Integrated circuit, device and method for coupling and inputting optical signal into integrated circuit

Abstract

The invention relates to an integrated circuit (1) comprising:-a light input (2) which can be coupled to an optical fiber (3), the optical fiber (3) being capable of supplying a light signal (4) to the light input (2),-a controllable liquid crystal element (5) into which the light signal (4) can be coupled via the light input (2), characterized in that the controllable liquid crystal element (5) is capable of supplying the light signal (4) to the light input (2). The invention relates to a liquid crystal display device (1) comprising a liquid crystal element (5), an optical waveguide (6) arranged directly on the liquid crystal element (5), and a control device (7) which is designed to control the liquid crystal element (5) in such a way that a refractive index of the liquid crystal element (5) can be modulated, whereby an optical signal (4) can be coupled at least partially into the optical waveguide (6). The invention further relates to a device (4) and to a method.

Description

Technical Field

[0001] The present invention relates to an integrated circuit having an optical input end, which can be coupled to an optical fiber, wherein an optical signal can be provided to the optical input end by the optical fiber. In addition, the integrated circuit has a controllable liquid crystal element, and the optical signal can be coupled into the controllable liquid crystal element through the optical input end.

[0002] Furthermore, the invention relates to a device having an integrated circuit and at least one optical fiber.

[0003] The invention further relates to a method for coupling an optical signal into an integrated circuit, wherein an optical fiber is coupled to an optical input of the integrated circuit, wherein the optical signal is provided by means of the optical fiber. The optical signal is coupled into a controllable liquid crystal element of the integrated circuit. Background Art

[0004] For example, WO 2013 / 115995 A1 discloses a device and system for actively guiding a light beam from an optical fiber to an optical waveguide integrated on a chip using one or more liquid crystal layers for optical alignment. An on-chip feedback mechanism can guide the light beam between the optical fiber and the grid-based waveguide to minimize the embedded attenuation of the system.

[0005] US2016 / 0 202 420A1 discloses an active optical coupling system. The active optical coupling system has a photonic chip having a photonic integrated circuit arranged thereon, wherein the photonic integrated circuit waveguide element includes an intermediate coupling element arranged on the waveguide element. Refraction of a liquid crystal element optically coupled to the waveguide element through the intermediate coupling element is provided, wherein the liquid crystal element has a first surface for receiving light and a second surface opposite to the first surface for outputting the received light.

[0006] In addition, US2015 / 0 156 661A1 discloses an optical circuit having an optical fiber array composed of solid-state waveguides, which performs beam steering of an optical signal. The optical radiation includes a modulator for modulating a bit sequence onto a carrier sequence of the optical signal. The beam-steering signal includes the modulated bit sequence. The optical circuit may have a photodetector. Summary of the invention

[0007] The technical problem to be solved by the present invention is to improve the coupling input of optical signals into an integrated circuit by increasing the coupling tolerance.

[0008] The above technical problem is solved by the integrated circuit, the device and the method according to the present invention. Advantageous embodiments are apparent from the following description.

[0009] One aspect of the present invention relates to an integrated circuit having:

[0010] - in particular an optical input which can be coupled to an optical fiber, wherein an optical signal can be provided to the optical input by means of the optical fiber,

[0011] - in particular a controllable liquid crystal element, a light signal can be coupled into the controllable liquid crystal element via the light input,

[0012] It is characterized in that

[0013] - in particular an optical waveguide which is arranged directly on the liquid crystal element,

[0014] In particular, the control device is designed to control the liquid-crystal element in such a way that the refractive index of the liquid-crystal element can be modulated, as a result of which the optical signal can be coupled at least partially into the optical waveguide.

[0015] The integrated circuit according to the invention makes it possible to improve the coupling of optical signals or optical beams into the integrated circuit, since, with the aid of a controllable liquid crystal element, effective coupling can be achieved independently of the position between the optical fiber and the optical waveguide. With the aid of a controllable liquid crystal element, the coupling tolerance or the tolerance with respect to the coupling can be increased. This makes the coupling easier and, in particular, reduces the time and costs for coupling in optical signals.

[0016] The integrated circuit can be an electronic-photonic co-integrated circuit. For this purpose, the principle of electronic-photonic co-integration in the chip can be used. Here, a silicon-on-insulator region for photonic components and a bulk silicon region for electronic circuits can be used in one technology. This has the advantage, in particular, that a high signal quality with low parasitic interference effects can be achieved at high data rates. The connection of a high-frequency circuit (including a frequency multiplier) for a radar antenna to an optical transceiver, for example, can be achieved without additional wires or flip-chip bonding. The optical circuit used here is integrated into a semiconductor, so that multiple optical signal transmission and logic circuits are used in the field of data centers, but also in the fields of telecommunications, radar technology and analog optical computing (Analogen-optischen-Computing, "AOC"). This can be an application field for the integrated circuit according to the invention.

