DE102007008320B4 - Optical two-channel rotary joint - Google Patents

Abstract

Optical rotation transmission system for the simultaneous transmission of two optical signals comprising an optical rotary transformer (10), wherein
- The optical rotary transformer (10) on a first side, with a first optical multiplexer (14) and on its second side with a second optical multiplexer (15) is connected, wherein both the first optical multiplexer (14), and the second optical multiplexers (15) each have a port P1 for a first wavelength lambda 1, a further port P2 for a second wavelength lambda 2 and a port P3 for both wavelengths lambda 1 and lambda 2,
- The first optical multiplexer (14) and the second optical multiplexer (15) are each connected to their port P3 for both wavelengths Lambda 1 and Lambda 2 with the optical rotary transformer,
- An optical signal having a wavelength Lambda 1 from a first optical transmitter (12) in a wavelength converter (13) is fed, which then with another ...

Description

Technical area

The The invention relates to a rotary transformer for optical Signals with two channels.

State of the art

For transmission of optical signals between mutually rotatable units are optical rotary joints known.

In the US 5,568,578 discloses a multi-channel optical rotary transformer with a Dove prism. With such a rotary transformer can be transmitted much more than two channels. It therefore offers excellent flexibility. However, the high cost of the complex mechanics makes such a rotary transformer for many applications uninteresting.

In the US 5,588,077 is disclosed a rotary transformer with two channels. In all embodiments, one beam path (channel B) is widened and recombined by a pair of lenses, while the optical elements of the other beam path (channel A) are arranged therein. In this device complex lens systems are required, in particular, a widening of the channel B must be made so far that takes place only an insignificant influence by the optical elements of the channel A. Furthermore, this Vorrich device can not be constructed rotationally symmetrical, since at least two light guides must be performed radially from the outside in the beam path. This asymmetry leads to a rotation angle-dependent damping.

In the DE 20018842 U1 Another two-channel rotary transformer is disclosed. In this case, in each case light from an optical fiber arranged at an angle to the axis of rotation is coupled into a further fiber, which is rotatably mounted relative to the latter and arranged in the axis of rotation. Another, corresponding coupler is provided for the opposite beam path. A disadvantage of this arrangement is that in single-mode fibers, the attenuation is very large. Furthermore, only signals can be transmitted in opposite directions. An excitation of two signals in the same direction is not possible.

The EP 0 982 608 A1 discloses an optical rotary transformer with multiplexer for 4 different wavelengths.

In the DE 196 31 109 C1 an optical multiplexer with wavelength converter is disclosed.

Presentation of the invention

Of the Invention is based on the object, a rotary transformer for transmission of two optical signals in such a way that this one having relatively low and largely rotation angle independent through-going attenuation. Another object of another aspect of the invention is a optical rotary transformer such that the two optical signals in the same Direction or optionally transferred in opposite directions can be.

Inventive solutions of this Task are in the independent claims specified. Further developments of the invention are the subject of the dependent claims.

The device according to the invention comprises an optical rotary transformer 10 , preferably a single-channel optical rotary transformer, for transmitting light from a first side to a second side via a rotation axis. Furthermore, on the first side of the rotary transformer is a wavelength converter 13 as well as a first multiplexer 14 intended. The wavelength converter receives optical signals having a wavelength λ 1 from a first optical transmitter 12 and converts these optical signals into signals having a second wavelength λ 2. These are connected by means of an optical waveguide in the first multiplexer 14 fed. The first multiplexer 14 has three ports, wherein a first port P1 of a wavelength lambda 1, a second port P2 assigned to a wavelength lambda 2, and a third port P3 for transmitting a combination of signals of wavelength lambda 1 and signals of wavelength lambda 2 is provided.

This Multiplexer, for example, an arrangement with wavelength-selective Be mirrors. It is preferably a direction independent multiplexer, as he for WDM systems is used. The multiplexer can with one or several interference filters, for example with thin film filters (TFF), but also with Fiber Bragg Gratings (FBG), possibly a circulator is necessary, or also realized with Arrayed Waveguide Gratings (AWG) be. Become signals of different wavelengths in different directions passed through this multiplexer, it could also be a direction-selective Component to be like a circulator. Likewise, he could in case that signals the wavelength Lambda 1 over the port P1 and signals of wavelength lambda 2 through the port P2 coupled in and out by the third port P3, a simple mirror or prism arrangement.

