ELECTRO-OPTICAL APPARATUS, SEMICONDUCTOR APPARATUS AND SEMICONDUCTOR DEVICE, ELECTRO-OPTICAL ARRANGEMENT AND USE

Abstract

The present invention relates to an electro-optical device (1) having two interaction regions (2), which each comprise a longitudinal waveguide section (3) and one or two active elements (5), which active element or the respective active element comprises or consists of at least one electro-optical active material, more particularly graphene, wherein the longitudinal waveguide sections (3) of the two interaction regions (2) are arranged spaced apart from one another, and the active element or the respective active element (5) extends at least in some sections above and/or below and/or within the waveguide longitudinal section (3) of the respective interaction region (2), and wherein two or more contact elements (6) are provided which are each in contact with at least one of the active elements (5).

Claims

1. Electro-optical device (1), in particular a photodetector or a modulator, having two interaction regions (2), which each comprise a longitudinal waveguide section (3) and one or two active elements (5), the active element or elements (5) each comprising or consisting of at least one electro-optically active material, in particular graphene, the longitudinal waveguide sections (3) of the two interaction regions (2) being arranged spaced apart from one another and the active element or the respective active element (5) extending at least in sections above and/or below and/or within the longitudinal waveguide section (3) of the respective interaction region (2), and two or more contact elements (6) being provided, which contact elements (6) are each in contact with at least one of the active elements (5), wherein at least one inner contact element (6), which is arranged between the two spaced-apart longitudinal waveguide sections (3) and serves as an inner signal contact, and two outer contact elements (6), which are each arranged on the other side of the respective longitudinal waveguide section (3) with respect to the inner contact element (6) and each serve as an outer ground contact, or one outer contact element (6), which is formed at least in sections at least substantially in a U-shape with two arms (6a) spaced apart from one another and a connecting section (6b) connecting the two arms (6a) and which engages around the outside of the two longitudinal waveguide sections (3), the two arms (6a) of the outer contact element (6) each serving at least in sections as an outer ground contact, are provided.

2. Device (1) according to claim 1, wherein an inner contact element (6) is provided, which inner contact element (6) is in contact both with the active element or one of the active elements (5) of one interaction region (2) and with the active element or one of the active elements (5) of the other interaction region (2), or wherein two inner contact elements (6) are provided, and one of the inner contact elements (6) is in contact with the active element or one active element (5) of one interaction region (2) and the other inner contact element (6) is in contact with the active element or one active element (5) of the other interaction region (2), and/or wherein an outer contact element (6) is provided, which is in contact both with the active element or one of the active elements (5) of one interaction region (2) and with the active element or one of the active elements (5) of the other interaction region (2), or wherein two outer contact elements (2) are provided, and one of the outer contact elements (6) is in contact with the active element or one active element (5) of one interaction region (2) and the other outer contact element (6) is in contact with the active element or one active element (5) of the other interaction region (2).

3. Device (1) according to claim 1, wherein the two longitudinal waveguide sections (3) are part of one waveguide (4).

4. Device (1) according to claim 3, wherein the waveguide (4) comprises a bifurcation with two branching arms (4c, 4d), and one of the longitudinal waveguide sections (3) is located in the region of one arm (4c, 4d) of the bifurcation respectively, preferably, wherein a splitter (16) is provided, by means of which an incoming light signal can be distributed to the two arms (4c, 4d) of the bifurcation, preferably in equal proportions.

5. Device (1) according to claim 3, wherein the waveguide (4) is characterized at least in sections by an at least substantially U-shaped course with two arms (4a) being spaced apart from one another, preferably extending at least substantially parallel to one another and in particular being rectilinear, and a preferably rectilinear connecting section (4b) connecting the two arms (4a), wherein one of the two longitudinal waveguide sections (3) lies in the region of one of the two arms (4a) respectively.

6. Electro-optical device (1), in particular a photodetector or a modulator, having an interaction region (2), which interaction region (2) has an at least substantially U-shaped longitudinal waveguide section (3), which longitudinal waveguide section (3) has two arms (4a) spaced apart from one another and a connecting section (4b) connecting the two arms (4a), and one or two at least sectionally at least substantially U-shaped active elements (5) having two arms (5a) spaced apart from one another and a connecting section (5b) connecting the two arms (5a), wherein the active element or the respective active element (5) comprises or consists of at least one electro-optically active material, in particular graphene, wherein the active element or the respective active element (5) extends at least in sections above and/or below and/or within the longitudinal waveguide section (3), and wherein two or more contact elements (6) are provided, which are each in contact with the active element or one of the active elements (5), wherein at least one inner contact element (6), which is arranged within the at least sectionally at least substantially U-shaped longitudinal waveguide section (3) and serves as an inner signal contact, and two outer contact elements (6), which are each arranged on the other side of the respective arm (4a) of the longitudinal waveguide section (3) with respect to the inner contact element (6) and each serve as an outer ground contact, or one outer contact element (6), which is formed at least in sections at least substantially U-shaped and has two arms (6a) spaced apart from one another and a connecting section (6b) connecting the two arms (6a) and which encompasses the outside of the longitudinal waveguide section (3), the two arms (6a) of the outer contact element (6) each serving at least in sections as an outer ground contact, are provided.

