Sensor unit and method for operating a sensor unit

Abstract

The invention relates to a sensor unit (100) having a waveguide (105, 105a, 105b) which is coupled to a ring resonator (115) by means of a coupling point (110). Furthermore, the sensor unit (100) comprises a Mach-Zehnder interferometer (120), the input (125) of which is coupled to the waveguide (105, 105a, 105b), and the Mach-Zehnder interferometer has at least one output (135). Finally, the sensor unit (100) comprises a detection unit (145), which has at least one detector (145a) for detecting a state applied or output at the at least one output (135).

Description

Field of technology

[0001] The present invention relates to a sensor unit, a method for operating a sensor unit, a corresponding controller and a corresponding computer program product. Background art

[0002] Current optical gyroscopes are either very large to ensure good sensitivity or not sensitive enough for chip integration applications. This type of implementation of gyroscopes hinders wide availability and general applicability, making very precise measurements very expensive and for specific applications. Summary of the invention

[0003] In this context, a sensor unit, a method for operating such a sensor unit, a sensor unit using this method and finally a corresponding computer program product are proposed according to the main claims. Advantageous configurations result from the corresponding dependent claims and the following description.

[0004] In the present case, a sensor unit is proposed having the following features:

[0005] - A waveguide which is coupled to a ring resonator by means of a coupling section;

[0006] - A Mach-Zehnder interferometer, the input of which is coupled to the waveguide and which has at least one output; and

[0007] - A detection unit having at least one detector for detecting the state applied at the at least one output

[0008] For example, the sensor unit can be constructed compactly, in particular integrated on a substrate or in a chip. In the present case, the coupling section can be understood, for example, as a multimode interferometer or also as an arrangement of waveguides arranged closely side by side (for example in the range from 50 nanometers to one millimeter).

[0009] The solution proposed here is based on the insight that by connecting a ring resonator upstream of a Mach-Zehnder interferometer, a significant improvement in accuracy can be achieved when detecting measured values. Here, by means of the solution proposed here, an implementation of an optical, chip-integrated gyroscope can be achieved which can measure rotational speed and has high sensitivity. The advantage of the solution proposed here can be that this is achieved in a compact sensor system which can be constructed chip-integrated. By means of the ring resonator, quantum states such as single photons and squeezed light can be generated. By making full use of certain quantum states and measurement methods, a robust sensor can be achieved over a wide temperature range.

[0010] The following embodiments of the solution proposed herein are particularly advantageous: The embodiment has a second waveguide that is coupled to the coupling site and / or is coupled to the input of the Mach-Zehnder interferometer bypassing the ring resonator and / or is coupled to the coupling site between the output and the detector bypassing the Mach-Zehnder interferometer. Advantageously, such an embodiment enables the determination of the physical action on the Mach-Zehnder interferometer, which can then be ensured by analyzing the results of the detector.

[0011] Furthermore, the following embodiment of the solution proposed herein can be considered: The output of the Mach-Zehnder interferometer is coupled to at least one additional output, wherein the detection unit has at least one additional detector for detecting the state applied at the at least one additional output. Advantageously, such an embodiment enables the analysis of different parameters in different detectors, which can be provided by the Mach-Zehnder interferometer. For example, the values provided by different detectors can be correlated with each other, and from this, a particularly accurate determination of the physical parameter as a measured value can be achieved.

[0012] According to another embodiment of the solution proposed herein, the detection unit can be configured to provide a sensor signal using the detection signal of the first detector and the additional detection signals of at least one additional detector, in particular, wherein the sensor signal represents the rotational speed and / or rotation of the sensor unit. Such an embodiment enables the very accurate or precise determination of the physical parameter with relatively simple technical devices.

[0013] Furthermore, the following embodiment of the solution proposed herein can be considered: The embodiment further includes at least one light source and / or laser light source, which are configured to send light into the waveguide, in particular, wherein an additional light source and / or additional laser light source are additionally provided, which are configured to send light into at least one additional waveguide, in particular, wherein the light source or the additional light source is configured to emit light of different wavelengths. Such an embodiment provides the following advantages: On the one hand, the sensor unit is compactly constructed, and on the other hand, very accurate measurement results are determined by using the advantageous properties of the light output by the light source and / or the additional light source.