[0017] For example, the circuit according to the invention may be more advantageous than "fiber-to-chip coupling". In this "fiber-to-chip coupling", in order to transmit signals from the optical fiber to the chip, the distance between the optical fiber and the coupling input point on the chip must be very small, so that the optical fiber output is mapped to the coupling structure. In addition, three spatial angles, namely the roll angle, the yaw angle and the pitch angle, must be adjusted with high precision according to the coupling structure. This requires complex technology. These problems can be solved by the integrated circuit and the controllable liquid crystal element according to the invention.

[0018] Another possibility for coupling in the prior art is "edge coupling", in which the distance between the end of the optical fiber with the core and the waveguide located on the semiconductor is very small, so that the electromagnetic radiation can be mapped onto the waveguide after being emitted at the end of the optical fiber and can be coupled into the semiconductor. Another possibility for coupling in is "grating coupling", which couples the fiber to the chip with the help of a grating coupler. In this case, the optical fiber is connected at a certain angle to the surface normal. The grating structure, which couples the electromagnetic radiation into the semiconductor integrated waveguide, is located on it. For example, the beam deviation and the resulting coupling losses can be measured by means of an LC element (“Liquid Crystal Element”). In the measurement, it can be determined that the LC element is integrated into the collimator and the fiber bundle is coupled into the integrated photonic circuit by “edge coupling”. In this case, structures composed of discrete components can be used. In this case, losses can occur due to incorrect positioning and due to lateral beam displacements caused by refractive index modulation in the LC element.

[0019] When using conventional integrated circuits, the possibilities of coupling in optical signals just mentioned present considerable problems. The present invention can advantageously solve the problem mentioned below of coupling the mentioned technology into conventional integrated circuits. In contrast to known methods, with the aid of the present integrated circuit, the precise positioning between the optical fiber and the coupling structure can be omitted. The mentioned method requires a "mode matching" of the emitted radiation and the coupling structure in order to transmit the radiation into the chip as losslessly as possible. To this end, the spatial intensity distribution must be modulated. This can be avoided in the integrated circuit according to the present invention. In addition, compared with the present invention, the mentioned methods have an increased cost overhead because these methods require discrete imaging optics. In addition, the present invention provides the advantage that the tolerance of the angular acceptance of the coupling input with minimal losses between the optical fiber and the chip can be increased. In contrast to the prior art, which is generally only able to achieve an angular acceptance between 7 degrees and 9 degrees. Another problem is the high quality of the positioning of the optical fiber relative to the chip, i.e., the adjustment time of the optical fiber to the chip coupling is currently automatically 60 seconds per application, which is considered to be a bottleneck for large-scale production. This can also be advantageously solved by the present invention. With the aid of the integrated circuit, an automated connection of an optical fiber to a photonic or electronic-photonic semiconductor can be performed or realized with a high coupling-in tolerance. In addition, an increase in the coupling-in speed can be realized for mass production.

[0020] So far, especially in single-mode optical fibers, due to the small core diameter, the coupling of optical signals, for example from optical waveguides to photonic structures on semiconductors, is extremely sensitive to translations in the x, y, z directions, but also extremely sensitive to rotations ("pitch", "roll", "yaw") and polarization. These problems can be solved by the integrated circuit according to the present invention. In addition, the problem in the coupling methods so far is that high-precision positioning is required to adjust all 6 degrees of freedom. Here, the positioning is optimized in an iterative method. These methods are extremely time-consuming, so the investment in these machines may be high, and the time required for production may become longer. Here, the integrated circuit according to the present invention advantageously intervenes and can provide a remedy here. The present integrated circuit uses the "Liquid Crystal" (LC) method or the "Liquid Crystal on Silicon" (LCOS) structure to produce a spatially and / or rotationally tolerant coupling structure, so that the optical fiber can be placed on the chip or circuit basically at will. Therefore, the coupling can be carried out or executed more efficiently, at a lower cost and more simply.

[0021] The present invention provides the following advantages, namely, a higher degree of miniaturization can be achieved at the chip level, and the chip surface can be reduced compared to traditional electronic devices or Epic technology. In addition, the amplitude of the coupled-in radiation can be modulated. The polarization of the coupled-in radiation can also be modulated. The optical fiber of the coupled-in radiation and the wavelength of the coupled-in radiation can also be modulated. In addition, the integrated circuit can be integrated on a semiconductor chip with CMOS-SIN-SMOS-WI-CMOS-Hybrid-BI-CMOS, LIND, INP processes on a photon-electronic co-integrated chip. In addition, the integrated circuit can be used for multi-chip solutions or flip-chip solutions. In addition, a liquid crystal element (LCOS) on a silicon substrate can also be used to replace the liquid crystal element.

