JPS58195813A - Plug for optical connector - Google Patents

Abstract

PURPOSE:To provide an inexpensive plug for an optical connector which has high productivity and high dimensional accuracy and can realize low connection loss by providing a pipe for supporting the strand of an optical fiber in the axial center part in a main cylindrical part of a plastic plug. CONSTITUTION:A hole 22 larger than the outside diameter of an optical fiber 4 is formed at the axial center in the forward end part in a main cylindrical part 21 of a plastic plug 2. A plastic pipe 30 having the outside diameter of the size at which the pipe can be press fitted into the hole 22 and having a hole 32 of the diameter larger by 1- several mum than the outside diameter of the strand 5 of the fiber 4 at the axial center is press fitted into the hole 22 of the plug 20, whereby the intended plug for an optical connector is produced. Said plug is used by coating an adhesive agent on the fiber 4 removed of the covering at the forward end, inserting the fiber into the plug 20 until the strand 5 penetrates through the hole 32 of the pipe 30 and finishing the forward end of the plug 20 by polishing upon setting of the adhesive agent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical connector plug used in an optical transmission line of an optical communication system, and particularly to a plastic optical connector plug.

Optical connectors used to connect optical transmission lines in optical communication systems are required to minimize connection loss. Factors that cause connection loss in optical connectors include misalignment of the axes of connected optical fibers, perpendicularity of the optical fibers to the mating end face of the connector plug, Fresnel reflection of the optical fibers, and other factors such as There are many factors such as the spacing between opposing faces, the roughness of the end face of the optical fiber, etc.

Among these factors of connection loss, it is known that the influence of axial misalignment on connection loss is particularly large. For this reason, alignment of the mutual axes of the optical fibers requires high accuracy of several μm or less. This meticulous coordination
C can be roughly divided into the following two types of glazes. In other words, there is a method using a fine sea bream trimming machine 4111, and a method using the optical connector parts with increased mechanical precision. On the other hand, there is a strong demand for optical fiber connection work to be performed easily on-site, and the latter is considered to be the main method these days. As shown in Fig. 1, the conventional plug structure of an optical connector intended for on-site assembly is as follows: An optical fiber 5 whose strands 4 are coated with polyamide is placed in the center of a metal collar 2, with a diameter of 4. It is attached to a plug 1 fitted with a capillary 5V, which has a microhole slightly larger than the capillary. The capillary 5 is made of ceramic or the like, and processing techniques used in the processing of jewelry bearings for watches are used to achieve micron or submicron processing accuracy. However, in manufacturing the plug 1, after drilling a pilot hole in the capillary 3, firing, polishing the hole, and polishing the outer diameter are performed, and the capillary 3 is assembled into the metal collar 2, soldered, and further removed. It is necessary to grind the outer periphery of the metal collar 2 based on the hole. therefore,
It requires special processing equipment and skill, has many processing steps, and has the drawbacks of low quantity and high price.

Therefore, there is a method of manufacturing the original connector by plastic molding, which is superior in productivity and economy, without using metals, ceramics, or the like.

FIG. 2 shows the plug of a typical conventional plastic optical connector. In other words, a plug 6 having a conical mating surface 7
The plug 6 has a tapered hole 8v so that it can be fixed to the fiber in a suitable manner. FIG. 591 shows a mold ff11OV for forming the plug 6. The core shaft 11 has the same shape as the groove 8 and has a wire-like end that is only slightly larger than the diameter of the optical fiber strand.

The end of the core shaft 11 extends through the orifice 12,
During the molding process, it is held by the break 154C. Here, in order to prevent damage to the core shaft 11 when fitting the core shaft 11 and the orifice 12, it is necessary to
Requires mating clearance of rlL@ degrees. Therefore, this mating clearance has the disadvantage of reducing the concentricity between the conical mating surface 7 and the fiber insertion hole, which can be life-threatening for the original connector. Due to the flow resistance of the core shaft 11
is deformed, and as a result, the hole 8 is deformed.