7. Device (1) according to claim 6, wherein the longitudinal waveguide section (3) is part of a non-annularly closed waveguide (6).

8. Device (1) according to claim 5, wherein the cross-sectional area in the region of one arm (4a) of the waveguide (4) is larger than the cross-sectional area in the region of the other arm (4a) of the waveguide (4), preferably, the cross-sectional area being larger in the first arm (4a) as viewed in the light propagation direction.

9. Device (1) according to claim 6, wherein an inner contact element (6) is provided, which is in contact both with the one arm (5a) of the active element or of one of the active elements (5) and with the other arm (5a) of the active element or of one of the active elements (5), or two inner contact elements (6) are provided, and one of the inner contact elements (6) is in contact with the one arm (5a) of the active element or of one of the active elements (5) and the other inner contact element (6) is in contact with the other arm (5a) of the active element or of one of the active elements (5), and/or wherein an outer contact element (6) is provided, which is in contact both with the one arm (5a) of the active element or of one of the active elements (5) and with the other arm (5a) of the active element or of one of the active elements (5), or two outer contact elements (6) are provided, and one of the outer contact elements (6) is in contact with the one arm (5a) of the active element or of one of the active elements (5) and the other outer contact element (6) is in contact with the other arm (5a) of the active element or of one of the active elements (5).

10. Device (1) according to claim 1, wherein the device is formed as a photodetector and the interaction region or the respective interaction region (2) comprises exactly one active element (5), preferably, wherein the inner contact element or one of the inner contact elements (6) and the outer contact element or one of the outer contact elements (6) are in contact with the one active element (5), particularly preferably on opposite sides of the one active element (5).

11. Device (1) according to claim 1, wherein the device is formed as a modulator, in particular as an electro-optical modulator, and the interaction region or the respective interaction region (2) comprises two active elements (5), preferably, wherein the inner contact element or one of the inner contact elements (6) is in contact with the active element (5) of the interaction region or of the respective interaction region (2) and the outer contact element or one of the outer contact elements (6) is in contact with the other active element (5) of the interaction region or of the respective interaction region (2), or the interaction region or the respective interaction region (2) comprises an active element (5) and an electrode, preferably, wherein the inner contact element or one of the inner contact elements (6) is in contact with the active element (5) of the interaction region or of the respective interaction region (2) and the outer contact element or one of the outer contact elements (6) is in contact with the electrode of the interaction region or of the respective interaction region (2) or vice versa.

12. Device (1) according to claim 11, wherein the two active elements (5) or the active element (5) and the electrode of the interaction region or of the respective interaction region (2) are spaced apart from one another and are arranged offset with respect to one another in such a way that they lie one above the other in sections in an overlap region.

13. Device (1) according to claim 1, wherein a waveguide bypass section (19) is provided, the waveguide bypass section (19) bridging the one interaction region (2) or the two interaction regions (2), so that light originating in particular from the same source can be guided past the one interaction region (2) or the two interaction regions (2) through the waveguide bypass section (19), preferably, wherein the device (1) is formed as an interferometer or as a component of an interferometer and/or a splitter (16) is provided by means of which light can be split on the one hand to the waveguide bypass section (19) and on the other hand to the longitudinal waveguide section (3) of the interaction region (2) or to the longitudinal waveguide sections (3) of the interaction regions (2).

14. Device (1) according to claim 1, wherein the longitudinal waveguide section (3) of the interaction region (2) or the longitudinal waveguide sections (3) of the interaction regions (2) is or are part of a waveguide (4), at one end of which a coupling device (17) for coupling light in and/or out is provided or at both ends of which a coupling device (17) for coupling light in and/or out is provided respectively.

15. Device (1) according to claim 1, wherein the at least one electro-optically active material is a material which absorbs electromagnetic radiation of at least one wavelength and generates an electrical photosignal as a result of the absorption, and/or whose refractive index changes as a function of a voltage and/or the presence of charge and/or an electric field, in particular, wherein the at least one electro-optically active material is graphene and/or at least one dichalcogenide, in particular two-dimensional transition dichalcogenide, and/or heterostructures of two-dimensional materials and/or germanium and/or lithium niobate and/or at least one electro-optical polymer and/or silicon and/or at least one compound semiconductor, in particular at least one III-V semiconductor and/or at least one II-VI semiconductor.

