NL8304463A - OPTICAL COUPLING DEVICE WITH ROTATING COUPLING. - Google Patents

Description

83A014 CZZJ '

Short designation: Optical coupling device with rotating coupling.

The present invention relates to a rotating coupling optical coupling device which allows to obtain optical transmission between sets of receiving and / or transmitting means which respectively. are attached to: a fixed frame and a frame which is driven with a rotary movement relative to an axle.

By way of non-limiting example, reference may be made to the exchange of data between a central data processing unit and peripheral units connected to a rotating antenna of certain types of radar.

The exchanges can be of one or two-way type and, according to the proposed application, take place along a single channel, optionally using multiplex techniques, or alternatively over several separate channels.

In addition to optical connections, a connection channel may optionally ensure other types of connections: e.g. the transmission of electrical channels via a coaxial cable or a waveguide.

Finally, it is necessary to supply the units attached to the rotating frame with electrical energy. This supply is done with the help of cables that generally carry strong currents using the connecting channel.

It is therefore necessary to provide rotating ring collectors or similar devices to ensure electrical continuity between the fixed and rotating parts.

25 In addition to other advantages inherent in optical connections, in particular the high transfer rate they allow, the devices and characteristics just described justify resorting to this type of connection, since they furthermore allow to largely 83 0 4 4 6 3 ί 1 \ 83Α014 - 2 - Escape the inevitable parasitic phenomena of the electromagnetic type, eg those caused by "sparking or splashing" rotating ring collectors.

More in particular, these optical connections are made with the aid of optical fibers which are mutually coupled with a rotating coupling. Generally, this type of device comprises two caps that rotate about one another relative to each other, each cap enclosing an optical fiber or a bundle of optical fibers placed end to end, the fibers having a propagation axis that is 10 their ends to be coupled coincide with the axis of rotation.

This establishment is not free from objections. In fact, it is necessary to ensure the alignment of the two fibers or fiber bundles to be coupled with great precision, regardless of the relative positions of the two caps about the axis of rotation. In fact, it is of paramount importance to ensure optical quality coupling in order to minimize transmission losses. It follows that the degree of precision in the manufacturing tolerances of the mechanical parts is of the order of the micrometer, especially for the connections of monomode optical fibers. The difficulty increases when it comes to rotating parts here, as the concepts of wear and mechanical play have to be introduced to account for the development of tolerances over time.

Finally, it may be advantageous to leave the axial region of the connecting channel free to permit the establishment of said other types of connections.

The object of the invention is to meet these needs and to provide a rotating optical coupling device which ensures the connections of optical type by means of one or more beams which are parallel to annular sections which release the axial region 30 for other uses and a allow an increase in mechanical tolerances.

The invention therefore relates to an optical coupling device comprising two caps which are mechanically coupled by a coupling which is rotatable about an axis of rotation, characterized in that it comprises at least 35: - opto-electronic means for generating at least one parallel beam transmission beam and of annular cross-section that propagates along an axis perpendicular to the axis of rotation; - a first mirror face attached to a first cap and inclined by an angle of 1/2 radians receiving a total of at least one transmission beam and transmitting it again to the second cap in a direction parallel to the second cap 8304463 <* t 83A014 - 3 to the propagation axis such that the optical coupling is effected; 5 - a second mirror surface attached to the second cap and inclined

through an angle of ^ / 4 radians with respect to the axis of rotation which I

collects this beam in its entirety and retransmits it in a direction perpendicular to the axis of rotation; and optoelectronic means for receiving and detecting this beam, and that the rotary coupling comprises an opening centered on the axis of rotation whose minimum size is greater than the largest outer diameter of the generated transfer beams.

Other features and advantages of the invention will become more apparent with reference to the description below in the accompanying figures, in which:

Fig. 1 schematically shows a first embodiment variant of an optical coupling device with rotatable coupling according to the invention.

