JPH0123126Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to connecting optical fibers using an optical fiber connector, and particularly relates to a jig for centering an optical fiber to be connected to a ferrule of an optical fiber connector.

Conventionally, various types of connectors for optical fibers of this type have been proposed. In general, connecting optical fibers is very difficult because the core of the fiber is thin, and in order to keep the connection loss low, the processing precision of the fiber insertion hole must be extremely high. The price of the product was becoming increasingly expensive. Conventionally, in order to keep the splicing loss low without significantly increasing the machining accuracy of the fiber insertion hole, a double eccentric sleeve can be rotated and fixed at the position where the core centers of the two fibers are best aligned when connecting the fibers. Although this conventional connector does not require high processing precision for the fiber insertion hole, the structure of the connector is complicated and the operation during connection is troublesome. Ta.

In view of such conventional technology, the purpose of the present invention is to develop an optical fiber connector in order to make it possible to easily connect optical fibers using an inexpensive optical fiber connector and to suppress connection loss. An object of the present invention is to provide a jig for centering a connected optical fiber with respect to a ferrule of the present invention.

Next, the present invention will be described in detail with regard to embodiments of the present invention based on the accompanying drawings.

FIG. 1 is a half-sectional view showing an array of components of an example of an optical fiber connector to which the centering jig of the present invention can be applied. This optical fiber connector includes a pair of ferrules 10 and a sleeve 2.
0 and a pair of fixing nuts 30. The ferrule 10 has a through hole 11 along the central axis for receiving the optical fiber to be connected. The diameter of this through hole 11 is slightly larger than the outer diameter of the coating of the optical fiber, and as indicated by reference numeral 11A, it is designed to limit the internal space for filling with adhesive for the purpose described later. It is preferable that it be narrowed at the front end. A flange 12 is formed on the outer periphery of the ferrule 10 at approximately the center thereof. The sleeve 20 has a through hole 21 along the central axis that receives the rear end 10A of the ferrule 10. The diameter of this through hole 21 is the same as that of the ferrule 10.
The outer diameter of the main body of the device is suitable for tightly receiving the outer diameter of the main body. Furthermore, male threads 22 are formed on the outer periphery of both ends of the sleeve 20. The dimension L ₁ between both end faces of the sleeve 20 is
It is preferable that the dimension from the rear surface portion 12A of the flange 12 to the rear end surface of the ferrule body be equal to or slightly smaller than the sum of L ₂ and L ₃ . By doing so, it is possible to ensure that the rear end surfaces of the ferrules 10 abut each other within the sleeve 20. In this example connector, L ₂ =L ₃ . The fixing nut 30 has a female thread 31 that engages with the male thread 22 of the sleeve 20, and has an inward protrusion 32 at its front end.

Next, a procedure for centering and connecting optical fibers using the centering jig of the present invention using the optical fiber connector configured as described above will be described. First, as illustrated in FIG. 2, an optical fiber 50 to be connected is inserted and fixed into each ferrule 10 using a centering jig 40 as an embodiment of the present invention. The structure of the tool 40 will be explained.

