DE10056600A1 - Electro-optical transceiver for wavelength multiplex system uses two phased array waveguide gratings - Google Patents

Abstract

The transceiver has a substrate (3) provided with 2 waveguide arrays (15,35) in the form of phased array waveguide gratings, one of which is coupled to at least one input waveguide (9) and a number of output waveguides (19), coupled to a respective opto-electrical transducer element of a reception unit (29), the other coupled to a number of input waveguides (31) coupled to respective electro-optical transducer elements of a transmission unit (41) and at least one output waveguide (37). An Independent claim for a manufacturing method for an electro-optical transceiver is also included.

Description

The invention relates to an electro-optical transceiver for a wavelength Genmultiplex system, in which the optical wavelength selective coupling units are designed as phased array waveguide gratings (AWGs).

It is known to use transceivers for wavelength division multiplexing systems of two optical wavelength-selective couplers and corresponding elec to build a trooptic or opto-electrical converter. The wavelengths selective couplers form optical multiplexers or demultiplexers, the (Demultiplexer) coupler for the receiving branch that is on an input Optical fiber incoming optical wavelength division multiplex signal on several right output optical fiber according to the individual optical channels divides and the (multiplexer) coupler for the transmission branch the several opti rule transmission signals, the optical transmission elements in one of each several input optical fibers can be coupled in on one off gangs fiber optic summarizes. Optical multiplexers are consequent their low insertion loss often using so-called phased Array waveguide gratings built. These optical systems exist in ih rem core of an optical fiber array, its individual optical fiber each form an optical path, the optical path length being each neighboring paths increases or decreases. This results in behavior the behavior of common interference grids in maxima of higher order equivalent. However, losses of a common grid are avoided, the by dividing the incident optical power between the different ones Diffraction maxima arise.  

In the manufacture of an electro-optical transceiver, it lends itself to that optical structures to form the multiplexer or demultiplexer or both phased array waveguide gratings on a single substrate hen. This reduces the assembly effort for the transceiver. Of Furthermore, there is a smaller size than when using two separate substrates, each with a single (de) multiplexer or one single phased array waveguide grating.

In the manufacture of phased array waveguide grating optical (de) multiplexer, it is also known the structures of two separate (de) multiplexers or phased array waveguide gratings in "devour" each other and for both (de) multiplexers or phased arrays Waveguide gratings use the same coupling areas, each one optical or output optical fiber with the central optical fiber Connect array. Such structures have so far been used in the manufacture of AWG's therefore used to make the committee technologically complex and therefore reduce error-prone production. After making one double entangled in such a way become the optical properties ten branches and the better branch selected. To the packaging is then only the inputs and outputs of the outside because better structure accessible.

At this point it should be noted that the term AWG is synonymous with one by means of an AWG in the narrower sense, d. H. the central fiber optic Array, built optical (de) multiplexer is used, unless out the context gives the meaning of an AWG in the narrower sense.  

Based on this state of the art, the object of the invention reasons, an electro-optical transceiver for a wavelength division multiplex To create a system that is as small as possible and the is relatively easy to manufacture. Furthermore, the invention is the Task based on a method for producing such a transceiver to accomplish.

The invention solves this problem with the features of the two claims 1 or 8.

The invention is based on the knowledge that an electro-optical transcei ver for a wavelength division multiplex system in a relatively simple manner and can be built up in a space-saving manner by the fact that the optical structures and the electrical or opto-electrical components on the same sub be applied strat. This is preferably silicon substrate.

Through the use of a known entangled structure for bil Formation of two "intertwined" phased array waveguide gratings there is the advantage of an extremely space-saving construction at opti side. According to the invention, however, both branches of one are opened built double AWG used.

According to one embodiment of the invention, at least the electrical are integrated connection lines for the receiver unit and / or the transmitter unit formed on the same substrate. In particular by using a Silicon substrate has the advantage that both optical and electrical  Structures with relatively simple processes on the substrate can be witnessed.

