JPS59803B2 - Magnetic connector for optical cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to optical fibers, and more particularly to magnetic connectors for optical cables comprising one or more optical fibers.

A very important practical problem that arises when using optical fibers in transmission systems is the provision of good coupling between fiber trunks to minimize coupling losses.

These impairments are caused by imperfect alignment of the fiber ends to be coupled, both the lack of parallelism and lateral misalignment of the fiber axes and discontinuities in the refractive index near the point of coupling.

Devices having sleeve guides or V-groove guides in which the fibers are held in precise positions by adhesive or elastic members are commonly used to obtain fiber end alignment and index matching. This is accomplished with a suitable liquid interposed between the fiber ends.

Although these devices make good permanent connections, they present some problems when used as connectors because their delicate structure does not withstand the frequent insertion and removal operations normally performed on connectors.

These drawbacks are overcome by the present invention, which relates to a magnetic connector for optical cables whose main feature is easy installation at the end of the cable, allowing a hassle-free connection and good alignment between single optical fibers. be overcome. Another feature of the connector that is the object of the invention is that it does not require any mechanical parts with extremely precise precision or calibration, and furthermore, the connection by the connector is made by two parts that are equal to each other, which saves manufacturing costs. It is at the point where it reduces to a minimum.

A specific object of the present invention is to provide a magnetic connector for an optical cable consisting of two identical parts provided at the end of each partial cable, the magnetic connector being parallel to the axis of the end of the optical fiber belonging to the optical cable to be connected. non-ferromagnetic for the end of said optical cable, comprising means capable of generating a magnetic field in the connector body with lines of magnetic flux, and an internal cylindrical guide capable of receiving and prealigning the end of the optical fiber; a housing and a ferromagnetic member affixed to the end of the optical fiber and capable of attracting and precisely aligning the opposing fiber ends along the lines of flux of the magnetic field as a result of induced magnetization; An object of the present invention is to provide a magnetic connector for the optical cable, characterized in that:

The above-mentioned as well as other features of the invention will become apparent from the following description, which is given by way of example and without limitation with reference to the accompanying drawing, which shows an embodiment of the invention in a longitudinal section through the device that is the object of the invention. It will be.

In the figure, the ends of the optical cables to be connected are shown as CO and Cα, and the respective ends are, for example, F,,F
2, F3 and Fl, , F'2, F''3, respectively.

C and C indicate two housings made of non-ferromagnetic material, in which the optical fibers belonging to the cable are placed.

They are provided with members S and S5, such as a packing box, for fixing the optical cable, and elastic contact members G and G' for preventing the occurrence of mechanical stress concentration in the cable near the connector. L and L5
shows two protrusions that can be accommodated in corresponding gaps N and N, which form two restraining points that can align the parts of the connector and prevent them from rotating relative to each other.

M and quality indicate two permanent magnets of cylindrical shape, the magnetic field inside these materials forms lines of magnetic flux parallel to the axis of rotation of the magnets, and the two connector parts are placed abutting each other with a connecting device. Sometimes the directions match. Finally, Rl, R2, R3 and R'1, R52, R''3 indicate several cylindrical covers made of ferromagnetic material provided at the end of each single fiber, and their operation is explained in detail in connection with the operation of the connector. This is explained in the description of

The cover can be formed using simple machining or well-known chemical or electrochemical deposition techniques.

There is no particular difficulty in assembling each connector section at the respective end of the optical cable, which consists of removing the protective coating and inserting the individual fibers whose ends are coated with the cylindrical cover of the ferromagnetic material. This is done simply by inserting it into the guide in the housing C, C5 and fixing this optical cable by means of the packing boxes S and S5.

In this respect, these connector portions have protrusions L and L.
5 are brought close to each other so as to coincide with the gaps N and N'.

