GB1559615A

GB1559615A - Mechanically controlled switch for connections by means ofbundles of optical fibres

Info

Publication number: GB1559615A
Application number: GB4734076A
Authority: GB
Original assignee: Thomson CSF SA
Current assignee: Thales SA
Priority date: 1975-11-12
Filing date: 1976-11-12
Publication date: 1980-01-23
Also published as: IT1073832B; FR2331801A1; FR2331801B1; ES453197A1; DE2651776A1

Description

(54) MECHANICALLY CONTROLLED SWITCH FOR CONNECTIONS BY MEANS OF BUNDLES OF OPTICAL FIBRES (71) We, THOMSON-CSF, a French Body Corporate, of 173, Boulevard Haussmann, 75008 Paris-France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be par ticularly described in and by the following statement :-- This invention is concerned with the field of electron-optical connections by bundles of optical fibres and relates to a switch for successively establishing, by a series of discrete mechanical displacements, an optical connection between a transmitting (or receiving) bundle and one or other of several receiving (or transmitting) bundles.

According to the present invention there is provided a mechanically controlled switch for permuting the optical connection of at least one first bundle of optical fibres from one to the other of n second bundles of optical fibres (n being an integer equal to at least two), wherein it comprises: -at least one first and n second inputs for receiving the respective ends of said first and second bundles; -a fixed part and a moving part capable of occupying at least two predetermined positions relative to said fixed part; -at least one first single optical mixing fibre integral with said moving part; and -at least n second single optical mixing fibres integral with said fixed part ; -the number of said mixing fibres being equal to at least that of said inputs ; n of said second mixing fibres having their first end respectively disposed in the n second receiving inputs opposite the end of said n second bundles; and the second end of at least one of said second mixing fibres being disposed opposite the end of a said first mixing fibre in each of said predetermined positions.

Other features and advantages of the invention will become clearly apparent from the following description in conjunction with the accompanying drawings, wherein : Figure 1 shows a conventional connector using a single optical mixing fibre for connecting two bundles of optical fibres.

Figure 2 shows a first embodiment of the switch according to the invention in which part of the bundles is integral with a moving part of the switch.

Figure 3 shows a second embodiment of the switch according to the invention in which all the bundles are integral with a fixed part of the switch.

Figure 4 shows a rotary switch according to the invention conforming to the principle of the switch shown in Fig. 2.

Figures 5a and 5b show a rotary switch according to the invention conforming to the principle of the switch shown in Fig. 3.

Figure 6 shows one particular embodiment of the switch according to the invention as illustrated in Figs. 5a and 5b.

Figure 1 is a diagrammatic section through a prior art connector using a single optical mixing fibre for optically connecting tw ( bundles of optical fibres.

This connector 1 is formed by a single fibre with a core 10 and a cladding 11, its core having the same diameter as the bundles of fibres to be connected. Ths single fibre is axially inserted into a cylindrical metal part 12 of which the two ends 120 form two female terminals. The two surfaces of the single fibre are polished and are slightly recessed relative to stops 121 which limit the penetration of the male terminals into the female part.

The two male terminals 2 fitted to the ends of the two bundles of fibres 20 to be connected are introduced into this connector. Each end of the bundle of fibres is stripped of its flexible protective cladding 21 and introduced into the axis of the terminal 2, a cylindrical metal element of which the rear is provided with a grip 22 holding the bundle and of which the front part 220 forms the male part which fits into the female part 120 of the connector. The front part of the bundle is slightly withdrawn relative to the front surface of the terminal.

The ends of the bundle of fibres and of the single fibre are thus held opposite one another, but without contact, in order to avoid their deterioration when the connection is being made. The distance between these two ends is less than 0.1 mm for a diameter of the single fibre of the order of 0.5 mm.

As can be seen from Fig. 1 the connector consists of two identical parts which are symmetrical in relation to a plane SS. Each part, which is formed by a male terminal and a female terminal, enables a bundle of optical fibres to be optically connected to a single optical mixing fibre and may be used anywhere where a connection such as this has to be made.

Hereinafter, the transmitting or receiving bundle or bundles which the switch enables to be successively connected to any one of an assembly of receiving or transmitting bundles of fibres, will be called the"first"bundle of fibres whilst one or other of the bundles of the assembly will be called the"second"bundle of fibres.