[0022] With the help of integrated circuits, an increase in the coupling tolerance in the "fiber-to-chip" alignment in translation (x, y, z) and rotation (pitch, roll, yaw) can be achieved. In addition, an increase in automated fiber-to-chip applications from the current 60 seconds to the single-digit second range (e.g. 5 seconds) can be achieved. The influence of environmental factors (e.g. additional temperature) caused by incorrect coupling can also be corrected by an active feedback loop in the LC element in order to actively optimize the coupling performance. In particular, the proposed integrated circuit can bring cost advantages because the coupling is simplified many times. In the liquid crystal element, which is also called LC element, it can also be integrated in the following integrated circuit, which can be a photonic integrated semiconductor circuit (PC). The optical fiber can be coupled or connected to the liquid crystal element. In this case, imprecise coupling or positioning can be performed. The radiation or optical signal of the optical fiber can be coupled into the liquid crystal element and propagated inside it. The optical waveguide can be located below the liquid crystal element. Instead of the optical waveguide, a coupling structure can also be used for optical coupling. With the aid of a control device, the refractive index of the liquid crystal element can be changed or adjusted so that radiation or light signals can be coupled into an optical waveguide or waveguide integrated in the integrated circuit. The controllable liquid crystal element can act similarly to a lens element so that the input light beam can be coupled in accordingly. The integrated circuit according to the invention can be used in a vehicle, in particular a motor vehicle. In this case, the integrated circuit can be used in driver assistance systems, such as parking assistance, radar-based environmental detection or automatic or autonomous driving systems.

[0023] Other fields of application of integrated circuits are use in quantum computers, containers, warehouse robots, logistics systems, "Big Data", cloud services, mobile phones or server facilities. For example, an integrated circuit can have a plurality of optical inputs, a plurality of controllable liquid crystal elements, a plurality of optical waveguides and at least one control device.

[0024] The control device may be an electronic control unit, such as a control device. In particular, the control device may be a microcontroller. With the aid of the control device, the refractive index of the liquid crystal element may be modulated or changed by controlling the liquid crystal element, so that the optical signal may be coupled into the optical waveguide depending on the type or positioning of the optical fiber. Thus, the liquid crystal element may be used as an intermediate piece or intermediate element between the optical input end and the waveguide.

[0025] In one embodiment, it is provided that the liquid crystal element has a plurality of electrodes, which are arranged in and / or on the liquid crystal element. The liquid crystal element is controlled by applying a voltage to the electrode or changing the voltage on the electrode, wherein the refractive index can be modulated according to the voltage. According to the application, in particular according to the design of the integrated circuit, the number of electrodes of the liquid crystal element can be predetermined or defined. Here, the electrode can be arranged or positioned inside or outside the liquid crystal element. For example, the electrode can be coupled or connected to a control device, so that the applied voltage can be changed or adjusted by means of the control device. The voltage applied to the electrode can also be disconnected or applied again. Depending on what kind of coupling input is to be performed and how the optical fiber associated with the integrated circuit is positioned, a voltage level or voltage size can be set or predetermined. The refractive index can be modulated according to the voltage. Therefore, there is a relationship or dependence between the applied voltage and the refractive index. Therefore, different coupling inputs can be performed by applying the voltage required accordingly to the electrode. In addition, here, a controllable matrix can be predetermined for a plurality of electrodes, and the plurality of electrodes can be controlled by the control device.

[0026] For example, the voltage-refractive index ratio can be given in a table such as a "look-up table".

[0027] By means of a variable voltage, and thus by means of modulation of the refractive index, it is possible to dispense with the exact or precise positioning of the optical fiber with the integrated circuit or the optical input. For example, an optical signal can be provided by means of an optical fiber and transmitted to the optical input. Here, for example, the optical fiber end of the optical input can be at least partially, in particular completely, placed on the liquid crystal element and, if necessary, bonded to the liquid crystal element. The optical signal is emitted from the optical fiber and can propagate inside the liquid crystal element, in particular in the material of the liquid crystal element. With the aid of a control unit and electrodes, the orientation of the molecules of the liquid crystal element can be changed by means of electronic switching, so that electromagnetic radiation or optical signals are coupled into a coupling structure, such as an optical waveguide or a "grating coupler", located below the liquid crystal element. The electromagnetic radiation or optical signal propagates through the coupling structure of the optical waveguide and is coupled into the optical waveguide of the integrated circuit.

[0028] By applying a voltage to the electrodes or changing the voltage on the electrodes, a refractive index matching (index-matching) can be performed or realized within the liquid crystal element, so that radiation or an optical signal is coupled from the liquid crystal element into an optical waveguide located underneath.

[0029] In one embodiment, it is provided that a feedback loop is provided, which is constructed to adjust the voltage applied to the electrode based on the optical signal coupled into the optical waveguide. The feedback loop can be referred to as a "feedback loop", for example. Therefore, since the corresponding adjustment is used, a continuous improvement of the coupling input can be achieved. Here, a control device can be used advantageously again. With the help of the feedback loop, therefore, with the help of feedback, the offset of the radiation or optical signal on all three axes (i.e., the x-axis, the y-axis, and the z-axis) and the three spatial angles can be changed so as to be able to carry out the best or improved coupling input into the integrated circuit or semiconductor. For this purpose, the feedback loop of the integrated circuit or the electro-optical feedback loop can be used, which can, for example, adjust the electrode for refractive index modulation, i.e., for modulating the refractive index. With the help of the feedback loop, even if the fiber-to-chip connection is not accurate, the optimal coupling input of the optical signal in the x, y, and z directions and the roll angle, pitch angle, and yaw angle in the optical waveguide can be adjusted. In addition to the optical connection between the optical fiber and the liquid crystal element, an electrical connection can also be used. The liquid crystal element can be bonded to the integrated circuit. The liquid crystal element can also be constructed as “liquid crystal on silicon” (LCOS). Furthermore, the integrated circuit can be an EPIC chip with integrated LCOS.