[0014] The following embodiments of the solution proposed herein are particularly advantageous: In said embodiments, a light source and / or a laser light source can be used or is used as a pump light source, and a further light source and / or a further laser light source can be used or is used as a signal light source. Such an embodiment offers the advantage that the physical properties of the ring resonator are utilized efficiently and fully in order to provide a quantum state, which can then advantageously be used in a Mach-Zehnder interferometer.

[0015] For this purpose, according to one embodiment of the solution proposed herein, it is particularly advantageous to use a ring resonator which is configured to generate a quantum state in the case of using three-wave mixing, four-wave mixing and / or the Kerr effect. Such a configured ring resonator can on the one hand be implemented very easily technically and on the other hand provides a quantum state which can advantageously be used in a subsequently arranged Mach-Zehnder interferometer.

[0016] Furthermore, the following embodiment of the solution proposed herein is also advantageous: In said embodiment, the waveguide has at least a second sub-waveguide, and the ring resonator is arranged between said second sub-waveguides. Such an embodiment offers the advantage that in particular certain wavelengths can be coupled in and / or out better than other wavelengths. This additionally has the advantage that interference and / or effects cannot be generated by the effect of a light source in the subsequent optical path.

[0017] In order to in particular also couple light outside the substrate into the sensor unit and / or couple light within the substrate out of the sensor unit, the sensor unit being integrally mounted in its own substrate, according to a particularly advantageous embodiment of the solution proposed herein, at least one grating coupler or a lateral coupling with a cone can be provided for coupling light into the waveguide or for outputting light from the output to at least one detector of the detection unit.

[0018] The following embodiments of the solution proposed herein are particularly advantageous: In said embodiments, at least one phase-shifting element is provided, which is used to change the state guided on the waveguide and / or a further waveguide and / or a Mach-Zehnder interferometer, in particular wherein at least one phase-shifting element can be controlled according to the signal of a temperature sensor, and / or wherein the detection unit is configured to infer the rotational speed from the frequency of the measured floating signal (Schwebesignal). Such an embodiment offers the advantage that by the possibility of a phase change of the quantum state on the line unit in the sensor unit, the sensor unit can be operated at a particularly advantageous operating point, in particular at said operating point, the sensor unit can detect certain physical parameters, such as rotational speed or rotation, very sensitively or sensitively.

[0019] In another embodiment, the phase shifter is located above or on the ring resonator in order to actively change the resonance conditions in the ring. This has the advantages that the generation of the quantum state is more reliable, the properties of the quantum state can be changed and the generation can be adjusted. For example, the phase shifter can be designed electro-optically with electrodes or thermally with a layer that can be heated, such as a metal conductor.

[0020] According to another embodiment of the solution proposed herein, at least the waveguide and / or the ring resonator can be at least partially shaped as a tab waveguide with a tab region and / or a slot waveguide with a slot region and / or be shaped from silicon and / or silicon nitride. Such an embodiment of the solution proposed herein enables the generation of individual quantum states more effectively, and the quantum states can then also advantageously be coupled from the waveguide into the resonator or vice versa.

[0021] Furthermore, the following embodiment of the solution proposed herein is advantageous: in this embodiment, at least one multimode interferometer adjoins the tab region and / or the slot region, in particular where the tab region and / or the slot region is arranged between two multimode interferometers. By using one or more multimode interferometers, as lossless as possible a transition can be achieved between the corresponding slot regions or tab regions of the waveguide, such that an increase in efficiency can thereby be achieved again in the case of this type of configuration of the sensor unit.

[0022] An embodiment of the solution proposed herein as a method for operating a sensor unit according to any one of the above claims is advantageous, wherein the method has the following steps:

[0023] - sending light into at least the waveguide; and

[0024] - analyzing the received light received by at least the detector in order to obtain a sensor signal.

[0025] By means of such an embodiment, the above advantages can also be achieved technically simply and efficiently.

[0026] In addition, the solution proposed herein implements a control unit that is configured to perform or carry out the steps of a variant of the method proposed herein in a corresponding device. By means of this implementation variant of the invention in the form of a control unit, the problem on which the invention is based can also be solved quickly and efficiently.