The jig 40 shown in a half-sectional view in FIG. 2 includes a cylindrical jig main body 41, a centering member 42, a fixing nut 43 as a fixing member, and a screw cap 44.
It is made up of. The jig body 41 has a center opening 41A that tightly receives the rear end 10A of the ferrule 10 of the optical fiber connector.
Furthermore, a male screw 4 is provided on the outer periphery of the front end of the jig main body 41.
1B is formed, and a fixing nut 43 is screwed into this male thread 41B. The centering member 42 is provided within the center aperture 41A, and in this embodiment consists of three rolls press-fitted into the center aperture 41A from the rear end. FIG. 3 is an enlarged cross-sectional view taken along line A--A in FIG. 2. As shown in FIG. 3, the centering member 42 consists of three precisely machined rolls 42 having the same outer diameter.
It consists of A, 42B, and 42C. The outer diameter dimensions of these three rolls are determined by the diameter of the cylinder circumscribing these three rolls within the inner region where these rolls touch each other and are surrounded by the fibers of the optical fiber to be applied. It is precisely machined so that it is equal to the maximum outer diameter of the center hole 41A and its center axis coincides with the center axis of the center hole 41A. In this way, by using a cylinder that circumscribes the three rolls for centering, precise centering can be performed relatively easily. This is because it is easier to machine a roll with a precise outer diameter than it is to machine a precisely centered and precisely diameter hole. The front end of the fixing nut 43 is provided with an inward protrusion 43A. This protrusion 43A is connected to the fixing nut 4
3 into the male thread 41B of the jig body 41, the flange 12 of the ferrule 10 is screwed into the jig body 4.
The ferrule 10 is inserted between the ferrule 10 and the front end surface 40A of the ferrule 1 to fix the ferrule 10 to the jig main body 41. If the male thread 41B of the jig main body 41 is the same as the male thread 22 of the sleeve 20 of the optical fiber connector, the fixing nut 43 may be replaced with the fixing nut 30 of the optical fiber connector. . The screw cap 44 is attached to the jig main body 4
1, and has a hole 44A in the center through which an optical fiber is passed.

The protective coating 51 on the tip of one of the optical fibers 50 to be connected to each other is peeled off to expose an appropriate length of the fiber 52, and the tip of this optical fiber is connected to one of the optical fiber connectors. Insert it into the ferrule 10. An adhesive 60, such as an epoxy resin, is then applied to the space between the exposed fiber 52 and the inner wall of the ferrule 10.
Fill it appropriately. Then, before the adhesive 60 hardens, the rear end portion 10A of the ferrule 10 is inserted into the center opening 41A of the jig 40. At this time, the exposed fiber 52 of the optical fiber 50
is passed through the center of the centering member 42 of the jig 40. This situation is best shown in FIG.
Next, attach the fixing nut 43 of the jig 40 to the male screw 41.
B, and connect the flange 12 of the ferrule 10 to the front end surface 40A of the jig main body 41 and the protrusion 4.
3A to fix the ferrule 10. In this state, the fiber 52 of the optical fiber 50
is centered by a precisely machined jig 40. After waiting for the adhesive 60 to harden, remove the fixing nut 43, pull out the ferrule 10 integrated with the optical fiber 50 from the jig 40, and remove the portion of the adhesive 60 protruding from the rear end surface of the ferrule 10 and the fiber. Finish by cutting the section 52 and polishing the tip surface. The same process as above is performed for the other connected optical fiber.

The combination of the two optical fibers to be connected and the ferrule processed as described above is inserted into the through hole 21 from both ends of the sleeve 20 of the optical fiber connector, as shown in a half-sectional view in FIG. , the corresponding fixing nuts 30 are screwed into the male threads 22 of the sleeve 20, so that the protrusion 32 of the fixing nuts 30 abuts against the flange 12 of each ferrule 10, and the rear end surfaces of each ferrule 10 are aligned within the sleeve 20. The connection of the optical fibers 50 is completed by tightening and fixing them in an abutting manner. As shown at 70, an adhesive may be applied between the ferrule 10 and the protective coating 51 of the optical fiber 50 to strengthen the connection between the ferrule and the optical fiber.

