JPS6232407A - Sleeve adapter for optical connector - Google Patents

Abstract

PURPOSE:To prevent the variation of the contacting condition between a sleeve and each ferrule from being caused by the rotative displacement in the peripheral direction of the sleeve accompanied with attachment and detachment of the ferrule, by providing a projecting stripe, which should be engaged with the sleeve, on the inside peripheral surface of an adapter member. CONSTITUTION:Screw parts 2A and 2B coupled attachably and detachably to plug nuts omitted in the figure are provided on outside peripheral surfaces of adapter members 11 and 12, and stepped through holes 3A and 3B to which a sleeve 4 should be fitted are formed in center parts of these members 11 and 12. A projecting stripe 13 to be engaged with a slot 4A of the sleeve 4 is formed in one position of the inside peripheral surface of the stepped through hole 3A of the adapter member 11. This projecting stripe 13 restrains the rotative displacement in the peripheral direction of the sleeve 4. The adapter member 11 is provided with a pess-fitting shaft part 14, and this part 14 is press- fitted to a press-fitting hole part 15 of the adapter member 12.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an optical connector in which a pair of opposing ferrules are aligned using a sleeve having slots to align the axis of an optical fiber core. This invention relates to a sleeve adapter for an optical connector that prevents free rotational displacement of the sleeve in the circumferential direction, which sometimes occurs.

(Prior art) Fig. 3 (A) is a schematic diagram showing the connection principle of an optical fiber connector when a conventional sleeve adapter is used, and Fig. 3 (B) is a schematic diagram showing the connection principle of an optical fiber connector when a conventional sleeve adapter is used. -Z sectional view.

IA and IB are sleeve adapter bodies, and plug nuts 9 are attached to the outer periphery of the sleeve adapter bodies IA and IB.
Threaded portion 2A that connects with A and 9B.

2B, and stepped through holes 3A and 3B into which the sliding sleeve 4 is loosely inserted are provided on the inside.

These sleeve adapter bodies IA and IB are integrally connected at an assembly port 7.

5A, 5B are ferrules, ferrules 5A, 5
Mounting holes 8A and 8B are provided at the center of the axis of B for mounting optical fibers 6A and 6B. Ferrules 5A and 5B connect to sleeve adapter body IA with plug nuts 9A and 9B.

Attached to IB. As a result, ferrule SA,
Since the end face 10A of 5B and the IOB are brought into close contact, the optical fibers 6A and 6B are also brought into close contact, making it possible to connect optical signals.

(Problem to be solved by the invention) The diameter of the core part of the optical fiber that transmits the optical signal is 0.009 mm in the case of a single mode optical fiber.
This is extremely small, and if the connection loss is 1 decibel, the optical fiber core axis misalignment is 0.002 mm.
It is required to stay within. However, it is not possible to completely eliminate precision errors in the optical fiber body, the ferrule of the optical connector, and the sleeve itself.

In terms of production technology, it is possible to achieve an accuracy of about 1 μm for the eccentricity of the outer diameter of each optical fiber with respect to the core axis, but during assembly and connection, errors of up to 5 μm can accumulate in the misalignment of the optical fiber core axis. There is sex.

For this reason, a simple method for single-mode optical fibers is to rotate each ferrule in the connected state and fix it at a phase that minimizes the connection loss. According to this method, the average misalignment of the axis of the optical fiber core can be adjusted to about 2 μm.

When the sleeve and each ferrule are aligned and inserted,
It has been experimentally confirmed that there is only one combination of angular phases that minimizes the connection loss. For this reason, even if the angular phase of the sleeve and each ferrule is initially determined to minimize connection loss, if the sleeve freely rotates in the inner circumferential direction during repeated attachment and detachment, the ferrules may The fiber core axis moves freely and reproducibility is completely lost.

FIGS. 4 to 6 are diagrams for explaining problems caused by rotation of the sleeve.

Due to the difference in the outer diameter of ferrules 5A and 5B, sleeve 4
is transformed as shown in FIG. In this case, Dl and D2 have a precision error of 1 μm for single mode.

In FIG. 5(A), the center of the ferrule 5A is set to 01.
The center of the ferrule 5B is set at 02. Now, connect the micro holes in ferrules 5A and 5B to ferrules 5A and 5B.
Suppose that they are matched by rotating them. This point is designated as point P. Point Q is the co-contact line of the ferrules 5A, 5B with the sleeve 4. As shown in FIG. 5(B), if the sleeve 4 is rotated 180 degrees, the center point 01 of the ferrule A remains stationary, and when the center point of the ferrule B moves to 02, the hole center P of the ferrule A, And the hole center P2 of ferrule A is shifted by δ.

Moreover, as shown in FIG. 6, each ferrule is not a perfect circle, and the circularity is allowed up to 0.7 μm. Therefore, if the relative position of the sleeve and ferrule is changed, the contact points (about 3 points) will change and the hole position P will change with respect to the sleeve hole center.

An object of the present invention is to provide a protruding strip on the inner surface of the sleeve adapter member that engages with the sliding portion of the sleeve, thereby regulating the rotational displacement of the sleeve in the circumferential direction, so that the alignment and fitting phase with each ferrule remains unchanged. It is an object of the present invention to provide a sleeve adapter for an optical connector, which prevents fluctuations in the axis misalignment of the optical fiber core of each ferrule even during repeated attachment and detachment, and improves the reproducibility of connection characteristics.

