JPH1184163A - Connecting structure of ferrule and optical fiber cord - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connecting structure of a ferrule and optical fiber cord which is capable of preventing an increase in the transmission loss of light and has excellent assembling workability. SOLUTION: A pair of notched grooves 20 are formed in both opposite side parts of the coating holding part of the ferrule 1 so as to cross the internal space thereof. A holding cap 30 has a pair of side pieces 32 made free insertable and removable into and from these notched grooves 20 from a vertical direction. The inside surfaces of the respective side pieces 32 are projectingly provided with cutting stoppers 36 along the vertical direction. The coating part of the optical fiber cord is inserted into the coating holding part and this coating part is exposed outside from the notched grooves 20. Both side pieces 32 of the holding cap 30 are respectively slid and inserted into the notched grooves 20 to cut off the coating part by the cutting stoppers 36 and the stoppers are bitten into this coating part, by which the optical fiber cord is positioned and fixed to the ferrule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure between a ferrule and an optical fiber cord used for connecting an optical element such as a photodiode to an optical fiber cord or connecting optical fiber cords.

[0002]

2. Description of the Related Art Usually, when an optical element such as a photodiode is connected to an optical fiber cord or optical fiber cords, an end of the optical fiber cord is inserted into a substantially cylindrical ferrule and fixed. Is used to perform optical axis alignment.

Conventionally, when an optical fiber cord is fixed to a metal ferrule, the ferrule is caulked or
Adhesives have been used, or they have been used in combination to fix.

[0004]

However, when the ferrule is fixed by caulking, it is necessary to increase the amount of deformation due to caulking in order to increase the fixing force. Then, the distortion of the optical fiber of the optical fiber cord increases, the transmission loss of light increases, and the light transmission distance may decrease.

In addition, when an adhesive is used, there is a problem that the process of applying the adhesive is complicated and it takes time until the adhesive is solidified, so that the assembling workability is poor.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is possible to prevent an increase in light transmission loss and to provide a ferrule and an optical fiber cord which are excellent in assembling workability. The purpose of the present invention is to provide a connection structure.

[0007]

In order to solve the above-mentioned problems, a connection structure between a ferrule and an optical fiber cord according to the present invention comprises a substantially cylindrical fiber for accommodating a fiber exposed portion at the tip of the optical fiber cord. A connection structure for connecting a ferrule and an optical fiber cord, comprising a housing portion, and a substantially cylindrical coating holding portion which is provided on a rear end side of the fiber housing portion and accommodates the coating portion of the optical fiber cord. A pair of cutout grooves are formed on opposite sides of the body of the coating holding portion so as to cross the internal space of the body, while the pair of cutout grooves are formed in the axial direction of the coating holding portion. A cutting stopper that has a pair of side pieces that are each slidably insertable and removable along a direction orthogonal to each other, and extends along the direction in which the side pieces are inserted into and removed from the notch grooves on opposing inner surfaces of the side pieces. Holding key In the state where the fiber exposed portion is inserted into the fiber housing portion and the coating portion is inserted into the coating holding portion, and the coating portion is exposed to the outside through the cutout groove, the holding portion is provided. The optical fiber cord was positioned and fixed to the ferrule by slidingly inserting both side pieces of the cap into the notch grooves, scraping the covering portion with the cutting stopper and biting the covering portion. And

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A connection structure between a ferrule and an optical fiber cord according to an embodiment of the present invention will be described below.

As shown in FIGS. 1 and 2, the connection structure between the ferrule and the optical fiber cord includes a ferrule 1 having a holding cap 30 mounted on a ferrule body 10.
The optical fiber cord A is inserted and fixed from the rear end side.

As shown in FIGS. 3 to 5, the ferrule main body 10 has a fiber housing portion 12 for housing an exposed portion B (see FIG. 7) formed by peeling off the coating portion of the end portion of the optical fiber cord A. And a coating holding portion 16 which is provided on the rear end side of the fiber housing portion 12 for housing the coating portion C near the exposed portion B, and an intermediate portion between the fiber housing portion 12 and the coating holding portion 16. And a peripherally provided flange portion 11.

The fiber accommodating portion 12 is formed in a substantially cylindrical shape, and the outer peripheral edge of the distal end portion is finished into a tapered surface 13 which is inclined inward toward the distal end side. A is almost the same as the outer diameter of the exposed portion B of A.

Further, the coating holding section 16 has a substantially cylindrical body 1.
A pair of left and right cutout grooves 20 extending in the vertical direction so as to cross the internal space of the body 17 is formed on both sides in the middle of the body 7 so that the body 17 is connected to the front body 18 at the front end and the rear body 18 at the rear end. In addition to being divided into rear body portions 19, the front body portion 18 and the rear body portion 19 are connected via a pair of upper and lower connecting curved pieces 21.