Magnets M and M5 attract each other as they are parallel to each other and form a coincident magnetic field, thus holding the two connector parts firmly together. If magnetic attraction is not sufficient, the two connector sections may be held in place by a bayonet joint, threaded ring, or any other known means.

The ends of the fibers Fl, F2 and F3, previously substantially aligned by cylindrical guides arranged in the housings C and C, are opposite the corresponding ends of the fibers FVl, FV2 and F'3, and the former The latter fiber is separated from the latter fiber by a small air gap.

Accurate alignment of the fiber is achieved by a magnetic field parallel to the fiber axis created by permanent magnets M and M. In fact, as a result of the induced magnetization in the ferromagnetic covers provided at the fiber ends, mutual attraction between opposing fibers in the direction along the flux lines of the magnetic field and alignment of each end is obtained. In other words, due to the magnetic field lines acting on the cylindrical covers (sleeves) fixed on one end of the fiber, forces are generated between the cylindrical covers (sleeves), which force them laterally and Move both in the longitudinal direction and align their cylindrical covers (sleeves).
According to the invention, the final guidance of the fiber is therefore essentially entirely magnetic, without resorting to sensitive mechanical means. By appropriately choosing the ratio of the length to the diameter of the magnet, it is possible to obtain a magnetic field that is almost constant and parallel to the axis of rotation of the magnet, and is therefore mechanically difficult to obtain even with complex experimental equipment. Fiber alignment is achieved with such precision as is possible.

In order to avoid index discontinuities, a fluid of suitable refractive index is interposed between the fiber ends, and this fluid is introduced into the connector through openings provided for this purpose in housings C and C. flowed down to.

The foregoing description is given by way of example only and is not intended to be construed as limiting in any way (1), and it is therefore clear that various modifications and improvements may be made without departing from the scope of the invention. It is.

In particular, this connector is not only axially symmetrical with respect to the radially arranged fibers, but can also be formed in any triangular prism shape with respect to the fibers arranged in overlapping planes. Furthermore, the magnetic field can be created by permanent magnets and electromagnetic forces or solenoids of any shape, provided that the magnetic flux lines are parallel to the individual fiber ends.

[Brief explanation of drawings]

The drawing is a longitudinal sectional view of an embodiment of the present invention. In the figure, CO, Cσ... end of optical cable, F1
~F3, F゛1~F''3...Optical fiber, C,
C''...Housing, M, Ml...Permanent magnet, R1 to R3, R5, ~R'3...Ferromagnetic cylindrical cover.

Claims (1)

[Scope of Claims] 1. Optical cables CO, CO, each consisting of two identical parts each placed at the end of the cable, and connected to each other.
’ optical fibers F_1, F_2, F_3 and F
means M, M' for generating a magnetic field in the connector body with lines of magnetic flux parallel to the axes of the ends of '_1, F'_2, F'_3 for receiving and prealigning the ends of the optical fibers; a non-ferromagnetic housing C, C' for the end of said optical cable with an internal cylindrical guide that causes the end of said optical fiber to be fixed and opposed along the flux lines of said magnetic field as a result of induced magnetization; Ferromagnetic members R_1, R_2, R_ for attraction and precise alignment of the fiber ends
3 and R'_1, R'_2, and R'_3. 2. said means M, M' for forming a magnetic field are partially integrated with one connector part and partially integrated with the other connector part, these means attracting and holding the two connector parts together; A magnetic connector for an optical cable according to claim 1, characterized in that the magnetic connector provides parallel and coincident magnetization so as to form the following. 3. A magnetic connector for an optical cable according to claim 1, characterized in that members S and S' are provided for fixing the optical cables CO and CO' to their respective connector parts. 4. Claim 1, characterized in that elastic members G, G' are provided to bring the cable into close contact with the connector in order to prevent mechanical stress concentration from occurring in the cable near the connector. Magnetic connector for optical cable as described in section. 5. A magnetic connector for an optical cable according to claim 1, further comprising means for matching the refractive indices of opposing fiber ends.