[0027] In the present context, the control unit can be understood as an electrical appliance that processes sensor signals and outputs control signals and / or data signals accordingly. The control unit can have an interface, which can be configured in hardware and / or in software. In the hardware configuration, the interface can be, for example, part of a so-called system ASIC that contains various functions of the control unit. However, it is also possible that the interface is a proprietary integrated circuit or at least partially consists of discrete structural elements. In the software configuration, the interface can be, for example, a software module that coexists with other software modules on a microcontroller.

[0028] A computer program product having program code that can be stored on a machine-readable carrier, such as a semiconductor memory, a hard disk memory, or an optical memory, is also advantageous, and when the program product is implemented on a computer or a control unit, the program code is used to execute the method according to one of the above-described embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Hereinafter, the solution proposed here will be explained in more detail exemplarily with reference to the accompanying drawings. The drawings show:

[0030] Figure 1A A schematic diagram showing an embodiment of a sensor unit;

[0031] Figure 1B A schematic diagram showing another embodiment of the sensor unit 100;

[0032] Figure 1C A schematic diagram showing an embodiment of a waveguide or a ring resonator having a tab area;

[0033] Figure 1D Two schematic diagrams are shown for explaining possible light guiding in the tab area of a waveguide or a ring resonator for use in an embodiment of a sensor unit;

[0034] Figure 1E A schematic diagram showing an embodiment of a waveguide or a ring resonator having a slot area;

[0035] Figure 1F Two schematic diagrams are shown for explaining possible light guiding in the slot area of a waveguide or a ring resonator for use in an embodiment of a sensor unit;

[0036] Figure 2 Two schematic diagrams showing different configurations or connections of a ring resonator to different sub-sections of a waveguide or a waveguide;

[0037] Figure 3Flowchart showing an embodiment of the method;

[0038] Figure 4 Block circuit diagram showing an embodiment of the control unit. Detailed implementation

[0039] In the following description of advantageous embodiments of the present invention, the same or similar reference numerals are used for elements shown in different figures and having similar functions, and the repeated description of these elements is omitted.

[0040] Figure 1A Schematic diagram showing an embodiment of the sensor unit 100. The sensor unit 100 includes a waveguide 105, which is subdivided, for example, into two sub-sections 105a and 105b, and the sub-sections are coupled or entangled with the ring resonator 115 via the coupling part 110. In addition, the sensor unit 100 includes a Mach-Zehnder interferometer 120 and a sensor section. The Mach-Zehnder interferometer has an input end 125 (in the form of a coupling part or a multimode interferometer, for example) for receiving quantum states or photons from the waveguide 105. The sensor section is divided into a first sensor sub-section 130a and a second sensor sub-section 130b. Here, the sensor sub-section 130 can be, for example, a waveguide with a pre-determined (advantageously the same) length, but for spatial reasons, the waveguide is installed or arranged spirally. Here, the sensor sub-sections 130a and 130b can also be realized to cross each other, and the waveguide paths can also intersect. The two sensor sub-sections are coupled and / or entangled with the output coupling part 140 via the coupling part serving as the output end 135 of the Mach-Zehnder interferometer 120. The output coupling part is configured to output quantum states or photons to the detector 145a of the detector unit 145. In addition, another output coupling part 150 is coupled and / or entangled with the output end 135 of the Mach-Zehnder interferometer 120. The output coupling part is configured to output quantum states or photons to another detector 145b of the detector unit 145. Here, for example, the detector unit 145 is configured to provide a sensor signal 147 in the case of using the sensor values of the sensors of the detector 145a and another detector 145b. The sensor signal represents, for example, the rotational speed and / or rotation of the sensor unit 100 around the rotation axis 148.

[0041] Additionally, according to Figure 1AThe embodiment for the sensor unit 100 shown in the figure is provided with an input coupling part 155 which is connected to the coupling part 110 via a second waveguide 157 and / or alternatively or additionally connected to the input end 125 of the Mach-Zehnder interferometer 120 while bypassing the ring resonator 155, and alternatively or additionally connected to the output coupling part 140 via a waveguide coupling part 160 and / or additionally or alternatively connected to another output coupling part 150 via the waveguide coupling part 160.