In addition to the electrical connection lines, of course passive or active electronic components are also integrated on the substrate be trained.

It is also possible to transmit one or more separate components unit and / or the receiving unit on the component to apply for example, stick on or solder, and if necessary connections of the separate Components with further processes, for example by bonding, with the To connect connecting lines.

Since the production of the optical structures of an AWG or the two ver limits trained AWGs, as stated above, runs the risk that the optical properties are not within the required narrow tolerances are according to a further embodiment of the invention, in particular in the multiple output optical fibers of the optical receiving branch or of the respective AWG, an optical resonator structure is formed in each case. This serves as a narrowband bandpass filter to reduce the crosstalk of the to improve each channel.

The provision of corresponding optical resonator structures in the several Input optical fibers of the optical part of the transmission branch AWG offers less of an advantage in terms of crosstalk attenuation of the individual optical channels, since the bandwidth is usually used th laser diodes is usually significantly smaller than the bandwidth of the respective opti channel. Optical resonator structures provided in the transmission branch can  however, serve for external feedback for laser diodes, their transmission spectrum without the external feedback too wide for a wavelength division multiplex system would be bandy. In this way it is possible to be relatively inexpensive Use laser diodes.

The manufacture of the resonator structures in the multiple input and output gangs optical fibers is preferably done by irradiating the respective against optical fibers with electromagnetic waves (e.g. by UV laser) or by particle radiation. Of course, the respective Optical fibers consist of a material or doped with a material be that under such irradiation a change in the refractive index dex enables.

One embodiment provides for the production of a transceiver according to the invention form of the invention, first the purely optical structures for the two to create entangled AWGs on the substrate. Then you can optical properties of the two AWGs measured and the in terms of crosstalk or crosstalk properties better branch than receiving branch to get voted. The electrical structures can then be produced in this way be made that the electrical structures for the receiving unit previously selected better AWG. Are resonator structures required as external resonators for the optical transmission elements, so this after measuring the optical structures (before or after of the electrical structures).

However, the production can also be carried out in such a way that in both cases resonator structures are produced in the respective plurality of input and output optical waveguides in both branches of the optical structure, ie in both AWGs. In this case, the measurement of the optical properties after the manufacture of the optical structures can also be omitted in the manufacture of such a transceiver. The manufacture of the resonator structures can in particular be carried out in a very simple manner by a method as described in the older German patent application (file number of file 19.151 ), which has not been published beforehand .

Further embodiments of the invention result from the subclaims chen.

The invention is explained below with reference to an embodiment shown in the drawing:
The single figure shows schematically an electro-optical transceiver 1 , the sen all components are arranged on a common substrate 3 . The substrate 3 is preferably made of silicon, since this material enables the integrated manufacture of both optical and electrical components and components.

The transceiver 1 comprises optical structures in the form of two interlocking AWGs 5 and 7 . In the exemplary embodiment shown, the AWG 5 consists of an input optical waveguide 9 which opens into a first optical coupling region 11 . The input optical waveguide 9 can be connected at the interface 9 a to an external optical waveguide 13 , which supplies the transceiver 1 with an optical wavelength division multiplex signal of the central wavelengths λ ₁ to λ _n . By means of the coupling area 11 , the field generated by the wavelength division multiplex signal is coupled into the central optical waveguide array of the AWG 5 . The optical phase differences of the individual optical fibers of the optical fiber array 15 and a second coupling region 17 , in which the individual optical fibers of the array 15 open, are dimensioned such that the optical signal is split and the individual partial signals of the central wavelengths λ ₁ to λ _n , in each case be coupled into one of n output optical fibers 19 .

The ends of the output optical waveguides 19 each open before an opto-electrical converter element of an opto-electrical converter unit 21 . The converter elements can be designed, for example, as individual diodes, which are combined in the form of a diode row forming the converter unit 21 .