Figures 2 and 3 illustrates two aspects of the switches according to the invention which al ways comprises a fixed part, to which the second bundles are connected, and a moving part. In the first version, which is shown in Fig. 2, the fixed part only comprises the con nections intended for the second bundles, the connections intended for the first bundles being disposed on the moving part. In the second version, which is shown in Fig. 3, the fixed part comprises both the connections intended for the second bundles and the connections in tended for the first bundles.

The switch shown in Fig. 2 comprises a fixed part 3 carrying a rail 30 on which the moving part 4 slides. Extending at regular intervals through the fixed part are five single optical mixing fibres 512 to 552 each provided with metallic female terminals 612 to 652 integral with the fixed part 3. Metallic male terminals 712 to 752 which fit into these female ter minals enable each of these single fibres to be connected to one of the second bundles of fibres 812 to 852. Two single optical fibres 501 and 511 with the same spacing as the fibres 512 to 552 extend through the moving part 3.

They are integral with female terminals 601 and 611 into which the male terminals 701 and 711 are plugged, enabling them to be respectively connected to the first bundles 801 and 811. A locating finger 40 provided on the moving part 4 engages in one of the four recesses 311,312,313 or 314 to determine four privileged positions of the moving part 4 in which the two free ends of the single fibres 501 and 511 are situated opposite two of the free ends of the single fibres 512 to 552, ensuring the connection of the corresponding bundles. Depending upon the position of the moving part, therefore, the switch shown in Fig. 2 connects the first bundle 801 to one of the second bundles 812,832 or 842, and the first bundle 811 to one of the second bundles 822, 832,842 or 852. The position of the moving part 3 relative to the fixed part 4 : s adjusted in such a way that the empty space between two single fibres, when they are situated opposite one another, is negligible relative to the diameter of the fibres, for example narrower than 0.1 mm for single fibres with a diameter of 0.5 mm.

Turning now to the switch shown in Fig. 3, it can be seen that, like the preceding switch, it comprises a fixed part 3 provided with a rail 30 on which slides a moving part 4. Disposed on the fixed part are six similarly spaced single fibres 511 and 521 and 512,522,532 and 534 provided with their respective female terminals 611 and 621 and 612,622,632 and 634. Two first bundles 811 and 821 are connected to the central single fibres 511 and 521 by means of the male terminals 711 and 721.

Four second bundles 812, 822,832 and 834 are connected to the single end fibres 512 and 522,532 and 534 by means of the male terminals 712,722, 732 and 734.

The moving part 4 carries two single fibres 510 and 520. Each fibre is curved in such a way that its two ends are disposed in the same plane parallel to the common plane in which the free ends of the single fibres carried by the fixed part 4 are disposed. In addition, if the spacing between the centres of the free ends of the single fibres carried by the moving part is equal to e, the spacing between the centres of the four ends of the fibres 510 and 520 will have this same value, the centres of the two ends of the fibres 510 and 520 being respectively separated by intervals of e and 3e.

By sliding the moving part 4 along the rail 30, it may be moved from the position shown in the Figure into a symmetrical position, the two positions being identified by the engagement of the moving finger 40 in one of the recesses 311 or 312. In the position shown in the Figure, to the two first bundles 811 and 821 are optically connected to the two second bundles 812 and 822. In the symmetrical position, they are connected to the two second bundles 832 and 834. The switch shown in Fig. 3 thus operates as a two-position switch acting simultaneously on two bundles.

A switch working on the principle of the device illustrated in Fig. 3 has the advantage over the device shown in Fig. 2 of not involv- ing any displacement of the first and second bundles of fibres. However, it is less favourable in terms of optical efficiency because two connected bundles are connected by three successive single fibres, whereas the device shown in Fig. 2 requires only two.

Figures 4 and 5 illustrate two preferred embodiments of the switch according to the invention, in which the movement of the moving part relative to the fixed part is a rotational movement.

The embodiment of the switch shown in Fig. 4 is based on the same principle as the embodiment described with reference to Fig.

2. The first and the second bundles of fibres are connected to single mixing fibres respectively disposed on the moving part and the fixed part, and the movement of the moving part brings the free end of the single fibres connected to the first bundle successively oppo- site the free ends of the single fibres connected to the second bundles.