(Means for Solving the Problems) In order to achieve the above object, the sleeve adapter of the optical connector according to the present invention has a pair of ferrules to which a pair of optical fibers are adhesively fixed, and the end surfaces of the ferrules face each other and are press-fitted. In a sleeve adapter for an optical connector that holds a sleeve with a slot formed over the entire length at one location in the axial direction and connects it to a plug, a stepped part is provided in the center to engage with the end surface of the sleeve. A pair of through holes, each having a protrusion formed on the inner peripheral surface of the through hole in the axial direction to engage with the slot of the sleeve, and a connecting portion that connects to the other pair of sleeve adapter members on the outer peripheral surface. The sleeve adapter member is configured to hold the sleeve.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings and the like.

FIG. 1(A) is a sectional view showing a first embodiment of a sleeve adapter for an optical connector according to the present invention, and FIG.
) is a sectional view taken along line XX in FIG.

The optical connector sleeve adapter shown in Figure 1 is
It is assumed that it will be manufactured primarily by molding plastic or metal.

The outer periphery of the adapter member 11.12 is provided with threaded portions 2A and 2B for attaching and detaching with a plug nut (not shown), and the central portion includes a stepped through hole 3A into which the sleeve 4 is fitted;
3B is formed.

A protrusion 13 that engages with the slot 4A of the sleeve 4 is formed at one location on the inner periphery of the stepped through hole 3A of the adapter member 11. This protrusion 13 is provided to restrict rotational displacement of the sleeve 4 in the circumferential direction.

The adapter member 11 is provided with a press-fit shaft portion 14, which is press-fitted into the press-fit hole portion 15 of the adapter member 12. If the adapter parts 11 and 12 are made of metal,
They are connected by press-fitting, but if they are made of plastic, it is easier to glue them together.

FIG. 2(A) is a sectional view showing a second embodiment of the sleeve adapter for an optical connector according to the present invention, and FIG.
) is a YY cross-sectional view of the same figure (A).

The optical connector sleeve adapter shown in FIG. 2 is mainly intended for machining of metal. Since it is difficult to machine the protruding strips 13 as shown in FIG.
6 is press-fitted into the press-fit hole portion 15 of the adapter member 12, and then the adapter member 11 is press-fitted and assembled integrally.

(Effects of the Invention) As explained in detail above, according to the present invention, since the protrusion that engages with the sleeve is provided on the inner circumference of one adapter member, rotation of the sleeve in the circumferential direction due to attachment and detachment of the ferrule is prevented. The contact conditions between the sleeve and each ferrule do not change due to displacement, and the optical fiber connector's axis misalignment can always be maintained at a constant value regardless of the number of times it is connected and disconnected.

For example, as mentioned above, in order to suppress the connection loss of a single-mode optical connector to within 1 decibel, it is necessary to adjust the misalignment of the optical fiber core between the ferrules to within 2 μm, but even if the initial adjustment is If the contact conditions between the sleeve and each ferrule change, the axis of the optical fiber core will shift by a maximum of about 5 μm, making it almost unusable, but it was confirmed that the optical connector according to the present invention hardly changes. .

Furthermore, since the sleeve adapter of the present invention employs a method of integrally assembling the adapter members by press-fitting, etc., it is possible to hold the sleeve with high structural rigidity.
Another effect is that stable connection characteristics can be obtained over a long period of time.

[Brief explanation of drawings]

FIG. 1(A) is a sectional view showing a first embodiment of a sleeve adapter for an optical connector according to the present invention, and FIG.
) is a sectional view taken along line XX in FIG. FIG. 2(A) is a sectional view showing a second embodiment of the sleeve adapter for an optical connector according to the present invention, and FIG.
) is a YY cross-sectional view of the same figure (A). Figure 3 (A) is a schematic diagram showing the connection principle of an optical fiber connector when a conventional sleeve adapter is used, and Figure 3 (B) is a 2-2 sectional view of Figure 3 (A). . FIGS. 4 to 6 are diagrams for explaining problems caused by rotation of the sleeve. IA, IB... Sleeve adapter body 4... Sliding sleeves 5A, 5B... Ferrules 6A, 6B... Optical fiber 7... Assembly bolts 9A, 9B... Plug nuts 11.12... Adapter Part 13.17...Protruding strip 16...Ring member Patent applicant Seiko Giken Co., Ltd. Agent Patent attorney Hisashi Inoro 71 Figure 2 Figure (A) (B) Figure 3 (A) CB)

Claims (2)

[Claims] (1) Face the end faces of a pair of ferrules to which a pair of optical fibers are adhesively fixed, and hold a sleeve with a slot formed over the entire length at one location in the axial direction for press-fitting. A sleeve adapter for an optical connector connected to a through hole includes a through hole provided with a stepped portion in the center that engages with the end surface of the sleeve, and an inner circumferential surface in the axial direction of the through hole that engages with a slot of the sleeve. A sleeve adapter for an optical connector, characterized in that the sleeve is held by a pair of sleeve adapter members each having a protruding strip and a coupling portion on the outer circumferential surface for coupling with another pair of sleeve adapter members. . (2) The sleeve adapter for an optical connector according to claim 1, wherein the coupling portions of the sleeve adapter member include a press-fit shaft on one side and a press-fit hole on the other side, and are coupled by press-fit or adhesive.