On the substrate 3 electrical connection lines 23 are also ausgebil det, which can be Herge with conventional methods for producing integrated components. The electrical connection lines 23 connect corre sponding connection contacts of the opto-electrical converter unit 21 with the connection contacts to further integrated components 25 or with the connection contacts of passive components 27 , which can be formed, for example, as resistors. The opto-electrical converter unit 21 , the electrical connection lines 23 and the integrated components 25 and the passive components 27 together form a receiver unit 29 which converts the optical signals into electrical signals and, if necessary, processes them further.

The second AWG 7 comprises n input optical fibers 31 , which are connected to the second coupling region 17 . In the ends of the input optical waveguide 31 , the signal of an electro-optical converter element of an electro-optical converter unit 33 is coupled. This can be designed, for example, as an array of n laser diodes with center wavelengths Λ ₁ to Λ _n . The optical signals of the electro-optical converter elements are via the input optical waveguide 31 and the second coupling region 17 , which is connected to the other ends of the input optical waveguide 31 , so into the individual optical waveguides of the central optical waveguide array 35 of the AWG 7th coupled, that through the appropriately selected, differently long optical paths of the array 35 in the first coupling area 11, a field arises which couples all partial signals of the center wavelengths Λ ₁ to Λ _n into an output optical fiber 37 of the AWG 7 . The end of the output optical fiber 37 can in turn be coupled to an external optical fiber 39 at an interface 37 a.

The electro-optical converter unit 33 in turn forms a transmission unit 41 together with further integrated or passive components 25 or 27 . This can be produced in the same way as described above in connection with the receiver unit 29 .

The electro-optical transceiver 1 shown in the figure has an extremely small design due to the use of the two entangled AWGs and the formation of the optical and electrical structures on the same substrate and can be produced with relatively simple means.

The production can be carried out by first producing the optical structures in the form of the two AWGs 5 , 7 . The optical properties of the two AWGs can then be measured before the electrical structures are produced. In this way, that branch or that AWG can be assigned to the later reception branch that has the better optical properties with regard to channel separation and crosstalk or crosstalk. If necessary, optical resonator structures 43 can be produced before or after the creation of the electrical structures and the application of separate electrical components in the ends of the plurality of input optical waveguides 31 . These can be used as external resonators for relatively inexpensive laser diodes. The resonator structures can be produced by “writing” corresponding structures into the input optical waveguides 31 already produced by means of electromagnetic radiation, for example a UV laser, or by partial radiation.

It is also possible to provide an optical resonator structure from the outset both in the input optical waveguide 31 of the AWG 7 and in the output optical waveguide 19 of the AWG 5 . In this case, the optical properties of the interlaced AWGs can be dispensed with. In particular with the method described in the unpublished older German patent application (file number file 19.151 ), the manufacture of optical resonator structures in the optical waveguide in question is possible in a simple manner, the resonator structures each having a slightly different center frequency.

The invention relates to an electro-optical transceiver for a wavelength division multiplex system with a first light waveguide array 15 arranged on a substrate 3 , which is designed as a phased array waveguide grating, one end region of which via a first coupling region 11 with at least one input Optical waveguide 9 and its other end region is coupled via a second coupling region 17 to a plurality of output optical waveguides 19 , with a receiver unit 29 arranged on the substrate 3 , which comprises an opto-electrical converter unit 21 , one opto-electrical converter element of the converter unit 21 each is assigned to a plurality of output optical fibers 19 , with a second optical fiber array 35 arranged on the substrate 3 , which is designed as a phased array wave guide grating, one end region of which via the first coupling region 11 has at least one output optical fiber 37 and whose other e rer end portion through the second coupling region 17 is coupled to a plurality of input optical waveguides 31, having disposed on the substrate 3 transmitter unit 41 comprising an electro-optical converter unit 33, where in each case an electro-optical transducer element of the transducer unit 33 with one of the plurality Input light waveguide 31 is assigned. Furthermore, the invention relates to a method for producing such a transceiver.