This device comprises two caps 1 and 2 which are rotatable relative to each other about an axis Λ. For the sake of simplicity, it will be assumed for the sake of simplicity below that the cap 1 is fixed in space, e.g. is attached to the frame of an installation.

The cap 2 is then attached to a rotating frame, e.g. a rotating antenna when it concerns a radar installation.

The two caps 1 and 2 are mechanically coupled in the usual manner by means of a rotary coupling 3 or a similar member.

These devices are common to most of the rotary coupling devices of the prior art.

One of the main features of the device according to the invention is that the transmission by optical path between the two caps 1 and 2 takes place by means of a beam Ffc of parallel rays with an annular cross-section whose axis of symmetry coincides with the axis of rotation Λ.

The beam is therefore in the form of a light "tube" with an internal radius and an external radius.

At the coupling 3, the only condition to be considered is that it is provided with an opening 30 which is centered on the shaft A and has dimensions that are larger than the outer diameter of the annular beam R

83 0 4.4 6 3

* V

83A014 - 4 -

According to an important feature, the device also comprises the flat mirrors and those resp. are fitted in caps 1 and 2 and are inclined at an angle equal to TtY4 radians with respect to the axis of rotation Δ such that the transmission beam F is bent according to two axes Λ ^ and Δ 2, which are perpendicular to the axis Δ.

In order to leave the axial region free, the mirrors according to an effective embodiment of the invention each comprise a central opening 10 and 20.

The projections at the center openings 10 and 20 on a plane perpendicular to the axis Δ must be inscribed in a circle with a radius 10 which is at most equal to the radius R ^. (¾) in the same way, the dimensions of the mirrors were determined to receive the total beam F ^. In a practical manner, the mirrors are preferably provided with an annular construction.

To complete this assembly, it is necessary to provide at least about light energy emitting means, in the case of one direction transfer, an optical element allowing the generation of a beam of parallel rays of annular cross-section outgoing of the beam emitted by the source.

For the intended applications of optical transmission 20, laser sources are generally used, which emit either a beam of parallel rays of annular cross section, as is the case of gas laser sources, or a divergent beam, as is the case of a laser source with semiconductor or for the output surface of an optical fiber. These beam conversion optics are indicated in FIG. 1 by references 11 and 21.

In order to capture the thoughts, it is assumed that the optical connection is of the one-way type between a transmitter 12, which is mounted in the fixed part 1 of the installation, and a receiver 22, in the movable part 2. It is also assumed that in practice the intermediate connections are made with the aid of the optical fibers resp. f1 and f2 are arranged between the transmitter 12 and the optical element 11 on the one hand and the receiver 22 and the optical element 21 on the other hand.

In the exemplary embodiment shown in Fig. 1, the optical elements 11 and 21 are intended for converting a bundle of parallel rays of annular cross-section into a bundle of parallel rays of circular cross-section, or vice versa.

Classically, provision is also made for converting the diverging beam at the output of the optical fiber f ^ j_n into a cylindrical beam using a lens or a lens system that is connected with L.

8 3 0 4 4 δ 3 • * * 83A014 - 5 - is indicated. Likewise, the cylindrical beam at the output of the optical element 11 is focused on the input face of the fiber f ^ using a second lens or a second lens system indicated by.

A simplified embodiment of the optical elements 11a1 21 would consist of a single diaphragm with the radius R 1 covering the center region of the cylindrical beam. In practice, this construction cannot be used since it causes energy losses proportional to the ratio of the shielded areas of the cross-sections and transferred by the beam. In addition, it is necessary to provide a beam extender such that the incident beams have a cross section with an outer diameter equal to 2 R ^.

An exemplary embodiment of an optical converter element of the beam according to a first approach, which may suitably be within the scope of the invention, is shown in FIG. This is an optical element known under the designation of "axicon".

To capture the thoughts it is assumed that this is the element of FIG. 1, where the element 21 may be identical.