As a result, the optical fiber is installed in hole 8! When incorporating IV,
This method has the disadvantage that the optical fiber cable is bent at an angle, resulting in increased splice loss.

The purpose of the present invention is to eliminate the drawbacks of the above-mentioned prior art, provide excellent productivity, low cost, and high dimensional accuracy (allow easy connection of optical fibers on-site, and low connection loss V).
*There is K, which provides plugs for optical connectors.

In order to achieve the above object, the present invention is characterized in that a pipe having a fiber insertion hole is provided concentrically inside the tip of the plug.

Embodiments of the present invention will be described below with reference to the drawings.

Figure 184 shows -fl of the optical connector plug according to the present invention.
In the same figure, a hole 22 larger than the outer diameter of the original fiber 4 is formed at the axial center of the tip of the main cylinder s21 of the plug 20.

The pipe 50 is formed to have an outer diameter large enough to be press-fitted into the hole 22K, and a hole 52 having an inner diameter 1 to several μm larger than the outer diameter of the strand 5 of the optical fiber 4 is formed at its axis.

In such a configuration, after molding the plug 2o and the pipe sav separately and press-fitting the pipe 50 into the hole of the plug 2o, a sea contact agent was applied to the Kunoaipa 4 to remove the aV at the tip, and 1 g Plug 20&C is inserted so that wire 5 passes through hole 32 of pipe 50. After the adhesive has hardened, the tip of the plug 20 is polished and finished.

Figure 5 shows an example of an optical connector using the above plug.
It is shown with . 4o is the sleeve of the optical connector.

With this configuration, the plug 20. The pipe 50 and the sleeve 401 are each made of epoxy resin and have excellent performance as optical connectors.

(1) Concentricity of the outer periphery of the main cylinder 21 of the plug 2o and the hole 52 of the pipe 50 after press-fitting the Vibro 0.

(2) After the optical fiber is inserted and fixed into the plug 20, the inclination angle of the strand 5 with respect to the fineness of the plug 20 is 0. (5) Splice loss when using an optical fiber with a core diameter of 50μ and a cladding diameter of 125μ.

The warpage measurement results are shown in the table below.

As mentioned above, we were able to reduce the connection loss to 40% of the conventional value.

In addition, FIG. 6 shows the -
? In the same figure, the mold 50 is equipped with a fixed side extension 1ii 51, a fixed side m-mount 52, and a movable member 55. A core 54 is embedded in the template 52, and a core pin 55 is erected at the tip thereof. lil] 1 The ejector pin 56 that allows the core 54 to slide freely is connected to a pair of ejector plates 57.
The ejector rod 58K is connected to the ejector rod 58K through the ejector rod 58K, and is biased by a spring 59. The template 52 and 'IJ! Meal 5
An annular runner 60 is formed between Wls2.3 and Wls2.3 through an annular gate 61. ss, an annular capite 4624C formed by the core 54 and the core pin 55 are in communication.

With such a configuration, it is possible to form a pipe in which the outer circumferential surface and the hole are highly concentric.

FIG. 7 shows an example of a plug mold according to the present invention.
6, a fixed side template 67, and a movable side template 68. A core 69 is embedded in the template 67, and a core pin 70 is erected at one end of the core 69.
K is formed with a hole 71 for degassing and a second cavity 72 that passes through this hole 71 and accommodates the contaminated resin. A lock pin 74 is attached to the additional cutout plate 66 so that a protrusion 73 formed at the tip protrudes into the cavity 72.
is supported. A core pin 76 is disposed to slidably pass through the axis of the ejector pin 75 that slidably fits into the mold 68, and its tip faces the core pin 70. An annular runner 77 is formed between the front F mold plate 67 and the mold plate 68, and is formed by the mold plate 67°68, the core 69, the core pins 70, 76, and the ejector pin 75 through the annular gate 78. It communicates with a first cavity 79.