16. Electro-optical arrangement, comprising at least one electro-optical device (1) according to claim 1, and a connection device (20) for connecting to a coaxial and/or coplanar conductor, wherein the connection device (20) comprises one or more inner connection contact elements (21) serving as a ground contact and one or more outer connection contact elements (21) serving as a signal contact, and wherein the inner contact element(s) (6) of the electro-optical device (1) is/are or can be connected to the inner connection contact element(s) (21) of the connection device (20), and wherein the outer contact element(s) (6) of the electro-optical device (1) is/are or can be connected to the outer connection contact element(s) (21) of the connection device (20).

17. Semiconductor apparatus comprising a chip and at least one, preferably a plurality of electro-optical devices (1) according to claim 1, wherein the device (1) or the devices (1) are preferably arranged on the chip or on a coat arranged above the chip.

18. Semiconductor apparatus according to claim 17, wherein the device or the respective device (1) is part of a photonic platform fabricated on the chip or bonded to the chip.

19. Semiconductor device comprising a wafer (8) and at least one, preferably a plurality of devices (1) according to claim 1, wherein the device (1) or the devices (1) are preferably arranged on the wafer (8) or on a coat arranged above the wafer (8).

20. Semiconductor device according to claim 19, wherein the device or the respective device (1) is part of a photonic platform fabricated on the wafer (8) or bonded to the wafer (8).

21. Use of an electro-optical device (1) according to claim 1 in such a way that the inner contact element or the inner contact elements (6) of the electro-optical device (1) is/are connected to the ground contact(s) of a coaxial or coplanar conductor or of a connection device (20) for connecting to a coaxial or coplanar conductor, and that the outer contact element or the outer contact elements (6) of the electro-optical device (1) is/are connected to the signal contact(s) of a coaxial or coplanar conductor or of a connection device (20) for connecting to a coaxial or coplanar conductor.

Description

[0115] In the drawing shows

[0116] FIG. 1 a top view of a photodetector according to the prior art;

[0117] FIG. 2 a partial section through a semiconductor device with the photodetector of FIG. 1;

[0118] FIG. 3 a top view of an embodiment of an electro-optical device according to the invention, which is formed as a photodetector according to the first aspect of the invention and comprises two interaction regions;

[0119] FIG. 4 a top view of an embodiment of an electro-optical device according to the invention, which is formed as a photodetector according to the first aspect of the invention and comprises a waveguide with a bifurcation and two interaction regions;

[0120] FIG. 5 a top view of an embodiment of an electro-optical device according to the invention, which is formed as a photodetector according to the second aspect of the invention and comprises a U-shaped interaction region;

[0121] FIG. 6 a top view of an electro-optical modulator according to the prior art;

[0122] FIG. 7 a partial section of a semiconductor device with the electro-optical modulator of FIG. 6;

[0123] FIG. 8 a top view of an embodiment of an electro-optical device according to the invention, which is formed as an electro-optical modulator and comprises two interaction regions;

[0124] FIG. 9 a top view of an embodiment of an electro-optical device according to the invention, which is formed as an electro-optical modulator and comprises a U-shaped interaction region;

[0125] FIG. 10 a top view of a Mach-Zehnder interferometer with an electro-optical modulator according to the prior art;

[0126] FIG. 11 a top view of an embodiment of a Mach-Zehnder interferometer according to the invention, which comprises an electro-optical modulator with two interaction regions;

[0127] FIG. 12 a top view of an embodiment of a Mach-Zehnder interferometer according to the invention, which comprises an electro-optical modulator according to the invention with two interaction regions, in a purely schematical representation;

[0128] FIG. 13 a top view of a further embodiment of an electro-optical device according to the invention, which can be formed as a photodetector or as an electro-optical modulator;

[0129] FIG. 14 a top view of three contact elements of an embodiment of an electro-optical device according to the invention, which are connected by means of wires to a connection device for a coaxial cable; and

[0130] FIG. 15 a sectional view showing components of an embodiment of an electro-optical device according to the invention, the contact elements of which are connected to connection device for a coaxial cable by a bonding layer.

[0131] All figures show purely schematic representations. In the figures, the same components or elements are provided with the same reference signs.

[0132] FIG. 1 shows a top view of an electro-optical device 1 according to the prior art, which is designed as a graphene-based photodetector. FIG. 2 shows a section of the detector. It comprises an interaction region 2 with a longitudinal section 3 of a waveguide 4 and an active element 5 in the form of a graphene film. As can be seen, the active element 5 extends in sections above the longitudinal waveguide section 3, specifically overlapping it at the right-hand end of the waveguide 4. Since the active element 5 obscures the underlying longitudinal waveguide section 3 in plan view, the latter is shown in the figure with dashed lines. In the present case, the waveguide 4 and, thus, the longitudinal section 3 thereof belonging to the interaction region 2 consists of titanium dioxide, whereby this is to be understood purely by way of example.