The axicon 11 includes a cone 111 and a mirror 110 formed by a revolution symmetry piece whose inner wall 1100 reflects the wavelength of the beam emitted by the laser source 12.

The cone 111 and the mirror 110 coincide with their axis of rotation with the axis h, 1.

The angles of inclination relative to the axis A-1 of the reflective surfaces, the inner surface 1100 of the frusto-conical mirror 110 and the surface 1110 of the cone 111 opposite the surface 1100, should be chosen such that after reflection and distribution over the surface 1110 and bouncing back on the surface 1100, the exiting beam Ft of the axicon 11 propagates in a direction substantially parallel to the axis J \ 1.

The two angles of inclination can e.g. be chosen equal to 7 4/4 radians.

The distance between the two reflecting surfaces determines the beam, taking into account the cross section of the incident beam F ^.

The mutual composition of the elements making up the axicon can be obtained in any suitable manner.

Fig. 3 presented a first practical implementation variant. The cone 111 is attached to the truncated conical mirror 110 by means of two ^ 7: Λ /.

Λ Q

83A014-6 - i 'small cross-section rods 112 and 113 which are preferably diametrically opposite to the top 0 and aligned on an axis Ar' perpendicular to the axis A jl * 08 small cross-section of the rods 112 and 113 allow only one also very small fraction of the energy transported by the bundle F 1 is collected.

Fig. 4 shows in cross section a second possible variant of the composition of the elements of the axicon 11. The frusto-conical mirror 110 comprises, in line with its exit plane 1101, an annular groove 1102 intended for receiving a blade 114 with 10 parallel major faces. This sheet must be transparent to the wavelength of the beam emitted by the laser source 12.

Furthermore, the top should be anti-reflective on these two main surfaces.

The cone 111 is then, as e.g. with the aid of screw means 115, fixed in the center of the blade 114, such that the point 0 is aligned on the axis A ^ at the expense of a small increase in complexity, this composition has the advantage of allowing more precise fixing and centering of the cone 111, which rests on a flat base and that no part of the bundle is received, as is the case in the embodiment described with respect to fig. 3, whereby a fraction of the annular bundle F is collected through rods 112 and 113.

It should be noted that the influence of the optical element 11 on the transfer of light energy does not depend on the transfer direction 25. When it is a one-way transfer, as shown in Figure 1, the element 21 will have a reciprocal effect and convert the incident beam Ft from an annular cross section to a cylindrical beam F2.

When it is a two-way transfer, each element, 11 or 21, performs the two conversions.

It should also be noted that when using two optical conversion elements, it causes four reflections of the beam, two in each element, of course and furthermore the reflections on the flat mirrors and M2.

A typical reflectance coefficient can be valued at about 0.95. It follows that under these conditions the reflection coefficient equivalent to the two elements 11 and 21 is 0.8.

It is possible to reduce the reflective losses by using other techniques 8304463 83A0I4 - 7. 1

Fig. 5 shows in cross section an optical conversion element 11 'according to I.

a second approach, which allows to improve energy efficiency. I

The configuration remains that of an axicon, but this is done in I.

5 is the shape of a monohlock prism with total reflections. tit concerns an I.

block of material with refractive power, registered on the one hand. I

between the two parallel planes forming the input and / or output plane I.

116 and 117 form the optical beam conversion element 111 and others

side between the two conical surfaces 1110 1 and truncated cone-I

10 shaped surfaces 11001, the axes of revolution of which coincide with I.

the axis These two surfaces form reflection surfaces for I.

the light rays and play the role of reflection surfaces 1110 and I.