The optical signals with the wavelength Lambda 2 from the third port P3 of the first multiplexer 14 are then by means of an optical waveguide 23 led to the optical rotary transformer. By this they are transmitted from the first side to the second side over the rotary gap and by means of another light waveguide 24 to the second multiplexer 15 guided. This second multiplexer 15 is the same as the multiplexer 14 a component having three ports, a first port P1 having a lambda wavelength 1, a second port P2 having a lambda 2 wavelength, and a third port P3 being provided for transmitting a combination of lambda 1 wavelength signals and lambda 2 wavelength signals , Preferably, the second multiplexer 15 identical to the first multiplexer 14 , The signal having the wavelength lambda 2 fed into this second multiplexer via the port P3 is output by the latter via the port P2 assigned to the wavelength lambda 2 and by means of the optical waveguide 26 to the first optical receiver 17 transmitted. Essential to the functioning of the invention is that optical receivers are generally relatively broadband. For example, an optical receiver can receive several wavelengths, in this case wavelengths lambda 1 and lambda 2. Through the multiplexer receives the optical receiver 17 only those for this particular optical signals with the wavelength lambda 2, which this can also receive due to its large bandwidth and convert it into electrical signals for further evaluation. The second optical path in a device according to the invention is basically bidirectional. The operation of the sake of clarity but shown according to a course in the reverse direction. So will light from a second optical transmitter 11 Light of a wavelength Lambda 1 by means of the optical waveguide 25 over the second multiplexer 15 by means of another optical waveguide 24 sent to the optical rotary transformer. From this it becomes after the transmission over the rotary gap over the optical waveguide 23 to the first multiplexer 14 guided. This first multiplexer 14 now outputs the light of the wavelength lambda 1 at the port P1 assigned to this wavelength and transmits it by means of the optical waveguide 20 to the second optical receiver 16 , This second optical receiver is the same as the first optical receiver 17 able to receive broadband signals and thus can evaluate the signal of the wavelength lambda 1.

alternative can the second optical path described here in reverse Be operated direction, that is, it may be the positions of transmitter and receiver be reversed. In a further alternative, the second optical path can also be operated bidirectionally. The mode of operation does not matter here because the second optical path is bidirectional in itself is and the first optical path, which due to the wavelength converter unidirectional is not affected.

It is particularly advantageous for the device according to the invention that these are independent of the special design of the optical transmitter 11 and 12 as well as the optical receiver 16 and 17 is working. Thus, the device is only tuned to the wavelengths, but not to the clock frequency of the transmitted data, the data format, the signal amplitude or other characteristics of these signals to be transmitted. This allows the optical transmitter 11 and 12 as well as the optical receiver 16 and 17 be commercially available standard components. According to the invention for transmission two identical optical transmitter 11 and 12 as well as two identical optical receivers 16 and 17 used. Especially in industrial bus systems in which several participants are to be connected to each other, of course, the bus standard, identical optical transmitter and receiver are provided.

Due to the wavelength conversion of the invention, a transmission of several channels now takes place via an optical single-channel transmitter, without the optical transmitters 11 and 12 or the optical receiver 16 and 17 must be adapted to the transmission line. Compared to conventional DWDM systems, the invention offers the advantage that a back conversion into the output wavelength is not necessary. Thus, due to the higher bandwidth of the optical receiver to a transformation of the wavelength lambda 2 in the wavelength Lambda 1 in the path of the optical waveguide 26 be waived.

• – Umsetzen eines ersten optischen Signals einer ersten Wellenlänge Lambda 1 aus einem ersten optischen Sender 12 mittels eines Wellenlängenumsetzers 13 in eine zweite Wellenlänge Lambda 2;
• – Kombination des Signals der zweiten Wellenlänge Lambda 2 mit einem zweiten Signal einer ersten Wellenlänge Lambda 1 aus einem zweiten optischen Sender 11 mittels eines optischen Multiplexers 14;
• – Drehübertragung des kombinierten optischen Signals mittels eines optischen Einkanal-Drehübertragers 10;
• – Separation des drehübertragenen kombinierten optischen Signals mittels eines optischen Multiplexers 15 in ein erstes Signal mit einer Wellenlänge Lambda 2 und ein weites Signal mit einer Wellenlänge Lambda 1;
• – Weiterleitung des ersten Signals mit der Wellenlänge Lambda 2 zu einem ersten optischen Empfänger 17 und Weiterleitung des zweiten Signals mit der Wellenlänge Lambda 1 zu einem zweiten optischen Empfänger 16.