[0133] The active element 5 is characterized by a greater width than the longitudinal waveguide section 3, so that it projects beyond the latter on both sides. On its sides lying laterally of the longitudinal waveguide section 3, the active element 5 is in contact in each case with one of two metallic contact elements 6 arranged on both sides of the longitudinal waveguide section 3. The contact elements 6 may comprise, for example, nickel and/or titanium and/or aluminium and/or copper and/or chromium and/or palladium and/or platinum and/or gold and/or silver or consist of one or more of these metals. It may be that the contact elements comprise several layers, which may comprise or consist of different metals.

[0134] Each of the two contact elements 6 associated with the interaction region 2 and in contact with the active element 5 is associated with a respective interconnection element 7 with which the respective contact element 6 is in contact, specifically on its underside. In other words, the respective contact element 6 connects the respective active element 5 to an interconnection element 7. Since the interconnection elements 7 are concealed by the contact elements in the top view, they are shown with dashed lines. The interconnection elements 7 are vertical electrical connections, which are also referred to in English as Vertical Interconnect Access, Via or VIA for short. The interconnection elements are—just like the contact elements—metallic, for example consist of copper, and extend in the vertical direction through a chip or a wafer or a substrate, in particular a semiconductor substrate, of a chip or a wafer, above which, in particular on which, the photodetector 1 is provided. In the present case, the detector 1 is located above a wafer 8 of a semiconductor device, a partial section of which is shown in FIG. 2. In the present case, wafer 8 comprises a single-piece silicon substrate 9 and a plurality of integrated electronic components 10, which, in the embodiment shown, extend in the semiconductor substrate 9. The integrated electronic components 10, which may in particular be transistors and/or resistors and/or capacitors, are only indicated in simplified form in the schematic FIG. 2 by a hatched line provided with the reference sign 10. At a corresponding position in the substrate 9, a large number of integrated electronic components 10 are found in a sufficiently known manner. These can also be components of processors, such as CPUs and/or GPUs, or form such components in a likewise known manner.

[0135] The wafer 8 has a front-end-of-line (FEOL for short) 11, in which the plurality of integrated electronic components 10 are arranged, and a back-end-of-line (BEOL for short) 12, lying there above, in which or via which the integrated electronic components 10 of the front-end-of-line 11 are interconnected by means of different metal planes. The integrated electronic components 10 in the FEOL 11 and the associated interconnection in the BEOL 12 form integrated circuits of the wafer 8 in a sufficiently known manner. A FEOL 11 is sometimes also referred to as transistor front-end and a BEOL 12 as a metal back-end. The metal planes comprise a plurality of further interconnection elements 7, which are presently given by VIAs.

[0136] On the wafer 8 there is a coat 13 of a dielectric material, presently silicon dioxide (SiO.sub.2) on which the waveguide 4 is located. There is also a further dielectric coat 14 on the waveguide 4 and the coat 13, on which the active element 5 is arranged.

[0137] An upper passivation coat 15 is still provided on the active element 5, which preferably consists of Al.sub.2O.sub.3 and/or SiO.sub.2.

[0138] The waveguide 4, the active element 5, the contact elements 6, the interconnection elements 7 and the coats 13, 14, 15 may have been obtained in a manner known from the field of chip or a wafer fabrication, for example by (multilayer) material deposition or a transfer process and possibly structuring.

[0139] In the embodiment shown, either the dielectric coat 13 or the dielectric coat 14 or both of these coats are designed as planarization coats, which are characterized by a roughness in the range of 1.0 nm RMS to 0.1 nm RMS, in particular 0.6 nm RMS to 0.1 nm RMS, preferably 0.4 nm RMS to 0.1 nm RMS. The abbreviation nm stands in a manner known per se for nanometer (10.sup.−9 m). Roughnesses in these ranges can be or have been obtained, for example, by chemical mechanical polishing (CMP) and/or resist planarization, as also described in the earlier German patent application with file number 10 2020 102 533.5, which also goes back to the applicant. As can be seen, a connection to one or more of the integrated electronic components 10 is realized via the interconnection elements 7 connected to the contact elements 6 of the photodetector 1 and the interconnection elements 7 from the wafer 8.

[0140] The shown photodetector 1 serves in a manner known per se for signal conversion back from the optical to the electronic world. In other words, a light signal conducted through the waveguide 4 can be converted into an electrical signal.