[0042] Furthermore, now according to the embodiment shown in Figure 1A the figure, a light source 165 is provided which is configured, for example, as a pump laser light source and is configured to send light into a (first) sub-segment 105a of the waveguide 105. Alternatively or additionally, another light source 170 is provided which is configured as a signal laser light source and is configured to send additional light into the input coupling part 155. In addition, it is also possible to use only the light source 170 without using the light source 165. Then, the light source 170 serves as both a pump laser light source and a signal laser light source. This is possible because in the ring resonator, signal photons with the same wavelength as the signal photons of the pump source can also be generated via four-wave mixing.

[0043] It is also possible to consider using a grating coupler 175 to couple the light of the light source 165 or the other light source 170 into the sensor unit 100 when the sensor unit 100 is integrated on a common substrate or chip and the light source 165 or the other light source 170 is arranged outside the substrate or chip. Similarly, a corresponding grating coupler 175 can also be used to couple the corresponding quantum state or photon out of the output coupling part 140 into the detector 145a and / or out of the other output coupling part 150 into another detector 145b, especially when one or more of the detectors in the detector unit 145 are not integrated with other components of the sensor unit 100 on a common substrate.

[0044] It is also possible to consider using a phase shifter or phase-shifting element 180 on and / or in the respective conductor components of the components of the sensor unit 100 and / or on the ring resonator 115, especially where the phase-shifting element 180 is configured such that the phase-shifting element is individually or jointly controlled such that the phase-shifting element can control a determined phase shift or delay of the state running on the respective conductor component. For this purpose, for example, the one shown in Figure 1AA control unit not shown in the figure can control each phase-shifting element 180. In addition, a temperature sensor 182 can be implemented in the system to detect external temperature fluctuations and, for example, adapt or change the system via the control unit by means of one or more phase shifters 180 and / or also change the reception sensitivity of detectors 145a and 145b, and / or also correct the sensor signal 147.

[0045] Figure 1B Schematic view showing a further embodiment of the sensor unit 100. Here, the embodiment of the sensor unit shown in Figure 1B is constructed in a similar manner to the sensor unit 100 depicted in Figure 1A but differs in that a slightly modified structure is used in the region of the coupling site 110 or the waveguide 105 (here, for example, two sub-waveguides 105a and 105b) and in the ring resonator 115. In particular, a waveguide structure can be used for the waveguide 105 or the ring resonator 115, which waveguide structure is at least partially produced as a fin waveguide, a slot waveguide, or made of a certain material in order to achieve particularly good coupling performance or efficiency performance between the two waveguide sections.

[0046] Figure 1C Schematic view showing an embodiment of the waveguide 105 or the ring resonator 115 having a fin region 185. For example, the fin region 185 can be formed by a section of the waveguide 105 or the ring resonator 115 in which the waveguide 105 or the ring resonator 115 has a reduced cross-section compared to other regions of the waveguide or the ring resonator. For example, the fin region 185 can be surrounded by a special three-wave mixing material, such as lithium niobate, or can also be surrounded by a four-wave mixing material, such as silicon or silicon nitride. It is also conceivable that the waveguide 105 or the ring resonator 115 has a rectangular or square shape in the fin region 185 in order to couple the light guided in this fin region to one or more external components as efficiently as possible.

[0047] Figure 1D Two schematic views are shown for illustrating possible light guiding in the fin region 185 of the waveguide 105 or the ring resonator 115 for use in an embodiment of the sensor unit 100. In both the left schematic view and the right schematic view, the cross-section of the waveguide 105 or the ring resonator 115 in the fin region 185 is shown. In Figure 1D the left schematic view in Figure 1DIn the right schematic diagram, when the TM mode is coupled into waveguide 105 or ring resonator 115 and passes through tab region 185, a lateral evanescent field can be recognized.

[0048] According to this embodiment, optical waveguide 105 is implemented as a tab waveguide having tab region 185, as shown in the subdrawings for the TE mode and TM mode in Figure 1D Light is guided in this tab region, and the cross-section is significantly reduced such that most of the light protrudes on the side of the waveguide and thus a large evanescent field is formed. Then, the material for three-wave mixing can be placed above the waveguide such that the evanescent field penetrates into this material on the side of the waveguide. If the intensity of the evanescent field is large enough, a quantum state is generated in the material for three-wave mixing: the quantum state is partially coupled into waveguide 105, as Figure 1C schematically shown.

