be variously modified without departing from the spirit of the present invention.

  That is, in the above-described process, the work is performed after the ferrule 22 (41) is inserted into the end of the multicore optical fiber 21 in advance. However, after the metal sleeve 23 is fixed to the end of the multicore optical fiber 21, the ferrule 22 A method of inserting and press-fitting into (41) may be adopted.

It is a figure which shows one Embodiment of the terminal processing method and terminal structure of the multi-core optical fiber of this invention, (a) is a perspective view (a ferrule is a female type) which shows the state in the middle of a terminal process, (b) is a terminal structure It is sectional drawing (a ferrule is a female type). It is a figure which shows other embodiment of the terminal processing method and terminal structure of the multi-core optical fiber of this invention, (a) is a perspective view which shows the state in the middle of terminal processing (a ferrule is a male type), (b) is It is sectional drawing (a ferrule is a male type) of a terminal structure. It is a block diagram of the optical module of a prior art example. It is sectional drawing of a ferrule and an optical fiber cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 Multi-core optical fiber 22 Ferrule 23 Metal sleeve 24 Optical fiber 25 Covering 26 Many bundled optical fiber 27 Insertion connection part 28 1st small diameter cylindrical part 29 Large diameter cylindrical part 30 2nd small diameter cylindrical part 31 1st flange 32 2nd Flange 33 Third flange 34 Through-hole 35 Optical connection end face 41 Ferrule 42 First small diameter cylindrical portion 43 Large diameter cylindrical portion 44 Second small diameter cylindrical portion 45 First flange 46 Wide second flange

Claims (6)

A first step including a step of removing the coating of a multi-core optical fiber terminal having a coating on the outside thereof in a state where a large number of optical fibers are bundled, and a step of fixing a metal sleeve to the terminal coating removal portion;
A second step of fixing the metal sleeve and the ferrule by inserting the metal sleeve of the terminal into a through-hole formed in the optical connection end surface of the ferrule;
The terminal processing method of the multi-core optical fiber characterized by including these. The terminal processing method of the multi-core optical fiber according to claim 1,
When the ferrule used in the second step is of a female shape, the first step is a step of performing end face processing of the optical fiber after fixing the metal sleeve to the end of the multi-core optical fiber. The terminal processing method of the multi-core optical fiber characterized by including these. In the terminal processing method of the multi-core optical fiber according to claim 1 or 2,
After the second step, the method further includes a third step of performing a fixing process on the ferrule and the coating. A multi-core optical fiber characterized in that a metal sleeve is provided at a coating removal portion of a multi-core optical fiber end provided with a coating on the outside in a state where a large number of optical fibers are bundled, and a ferrule is attached to the outside of the metal sleeve. Terminal structure. In the terminal structure of the multi-core optical fiber according to claim 4,
The metal sleeve and the ferrule are fixed by press fitting, and the ferrule and the coating are fixed by caulking or welding. In the terminal structure of the multi-core optical fiber according to claim 4 or 5,
A terminal structure of a multi-core optical fiber, wherein an insertion connection portion to a counterpart ferrule is formed before an optical connection end face of the ferrule to make the ferrule female.

Images