The switch shown in section in Fig. 4 comprises a positioning supporting plate designed for step-by-step rotation, which plate consists essentially of a fixed part 3 and a moving part 4, both bodies of revolution about the axis AA, which are kept in contact with one another by the return spring 9 fixed by the two mobile holders 90 and 91. Contact between the two parts 3 and 4 is established by three hemispherical knobs integral with the part 4 and disposed at angles of 120 from one another. Only two of these knobs are shown in the Figure where they are denoted by the references 42 and 43. In the section on which the knobs rest, the fixed part 3 com prises 3 equal sectors, one comprising a series of circular ledges, such as 31, the other an equal number of grooves (not shown in the Figure) and the third being formed by a flat ledge 32. The circular ledges and grooves are disposed at angles of 120 from one another and, by virtue of as many"point-line-plane" combinations as there are ledges and grooves, enable a triple number of discrete angular positions to be precisely determined during the rotation of the part 4 about the axis AA A single mixing fibre 51 extends through the moving part 4. It is fitted with a male ter minal 61 around which fits the female ter minal 71 fastened to the end of the first bundle of fibres 81. The fixed part 3 is similarly traversed by as many single mixing fibres 512, 522..., provided with their male terminals 612,622..., as there are second bundles of fibres 812,822..., respectively provided with their female terminals 712,722... For each discrete angular position of the support ing plate, which is determined by a line point-plane combination, the free end of the mixing fibre 51 connected to the first bundle 81 is disposed opposite the free end of one of the mixing fibres 512,522... etc. connected to one of the second bundles 812,822..., thus establishing the optical connection be tween these two bundles. Two stops (not shown in Fig. 4) respectively disposed on the fixed and moving parts limit the rotation of the moving part to a value slightly below 360 .

An arrangement such as this enables the two single fibres to be positioned opposite one another with a precision of less than 10 fxm.

The second embodiment of the rotary switch according to the invention, which is shown in Figures 5a and 5b, adopts the principle already illustrated in Fig. 3. The first and the second bundles of fibres are both connected to single mixing fibres disposed on a fixed part, whilst single mixing fibres disposed on a moving part successively establish the optical connection between the single fibre connected to the first bundle and each of the single fibres connected to the second bundle.

Figure 5a shows the rotary switch according to the invention in a partial section taken along its axis of revolution. Figure 5b shows the same switch in a section taken along a plane perpendicular to the same axis and marked PP in Fig. 5a. Figures 5a and 5b show the same supporting positioning plate rotatable in steps as Figure 4, its various constituent ele- ments being denoted by the same reference numerals.

Six single mixing fibres 51 and 512 to 552 provided with male terminals 61 and 612 to 652, respectively, are disposed at angles of 60 from one another on the ring of the fixed part 3. The single fibre 51 provides for connection to a first bundle of fibres, whilst the five other single fibres 512 to 552 provide for connection to five second bundles of fibres.

Three mixing fibres 510, 520 and 530 are disposed on the moving part 4. A knurled button 400 enables the moving part 4 to be rotated about the axis of rotation from one to the other of six positions. This button may be replaced by a remote-controlled step-by-step electrical motor of which the stator and the rotor are respectively integral with the fixed part 3 and the moving part 4.

In Fig. 5b, the moving part is shown in a first position in which the ends of the fibre 510 are disposed opposite the free ends of the fibres 51 and 532, enabling the luminous flux to pass from one to the other of the two fibres. At the same time, it can be seen that the fibre 530 optically connects the fibres 542 and 552.

By rotating the moving part clockwise about the axis of rotation, there are successively obtained from the first position shown in Fig.

5b : -for a first rotation of 30 , a second position in which the fibre 51 is connected to the fibre 542 by the fibre 520; -for a second rotation of 30 , a third position in which the fibre 51 is connected to the fibre 552 by the fibre 530 (at the same time the fibre 510 connects the two fibres 512 and 542); -for a third rotation of 60 , a fourth position in which the fibre 51 is connected to the fibre 512 by the fibre 530 (at the same time the fibre 510 connects the two fibres 522 and 552) ; -for a fourth rotation of 30 , a fifth position in which the fibre 51 is connected to the fibre 522 by the fibre 520.

It is possible, in accordance with the invention, to construct a rotary switch of the type in question for associating a first bundle with any number n of second bundles by dis posing on the moving part single mixing fibres equal in number to (n + 1)/2, if n is odd, and to n/2 if n is even.

Figure 6 shows a rotary switch which is similar to that illustrated in Figs. 5a and 5b but which, by disposing n single mixing fibres on the moving part, enables a large number of switching operations to be carried out between the n+1 single mixing fibres regularly disposed around the periphery of the fixed part.