[0049] Figure 1E Schematic diagram showing an embodiment of waveguide 105 or ring resonator 115, which waveguide or ring resonator has a slot region 190. In this slot region 190, waveguide 105 or ring resonator 115 has a slot 192 or an opening. Additionally, as described above, waveguide 105 or ring resonator 115 can also have a special three-wave mixing material or be made of this material in protection region 190. Optionally, slot region 190 can also be adjacent to multimode interferometer 195 or arranged between two multimode interferometers 195a and 195b.

[0050] Figure 1F Two schematic diagrams are shown for illustrating possible light guiding in slot region 190 of waveguide 105 or ring resonator 115 for use in an embodiment of sensor unit 100. In both the left schematic diagram and the right schematic diagram, the cross-section of waveguide 105 or ring resonator 115 in slot region 185 is shown. In Figure 1F the left schematic diagram, when the TE mode is coupled into waveguide 105 or ring resonator 115 and passes through slot region 190, a high light intensity can be recognized as the field in slot 192, while in Figure 1F the right schematic diagram, when the TM mode is coupled into waveguide 105 or ring resonator 115 and passes through slot region 190, a high light intensity can be recognized as the field outside slot 192.

[0051] As in Figure 1E or in Figure 1FAs shown in the sub - drawings for TE mode and TM mode, the optical waveguide 105 is implemented as a slot waveguide having a slot region 190. According to this embodiment, light is guided in the optical waveguide. Here, the largest field components are located between the waveguide tabs having a very large intensity. As in the case of using the tab region in the above - mentioned embodiment, now, the material for three - wave mixing can also be placed above the waveguide 105 and thus also within the slot 192. Light interacts with the three - wave mixing material in the slot 192 and quantum states are generated therein.

[0052] Optionally, the transition of the optical waveguide 105 to the slot waveguide or the slot region 190 can be provided with a multimode interferometer 195 to achieve a lossless transition. Since the states have already been generated in the slot 192, the advantage is that a lower pump intensity is sufficient compared to the first case (i.e., using the tab region 185), and more components of the generated quantum states are coupled into the waveguide 105.

[0053] The optical waveguide 105 can also be directly produced from the material for three - wave mixing. This is more complex in terms of processing, but can achieve significantly more efficient generation of quantum states. Here, any waveguide shape can be used. For this purpose, rib waveguides can be used to minimize losses.

[0054] Now, in the case of using one of the possibilities mentioned above, the sensor unit 100 shown in Figure 1B can be used. For this purpose, the light from the laser source can either be directly generated on the optical chip or be coupled into the optical chip via lateral coupling. In another possibility, the laser can be directly positioned above the grating coupler and be introduced into the waveguide via a tapered - structure grating coupler, which is typically made of silicon (SI) or silicon nitride (SiN). Here, the laser corresponds, for example, to the pump laser. For example, the laser is introduced into the region where squeezed light is generated via three - wave mixing. In another embodiment, this region can be a straight waveguide or a resonator structure. Here, three - wave mixing can be achieved. This can be realized via the possibilities explained above, which implement tab regions, slot regions, and / or waveguides or ring resonators made of or with the material for three - wave mixing.

[0055] The three-wave mixing material can be realized by means of lithium niobate or preferably periodically poled lithium niobate (PPLN), or can be realized by means of any other material with a high second-order inductance. Here, due to the phase conditions that can be adapted during production, PPLN has a significantly higher conversion efficiency than lithium niobate. In one embodiment, both cases are realized in a straight waveguide 105, and in another embodiment, they are realized in a resonator or a ring resonator 115. For example, the resonator or ring resonator is composed of a ring, and light can be coupled into the ring through waveguide coupling or via a multimode interferometer. The light circulates in the ring and generates a significantly higher intensity of light. The advantage of using a resonator is that a smaller pump function is required to achieve three-wave mixing. Then, the generated quantum state can be coupled out of the ring and used for the subsequent sensor area. Additionally, for example, a certain component that transmits the pump light can be filtered out optionally.