The inner diameter of the front body 18 and the rear body 19 is substantially the same as or slightly larger than the outer diameter of the optical fiber cord A. C is configured to be accommodated.

The connecting curved pieces 21 are finished so that the thickness dimension is smaller than the thickness dimensions of the peripheral walls of the front body section 18 and the rear body section 19. The outer curved surface of the connecting curved piece 21 is recessed by one step. The width of the connecting pieces 21 when viewed from above or below is smaller than the diameter of the covering section C, and the covering section C inserted into the body portion 17 is 21 so as to protrude on both sides thereof without being accommodated within the width dimension.

A flange 11 provided around an intermediate portion between the fiber accommodating portion 12 and the coating holding portion 16 is engaged with an optical connector housing (not shown) to move the ferrule 1 in the front-rear direction. It is for regulating.

On the other hand, the holding cap 30 is shown in FIGS.
As shown in the figure, a metal (for example, brass) or a hard resin (for example, PB) harder than the coating portion C of the optical fiber cord A
T), and a pair of left and right side pieces 32 are connected by connecting pieces 34 at their upper ends, and are substantially inverted U in front view.
It is formed in a character shape. The corners at the four outer corners of the holding cap 30 are each beveled. The connecting piece 3
The inner surface of 4 is formed in a circular curved surface corresponding to the outer surface of the connecting curved piece 21 of the ferrule main body 10.

A pair of front and rear cutting stoppers 36 are formed on the inner surface of each side piece 32 along the vertical direction. Each of the cutting stoppers 36 is formed in a long column shape, and a lower corner portion thereof is formed into a sharp orthogonal surface to form a cutting blade portion 36a extending in the front-rear direction.

The length L3 of the holding cap 30 in the front-rear direction is substantially the same as the length of the connecting curved surface 21 in the front-rear direction. The distance between the inner surfaces of the side pieces 32 is substantially the same as or slightly larger than the diameter of the optical fiber cable A, and the left and right cutting stoppers provided on the side pieces 32 are provided. The spacing between the 36 cutting blades 36a is almost the same as the width when both connecting pieces 21 on the ferrule main body 10 side are viewed from above or below.

Next, the procedure for assembling the connection structure between the ferrule 1 and the optical fiber cord A will be described.

First, the covering portion at the distal end of the optical fiber cord A is peeled off over a predetermined length to form a fiber exposed portion B having a predetermined length.

Next, as shown in FIG. 7, the tip of the optical fiber cord A is approached from behind the ferrule main body 10 and
As shown in FIG. 8, the fiber exposing portion B is accommodated in the fiber accommodating portion 12, and the coating portion C is accommodated in the coating holding portion 16. Then, the covering portion C protrudes left and right from between the two connecting bent pieces 21, and the covering portion C is exposed to the outside via the cutout groove 20.

The side caps 32 of the holding cap 30 are slidably inserted into the guide grooves 20 from above, and the holding cap 30 is attached to the covering holding section 16.
At this time, since the spacing between the cutting blades 36a of the left and right cutting stoppers 36 is finished to be approximately the same as the width of the connecting curved pieces 21, the cutting blades 36a of the cutting stoppers 36 are connected to each other. The covering portion C protruding from both sides of the piece 21 to the left and right sides is scraped off like a flat chisel. Then, the inner surface of the connecting piece 34 of the holding cap 30 is
When the holding cap 30 is inserted until it comes into contact with the upper surface of the ferrule 1, the cutting stopper 36 is engaged with the covering portion C, and the optical fiber cord A is positioned and fixed to the ferrule 1.

In FIG. 8, the tip of the fiber exposed portion B is projected from the tip of the fiber housing portion 12 for the sake of convenience when mirror-finishing the tip of the fiber exposed portion B later. That's why.

According to the connection structure between the ferrule 1 and the optical fiber cord A configured as described above, each of the cutting stoppers 36 of the holding cap 30 cuts the covering portion C, and the cutting stopper 36 is attached to the covering portion C. Because it is bitten,
The optical fiber cord A can be positioned and fixed in the axial direction without causing a large distortion in the optical fiber in the coating portion C. Therefore, it is possible to position and fix the optical fiber cord A in the axial direction while suppressing the loss of light caused by the distortion of the optical fiber.

Further, since the cutting blade portion 36a, which is a corner portion of the cutting stopper 36, is finished in a sharp orthogonal plane, the covering portion C can be reliably removed.

Further, after the end of the optical fiber cord A is inserted into the ferrule 1, the coating holding portion 1
By attaching the holding cap 30 to the optical fiber 6, the optical fiber cord A is fixed, so that it is not necessary to use an adhesive as in the related art, and the assembling workability is excellent.