With such a configuration, a desired plug can be formed.

Note that if the pipe and plug are molded from plastic, the pipe and plug will
The hardness is extremely low (as a result of polishing after assembly, the amount of wire protruding from the end face of the plug increases, so it can be used as a fiber for plastics, such as glass beads, hollow glass bulbs, volcanic glass, metals and their oxides, etc.) It is desirable to mix graphite, rehydrated calcium, etc.

Furthermore, for repeated insertion and removal of the plug, it is desirable to add a lubricant such as tetrafluoroethylene or molybdenum disulfide to the resin.

FIG. 8 shows another embodiment of the present invention, in which a pipe 55 having a plurality of protrusions 54 having the same diameter as the main cylinder 21 is integrally formed at the tip of the plug 25 by insert molding. Fixed. The optical fiber 4 is constructed in the same manner as in the previous embodiment.

Attached to plug 25.

By cutting in this way, a part of the pipe 55 becomes part of the main cylindrical part 21 of the plug 25, so the position of the optical fiber 4's 11i115 is all regulated by the precision of the pipe. Therefore, it can be formed with higher precision than in the case of about one embodiment.

Note that the pipe 55 can be molded using a molding die having a structure similar to that shown in FIG.
5 can be molded using a mold w65' having the same structure as shown in Figure 10 (l@7). However, this molding '
! In J65', the core pin 70' is formed to a thickness that fits into the hole in the pipe.
Different from 65. By performing such molding, the protrusion 54 of the pipe 5S is in contact with the inner circumference of the cavity 79, so the accuracy of the main cylindrical portion 21 of the plug 25 is
Follow the accuracy of Further, as described above, according to the present invention, the core pin 70' is not subjected to any bending force due to the flow of the resin. Since a supporting pipe is provided, a high-precision plug 1 can be manufactured inexpensively and efficiently.Furthermore, the connection loss of the optical connector can be reduced.

[Brief explanation of the drawing]

Figure 1 shows an example of a conventional optical connector plug.
21 is a side sectional view showing an example of a conventional plastic type optical connector plug,
Kite 3- is a side sectional view showing the plug mold shown in FIG. 2, FIG. 4 shows an example of the optical connector plug according to the present invention, (P) C1IllEIIvfI side view, <b> t
Figure 6 is a side cross-sectional view of the optical connector using the plug shown in Figure 4, and Figure 6 is the glue surface showing the mold for the pipe in Figure 4. Compiled from F1 side view and Figure 7. Side sectional view showing the molded product of the plug in Figure 4, Figure 8.
The figure shows another embodiment of the invention, a side view of a plug, FIG. 9, 4XIl! FIG. 8 is an enlarged front view, FIG. 10 is a thin sectional view showing the molding of the plug shown in FIG. 8, and FIG. 11 is a view taken along the line A--A of FIG. 20.25...Plug so, ss...Pipe agent lawyer thin 1) Wa', =l:;*I51.・
1. +l koj Figure 1 Figure 2 Spear 3C 0 72/3 O 4 Mouth (0-) Sai 5n n O Otsu prisoner off 0;+3 days O 9 Leap O/θ Fungus rice 110 59

Claims (1)

[Scope of Claims] 1. In a plastic optical connector plug for connecting optical fibers, a through hole is formed inside the tip of the plug, the inner diameter of which is one to several pitches larger than the outer diameter of the optical fiber. A plug for an optical connector, characterized in that one or more pipes are provided so that the axis of the through hole coincides with the center of the plug, and the through hole of the pipe supports the bare wire of the original fiber. 2. In a plastic optical connector plug for connecting an optical fiber, one or more pipes are passed through to form a through hole in which the inner diameter of the tip of the plug is one to several m larger than the outer diameter of the optical fiber. Insert molding is performed during plug molding so that the axis of the hole coincides with the axis of the plug, and the optical fiber element a is inserted into the through hole of the pipe.
A plug for optical connectors whose K is designed to support.