[0056] Then, according to this embodiment, the quantum state is conducted to the input end of the Mach-Zehnder interferometer 120. The Mach-Zehnder interferometer is composed of two input ends, for example, which lead to a beam splitter with two output ends. For example, the sensor area is attached to the beam splitter, and the beam splitter in turn leads to another beam splitter, which has two output ends. For example, the beam splitter is realized by a multimode interferometer.

[0057] For example, additionally, a second laser with the wavelength of the quantum state or only a vacuum state can enter the other input end, and the second laser is hereinafter referred to as the signal laser. In another embodiment, two squeezed states or coherent squeezed states (gequetschte oder gequetschte ) can also be generated by one or two ring resonators and respectively guided to one input end. Therefore, for example, a variation can be realized by means of this system, that is, at the two input ends of the Mach-Zehnder interferometer, a quantum state and the pump laser enter respectively. If the pump laser is used at one or both input ends, there is an advantage that the intensity of the Mach-Zehnder interferometer is greater.

[0058] Then, for example, at the first beam splitter of a Mach-Zehnder interferometer, two states interfere, become entangled with each other, and reach the sensor region. In this sensor region, the Sagnac effect acts on the entangled state. Thereby, depending on the applied rotational speed, a phase shift takes effect. Next, this state reaches the second beam splitter, and depending on the phase shift, the entangled state is or is not disentangled. Next, this can be measured, for example, by means of different measurement methods. For example, by means of product detection. This is based on homodyne detection. Here, for example, the signal laser is combined with the output signal in a beam splitter, and the resulting interference is measured by one or two detectors. In the latter case, balanced homodyne detection is spoken of, which offers the advantage of low measurement noise. Here, for example, the phase of the signal laser can be changed by means of one or more phase shifters in order to optimize the detection. For example, if homodyne detection is carried out at the outputs of two Mach-Zehnder interferometers, product detection can be achieved. In another embodiment, an intensity difference measurement is carried out. Here, the output signals are, for example, each directly measured by a detector, and the results are subtracted from each other. In a further embodiment, coincidence measurement or parity check measurement can also be achieved with the aid of the above-described configuration In all variants, the detectors can be produced directly integrally, or the output signals can be coupled via a grating coupler or a lateral coupler and the signals can be measured outside the chip. As already mentioned, the entire configuration is as Figure 1B shown. Exemplarily, two lasers are shown, the light of which is coupled into the chip via a grating coupler. This light first reaches the region for generating three-wave mixing. In this Figure 1B region, the generation zone is shown as a ring resonator. The light, for example, next reaches the first multimode interferometer of the Mach-Zehnder interferometer from this ring resonator. The sensor region adjoins this first multimode interferometer and is realized, for example, by a long waveguide. Next, the waveguide is again guided to the multimode interferometer, the output of which leads to the detector via a grating coupler. The path of the signal laser serves to pump the ring resonator and serves as the signal for the input of the Mach-Zehnder interferometer and for homodyne detection. It should be noted that any one of these uses can also be omitted. Thus, for example, only one vacuum state can be used for the Mach-Zehnder input, or any number of phase shifters can also be used in the lowest waveguide path and / or the sensor region, or the order and number of the multimode interferometers used in this path can be changed such that the first interferometer already has four outputs.

[0059] In a further embodiment, the entire Mach-Zehnder interferometer can be produced such that three-wave mixing occurs in the interferometer region and thus an SU11 Mach-Zehnder interferometer is realized. This has the advantage that additional quantum states can be generated in the entire sensor region and thus losses can be compensated. As a result, higher or very high sensitivities can be achieved.

[0060] Figure 2 Two schematic views showing different configurations or connections of the ring resonator 115 to the waveguide 105 or to different sub-sections 105a or 105b of the waveguide 105. In Figure 2 the left schematic view in, the arrangement or entanglement of the ring resonator 115 with two sub-sections 105a and 105b of the waveguide 105 via the coupling site 115 is shown. In Figure 2 the right schematic view in, an alternative arrangement of the ring resonator 115 between the first sub-section 105a and the second sub-section 105b of the waveguide 105 is shown. Here, an auxiliary coupling site 200 is used, which is arranged, for example, opposite the coupling site 110 on a half-path of the length of the ring resonator 115 and which is configured to output the state running in the ring resonator 115.