[0030] Furthermore, it is conceivable that the optical waveguide is arranged at different positions or on different sides of the liquid crystal element. For example, coupling-in can be carried out in the upper substrate. Here, the total internal reflection limit (total internal reflection grenze, TIR) can be used. The total internal reflection limit is, for example, glass-air and glass-liquid crystal, and by changing the liquid crystal orientation, the refractive index Δ of the glass-liquid crystal can be controlled to enable, for example, coupling-in into the grid. Since the liquid crystal element is scattering, this embodiment can be used advantageously.

[0031] In one embodiment, it is provided that the integrated circuit has an optical distributor, by means of which the optical signal coupled into the optical waveguide can be provided to the feedback loop and the functional units of the integrated circuit. For example, the functional units can provide the control device, the control device or the output of the integrated circuit accordingly based on the information of the coupled-in optical signal. Thus, by means of the optical distributor, in particular the control device can provide corresponding information about the quality or quality of the coupled-in optical signal, so that the voltage on the electrode can be adjusted accordingly, so that the coupling-in can be continuously improved.

[0032] Additionally or alternatively, the integrated circuit has a photodiode, with which the optical signal can be converted into a corresponding electrical signal before it can be supplied to the feedback loop. The feedback loop is in particular an electronic feedback, so that the optical signal must be converted photoelectrically. In particular, the control device also requires electrical signals in order to be able to control and / or regulate the electrodes, in particular the liquid crystal element.

[0033] The photodiode may be, for example, a phototransistor or a photoelectric converter unit.

[0034] In one embodiment, it is provided that the electrodes of the liquid crystal element are arranged in and / or on the liquid crystal cell with a predetermined electrode structure. Depending on the application area of ​​the integrated circuit and the possible or to-be-performed coupling-in processes, the electronic structure can be defined or predetermined accordingly. In particular, the electrode structure is designed so that, depending on the application, in particular depending on the coupling-in to be performed, a corresponding modulation of the refractive index can be achieved by the voltage applied to the electrodes. Different electrode structures are conceivable here. In particular, matrix control can be provided for the individual electrodes.

[0035] Additionally or alternatively, the electrodes may be uniformly distributed in or on the liquid crystal element. For example, the electrodes may always be uniformly distributed on two opposite sides, so that the refractive index can be modulated accordingly according to the current situation or circumstances.

[0036] In one embodiment, it is provided that a coupling unit is arranged between the optical input and the liquid crystal element, wherein the coupling unit is designed to couple the optical signal of the optical fiber into the liquid crystal element independently of the positioning of the optical fiber relative to the integrated circuit. In other words, by means of the coupling unit, a coupling aid or an aid can be provided, so that a simple, cost-effective and uncomplicated positioning of the optical fiber relative to the integrated circuit can be achieved and the optical signal can be coupled into the liquid crystal element in any case, that is, regardless of the positioning of the optical fiber.

[0037] Another aspect of the invention relates to an arrangement having an integrated circuit according to the above-mentioned aspect or an advantageous development thereof and at least one optical fiber, wherein the optical fiber is coupled to an optical input of the integrated circuit in order to transmit an optical signal of the optical fiber to the integrated circuit. The proposed arrangement can thus be an integrated situation or an installation situation of the integrated circuit in the possible application fields of the integrated circuit already mentioned above. In particular, the integrated circuit can be coupled to a plurality of optical fibers, and in this case an optical input can be provided for each optical fiber.

[0038] In this case, the optical fiber can be positioned at the light input by means of automated equipment and then coupled.

[0039] Another aspect of the invention relates to a method for coupling an optical signal (4) into an integrated circuit (1), the method comprising:

[0040] - in particular coupling the optical fiber (3) to the optical input (2) of the integrated circuit (1), wherein the optical signal (4) is provided by means of the optical fiber (3), and

[0041] - in particular coupling the optical signal (4) into a controllable liquid crystal element (5) of the integrated circuit (1),

[0042] It is characterized in that

[0043] - controlling the liquid crystal element (5), in particular by means of a control device (7) of the integrated circuit (1), so that the refractive index of the liquid crystal element (5) is modulated, and

[0044] - In particular, the optical signal (4) is coupled from the liquid crystal element (5) into an optical waveguide (6) of the integrated circuit (1) as a function of the modulated refractive index.

[0045] In particular, the method described above can be used to couple optical signals into an integrated circuit according to one of the aforementioned aspects or an advantageous development thereof. The coupling of the optical fiber to the optical input or the positioning of the optical fiber to the optical input can be performed manually or automatically. Based on the modulated refractive index of the liquid crystal element achieved by controlling the liquid crystal element, the optical signal can be coupled to the optical waveguide of the integrated circuit independently of the positioning or position quality or coupling quality.