[0141] The active element is arranged relative to the longitudinal waveguide section 3 of the interaction region 2 in such a way that it is exposed, at least in sections, to the evanescent field of electromagnetic radiation guided in the waveguide 4 and thus the longitudinal section in operation, so that an interaction can take place. In the present case, the distance between the upper surface of the longitudinal waveguide section 4 and the lower surface of the overlying section of the active element 5 is about 10 nm.

[0142] FIG. 3 shows a top view of an embodiment of an electro-optical device according to the invention, which is also designed as a photodetector 1. It is characterized—in contrast to the pre-known photodetector according to FIG. 1—by a G-S-G-configuration.

[0143] In concrete terms, it has two interaction regions 2, each comprising a longitudinal waveguide section 3 and an active element 5, which comprises or consists of at least one electro-optically active material, in particular graphene. In the shown embodiment, the active element 5 of the device according to the invention is also given by a graphene film 13. However, it should be emphasized that according to the invention it is also possible for the active element 5 to be given by a film comprising or consisting of at least one other or further electro-optically active material, for example a film comprising or consisting of a dichalcogenide-graphene heterostructure consisting of at least one layer of graphene and at least one layer of a dichalcogenide, or by a film comprising at least one layer of boron nitrite and at least one layer of graphene.

[0144] The two longitudinal waveguide sections 3 of the two interaction regions 2 of the photodetector of FIG. 3 are spaced apart from each other. They are part of a waveguide 4. The waveguide 4 is characterized in sections by an at least substantially U-shaped course with two rectilinear arms 4a, which are spaced apart from one another and extend at least substantially parallel to one another and a rectilinear connecting section 4b, which connects the two arms 4a, and in each case one of the two longitudinal waveguide sections 3 lies in the region of one of the arms 4a.

[0145] In analogy to the previously known detector from FIG. 1, it applies to the two active elements 5 here that they extend at least in sections above the longitudinal waveguide section of the respective interaction region 2.

[0146] Furthermore, not only two but a total of three contact elements 6 are provided, each of which is in contact with at least one of the active elements 5. Specifically, an inner contact element 6 is provided, which is arranged between the two spaced-apart longitudinal waveguide sections 3 and serves as an inner signal contact, and two outer contact elements 6 are provided, which are each arranged on the other side of the respective longitudinal waveguide section 3 with respect to the inner contact element 6 and each serve as an outer ground contact. The inner contact element 6 is in contact both with the active element of one of the two interactional regions 2 and with the active element 5 of the other of the two interaction regions 2. For the two outer contact elements 6, it applies that one is in contact with the active element 5 of one interaction region 2 and the other is in contact with the active element 5 of the other interaction region 2.

[0147] As can be seen, the inner contact element 6 and the two outer contact elements 7 lie on a line and are aligned with each other. They form a symmetrical G-S-G contact arrangement with an inner signal contact and two outer ground contacts enclosing the inner signal contact. As a result, a symmetrical arrangement with respect to ground and signal and thus a very advantageous arrangement is given, from which high-frequency signals can be transmitted more interference-free to coaxial arrangements, which will be discussed further below.

[0148] While the U-shaped waveguide section is very well suited to provide a space for the inner signal contact, there can be a disadvantage associated with it in terms of the symmetry of the electrical signal. According to Lam bert-Beer's law, the absorption of the electromagnetic radiation along the propagation direction causes more to be absorbed in the active element(s) in the region of the first arm 4a in the direction of light propagation, i.e. the left arm 4a in FIG. 3, than in the active element 5 of the second arm 4a, the right arm in FIG. 3. Then the high-frequency mode can be asymmetrically excited in an unfavorable manner. This problem is prevented by the fact that the waveguide cross-section in the U-shaped region of the waveguide 4 is specifically adapted in such a way that the interaction of the light per length along the propagation direction with the active elements 5 in the first arm 4a is just so much less in comparison to the second arm 4a that the absorbed power in both arms 4a is just identical. For this purpose, the waveguide cross-section in the first, left arm 4a is wider than in the second, right arm 4a. Thus, the optical mode in the first arm 4a is guided further inside the waveguide 4, reducing the interaction in the first arm 4a. In other words, the cross-sectional area in the region of the first, left arm 4a of the U-shaped waveguide section is larger than the cross-sectional area in the region of the second, right arm 4a. The ratio is chosen in such a way that half the power of the incident light is absorbed in the first, left arm 4a.