Further, since the pair of cutting stoppers 36 are provided separately at the front and rear, the cutting stoppers 36 are dispersed at the two front and rear portions to hold the covering portion C, and the optical fiber cord A is held with a stronger force. Can be fixed.

Further, since the pair of cutting stoppers 36 are arranged to face each other, the covering portion C is more effectively cut by the respective cutting stoppers 36 and the cutting stoppers 36 are engaged with the covering portion C. Also in this respect, the optical fiber cord A can be fixed with a stronger force.

The covering portion C of the optical fiber cord A has a high tensile strength, such as polypropylene (PP),
If hard polyethylene (PE), hard nylon, or the like is used, the optical fiber cord A can be fixed with a stronger force.

As an example of the first embodiment, the following connection structure between a ferrule and an optical fiber cord was actually manufactured. That is, the front and rear length dimension L1 (see FIG. 4) of the body 17 of the ferrule 1 is 11 mm, the front and rear length dimension L2 of the connecting curved piece 21 which is also the width dimension of the notch groove 20 is 4 mm,
The width W1 of the connecting bent piece 21 when viewed from above or below is 2.2 mm, the height H (see FIG. 6) of the holding cap 30 is 4.2 m, and the width W2 is 4. 2
mm, and the length dimension L3 before and after was finished to 4 mm. Also,
These ferrule 1 and holding cap 30 were formed of brass. Further, as the optical fiber cord A, an optical fiber having an outer diameter of 2.5 mm obtained by coating an optical fiber having an outer diameter of 1 mm with PP was used.

According to the connection structure using the ferrule 1 and the optical fiber cord A, an increase in light loss due to the fixing of the optical fiber cord to the ferrule 1 is reduced to 0.
At the same time, the tensile strength was suppressed to 1 dB or less, and a tensile strength of 110 N or more was obtained.

[0032]

As described above, according to the connection structure between the ferrule and the optical fiber cord according to the present invention, the exposed fiber portion is inserted into the fiber housing portion, and the coating portion is inserted into the coating holding portion. With the both sides slid into the notch groove, respectively, and exposed to the outside from the notch groove, the coating is cut off with a cutting stopper and bitten into the coating, thereby positioning and fixing the optical fiber cord to the ferrule. As a result, the optical fiber cord can be positioned and fixed in the axial direction without causing a large distortion in the optical fiber in the coating portion. Therefore, while minimizing light loss due to optical fiber distortion,
The optical fiber cord can be firmly fixed.

Also, the optical fiber cord is fixed by inserting the end of the optical fiber cord into the ferrule and attaching a holding cap to the coating holding portion of the ferrule, so that the adhesive is used as in the conventional case. There is no necessity, and the assembly workability is excellent.

[Brief description of the drawings]

FIG. 1 is a side view showing a connection structure between a ferrule and an optical fiber cord according to an embodiment of the present invention.

FIG. 2 is a bottom view showing the connection structure of the above.

FIG. 3 is an exploded perspective view showing a ferrule.

FIG. 4 is a side view showing a ferrule main body.

FIG. 5 is a plan view showing a ferrule main body.

FIG. 6A is a plan view showing a holding cap, and FIG.
6B is a front view showing the holding cap, FIG. 6C is a bottom view showing the holding cap, and FIG. 6D is a side view showing the holding cap.

FIG. 7 is a side view showing a process of assembling a connection structure between the ferrule and the optical fiber cord.

FIG. 8 is a side view showing another assembling step of the connection structure of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Fiber accommodation part 16 Coating holding part 17 Body 20 Notch groove 30 Coating holding cap 32 Side piece 36 Cutting stopper A Optical fiber cord B Exposed part C Coating part

Claims (1)

[Claims] An optical fiber cord includes a substantially cylindrical fiber accommodating portion for accommodating a fiber exposed portion at an end portion of the optical fiber cord, and a covering portion of the optical fiber cord, which is connected to a rear end of the fiber accommodating portion. And a connection structure between the ferrule and the optical fiber cord having a substantially cylindrical coating holding portion, for traversing the internal space of the body portion on opposite sides of the body portion of the coating holding portion. While a pair of notch grooves are formed, the pair of notch grooves has a pair of side pieces which are respectively slidably insertable / removable along a direction orthogonal to the axial direction of the coating holding portion, and the sides thereof A holding cap is provided on the opposing inner surfaces of the pieces, the holding cap having a cutting stopper protruding along a direction in which the side piece is inserted into and removed from the cutout groove. Cover the part In a state where the cover portion is inserted into the holding portion and the covering portion is exposed to the outside from the notch groove, both side pieces of the holding cap are slid and inserted into the notch grooves, and the covering portion is scraped with the cutting stopper. A connection structure between a ferrule and an optical fiber cord, wherein the optical fiber cord is positioned and fixed to the ferrule by being bitten into the covering portion.