[0046] In particular, the aforementioned integrated circuit or the aforementioned apparatus of the aforementioned aspect may have components for implementing the method just described.

[0047] In one embodiment of this further aspect, it is provided that the optical signal is coupled into the liquid crystal element so that the optical signal propagates in the material of the liquid crystal element. In other words, the coupled optical signal or optical radiation can diffuse or expand in the liquid crystal element. Depending on the degree to which the liquid crystal element is controlled, the refractive index can be modulated and the optical signal propagating in the liquid crystal element can be coupled into the optical waveguide.

[0048] In another embodiment of this another aspect, it is provided that, when controlling the liquid crystal element, a voltage is applied to a plurality of electrodes of the liquid crystal element or the voltage on the electrodes is changed, thereby changing the orientation of the molecules in the liquid crystal element so as to modulate the refractive index. Therefore, here, the refractive index is modulated or modulated according to the voltage. With the aid of the applied or changed voltage and the molecules of the liquid crystal element after the molecular orientation is changed, the optical signal propagating in the liquid crystal element can be coupled into the optical waveguide.

[0049] Advantageous embodiments of one aspect of the invention may be regarded as advantageous embodiments or configurations of all other aspects, and vice versa.

[0050] For use cases or usage scenarios that can be obtained in the method but are not explicitly described here, it can be provided that, according to the method, error messages and / or requests for input of user feedback are output and / or default settings and / or predetermined initial states are set.

[0051] The present invention also includes extensions of the device according to the present invention and of the method according to the present invention, which have the features already described in conjunction with the extension of the integrated circuit according to the present invention. For this reason, the corresponding extensions of the device according to the present invention and of the method according to the present invention are not described again here.

[0052] The invention also includes combinations of features of the described embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The embodiments of the present invention are described below. To this end:

[0054] Figure 1 shows a schematic cross-sectional view of an integrated circuit with a controllable liquid crystal element;

[0055] Figure 2 A schematic diagram showing the coupling of an optical signal into a liquid crystal element, which in turn can couple the optical signal into an underlying waveguide by means of refractive index modulation;

[0056] Figure 3 shows the integrated circuit of the previous figures with an additional electronic feedback loop for controlling the coupling-in of the optical signal;

[0057] Figure 4 shows a schematic side view of the integrated circuit from the previous figures, wherein electrodes of a liquid crystal element are shown here, by means of which a voltage can be applied in order to achieve a refractive index modulation;

[0058] Figure 5 based on Figure 4 An embodiment is shown in which a voltage is applied to the electrodes and an optical signal is coupled into the waveguide from the liquid crystal element;

[0059] Figure 6 Another arrangement of electrodes of a liquid crystal element is shown;

[0060] Figure 7 Another possible coupling input situation between the optical fiber and the integrated circuit is shown;

[0061] Figure 8Another conceivable coupling input situation between an optical signal in an integrated circuit and an optical fiber is shown;

[0062] Fig. 9 Another schematic cross-sectional view of the integrated circuit in the previous figure is shown, wherein an optical fiber connector (Fasertapper) is provided here to facilitate the coupling input between the optical fiber and the integrated circuit;

[0063] Fig.10 based on Fig. 9 A possibility of facilitating input coupling by means of an additional structure between the optical fiber and the integrated circuit is also shown;

[0064] Fig.11 Another schematic transverse cross-sectional view of an integrated circuit is shown, wherein a prism coupler may be provided here to facilitate coupling of optical signals into the integrated circuit;

[0065] Fig.12 based on Fig.11 Another embodiment of a prismatic coupler is shown, wherein here the prismatic coupler has an additional highly reflective layer;

[0066] Fig.13 Another schematic cross-sectional view of an integrated circuit is shown, wherein a block coupler is provided here to facilitate the coupling input of an optical fiber into the integrated circuit; and

[0067] Fig.14 A further conceivable embodiment of an integrated circuit is shown, wherein here the liquid crystal element has a structured electrode arrangement in order to allow a targeted refractive index modulation. DETAILED DESCRIPTION

[0068] The embodiments described below are preferred embodiments of the present invention. In these embodiments, the components described are correspondingly individual features of the present invention that should be considered independent of each other, and these features also expand the present invention independently of each other, and therefore can also be considered as components of the present invention individually or in a combination different from the combination shown. In addition, the described embodiments can also be supplemented by other features of the features of the present invention that have been described.

[0069] In the figures, functionally identical elements are correspondingly provided with the same reference symbols.

[0070] exist Figure 1, in particular in a transverse cross-sectional view, shows a schematic diagram of an integrated circuit 1 or a semiconductor. The integrated circuit 1 can have an optical input 2 for providing an optical signal or optical radiation. For example, an optical fiber 3 can be positioned or coupled at the optical input. In turn, an optical signal 4 can be provided or supplied to the input 2 of the integrated circuit 1 by means of the optical fiber 3. Thus, the optical signal 4 can be coupled in here. The coupled in or provided optical signal 4 can in turn be coupled in to a controllable liquid crystal element 5.