An inventive method for multi-channel rotation transmission of optical signals, each with identical optical transmitters ( 11 ) 12 ) and identical optical receivers in the same direction includes the following steps:

• - Converting a first optical signal of a first wavelength Lambda 1 from a first optical transmitter 12 by means of a wavelength converter 13 in a second wavelength Lambda 2;
• - Combining the signal of the second wavelength Lambda 2 with a second signal of a first wavelength Lambda 1 from a second optical transmitter 11 by means of an optical multiplexer 14 ;
• - Rotary transmission of the combined optical signal by means of a single-channel optical rotary transformer 10 ;
• - Separation of the rotary transmitted combined optical signal by means of an optical multiplexer 15 in a first signal with a wavelength Lambda 2 and a wide signal with a wavelength Lambda 1;
• - Forwarding of the first signal with the wavelength lambda 2 to a first optical receiver 17 and forwarding the second signal having the wavelength lambda 1 to a second optical receiver 16 ,

• – Umsetzen eines ersten optischen Signals einer ersten Wellenlänge Lambda 1 aus einem ersten optischen Sender 12 mittels eines Wellenlängenumsetzers 13 in eine zweite Wellenlänge Lambda 2;
• – Weiterleitung des Signals der zweiten Wellenlänge Lambda 2 mittels eines optischen Multiplexers 14;
• – Drehübertragung des Signals der zweiten Wellenlänge Lambda 2 mittels eines optischen Einkanal-Drehübertragers 10;
• – Weiterleitung des drehübertragenen Signals der zweiten Wellenlänge Lambda 2 mittels eines optischen Multiplexers 15 in einen ersten optischen Empfänger 17; und die folgenden Schritte zur Übertragung in die entgegengesetzte, zweite Richtung:
• – Weiterleitung eines zweiten optischen Signals der Wellenlänge Lambda 1 von einem zweiten optischen Sender 11 mittels eines optischen Multiplexers 15 zu einem optischen Drehübertrager 10;
• – Drehübertragung des Signals der Wellenlänge Lambda 1 mittels eines optischen Einkanal-Drehübertragers 10;
• – Weiterleitung des Signals mit der Wellenlänge Lambda 1 mittels eines optischen Multiplexers 14 zu einem zweiten optischen Empfänger 16.

An inventive method for multi-channel rotation transmission of optical signals, each with identical optical transmitters ( 11 ) 12 ) and identical optical receivers in the opposite direction comprises the following steps for transmission in the first direction:

• - Converting a first optical signal of a first wavelength Lambda 1 from a first optical transmitter 12 by means of a wavelength converter 13 in a second wavelength Lambda 2;
• - Forwarding the signal of the second wavelength lambda 2 by means of an optical multiplexer 14 ;
• - Rotary transmission of the signal of the second wavelength Lambda 2 by means of a single-channel optical rotary transformer 10 ;
• - Forwarding of the rotationally transmitted signal of the second wavelength lambda 2 by means of an optical multiplexer 15 in a first optical receiver 17 ; and the following steps for transmission in the opposite, second direction:
• - Forwarding of a second optical signal of wavelength lambda 1 from a second optical transmitter 11 by means of an optical multiplexer 15 to an optical rotary transformer 10 ;
• - Rotary transmission of the signal of the wavelength lambda 1 by means of a single-channel optical rotary transformer 10 ;
• - Forwarding the signal with the wavelength lambda 1 by means of an optical multiplexer 14 to a second optical receiver 16 ,

A inventive device can also for transmission be configured of more than two signals. These are accordingly The invention has several wavelength conversions different wavelengths provided. The multiplexers are then also corresponding to the different ones wavelength embody. It can Any number of multiplexers either on the first or the second Side of the rotary transformer be arranged.

It is basically here only from a first side and a second side of the rotary transformer spoken. Since the rotational movement anyway only a matter of location reference is, was based on a reference to a rotating (rotor) and a standing (stator) side omitted.