1100 (Figures 2 to 4) with a reflectance coefficient similar to the unit. I

The losses due to the parasitic reflections against the I

Input and / or output surfaces 116 and 117 can be kept at a minimum

by performing a classic anti-reflective treatment. The rebound I

sings coefficient can be made much lower than 1¾. I

The internal radius of the annular beam Ft hangs only I.

away from the radius of the input face 116 when I

20, the point 0 of the conical surface 1110 "emerges in the j surface 116, the input surface of the beam in the j shown

example. More generally, the radius depends only on the I.

existing distance between the two surfaces 1100 'and 11101. I

The radius of the beam Ft depends on the one hand on the I

Radius of the cylindrical beam and on the other side of the distance I.

between the two bouncing surfaces. I

It is still possible to use one or the other of the two input I

and / or extend exit surfaces with a uniform thickness of the I.

material with refractive power. This embodiment variant is shown I

30 in fig. 5. The conical surfaces 1110 'and 1100' of the monoblock prism 11 'are elongated by the "blades" 118 to 119 of the material having light refractive power. Naturally, the new entrance and / or I

output surfaces 116 'ai 117' mutually parallel and perpendicular to the axis I.

Λ 1 to stay. (¾) the same way remains the vertex 0 of the cone-I

35 shaped surface 1110 'centered on the axis A ^.

Typically, elements 12 and 22 (FIG. 1) for emitting and / or receiving light energy, for emitting, may comprise laser diodes or electroluminescent diodes, and for receiving "PIN1" type photodies or photodiodes with avalanche It is also -T 'l'- ·· C' j

4 V.

83A014-8 - Known to use an optoelectronic component capable of alternating operation as an attic and as a detector of light energy of the same wavelength. This component is preferably the semiconductor diode described in patent FR-B-2 396 419. This patent 5 relates to a semiconductor diode which, in the polarized direction, emits light and which, when polarized in the reverse direction, is capable of detecting light of the same wavelength.

One of the main features of the device according to the invention is the release of the axial region, i.e. a cylinder with a radius 10 equal to. This feature can be used to transport electrical signals through this channel.

Fig. 7 shows such a contraction.

In reality, parts 1 and 2 of the device described with respect to FIG. 1 are only the caps of an optical coupling, which caps, e.g. resp. are fixed to a fixed frame 4 and a movable frame 5. It goes without saying that the rotating coupling 3 only serves to ensure the relative movability of the two caps 1 and 2. The movable frame 5., e.g. the antenna mast in a radar is not supported in any way by the rotating coupling 3, but by any suitable means (not shown in fig. 7).

A construction example can be taken within the scope of the invention and is described in French patent application FR-A-2 448 728.

In the example shown, the electrical signals are transported by a coaxial cable, which is split into two parts and C2IS and which is on the rotation axis Δ. is aligned.

The coupling between these two parts of the coaxial cable is ensured by an additional rotating coupling 6 which is arranged between the two mirrors and, preferably in the space 30 left at the height of the rotating coupling 3. The coaxial cable must be sufficiently rigid 2Q in order to avoid any excessive bending, which could cause the interception of the light flux of the beam F, in particular through the rotating coupling 6.

Means for tensioning and holding the cable 40 and 41 may be provided at the passages through the walls of the caps 35 1 01 2 *

The transmission and handling of electrical signals is done outside the caps 1 and 2 by conventional means.

It may be the same for optical signals, as shown in Figure 7 8304463 * t 83A014-9. In the apparatus shown in this Figure, the optical fibers and f2 leave caps 1 and 2 to be coupled to means (not shown) for emitting and / or receiving light energy.

The coaxial cable (C ^, <Z ^) can be replaced by any other connection type, such as e.g. a waveguide.

The device according to the invention which has just been described therefore has the following advantages: the availability of the rotation axis; the easy adjustment of the size of the hollow light-10 cylinder transferred in air by simple changes of the geometric dimensions of the optical elements used: lenses and L, mirrors and beam transducer elements 11 and 21; the increase in mechanical tolerances over those associated with the optical rotary couplings of the prior art, due to the increase in the diameter of the transmitted optical beam; - small energy losses, even in the embodiment described with respect to fig. 7.

In fact, in this embodiment, the bundle Ffc with two repetitions 20 is received by the parts and the coaxial cable.