[0071] The liquid crystal element 5 can be a "liquid crystal element" or a "liquid crystal on silicon" element. In this case, the optical signal 4 can be coupled into the liquid crystal element so that it propagates in the material of the liquid crystal element or inside the liquid crystal element 5. In this case, firstly, the positioning of the optical fiber 3 relative to the optical input end or the integrated circuit is not important, because the coupling into the liquid crystal element 5 is first performed. Now, in order to provide the optical signal 4 in the integrated circuit 1 or to provide other functions and / or circuits there, such as in Figure 1 As schematically and exemplarily shown in the figure, an optical waveguide 6 or a coupling structure can be arranged immediately below the liquid crystal element 5. As will be further explained in the following figures, it can be arranged at different positions or on different sides of the liquid crystal element 4. The optical waveguide 6 is used in particular to conduct or distribute optical signals within the integrated circuit 1. In order to be able to couple the optical signal 4 of the optical fiber 3 into the optical waveguide 6 independently of the positioning of the optical fiber 3 relative to the integrated circuit 1, the liquid crystal element 5 is controllable or controllable. For this purpose, the integrated circuit 1 can have a control device 7 (see Figure 3 ), such as a microcontroller or other control unit.

[0072] The liquid crystal element 5 can be controlled or driven by means of the control device 7 so that the refractive index of the liquid crystal element can be modulated or changed. By means of this refractive index modulation, in particular, the optical signal 4 propagating inside the liquid crystal element 5 can be coupled into the optical waveguide 6 in a targeted manner. In order to modulate the refractive index, the orientation of the molecules 8 of the liquid crystal element 5 can be changed.

[0073] For example, the integrated circuit 1 and the optical fiber 3 can be bundled or combined into a device 9. The device 9 thus has an integrated circuit 1 and at least one optical fiber 3. Such a device 9 can be used, for example, in radar technology, telecommunication technology, automotive technology, quantum computer technology or other application fields of integrated circuits and optical signals.

[0074] Now, in the next Figure 2 In, based on Figure 1 It is shown that the liquid crystal element 5 is controlled so that at least some of the molecules 8 change their orientation and the refractive index of the liquid crystal element 5 is modulated accordingly. Figure 2 As can be seen in the figure, the optical signal 4 or radiation propagating inside the liquid crystal element 5 can be coupled into the optical waveguide below it, thereby providing the optical signal 4 to the integrated circuit 1, without the need for complex, costly and time-consuming coupling between the optical fiber and the integrated circuit.

[0075] In particular, the figure shows an exemplary fiber coupling of an optical fiber 3 by means of a liquid crystal element 5. By modulating the refractive index in the liquid crystal element 5 or LC element, refractive index matching can be achieved so that the radiation or optical signal 4 from the liquid crystal element 5 is coupled into the semiconductor or optical waveguide 6 below it. The modulation of the refractive index can be achieved, for example, by applying an electrode 10 (see Figure 4 ) is performed by applying a voltage.

[0076] exist Figure 3 1 shows the already mentioned and described integrated circuit 4 with a feedback loop 11. In order to be able to improve the coupling input of the optical signal 4 into the waveguide 6, the optical signal 4 can be divided after being coupled in. For this purpose, an optical distributor 12 can be provided. The optical distributor 12 can be, for example, a "beam splitter structure". A part of the optical signal 4 can be provided or supplied to a functional unit 13 of the integrated circuit 1, for example. The functional unit 13 can be a chip function associated with the integrated circuit 1. Here, the corresponding signal, for example, a converted electrical signal can be provided to other functions. It is also conceivable to provide such a divided and converted electrical signal on the integrated circuit 1 or in a separate component. Here, the corresponding signal can be transmitted or forwarded by means of an electrical connection or an optical connection. Regarding the feedback loop 11 or feedback, an optical photodiode 14 can be provided after the distributor 12. With it, the optical signal 4 can be converted into an electrical signal 15, which in turn can be provided to the control device 7. Based on the electrical signal 15, adjustments related to the modulation of the refractive index can be performed. To this end, the electrode 10 can be controlled accordingly to change or modify the voltage applied to the liquid crystal element 5 .

[0077] Furthermore, an electrical output 16 can be provided, by means of which the electrical signal 15 can be transmitted or made available to a central evaluation unit or computing unit.

[0078] In particular, by means of the feedback loop 11, an optimal coupling input of the optical signal 4 into the waveguide 6 can be automatically adjusted or regulated in imprecise fiber-to-chip applications.

[0079] exist Figure 41 shows another illustration of the integrated circuit 1 already described in the previous figures. Here, the electrode 10 can be seen. A voltage can be applied to the electrode 10 or the voltage on the electrode 10 can be changed in order to be able to modulate the refractive index or modulate the refractive index depending on the voltage level or the voltage level. In this case, in this embodiment, the electrodes 10 can be arranged vertically distributed. In addition, the optical waveguide 6 is shown here as a grating coupler.