The basic idea of the invention relates to designing a rotation transmission device with a single-channel optical rotary transmitter for two or more channels. Basically, however, with a device according to the invention, the number of channels of a multi-channel optical rotary transformer, such as a rotary transformer as in the US 5,568,578 is disclosed enlarged.

Even though a device according to the invention especially is suitable for coupling singlemode components, this can in principle also used for the coupling of multimode components and others become. These are of course adjust the optical components accordingly. The basic idea However, the invention remains applicable.

Description of the drawings

The Invention will be described below without limiting the general inventive concept an embodiment described by way of example with reference to the drawing.

1 shows in a general form schematically a rotary transmission device according to the invention.

2 shows in general form schematically a further embodiment of a rotation transmission device according to the invention.

In 1 a rotary transmission device according to the invention is shown schematically. For coupling light over the axis of rotation is a corresponding in the prior art single-channel rotary transformer 10 intended. On the first side of the rotary transformer is a first optical transmitter 12 , which generates an output signal with a lambda 1 wavelength. This signal is transmitted by means of an optical waveguide 21 into a wavelength converter 13 coupled. This wavelength converter converts the signal having an input wavelength Lambda 1 into a signal having an output wavelength Lambda 2. Optionally, this can also amplify the signal. The output signal of the wavelength converter is via a light guide 22 to a first multiplexer 14 guided. This separates signals of different wavelengths into different optical paths. Here it carries the input signal at the port P2 with the wavelength Lambda 2 to a port P3 for both wavelengths. This signal with the lambda 2 wavelength is now transmitted via the optical waveguide 23 to the optical rotary transformer 10 passed, and transferred from this on the rotary gap. On the second page, the signal now enters the port P3 of a second multiplexer 15 one. According to its wavelength, it is output at the corresponding port P2 for the wavelength lambda 2 and by means of an optical waveguide 26 to the first optical receiver 17 ge leads. Furthermore, located on the second side of the rotary transformer, a second optical transmitter 11 , which is an optical signal with the wavelength lambda 1 via the optical waveguide 25 into the port P1 of the second multiplexer 15 couples. This emits the signal at a port P3 and passes it over the fiber optic cable 24 in the optical rotary transformer 10 , From there, the signal is transmitted via the fiber optic cable 23 to port P1 of the first multiplexer 14 forwarded. According to its wavelength lambda 1, the signal is now output to the corresponding port P1 of the multiplexer and via the optical waveguide 20 to the second optical receiver 16 guided.

In 2 a further embodiment of the invention is shown schematically. The first optical path between the first optical transmitter 12 and the first optical receiver 17 corresponds to the one of 1 , The second optical path between the second optical transmitter 11 and the second optical receiver 16 runs here in the opposite direction to the embodiment of 1 , it will be here that of the second optical transmitter 11 generated signal having a wavelength lambda 1 by means of the optical waveguide 20 in the first multiplexer 14 fed. This transmits the signal via its port P3 via the optical waveguide 23 to the rotary transformer 10 , From there, the signal is transmitted via the fiber optic cable 24 to the second multiplexer 15 transfer. This now gives the signal with the wavelength Lambda 1 via the optical waveguide 25 to the second optical receiver 16 out.

A device after 1 can also be extended for independent transmission of multiple channels. For this purpose, for example, on the first page another wavelength converter for conversion of another input signal with the wavelength lambda 1 to provide another output signal with the wavelength lambda 2. Accordingly, the multiplexers 14 and 15 to design three channels. The wavelength λ 2 can then be received by a second optical receiver on the second side. Alternatively, a second optical transmitter on the second side could be provided for converting an optical signal having the wavelength lambda 1 to another output signal having the wavelength lambda 2. A corresponding receiver would then be provided on the first side at the corresponding output of the multiplexer for the signal of the wavelength lambda 2. Accordingly, any further wavelength converter can also be provided on the first or second side.