[0149] Apart from the fact that the detector 1 according to the invention of FIG. 3 has a waveguide with a U-shaped section and a second interaction region 2 with a second longitudinal waveguide section 3 and a second active element 5 as well as a third contact element, it can otherwise correspond to that according to FIG. 1. In particular, as far as the materials and the fabrication possibilities mentioned above in relation to FIG. 1 are concerned, there can be conformity with the arrangement of FIG. 1 or there is conformity. The detector 1 according to the invention in FIG. 3 is also arranged above a wafer 8 and a dielectric coat 13, and coats 14 and 15 are present, so that in this respect there is conformity with FIG. 2. In other words, in the embodiment shown, the detector 1 according to the invention is integrated in a semiconductor device comprising a wafer 8. This semiconductor device is an embodiment of a semiconductor device according to the invention. Such a device may comprise a plurality, for example several ten, several hundreds or even several thousands, of electro-optical devices according to the invention, which may be identical in design of different. From a semiconductor device according to the invention with a wafer 8, a plurality of semiconductor apparatuses according to the invention can be obtained by dicing, which is sufficiently known from the prior art, which semiconductor apparatus each can comprise a chip and one or more electro-optical devices according to the invention. The electro-optical device(s) according to the invention may be components of an integrated photonic platform.

[0150] Alternatively to a design in which the two spaced longitudinal waveguide sections 3 of the two interaction regions 2 may be located in the region of the two arms 4a of a U-shaped waveguide section, a bifurcation may also be provided. An embodiment of a corresponding photodetector 1 is shown in FIG. 4 in top view. As can be seen, the waveguide 4 comprises a bifurcation with two branching arms 4c, 4d and one of the longitudinal waveguide sections 3 of each of the two interactional regions 2 lies in the region of one arm 4c, 4d of the bifurcation here. Alternatively to space being provided within a U-shaped waveguide section for at least one inner contact element 7 serving as a signal contact, the space is provided here between the two bifurcation arms 4c, 4d. A splitter 16 is also provided with which an incoming light signal can be distributed to the two arms 4c, 4d of the bifurcation, namely in equal proportions. It is therefore a 50/50 splitter. The splitter can, for example, be designed as an MMI splitter or a directional coupler or comprise such a coupler.

[0151] The design with a bifurcation offers the advantage of symmetrical absorption. A different waveguide cross-section in the two arms 4c, 4d is therefore not necessary.

[0152] An embodiment of a photodetector 1 according to the second aspect of the invention is shown in FIG. 5. In contrast to the two embodiments shown in FIGS. 3 and 4, this embodiment does not comprise two separate interaction regions spaced apart from each other, but a continuous, at least substantially U-shaped interaction region 2. This interaction region 2 has—in analogy to FIG. 3—an at least substantially U-shaped longitudinal waveguide section 3 with two spaced-apart arms 4a and a connecting section 4b connecting the two arms 4a, and a likewise at least substantially U-shaped active element 5 with two spaced-apart arms 5a and a connecting section 5b connecting the two arms 5a. The longitudinal waveguide section 3 is, as can be seen, part of a waveguide 4, which is not annularly closed, but open.

[0153] The U-shaped active element 5 again comprises or consists of at least one electro-optically active material. In the embodiment according to FIG. 5, the active element 5 is also provided by a graphene film, whereby this is again to be understood purely by way of example. The active element extends in sections above the longitudinal waveguide section 3. Two contact elements 6 are also provided, each of which is in contact with the active element 5. Exactly one inner contact element 6 is provided, which is arranged inside the at least sectionally at least substantially U-shaped longitudinal waveguide section 3 and serves as an inner signal contact, and exactly one outer contact element 6 is provided, which is at least substantially U-shaped with two arms 6a spaced apart from one another and a connecting section 6b connecting the two arms 6a, and surrounds the U-shaped longitudinal waveguide section 3 on the outside. The two arms 6a of the outer contact element 6 each serve here, at least in sections, as an outer ground contact. As can be seen, the U-shaped outer contact element 6 completely surrounds the U-shaped active element 5, in other words over the entire extent of the U. The U-shaped longitudinal waveguide section 3 is almost completely embraced or enclosed.

[0154] Not only is there one interconnection element 7 associated with the outer U-shaped contact element, but this is in contact with a total of six such elements on the underside, as can be seen. A particularly uniform ground potential can be established via the several interconnection elements 7. The interconnection elements 7 are expediently arranged at a distance from each other, in particular evenly distributed over the extent of the outer contact element 6.

[0155] For the sake of completeness, it should be noted that it is of course possible that in the embodiment in FIG. 3, instead of the two separate outer contact elements 6, a continuous outer contact element 6 could be provided, which surrounds or encloses the U-shaped waveguide sections on the outside. For example, the U-shaped outer contact element 6 of FIG. 5 could be used with the detector 1 of FIG. 3. In an analogous manner, it is in principle possible that in the embodiment shown in FIG. 5, instead of the one U-shaped outer contact element, two separate outer contact elements 6 are provided, as shown in FIG. 3.