Claims (8)

1. Electro-optical transceiver for a wavelength division multiplex system

• a) with a arranged on a substrate ( 3 ) first Lichtwellenlei ter array ( 15 ), which is formed as a phased array waveguide grating, one end region of which via a first coupling region ( 11 ) with at least one input optical waveguide ( 9 ) and whose other end region is coupled to a plurality of output optical fibers ( 19 ) via a second coupling region ( 17 ),
• b) with a receiver unit ( 29 ) which is arranged on the substrate ( 3 ) and which comprises an opto-electrical converter unit ( 21 ), an optoelectric converter element of the converter unit ( 21 ) being assigned to one of the plurality of output optical fibers ( 19 ),
• c) with a arranged on the substrate ( 3 ) second Lichtwellenlei ter array ( 35 ), which is formed as a phased array waveguide grating, one end region of which via the first coupling region ( 11 ) with at least one output optical waveguide ( 37 ) and whose other end region is coupled via the second coupling region ( 17 ) to a plurality of input optical waveguides ( 31 ), and
• d) with a transmission unit ( 41 ) arranged on the substrate ( 3 ), which comprises an electro-optical converter unit ( 33 ), one electro-optical converter element being associated with the converter unit ( 33 ) with one of the plurality of input optical waveguides ( 31 ).

2. Transceiver according to claim 1, characterized in that the first ( 15 ) and second ( 35 ) phased array waveguide grating, the coupling areas ( 11 ), ( 17 ), the plurality of input ( 31 ) and output ( 19 ) optical fibers and the at least one input ( 9 ) and the at least one output optical waveguide ( 37 ) are arranged on the substrate ( 3 ) in integrated optics. 3. Transceiver according to claim 1 or 2, characterized in that the electrical connection lines ( 23 ) for the receiver unit ( 29 ) and / or the transmitter unit ( 41 ) are integrally formed on the substrate. 4. Transceiver according to claim 3, characterized in that the transmitter unit ( 41 ) and / or receiver unit ( 29 ) as one or more separate components ( 25 , 27 ) is applied to the substrate ( 3 ). 5. Transceiver according to one of the preceding claims, characterized in that in the plurality of output optical fibers ( 19 ) and / or the multiple input optical fibers ( 31 ) each have an optical resonator structure ( 43 ) or each of the output ( 19 ) and / or input ( 31 ) optical waveguide is connected to an optical resonator structure ( 43 ), each of the resonator structures ( 43 ) being designed as a narrowband bandpass filter, the center frequency of which is matched to the center frequency of a channel of the wavelength division multiplex system. 6. Transceiver according to claim 5, characterized in that the resona tor structures ( 43 ) are inscribed by irradiation with electromagnetic waves or by particle beams in the previously produced output ( 19 ) or input ( 31 ) optical waveguide. 7. Transceiver according to claim 5 or 6, characterized in that the optical resonator structures ( 43 ) in the plurality of input ( 31 ) optical waveguides are designed and used as resonators for the external feedback of the electro-optical transducer elements designed as laser diodes. 8. A method for producing a transceiver according to one of claims 3 to 7, characterized in that first the optical waveguide arrays ( 15 , 35 ), the coupling areas ( 11 , 17 ) and the plurality of input ( 31 ) and output ( 19 ) Optical waveguide and the at least one input ( 9 ) and output ( 37 ) optical waveguide on the substrate ( 3 ) who the that the optical crosstalk or crosstalk properties of the two optical branches formed thereby are measured, that the branch that has better crosstalk or crosstalk properties, is selected as the receiving branch and that the electrical connection lines ( 23 ) for the receiving unit ( 29 ) for the selected branch and / or the electrical connecting lines ( 23 ) for the transmitting unit ( 41 ) are assigned to the non-selected branch and be made.