10

optical Rotary joint

11

second optical transmitter

12

first optical transmitter

13

Wavelength converter

14

first multiplexer

15

second multiplexer

16

second optical receiver

17

first optical receiver

20

optical fiber (Lambda 1)

21

optical fiber (Lambda 1)

22

optical fiber (Lambda 2)

23

optical fiber (Lambda 1 and lambda 2)

24

optical fiber (Lambda 1 and lambda 2)

25

optical fiber (Lambda 1)

26

optical fiber (Lambda 2)

21

first Port of a multiplexer (Lambda 1)

22

second Port of a multiplexer (Lambda 2)

23

third Port of a multiplexer (Lambda 1 and Lambda 2)

Claims (5)

Optical rotation transmission system for the simultaneous transmission of two optical signals comprising an optical rotary transformer ( 10 ), wherein - the optical rotary transformer ( 10 ) on a first side, with a first optical multiplexer ( 14 ) and on its second side with a second optical multiplexer ( 15 ), wherein both the first optical multiplexer ( 14 ), as well as the second optical multiplexer ( 15 ) each have a port P1 for a first wavelength Lambda 1, a further port P2 for a second wavelength Lambda 2 and a port P3 for both wavelengths Lambda 1 and Lambda 2, - the first optical multiplexer ( 14 ) and the second optical multiplexer ( 15 ) are each connected with their port P3 for both wavelengths Lambda 1 and Lambda 2 with the optical rotary transformer, - an optical signal having a wavelength Lambda 1 from a first optical transmitter ( 12 ) into a wavelength converter ( 13 ), which is then output at a different wavelength Lambda 2 and to the port P2 for the wavelength Lambda 2 of the first multiplexer ( 14 ) and over the port for both wavelengths P3 of the first multiplexer ( 14 ) via the rotary transformer ( 10 ) to the port for both wavelengths P3 of the second multiple ( 15 ) is passed to this second multiplexer ( 15 ) via its port P2 for the wavelength lambda 2 to a first optical receiver ( 17 ), and - in one of the ports P1 for the wavelength Lambda 1 optionally of the first multiplexer ( 14 ) or the second multiplexer ( 15 ) is fed a second optical signal having a wavelength Lambda 1, which via the port P3 for both wavelengths this multiplexer is transmitted via the rotary transformer and fed into the port for both wavelengths P3 of the respective other multiplexer, and outputted via the port P1 for the first wavelength of the respective other multiplexer and to a second optical receiver ( 16 ), and - the optical transmitters ( 11 ) 12 ) as well as the optical receivers ( 16 ) 17 ) are identical. Device according to claim 1, characterized in that in that at least one of the ports P1 or P2 is wavelength-selective Features. Device according to claim 2, characterized in that in that at least one of the ports P1 or P2 is an interference filter having. Method for rotational transmission of two optical signals in the same direction, each with identical optical transmitters ( 11 ) 12 ) and identical optical receivers comprising the following steps: - converting a first optical signal of a first wavelength Lambda 1 from a first optical transmitter 12 by means of a wavelength converter 13 in a second wavelength Lambda 2; - Combining the signal of the second wavelength Lambda 2 with a second signal of a first wavelength Lambda 1 from a second optical transmitter 11 by means of an optical multiplexer 14 ; - Rotary transmission of the combined optical signal by means of a rotary optical transmitter 10 ; - Separation of the rotary transmitted combined optical signal by means of an optical multiplexer 15 in a first signal with a wavelength lambda 2 and a wide signal with a wavelength lambda 1 ; - Forwarding of the first signal with the wavelength lambda 2 to a first optical receiver 17 and forwarding the second signal having the wavelength lambda 1 to a second optical receiver 16 , Method for rotational transmission of two optical signals in opposite directions, each with identical optical transmitters ( 11 ) 12 ) and identical optical receivers comprising the following steps: - converting a first optical signal of a first wavelength Lambda 1 from a first optical transmitter 12 by means of a wavelength converter 13 in a second wavelength Lambda 2; - Forwarding the signal of the second wavelength lambda 2 by means of an optical multiplexer 14 ; - Rotary transmission of the signal of the second wavelength lambda 2 by means of a rotary optical transmitter 10 ; - Forwarding of the rotationally transmitted signal of the second wavelength lambda 2 by means of an optical multiplexer 15 in a first optical receiver 17 ; - Forwarding of a second optical signal of wavelength lambda 1 from a second optical transmitter 11 by means of an optical multiplexer 15 to an optical rotary transformer 10 ; - Rotary transmission of the signal of the wavelength lambda 1 by means of a single-channel optical rotary transformer 10 ; - Forwarding the signal with the wavelength lambda 1 by means of an optical multiplexer 14 to a second optical receiver 16 ,