[0080] In particular, currently Figure 4 In the illustration in FIG. , no voltage is applied, so the optical signal 4 propagates without modulating the refractive index in the liquid crystal element 5. Figure 4 ,exist Figure 5 , in which a predetermined or set voltage is now applied to the electrode 10. Correspondingly, the refractive index is modulated here so that a refractive index matching can be achieved, so that the optical signal 4 or radiation from the liquid crystal element 5 can be coupled into the semiconductor located below it, for example, the optical waveguide 6 here. For example, the liquid crystal element 5 can be surrounded by a substrate 17 (see Figure 4 ).

[0081] exist Figure 6 , another embodiment or another illustration of a fiber coupling in connection with an integrated circuit 1 is shown. Here, the electrodes are now only located in one plane, for example here on the side of the liquid crystal element 5 facing the waveguide 6. Here, as can be seen, a refractive index modulation can again be carried out by applying a voltage, wherein the orientation of the molecules 8 changes and, correspondingly, the light signal 4 can be coupled into the waveguide 6.

[0082] In the next Figure 7 and Figure 8 1 shows the integrated circuit 1 in the case of fiber coupling, wherein a voltage is applied here again to couple the optical signal 4 into the waveguide 6. Figure 7 and Figure 8 , a vertical coupling-in of an optical signal 4 from an optical fiber 3 into an integrated circuit 1 is shown. In other words, here, the fiber coupling-in is performed by means of a coupling-in at, for example, 90° relative to the chip surface of the integrated circuit 1.

[0083] As already mentioned several times at the outset, the coupling between the optical fiber and the integrated circuit 3 can therefore be carried out in any desired manner, since the actual coupling of the optical signal takes place via the controllable or activatable liquid crystal element 5 .

[0084] In the next Figures 9 to 13, in particular fiber coupling, are shown in the figures. In this case, an additional coupling unit 18 is provided in these figures, which can be arranged, for example, at the light input or between the optical fiber 3 and the liquid crystal element 5. With the aid of the coupling unit 18, the optical signal 4 of the optical fiber 3 can be coupled into the liquid crystal element 5 independently of the positioning of the optical fiber relative to the integrated circuit 1. Therefore, the coupling unit 18, which can be designed differently as described in the following figures, is used to simplify or improve the coupling of the optical signal 4 and the optical fiber 3 into the integrated circuit.

[0085] exist Fig. 9 In the embodiment, the coupling unit 18 can be a fiber optic connector 19. For example, such a fiber optic connector 19 can be referred to as a "connector", "GLOW" or "connector". Fig. 9 As schematically shown in FIG. 1 , the optical fiber connector 19 has a function of gradually becoming thinner, thereby facilitating the coupling input of the optical signal 4 .

[0086] exist Fig.10 In the embodiment, the coupling unit 18 is constructed as an additional structure 20, which can be arranged in front of the light input end 2, for example. The structure 20 can be, for example, a "V-shaped groove", a "U-shaped groove", a microstructure or a nanostructure. It is also used to facilitate coupling input.

[0087] exist Fig.11 In the embodiment, the coupling unit 18 is designed as a prism coupler 21. Fig.11 As exemplarily shown in FIG. 1 , the prism coupler 21 may be arranged on a side of the liquid crystal element 5 opposite to the waveguide 6. In other words, as shown here in Fig.11 As shown in FIG, the prismatic coupler 21 can be arranged on the surface of the integrated circuit 1, ie the surface seen from above. By means of the prismatic coupler 21, which can have a large surface or size, the coupling-in of the optical signal 4 of the optical fiber 3 can be facilitated.

[0088] exist Fig.12 , another design of the coupling unit 18 is shown. This is a prism coupler 22 that additionally has a high reflection layer (HR coating). As a result, the optical signal 4 coupled into the prism coupler 22 can be guided or radiated to the liquid crystal element 5 accordingly. Instead of the HR coating, the prism coupler 22 can have a grid structure.

[0089] exist Fig.13 In the embodiment, a block coupler 23 is provided as a coupling unit 18. The block coupler 23 also facilitates the coupling of the optical signal 4 from the optical fiber 3 into the liquid crystal element 5. The block coupler 23 may, for example, have two different regions 24 and 25, which may have different refractive indices, so that the coupled optical signal 4 can be coupled from the block coupler 23 into the liquid crystal element 5 in the simplest way.

[0090] The optical fiber 3 may be, for example, a glass optical fiber.

[0091] exist Fig.14 2 shows a further embodiment of an integrated circuit 1, in particular a fiber-coupled embodiment. Here, there may be a different arrangement between the liquid crystal element 5 and the waveguide 6 than in the previous figures. In particular, Fig.14 , a view from above the chip surface of the integrated circuit 1 is shown. In this case, the liquid crystal element 5 can be designed as a planar element, and the waveguide 6 or the coupling structure is arranged above the liquid crystal element 5, in particular in the middle. In the electrode structure 26, the electrode 6 can in turn be arranged around the waveguide 6. This makes it possible to realize a lens or prism structure, i.e. a two-dimensional structure, so that any coupling input can be performed by modulating the refractive index of the liquid crystal element 5. In this case, the electrodes 10 can be arranged differently and interconnected with each other. The electrodes 10 can be controlled, for example, by means of a control device via a bus system, such as a communication bus 27. In particular, in Fig.14 , in which a structured electrode arrangement or structure 26 is present in order to be able to form a lens or a grid in the liquid crystal element 5 . This enables an adapted and arbitrary coupling from the liquid crystal element 5 into the waveguide 6 .