Fig. 8 shows a section perpendicular to the axis A ^ of the outgoing beam F of the transducer element of the beam 11. The portion of the light energy transported by the beam Ft is intercepted by the cable d. This phenomenon occurs after reflection of the beam Ft on the mirror. The energy intercepted depends on the diameters of the cables and C2, which will be assumed to be equal in the other, and on the ratio existing between the rays R. and R.

X o

The maximum transfer loss in db is given by the formula 30 11 ^

PM = 10 log i - ^ - L-J

M ir <R 2 - R2) -2 (R -R) d ei e 1 where d is the common diameter of the coaxial cables and C ^.

When the shadow plane of the conductor and the conductor C2 is coincident, the transmission loss is reduced to: (R 2-Ri2 35 Ρ · ". 10 log f-2 = - * 5—-1" - M (R 2 -R, 2) - (RR.) Dq - λ *,. T 1 ei * Λ N * - ï - «ft * '* - · -:» k / 83A014 - 10 - •%

By way of example, typical values are: d = 2 cm, = 4 cm, R = 8 cm.

e / »'>

Under these conditions PM "ψΖ 0.49 db and 0.24 db.

The test results confirm this data. In addition, it has been found that the beatings due to the rotation are of small amplitudes and only slightly affect the optical transmission, especially when it occurs through light waves encoded in numerical code or in frequency modulation.

Heretofore, it has been implicitly considered that the device according to the invention allowed the transfer of a single information channel.

However, the conventional techniques of time or frequency multiplexing using different wavelengths allow two or more generally different signals to be transported simultaneously or sequentially.

The use of differently polarized light waves, e.g. two waves with mutually perpendicular polarization directions, also allows to transport a number of different signals. Two sets of polarizer analyzer are used for this.

However, the invention also allows, an additional advantage, to form a number of physically different transfer channels.

A first example of the coupling device with rotating multi-channel coupling is schematically shown in Fig. 9.

A first set of two mirrors and inclining about 7T / 4 radially with respect to the axis of rotation Δ allow the formation of a first optical transmission channel, by means of the transmission beam R 1 with rays parallel to the annular cross section, with the inner radius R ^ and the outer radius R0 ^. The mirrors Mj ^ and bend the beam over an angle of 7Γ / 2 radial and. The curved beams propagate along axes A11 and A21 perpendicular to axis A. All these arrangements are identical to those described with respect to the beam and mirrors 1 and M 1 shown in Figure 1.

A second optical transmission channel is formed using a second set of mirrors and M22 which also tilt about 1/4 radians with respect to the axis zodanig such that a second transmission beam Ft2 35 is folded in two, with parallel rays of annular cross section, with the inner radius Ri2 and the outer radius R02. The double-folded bundles propagate along axes A ^ 2 and A 22 perpendicular to axis A.

Two sets (not shown in Fig. 9), beam converters intercept 8304453 83A014 - 11 - * * Folded beams identically as described with respect to Fig. 1. Light energy transmitting and / or receiving means are also provided and are not shown for simplicity. These members also play an identical role to that described with respect to Figure 1.

In order for the device to work correctly, it is necessary that the following conditions are simultaneously fulfilled: a / κΛ <K12 b / that the dimensions outside the mirrors and projected on 10 a plane perpendicular to the axis 4 are smaller than c / that the mirrors, on the one hand, and on the other hand, are arranged along the axis Δ such that only the transmission beam intended for them is intercepted or d / that the projections of the center opening and of the mirrors on a plane perpendicular to the axis 4: 101 and 201 for the mirrors ML ^ and M ^, 102 and 202 for the mirrors and M ^, must be smaller or equal to respectively. and R ^ -

The number of individual channels is, of course, not limited to two. In Fig. 9, the direction of propagation of the beams is indicated arbitrarily. The transfer can also be two-way.

Finally, the above-mentioned devices of known type, multiplexing in time or in frequency, for example, can be used over all or part of the transmission channels.