Figure 6, which shows one example where n is equal to 5, comprises six single fibres 502 to 552 disposed at 60 from one another around the periphery of the fixed part 3, and five single fibres 510 to 550 disposed on the moving part 3. The orifices of the fibres situated on the moving part are disposed on the circle of radius R defining this moving part at the ends of the following arcs with the same origin 0: for the fibre 510: R/6 and-R/6 for the fibre 520: 2-R/6 and-2-R/6 for the fibre 530: 3,-, R/6 and-3-R/6 for the fibre 540: 4 ; rR/6 and 4rR/6 for the fibre 550: 5R/6 and-5R/6 For six angular positions of the positioning plate each corresponding to a rotation of 30 and characterised by six marks A, B, C, D, E, F placed on the fixed part 3 opposite which the point 0 is situated, the following Table shows those of the fibres 502 to 552 which are interconnected and those of the intermediate fibres 510 to 550 which connect them.

Position Connected Intermediate of point 0 Fibres Fibres A 502-512 510 522-552 530 532-542 550 B 502-522 520 532-552 540 C 502-532 530 512-522 510 542-552 550 D 502-542 540 512-532 520 E 502-552 550 512-542 530 522-532 510 F 512-552 540 522-542 520 By giving the positioning plate 12 discrete positions, the arrangement shown in Fig. 6, by making the moving part 3 rotate in still the same direction, provides for five positions where the first bundle is successively connected to the five second bundles and a sixth position in which it is not connected to anything, the same cycle being repeated with each half turn.

Claims

WHAT WE CLAIM : 1. A mechanically controlled switch for permuting the optical connection of at least one first bundle of optical fibres from one to the other of n second bundles of optical fibres (n being an integer equal to at least two), wherein it comprises: -at least one first and n second inputs for receiving the respective ends of said first and second bundles; -a fixed part and a moving part capable of occupying at least two predetermined positions relative to said fixed part; -at least one first single optical mixing fibre integral with said moving part; and -at least n second single optical mixing fibres integral with said fixed part ; -the number of said mixing fibres being equal to at least that of said inputs; n of said second mixing fibres having their first end respectively disposed in the n second receiving inputs opposite the end of said n second bundles; and the second end of at least one of said second mixing fibres being disposed opposite the end of a said first mixing fibre in each of said predetermined positions.
2. A switch as claimed in Claim 1, wherein said first and second inputs are respectively disposed on said moving and fixed parts, and which comprises as many said first and second mixing fibres as there are respectively said first and second inputs; the first ends of said mix- ing fibres being disposed in said receiving inputs opposite the ends of said bundles; and the second end of said first mixing fibre being disposed opposite the end of a second different mixing fibre in each of said predetermined positions.
3. A switch as claimed in Claim 1, wherein said first and second inputs are disposed on said fixed part and the number of said second mixing fibres is equal to the total number of said inputs ; said second mixing fibres having their first end respectively disposed in said first and second receiving inputs opposite the orifices of said bundles; and said first mixing fibre having its two ends respectively disposed opposite the second ends of a first and second mixing fibre in at least one of said predetermined positions.
4. A switch as claimed in any of Claims 1 to 4, wherein said moving part rotates about an axis to occupy said positions, the ends of said first mixing fibre on the one hand and the second ends of said second mixing fibres on the other hand being respectively disposed on a first and second circumference having said axis as their common axis.
5. A switch as claimed in Claims 2 and 4 wherein said first input is the sole input and said moving part is capable of occupying n predetermined angular positions in each ot which the second end of said first mixing fibre is disposed opposite the second end of a second different mixing fibre.
6. A switch as claimed in Claims 3 and 4, wherein said first input is the sole input and where said first mixing fibres are equal in number to at least n/2 and to at most (n+1)/2 ; said moving part being capable of occupying n predetermined angular positions.
7. A switch as claimed in Claims 3 and 4, wherein, where said first input is the sole input, where the second ends of said second mixing fibres are regularly spaced around said second circumference at intervals of 360/ (n+l) degrees and where said moving part is capable of occupying at least n predetermined angular positions, two successive angular positions forming an angle of 180/ (n+1) degrees with one another, said first mixing fibres are n in number and have their second ends disposed symmetrically in relation to a common diameter of said first circumference.
8. A switch as claimed in any of Claims 1 to 7, wherein it additionally comprises displacement means for controlling the movement of said moving part relative to said fixed part.
9. A mechanically controlled switch substantially as hereinbefore described with reference to any one of Figures 2 to 6 of the accompanying drawings.