JPH1039169A - Sleeve for optical connection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of a light loss characteristic by dust by providing the inner peripheral surface of the throughhole of a sleeve with a groove part approximately along its circumferential direction. SOLUTION: The sleeve for optical connection is a split sleeve 1 made of a ceramic having a slit 1A in the longitudinal direction and on the inner peripheral surface of the through-hole 1B of the split sleeve 1, the groove part 4C having a corrugated shape is formed in section along the circumferential direction over the entire area of the inner peripheral surface. The inner peripheral surface in contact with a ferrule is finished with a tolerance of micron order. The two ferrules fixing an optical fiber are inserted into the through-hole 1B from both ends and are pressed to each other so as to face each other. Since the groove part 1C of the split sleeve 1 is formed in a circumferential direction, the dust sticking to the outer peripheral surfaces of the ferrules intrudes into the groove part 1C of the split sleeve 1 at the time the ferrules are inserted into the sleeve. Even if the dust sticks to the inner peripheral surface of the through-hole 1B of the split sleeve 1, i.e. the inner peripheral surface in contact with the ferrules, the dust similarly intrudes into the groove part 1C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical connection sleeve for holding a ferrule to which an optical fiber is fixed.

[0002]

2. Description of the Related Art Conventionally, for example, an optical connector or an optical module has been known as a connecting portion for transmitting light in an optical fiber. In the case of an optical connector, two plugs each containing a ferrule to which an optical fiber is fixed are inserted and fixed from both ends of an adapter housing having a sleeve as a typical shape, and the ferrules face each other in the sleeve. The optical module is formed by connecting parts such as a light emitting element and a light receiving element to a ferrule. An important component that most contributes to characteristics such as light loss at these connection portions is a ferrule and a sleeve holding the ferrule. In other words, the optical fiber fixed in the ferrule has a very small diameter, for example, 10 μm in the diameter of the core through which light is transmitted. Tends to occur. Therefore, the tolerance between the outer diameter of the ferrule and the diameter of the through hole of the sleeve requires a precision on the order of microns, and in this sense, the ferrule and the sleeve member are extremely important points in the connection portion for transmitting light. It is.

[0003]

However, since extremely high precision is required as described above, invisible fine dust adheres to the outer peripheral surface of the ferrule or the inner peripheral surface of the through hole of the sleeve. However, its light performance is greatly affected. For this reason, the ferrule and the sleeve are usually sufficiently cleaned to remove dust, but this method requires time and labor, and it is difficult to remove 100% of invisible fine dust. Was. As a method for solving this problem, for example, there is a method in which a longitudinal groove is provided on the inner peripheral surface of the through hole of the sleeve.
-15013). Although this method has a great advantage in that the ferrule can be easily fitted, it is effective in removing dust, but since the groove is provided in the longitudinal direction, that is, parallel to the ferrule insertion direction, the ferrule is provided. When the is inserted into the sleeve, there is a possibility that dust at the contact portion may be caught in the insertion direction, which is not a fundamental solution. In particular, in the case of a miniaturized connector (for example, a MU connector has a ferrule outer diameter of 1.25 mmφ) recently required or a ferrule sleeve having a diameter smaller than that, cleaning is extremely difficult because it is too small.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made as a result of intensive studies in view of the above problems, and is characterized in that a groove is provided on the inner peripheral surface of a through hole of a sleeve along a substantially circumferential direction. With this configuration, even if fine dust adheres, no deviation occurs between the optical fibers to be brought into contact, and deterioration of the optical loss characteristics can be prevented.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The optical connection sleeve of the present invention is shown in FIGS.
This will be specifically described based on FIG. FIG. 1 is a sectional view showing an optical connection sleeve of the present invention, FIG. 2 is a sectional view showing an AA line in FIG. 1, and FIG. 3 is a sectional view showing a state in which a ferrule is inserted into a through hole of the sleeve in FIG. FIG. The optical connection sleeve is a ceramic split sleeve 1 having a slit 1A in the longitudinal direction.
A groove 1 having a corrugated cross section along the circumferential direction
C is formed on the entire inner peripheral surface, and the inner peripheral surface that comes into contact with the ferrule is machined with a micron-order tolerance. Two ferrules 3 to which the optical fiber 2 is fixed are inserted into the through holes 1B from both ends, and are abutted against each other. Since the groove 1C of the split sleeve 1 is formed in the circumferential direction, when the ferrule 3 is inserted, dust adhering to the outer peripheral surface of the ferrule 3 enters the groove 1C of the split sleeve 1. Also, when dust adheres to the inner peripheral surface of the through hole 1B of the split sleeve 1, that is, the inner peripheral surface that comes into contact with the ferrule 3, the dust similarly enters the groove portion 1C. Furthermore, since the shape of the groove portion 1C is corrugated, the ferrule 3 is easily inserted, and has the characteristics that scratches and dust due to friction between the ferrule 3 and the split sleeve 1 are less likely to occur. Here, as a material of the split sleeve, a resin or a metal may be used in addition to the ceramic, and the split sleeve is formed by injection molding, press molding, or extrusion molding. Further, in this embodiment, the split sleeve having the slit in the longitudinal direction was used,
A pipe-shaped precision sleeve without a slit may be used.

FIG. 4 is a sectional view showing another embodiment of the groove provided on the inner peripheral surface of the through hole of the optical connection sleeve. A female thread-shaped groove 11C is provided along the direction. Also in this case, the same effect is obtained in that dust is inserted into the groove when the ferrule is inserted. In addition, although not shown, as the cross-sectional shape of the groove, a semicircle, square, or trapezoid other than the above-described waveform and triangle can be used.

[0007]

According to the present invention, when the ferrule is inserted into the sleeve, minute dust is pushed into the groove, so that the dust can be naturally cleaned at the time of connection without taking time and labor, and therefore, the contact can be achieved. Optical fibers do not shift each other,
Deterioration of light loss characteristics due to dust can be prevented.
In particular, the present invention has a remarkable effect in a miniaturized connector (for example, a MU connector having a ferrule outer diameter of 1.25 mmφ), which has conventionally been difficult to clean, and in ferrules and sleeves smaller than this.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an optical connection sleeve of the present invention.

FIG. 2 is a cross-sectional view taken along line AA of FIG.

FIG. 3 is a sectional view showing a state in which a ferrule is inserted into the sleeve of FIG. 1;

FIG. 4 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 1 Split Sleeve 1B Through Hole 1C Groove 3 Ferrule 11 Split Sleeve 11C Groove

Claims (1)

[Claims] An optical connection sleeve for transmitting light while holding a ferrule to which an optical fiber is fixed, comprising:
An optical connection sleeve, characterized in that a groove portion is provided on an inner peripheral surface of a through hole of the optical connection sleeve along a substantially circumferential direction.