The orientations of the mirrors and about the axis A and thereby the relative angular shifts of the axes A H to A 22 in a plane perpendicular to the axis A are shown arbitrarily and can be selected as desired by the user.

The construction of the device just described allows for large decoupling of transmission channels and minimizes the risk of crosstalk between these channels. However, this construction requires the use of two sets of inclined mirrors. It is possible to escape this requirement and apply the construction shown in fig. 10. The same mirrors, identical to those shown in FIG. 1, serve to double-fold the various transmission beams, reduced for simplicity to two F ^ and F ^ in the example shown in FIG. 10.

As before, it is necessary that the condition Ri2 is met, and that the dimensions of the center apertures 10 and 20 are such that their projections on a plane perpendicular to the axis Λ are smaller than or 8304463 \ 83A014-12 - radius F ^.

Under these conditions, two sets of optical beam conversion elements 111 and 211 on the one hand, 112 and 212 on the other are cascaded along the resp. propagation axes A1 and Δ 2 of the beams and 5 F ^ folded by the mirrors and ML, - These axes are, of course, as before, perpendicular to the axis of rotation Δ -

The optical elements 111, 112, 211 and 212 convert the transfer beams and F F of annular cross-sections into beams F,, F ^, l1 and F22 of circular cross-section or vice versa.

The latter can be generated and / or received as before using focusing lenses L ^, L ^, »^ ^ 22 'cooperating with the optical fibers i F ^, F ^, F2 ^ and F22 coupled with (not shown ) transmitting and / or detecting means of light energy.

An additional condition that must be met is that the overall outer dimensions of the beam converter elements 111 and 211 which cooperate with the transmission beam F .. of the smallest cross section be less than t1 than the inner diameter (2 R ^) of the transmission beam Ft2 so that it does not is collected.

Under these conditions, a very small part of the energy of this latter beam, after reflection on the mirrors and M2, is collected, on the one hand by the optical fibers f ^ and f2 ^, which is negligible, and on the other hand by the fasteners of the optical beam conversion elements 111 ai 211 on caps 1 and 2 (fig. 1 25 and 7). These fasteners 1110 and 2110 can be formed by thin rods, which can be arranged in space such that they coincide with the shadow surfaces of an optional central connecting channel (fig. 7: C2). It is also possible to use fasteners which are transparent to the wavelengths used, which fasteners have obtained an anti-reflective treatment.

The invention is not limited to the few exemplary embodiments described here. All variants that are within the scope of the skilled person are within the scope of the invention. For example, combinations of different constructions of the multichannel coupling device can be made in the accessory station.

'i> ll <- - - 1 .:

Claims (11)