[0156] Also, in the embodiment shown in FIG. 5, it is preferably the case that the cross-sectional area of the waveguide 6 is larger in the region of the first, left arm 4a than in the region of the second, right arm 4a, in particular in such a way that half the power is absorbed in the first arm, for the same reasons as explained above in connection with FIG. 3. For the coupling of light into waveguide 4, a coupling device 17 is provided in each case, which is located at the left-hand end of the waveguide 4 in FIGS. 1, 3, 4 and 5. The modulator 1 is located at the other end of the waveguide 4, which is on the right hand side in each case in the figures. The waveguide ends behind the modulator respectively.

[0157] Alternatively to an electro-optical device 1 according to the invention being designed as a photodetector, such a device can also be an electro-optical modulator, for example. In that case, it differs from a photodetector substantially in that the interaction region or the respective interaction region comprises two active elements 5 or one active element 5 and a (conventional) electrode, for example comprising or consisting of titanium nitrite or indium tin oxide.

[0158] Examples of electro-optical modulators according to the invention can be taken from FIGS. 8 and 9. FIG. 6 shows—in analogy to FIG. 1—a top view of a conventional electro-optical modulator as known from the prior art. FIG. 7 shows a sectional view of the modulator from FIG. 6. In analogy to FIG. 2, this again is a component of a semiconductor device with a wafer 8.

[0159] As can be seen in particular in the sectional view in FIG. 7, the two active elements 5a, 5b are spaced apart from one another in the vertical direction and one active element 5a extends in sections above the other active element 5b. The distance can be 1 nm, for example. A further coat 18 comprising or consisting of a dielectric material is provided between the two active elements 5a, 5b, the thickness of which between the two active elements 5a, 5b is corresponding.

[0160] The two active elements 5 are furthermore, as can be seen well in the sectional view, arranged offset to each other in the horizontal direction in such a way that they lie one above the other in an overlap region in sections (with spacing in the vertical direction). The overlap region is located above the longitudinal waveguide section. For the embodiment according to the invention as shown in FIG. 8, it applies that in both interaction regions 3 the active elements are arranged correspondingly to each other and relative to the longitudinal waveguide section 3. For the embodiment according to FIG. 9, this applies to one U-shaped interaction region 2, namely over its entire extent. In the top views from FIGS. 6, 7 and 8 (and also FIGS. 10 to 12) the offset and sectional overlap of the active elements 5 is indicated by corresponding dashed lines.

[0161] In case of a modulator with two active elements or one active element and one electrode in the respective interaction region, it is expedient that the inner contact element or one of the inner contact elements 6 is in contact with the active element 5a of the interaction region or of the respective interaction region and the outer contact element or one of the outer contact elements 6 is in contact with the other active element 5b or the electrode of the interaction region or of the respective interaction region 2, or vice versa.

[0162] In the embodiment of FIG. 8, which corresponds in its remaining construction to that of FIG. 3, the inner contact element 6, arranged between the two longitudinal waveguide sections 3 of the two interaction regions 2, is in contact with an active element 5a, 5b of both interaction regions 2, specifically on opposite sides. With regard to the two outer contact elements 6, it applies here that these are each in contact with only one active element 5a, 5b of an interaction region 2.

[0163] In the embodiment in FIG. 9 with only one continuous, U-shaped interaction region 2, which corresponds in its other structure to that in FIG. 5, the inner contact element 6 is in contact with one 5a of the two active elements 5a, 5b and the one outer contact element 6 is in contact with the other 5b of the two active elements 5a, 5b. In each case this applies over the entire inner or entire outer circumference of the respective active element 5a, 5b.

[0164] An electro-optical modulator according to the invention can be used in particular for optical signal coding.

[0165] Since the light signal is not absorbed but modulated, coupling devices 17 are provided here at both ends of the waveguide 4 respectively. In operation, one of the coupling devices is used for coupling in and the other for coupling out an optical signal.

[0166] An electro-optical device 1 according to the invention can also be designed as a component of an interferometer, for example a Mach-Zehnder interferometer, for example a Mach-Zehnder interferometer serving as a phase modulator. This is particularly the case if the electro-optical device 1 is a modulator. Associated embodiments can be taken from FIGS. 11 and 12. FIG. 10 shows—again in analogy to FIGS. 1 and 6 with detectors and modulators known from the prior art—a Mach-Zehnder interferometer serving as a phase modulator with an electro-optical modulator known from the prior art (cf. FIG. 6).

[0167] As can be seen, the interferometer of FIG. 11 comprises a modulator 1 according to the invention of the configuration shown in FIG. 8 and the one in FIG. 12 comprises a modulator according to the invention of the configuration shown in FIG. 9. Both the interferometer of FIG. 10 and the interferometers of FIGS. 11 and 12 comprise, in addition to the modulators 1 of FIGS. 6, 8 and 9, respectively, a waveguide bypass section 19, which “bridges”, so to speak, the respective modulator and thus its interaction region 2 (FIGS. 10 and 12) or interaction regions 2 (FIG. 11), so that light originating in particular from the same source can be guided past the interaction region 2 or the two interaction regions 2 through the waveguide bypass section 19. As can be seen, the waveguide 4 is not an annularly closed waveguide, but has two open ends at which optical signals can be coupled in and out, specifically by means of the coupling devices 17.