[0061] Thus, by way of example, an architecture is proposed in which, for example, quantum states are generated in the ring resonator 115 via four-wave mixing. For this purpose, for example, one ring resonator and two lasers are used as light sources 165 and 170. Then, one laser corresponds to the pump laser and the other laser corresponds to the signal laser. Then, the ring resonator 115 is pumped with the pump laser. For example, the geometry of the ring resonator structure is designed such that the resonator condition for a defined wavelength is met. Then, squeezed photons or coherent squeezed photons of the wavelength of the signal laser and other wavelengths for which the resonator condition applies are generated in the ring resonator 115 via four-wave mixing. Next, the generated light at the wavelength of the signal laser is conducted into the input 125 of the Mach-Zehnder interferometer 125, which includes the sensor region 130. There, this light can interfere with the light of the signal laser. According to the Sagnac effect, a phase shift occurs, which, according to a defined detection method, results in a defined interference pattern and can thus be measured.

[0062] Thus, light is generated either directly on the optical chip by two laser sources of different wavelengths, for example, or coupled into the optical chip via a grating coupler structure 175, for example. In the second possibility, the lasers can be arranged above the grating coupler 175 and conducted from the grating coupler 175 to the waveguide 105 via a tapered structure. Here, one laser corresponds to the pump laser and the other laser is the signal laser. Next, the two lasers (or, as a second embodiment, only the pump laser) are coupled into the ring resonator 115 via a multimode interferometer, for example, serving as the coupling site 110. Depending on whether only the pump laser is coupled in or both are coupled in, squeezed photons or coherent squeezed photons are generated, for example, based on four-wave mixing, and the squeezed photons or the coherent squeezed photons are further described as quantum states. These squeezed photons or coherent squeezed photons are coupled out either via the multimode interferometer for coupling in, i.e., the coupling site 110, or via another multimode interferometer serving as an (auxiliary) coupling site. Here, the coupling out can be designed such that only the signal wavelength is coupled out at the desired coupling-out site 110 or 200. This is schematically shown in Figure 2 Here, one ring resonator with different coupling-ins or coupling-outs is shown each. One has two input and output ends ( Figure 2 schematic on the left in Figure 2 ), and one has three input and output ends ( Figure 2 schematic on the right in

[0063] Light is coupled into the ring resonator 115 via the input end or the first sub-segment 105a at the upper left of the waveguide. Here, the coupling site 110 or 200 can be designed such that a certain wavelength is coupled out better compared to other wavelengths. Thus, in the Figure 2 schematic on the right in

[0063] the coupling site 110 or 200 can be designed such that, for example, only the quantum state is coupled out at the lower left output end. This has the advantage that no interference or effects based on the pump laser can occur in the further path.

[0064] A signal laser, or an optical signal provided by the signal laser via the input coupling part 155, or only a vacuum state can enter another input end of the input end 125 of the Mach-Zehnder interferometer 120. In another embodiment, two squeezed states or coherent squeezed states can also be generated by one or two ring resonators 115, and the two squeezed states or coherent squeezed states can be respectively guided to the input end attachment ends of the input end 125 of the Mach-Zehnder interferometer 120.

[0065] Then, on the first beam splitter (here called the input end 125) of the Mach-Zehnder interferometer 120, two quantum states interfere, become entangled with each other, and reach the sensor area 130. In this sensor area, the Sagnac effect acts on the entangled state. Thus, according to the applied rotational speed, a phase shift takes effect. Next, this state is incident on the second beam splitter (here called the output end 135), and depending on the phase shift, the entangled state is or is not disentangled. Next, this can be measured in one or more detectors of the detector unit 145 by means of different measurement methods, for example by means of product detection. This is based on homodyne detection. Here, the signal laser is combined with the output signal of the Mach-Zehnder interferometer 120 in a beam splitter, which serves as the output coupling part 140 or as another further output coupling part 150, and the resulting interference is measured by one or two detectors 145a or 145b. In the latter case, balanced homodyne detection is mentioned, which offers the advantage of low measurement noise. Here, the phase of the signal laser can be changed by means of a phase shifter 180 in order to optimize the detection. If homodyne detection is performed on the two Mach-Zehnder interferometer output ends or on the output end 135, product detection can be achieved. In another embodiment, an intensity difference measurement is performed. Here, the output signals are directly measured by detectors respectively, and the results are subtracted from each other. In a further embodiment of the proposed scheme here, coincidence measurement or parity check measurement can also be achieved by means of the above-mentioned configuration In all variants, the detectors 145a or 145b can be produced directly on the substrate integrally with other components, or the output signals are coupled via a grating coupler 175 and the signals are measured outside the chip.

