FR2558965A1 - Universal coupler for optical fibres - Google Patents

Abstract

The present invention recommends the use of two or more Mangin mirrors for producing a fibre-optic coupler capable of: - connecting two identical or different fibres; - separating or combining signals from a single channel into several; - separating various spectral bands.

Description

 Optical fibers are used to carry various signals.

We may be led to
- connect fibers of the same type
- connect fibers of different types;
- separate into two, three or n equal parts or not the energy flow transmitted by a fiber on two, three or n fibers;
- concentrate on a single fiber the signals transmitted on two, three or n fibers
- separate by absorbent or interference filters different spectral bands of the energy conveyed by lightning.

 Different coupler devices already exist, a number of which use the principle shown diagrammatically in FIG. 1, for simple connection.

 (l) represents the fiber from which the energy signal comes.

 (2) and (2 ') represent optics whose composition is not specified, (2) making the energy coming from (l) parallel, and (2') reconcentrating it on a fiber (3j.

 We can, using two, three or n optics (2 '), separate the energy.

We can also absorb spectral bands by inserting between (2) and (2 ') filters. These filters, whatever their type, work in parallel light, therefore in good conditions to frankly limit the spectral bands.

 The present invention relates to a coupler d @ of this type. Figure 2 will facilitate the description of the device.

The end of the fiber (i) is placed at the focus of a portion of mirror
Mangin (4) of axis of revolution (5). The radiation from (1) and limited by the cone (6) - (7) is refracted by the first spherical diopter (8), reflected on the second silver spherical diopter (9), refracted again by (8) and, rendered thus parallel, is reconcentrated by a second portion of mirror
Mangin (10) on the fiber (3).

 The mirror (10) can be identical or different from (4), provided that the axes of revolution (5) and (11) are parallel and that the energy beam is not obscured.

 We know that a well-calculated and correctly executed Mangin mirror, which is relatively easy for spherical diopters, gives very few angular aberrations. In addition, the use of two axes of revolution-parallel but not confused, as shown in Figure 2, and provided that the distance (4) - (10) is small, leads to partial compensation for residual aberrations.

 FIG. 3a represents, along a plane perpendicular to (5), the device for separating the radiation into two equal parts. (10) and (10 ') are two Mangin mirror portions whose axes of revolution (11) and (li') are parallel to the axis (5). The separation plane (12) of (10) and (10 ') is also parallel to (11) and (il').

 Figure 3b shows, in a perpendicular plane, the separation into three unequal parts. The 4 axes: (5), (11), (11 '), (13) are parallel.

The two portions (10) and (10 ') of Mangin mirror are separated by a third portion (14) of Mangin mirror.

 Of course, the system can also be completed by one or more filters perpendicular to the axes (5), (11), etc., placed between (2) and (4).

 Figure (4) shows another possible use of the device.

The two Mangin mirror portions (4) and (10) have their axes of revolution combined. Under these conditions, the chromatic angular aberrations are added and in (3), it is possible to separate several spectral bands. Of course, filters can complete the device.

Claims (7)

 1. Use of a Mangin mirror or a portion of this mirror to make the energy transmitted by an optical fiber parallel.  2. Association of two assemblies according to claim 1, whose axes are parallel but not confused, to produce a fiber coupler identical or not.  3. Use of a device according to claim 1 with several similar devices, the mirror portions of which have smaller useful surfaces and all of whose axes are parallel, for producing separators or gatherers.  4. Association of filters with an assembly according to claim 2, to produce a spectral band selector.  5. Association of filters with an assembly according to claim3, to produce a spectral band switcher.  6. Use of two assemblies according to claim 1, the axes of which coincide, to produce a spectral band separator.  7. Use of filters with an assembly according to claim 6, to produce a spectral separator.