Optical coupling device comprising two caps (1, 2) which are mechanically coupled by a coupling (3) rotatable about an axis of rotation (Λ), characterized in that it comprises at least: - opto-electronic means (12, f ^ Lp 11) for generating at least one parallel beam and annular cross-section transfer beam (Ft) which propagates along an axis (Λ ^) perpendicular to the axis of rotation (Δ); - a first flat mirror (M ^) which is attached to a first cap (1) egg inclines by an angle of 'fr / 2 radial and which collects at least one transmission beam (F ^) in total and retransmits it to the second cap (2) in a direction parallel to the propagation axis (A) such that the optical coupling is effected; I - a second flat mirror (H ^) attached to the second cap (2) and inclined at an angle of 7Γ / 4 radians from the 15 axis of rotation (A) / which totally captures this beam (F ^) and retransmits it in a direction (^) perpendicular to the axis of rotation (Λ); optoelectronic means (21, Lp f2, 22) for receiving and detecting this beam (F ^); and that the rotary coupling (3) is provided with an opening (30) 20 centered on the axis of rotation (A), the opening of which has the minimum dimension greater than the largest outer diameter (2 R ^) of the generated transfer beams (Ft ). Device according to claim 1, characterized in that the inclined mirrors (M ^,) comprise opening and (10, 20) centered on the axis of rotation (A), the maximum dimensions of which are projected on a plane perpendicular to this axis (A) less than or equal to the smallest inner | diameter (2 R ^} of the generated transfer beams (Ffc). 3. Device according to claim 2, characterized in that it furthermore comprises a channel (C1, C1) for the transmission of electrical signals comprising a rotary coupling (6) mounted on the axis of rotation (A). is centered and that the cross section of this channel has a maximum dimension smaller than the smallest inner diameter (2 R ^) of the generated transfer beams (Ft). Device according to one or more of claims 1 to 3, characterized in that the optoelectronic means for generating and receiving the transfer beams (F 1) comprise optical beam conversion elements (11, 21) way a beam (F ^, F2) of. 3304463 / · «83A014 -ΜΙ Transforming parallel beams of circular cross section propagating along an axis perpendicular to the axis of rotation (Δ) into a bundle (F ^) of parallel beams of annular cross section traveling along the same axis (λ). Device according to claim 4, characterized in that the optical beam conversion elements (11, 21) are each formed by an axicon comprising a cone (111) with a reflecting inner wall (1110) whose axis of rotation coincides with the beam propagation axis (Δ ^) and a mirror (110) comprises a frusto-conical cavity with reflective wall (1100), the revolution axis of which coincides with the propagation axis (Δ] _), and i that the reflection surfaces (1100, 1110) with this axis (4 ^) angle shapes equal to TF / 4 radians. 6. Device according to claim 4, characterized in that the optical beam conversion elements are formed by prisms with total reflections, which are in the form of parallel blades. surfaces (116,117) of light-refracting material, comprising a conical-wall cavity (1110 1) whose axis of revolution coincides with the beam propagation axis (^ i) and is circumferentially bounded by a frusto-conical wall whose axis of rotation also coincides with the 20 beam propagation axis (Δ ^), and that the walls (1100 ', 1110') are surfaces with total reflection for the rays propagating within the material with refractive power and slanting at an angle equal to / ^ / 4 radians with respect to this axis (Δ - ^). 7. Device according to one or more of claims 4 to 6, characterized in that the opto-electronic means for generating and collecting the bundle comprise optical fibers (f 1, f2) coupled to the bundles (F ^, F2) of parallel rays with circular cross-sections by means of focusing lenses (L ^, L ^). 8. Device according to one or more of claims 1 to 7, characterized in that it comprises at least one first (f ^, H1, 211, L ^, f ^ j and a second (f ^ 2, L ^ 2, 112, 212, L22, f22) comprises an optoelectronic means for generating and receiving parallel beam beams of annular cross section such that the two caps (1, 2) are coupled using at least two concentric transfer 35 beams (F ^), Ffc2), and that the internal (R ^, R ^) and external (Rg ^ Re2) radii of the annular cross-sections of the transfer beams are determined such that these annular cross-sections do not have any common parts. O - Λ: - * I 83A014 - 15 - 9. Device according to claim 8, characterized in that it is provided with a single set of two mirrors (M ^,) inclined over I at an angle equal to 7Γ / 4 radians, each of which represents the total of the transmission 1 collect bundles (, F ^) and fold them in half according to directions I 5 (^ 1 '^ 2} perpendicular to the axis of rotation (^). I Device according to claim 8, characterized in that it comprises different sets of two mirrors (M ^ - 01 I), each set of mirrors receiving a transfer beam (F ^, F ^) and folding it I according to the directions (Δ - ^ - & 2ΐ '> Ay ^ ~ A22 ^ l ° ° <^ straight I 10 are on the axis of rotation (Λ) - I Device according to one or more of claims 1 to 10, I, characterized in that the optical coupling is of the two-way type, each cap (1,2) being provided with opto-electronic means ensuring the simultaneous functions of generating and collecting I15 at least one transfer bundle (Ffc). I 5304463