[0092] in particular, Fig.14 This embodiment in offers the advantage that a continuously variable lens or prism can be produced steplessly, so that the optical signal 4 can be coupled back into the waveguide 6 in this way.

[0093] In particular, the embodiments in the figures show improved fiber-to-chip coupling.

[0094] Reference numerals list

[0095] 1 Integrated Circuit

[0096] 2 Optical input port

[0097] 3 Fiber Optics

[0098] 4 light signals

[0099] 5 Liquid crystal element

[0100] 6 Optical waveguide

[0101] 7 Control Devices

[0102] 8 molecules

[0103] 9. Installation

[0104] 10 Electrodes

[0105] 11 Feedback Loop

[0106] 12 Optical Distributor

[0107] 13 Functional Units

[0108] 14 Photodiode

[0109] 15 Electrical signal

[0110] 16 Output

[0111] 17 Structure

[0112] 18 Coupling unit

[0113] 19 Connectors

[0114] 20 Additional Structure

[0115] 21 Prism Coupler

[0116] 22 Prism coupler with additional HR coating

[0117] 23 couplers

[0118] 24, 25 coupler area

[0119] 26 Electrode structure

[0120] 27 Communication bus

Claims

1. An integrated circuit (1), comprising: - an optical input end (2), which can be coupled to an optical fiber (3), wherein The optical fiber (3) can provide an optical signal (4) to the optical input end (2). a controllable liquid crystal element (5), into which the optical signal (4) can be coupled via the optical input end (2), It is characterized in that - an optical waveguide (6) arranged directly on the liquid crystal element (5), A control device (7) is designed to control the liquid crystal element (5) so that the refractive index of the liquid crystal element (5) can be modulated, thereby at least partially coupling the optical signal (4) into the optical waveguide (6).

2. The integrated circuit (1) according to claim 1, It is characterized in that The liquid crystal element (5) has a plurality of electrodes (10), which are arranged in and / or on the liquid crystal element (5), wherein the liquid crystal element (5) is controlled by applying a voltage to the electrodes (10) or changing the voltage on the electrodes (10), wherein the refractive index can be modulated according to the voltage.

3. The integrated circuit (1) according to claim 2, Features A feedback loop (11) is designed to regulate a voltage applied to the electrode (10) based on an optical signal (4) coupled into the optical waveguide (6).

4. The integrated circuit (1) according to claim 3, Features An optical distributor (12) by means of which an optical signal (4) coupled into the optical waveguide (6) can be provided to a feedback loop (11) and a functional unit (13) of the integrated circuit (1), in particular the integrated circuit (1) has a photodiode (14) by means of which the optical signal (4) can be converted into a corresponding electrical signal (11) before being provided to the feedback loop (11).

5. The integrated circuit (1) according to claim 2 or 3, It is characterized in that The electrodes (10) of the liquid crystal element (5) are arranged in and / or on the liquid crystal element (5) with a predetermined electrode structure (26), and in particular the electrodes (10) are arranged in a uniformly distributed manner.

6. Integrated circuit (1) according to any one of the preceding claims, It is characterized in that A coupling unit (18) is arranged between the optical input end (2) and the liquid crystal element (5), wherein the coupling unit (18) is configured to couple the optical signal (4) of the optical fiber (3) into the liquid crystal element (5) independently of the positioning of the optical fiber (3) relative to the integrated circuit (1).

7. A device (9) having an integrated circuit (1) according to any one of the preceding claims and at least one optical fiber (3), wherein: The optical fiber (3) is coupled to the optical input end (2) of the integrated circuit (1) so as to transmit the optical signal (4) of the optical fiber (3) to the integrated circuit (1).

8. A method for coupling an optical signal (4) into an integrated circuit (1), the method comprising: - coupling an optical fiber (3) to an optical input end (2) of the integrated circuit (1), wherein: Providing an optical signal (4) using the optical fiber (3), and - coupling the optical signal (4) into a controllable liquid crystal element (5) of the integrated circuit (1), It is characterized in that - using the control device (7) of the integrated circuit (1) to control the liquid crystal element (5) so that the refractive index of the liquid crystal element (5) is modulated, and - coupling the optical signal (4) from the liquid crystal element (5) into an optical waveguide (6) of the integrated circuit (1) in dependence on the modulated refractive index.

9. The method according to claim 8, It is characterized in that The optical signal (4) is coupled into the liquid crystal element (5) so that the optical signal (4) propagates in the material of the liquid crystal element (5).

10. The method according to claim 8 or 9, It is characterized in that When controlling the liquid crystal element (5), voltage is applied to a plurality of electrodes (10) of the liquid crystal element (5) or the voltage on the electrodes is changed, thereby changing the orientation of molecules (8) in the liquid crystal element (5) to modulate the refractive index.

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