[0168] In a manner known per se, the respective waveguide bypass section 19 forms one of two interferometer arms and the upper arm, in which the respective modulator is located, forms the second. The two interferometer arms have, as it is sufficiently known from the prior art, expediently different path lengths.

[0169] At the bifurcation points, from which the interferometer arms depart and rejoin, there is in each case a splitter 16, which can be designed, for example, as an MMI (multimode interferometer) or directional coupler or can comprise at least one such coupler. In particular, it can be a reciprocal MMI or a reciprocal directional coupler. This means that light coming from the side with one arm is divided in half between the two waveguide connections located on the opposite side of the MMI or directional coupler and vice versa, i.e. light coming from the side with two arms combined on the side with one connection.

[0170] At the input of the interferometer, optical signals are split and guided, for example, in two arms. Via an active component or several active components, shown in FIGS. 11 and 12 for one active component for example, a phase shift of the light propagating in both arms is generated. Active components can be located in all arms of an interferometer. At the output of the interferometer, the optical paths are merged and the light is superimposed. Constructive or destructive interference results from the phase position.

[0171] It should be noted that, as an alternative to coupling in and coupling out the optical signal from two opposite sides, as shown in FIGS. 8, 9, 11 and 12, the arrangement can in principle also be as shown in FIG. 13. Then the coupling in and coupling out can take place from the same side, which can be advantageous with regard to the coupling of optical fibers, which can be pre-assembled into groups in fiber blocks. For example, the waveguide 4 can be at least substantially U-shaped over all. In the high least simplified, purely schematic FIG. 13, this is shown as an embodiment of an electro-optical device 1 according to the invention, of which only one inner and two outer contact elements 6 are shown. As can be seen, the coupling devices 17 arranged at the two ends of the waveguide 4 are here adjacent to each other. Even though two separate outer contact elements 6 are shown here as an example, which corresponds to FIGS. 8 and 11, it is understood that the coupling in and coupling out from the same side, for example with the waveguide course shown in FIG. 13, can also be selected for the case of a U-shaped outer contact element 6, as can be seen in FIGS. 9 and 12.

[0172] The inventive G-S-G contact configuration of all above-described embodiments according to the invention offers the great advantage that high-frequency signals can be transmitted more interference-free to coplanar or coaxial arrangements.

[0173] For example, at least one connection device 20 can be provided for connection to a coaxial and/or coplanar conductor, as shown schematically in FIG. 14 in top view and in FIG. 15 in sectional view. The connection device 20 itself comprises three connection contact elements 21, specifically an inner connection contact element 21 serving as a ground contact and two outer connection contact elements 21, which are arranged on two sides of the inner contact element, thus practically enclosing it, and serve as signal contacts. This is therefore a G-S-G contact arrangement. It also has connection means, not further shown in the figure, for connecting a coaxial cable and/or a coplanar conductor.

[0174] The electrically conductive connection of an electro-optical device 1 according to the invention to a connection device 20 for connection to a coaxial and/or coplanar conductor can be realized, for example, by means of wires 22, as shown in FIG. 14. For this purpose, one free end of the respective wire 22 is in contact with one of the contact elements 6 of the electro-optical device 1 according to the invention and its other free end is in contact with one of the connection contact elements 21 of the connection device 20. The wires may in particular be made of metal, for example aluminium or gold.

[0175] As can be seen, the connection contact elements 21 of the connection device 20 diverge with their ends pointing upwards in the figure, which can serve to the generally larger dimensions of conventional coaxial cables or coplanar conductors.

[0176] Alternatively or in addition to a connection by means of wires 22, a bonding is also possible, as shown schematically in FIG. 15. In this case, a respective connection contact element 21 of the connection device 20 is arranged above a contact element 6 of a device 1 according to the invention or—as far as the embodiments from FIGS. 5, 9 and 12 with the continuous U-shaped outer contact element 6 are concerned—above one of the arms of the outer contact element 6. The electrically conductive connection is realized here via a bonding coat 23, via which the contact elements 6, 21 are bonded to each other. The bonding coat can consist of conductive adhesive, for example silver or gold.

[0177] It should be noted that the arrangement shown in FIGS. 14 and 15 with an electro-optical device 1 according to the invention and a connection device 20 for connection to a coplanar or coaxial conductor is an embodiment of an electro-optical arrangement according to the invention.