According to the centering jig of the present invention, after a fiber to be connected is inserted into the ferrule of an optical fiber connector and adhesive is filled between the exposed fiber and the inner wall of the ferrule, the jig is used to align the fiber against the ferrule. Since it performs centering and allows the filling adhesive to solidify in that centered state, there is no possibility that unhardened adhesive may adhere to the jig or that the adhesive may cause the jig and ferrule or the jig and fiber to bond. The optical fiber to be connected to the ferrule can be centered and fixed to the ferrule very easily and quickly while preventing the possibility of adhesion. That is, when filling the space between the inner wall of the ferrule and the exposed fiber with adhesive, the adhesive may accidentally adhere to the rear end surface or outer peripheral surface of the ferrule, or the adhesive filled in the space may Even if a considerable amount of adhesive flows out from the tip of the through-hole onto the protruding fiber or onto the rear end surface or outer peripheral surface of the ferrule and adheres thereto, remove the excess adhesive before inserting them into the jig. If you wipe it off, the adhesive will not stick to the jig. Therefore, there is no need to take the trouble of inserting the jig each time, and there is no possibility that the jig and the ferrule or the jig and the fiber are bonded together with adhesive, and the fiber can be bonded quickly at all times. Centering and fixing for the ferrule can be performed. In addition, in the centering jig of the present invention, the adhesive is filled between the inner wall of the ferrule and the fiber, where the optical fiber to be connected is temporarily held by the ferrule, before being attached to the jig. The centering jig itself is very simple and does not require any complicated forming equipment, and therefore the structure of the centering jig itself is also very simple.

Furthermore, as mentioned above, the centering jig according to the present invention allows the adhesive to solidify while the optical fiber is centered and is fixed in that centered state. Even without increasing the processing accuracy of the fiber insertion hole of the connector, it is possible to connect optical fibers with extremely low connection loss by simply processing the jig precisely. This makes it possible to connect optical fibers very simply and at low cost.

And even in precision machining of this centering jig,
As mentioned above, in the present invention, by using a circumscribed cylinder inside at least three rolls, it is possible to achieve high precision relatively easily. This is because it is easier to machine a roll with a precise outer diameter than it is to machine a precisely centered and precisely diameter hole.

[Brief explanation of the drawing]

FIG. 1 of the accompanying drawings is a half-sectional view showing an arrangement of parts of an example of an optical fiber connector to which the centering jig of the present invention can be applied, and FIG. Fig. 3 is an enlarged cross-sectional view taken along the line A-A in Fig. 2, and Fig. 4 shows the optical fiber connected with the optical fiber connector shown in Fig. 1. FIG. 10...Ferrule, 11...Through hole, 12...Flange, 20...Sleeve, 21...Through hole, 22...Male thread, 30...Fixing nut, 31...Female thread, 32
... protrusion, 40... centering jig, 41... jig body,
41A...Center opening, 41B...Male thread, 42...Centering member, 43...Fixing nut, 43A...Protrusion part,
50... Optical fiber, 51... Protective coating, 52... Fiber, 60... Adhesive.

Claims (1)

[Scope of utility model registration request] A ferrule for an optical fiber connector,
A through hole for receiving the optical fiber to be connected is provided along the central axis, and the diameter of the through hole is slightly larger than the outer diameter of the coating of the optical fiber to be connected; A jig for centering an optical fiber to be connected to a ferrule having a flange at an approximately intermediate outer periphery includes a jig main body, a fixing nut attached to the front end of the jig main body, and a fixing nut attached to the front end of the jig main body. a centering member provided at a rear end, and the jig main body has a front end surface that abuts the rear surface of the flange of the ferrule, a center opening opening in the front end surface, and a front end portion. a male threaded portion on the outer periphery, the front end of the center hole is adapted to tightly receive the rear end of the ferrule, and the centering member is disposed behind the center hole. Consisting of three rolls press-fitted into the end, the three rolls having the same outer diameter,
The outer diameter of the roll is such that the diameter of the cylinder circumscribing the three rolls in the inner region where the three rolls touch each other and is surrounded by the rolls is equal to the diameter of the cylinder that is circumscribed to the fiber from which the coating of the optical fiber has been stripped. The fixing nut has a female threaded portion that engages with the male threaded portion of the jig body at its rear end. It has a protruding part on the inner peripheral part and protrudes radially inward at the front end, and the female thread part is engaged with the male thread part of the jig main body. An optical fiber centering jig, characterized in that the ferrule can be fixed to the jig main body by sandwiching the flange of the ferrule between the front end face and the protrusion. .