[0066] If squeezed photons are used as the quantum state, the light from paths 130a and 130b interferes with each other on the coupling part 135, and an intensity difference measurement can be performed, for example, to detect the sensor signal. The squeezed light ensures that the noise in the system becomes smaller and thus a higher measurement resolution becomes possible.

[0067] In summary, it should be noted that FIG1 illustrates the configuration of the proposed solution according to one embodiment. Two lasers are shown, whose light is coupled into the chip via a grid coupler 175. This light first reaches the ring resonator 115 and then the first multimode interferometer 125 of the Mach-Zehnder interferometer 120. Adjacent to this first multimode interferometer is the sensor region 130, which is implemented by a long waveguide. The waveguide is then directed again to the multimode interferometer as output 135, which leads to detectors 145a or 145b via a grid coupler 175. The path of the signal laser is used to pump the ring resonator 115, serving as the signal for the Mach-Zehnder interferometer input 125 and for homodyne detection. It should be noted that either of these paths can be omitted. In this way, only one vacuum state can be used for the Mach-Zehnder interferometer input 125, or any number of phase shifters 180 can be used in the lowermost waveguide path and / or sensor area, or the order and number of multimode interferometers 120 used in this path can be changed so that the first interferometer already has four outputs.

[0068] Figure 3 A flow chart shows an exemplary embodiment of a method 300 for operating a variant of the sensor unit proposed herein, wherein method 300 includes a step 310 of irradiating at least the waveguide with light and a step 320 of evaluating the received light received by at least the detector to obtain a sensor signal. Irradiation and / or detection can be performed either continuously or at specific times.

[0069] Figure 4 A block circuit diagram of an embodiment of a control unit 400 for implementing a variant of the method 300 for operating a variant of the sensor unit proposed here is shown, wherein the control unit has a unit 410 for controlling the irradiation of at least the waveguide with light and a unit 420 for analyzing the received light received by at least the detector to obtain a sensor signal.

[0070] The exemplary embodiments described and shown in the drawings are selected only by way of example. Different exemplary embodiments can be combined with one another completely or in terms of individual features. An exemplary embodiment can also be supplemented by features of other exemplary embodiments.

[0071] Furthermore, the method steps presented here can be performed repeatedly and in an order different from that described.

[0072] If an exemplary embodiment includes an “and / or” connection between a first feature and a second feature, this can be interpreted such that the exemplary embodiment includes both the first feature and the second feature according to one exemplary embodiment and either only the first feature or only the second feature according to another exemplary embodiment.

Claims

1. A sensor unit (100), the sensor unit having the following characteristics: - Waveguides (105, 105a, 105b) which are coupled to a ring resonator (115) by means of coupling sites (110); - A Mach-Zehnder interferometer (120), the input (125) of the Mach-Zehnder interferometer being coupled to the waveguides (105, 105a, 105b), and the Mach-Zehnder interferometer having at least one output (135); and - A detection unit (145), the detection unit having at least one detector (145a) for detecting the state applied or output at the at least one output (135).

2. The sensor unit (100) according to claim 1, the sensor unit having a second waveguide (157) which is coupled to the coupling site (110) and / or which is coupled to the input (125) of the Mach-Zehnder interferometer (120) bypassing the ring resonator (115) and / or which is coupled to a coupling site (140) between the output (135) and the detector (145a) bypassing the Mach-Zehnder interferometer (120).

3. The sensor unit (100) according to any one of the above claims, wherein, The output (135) of the Mach-Zehnder interferometer (120) is coupled to at least one further output (150), wherein the detection unit (145) comprises at least one further detector (145b) for detecting the state applied at the at least one further output (150), in particular wherein the detection unit (145) is configured to provide a sensor signal (147) using the detection signal of the first detector (145a) and the further detection signals of the at least one further detector (145b), in particular wherein the sensor signal (147) represents the rotational speed and / or rotation of the sensor unit (120).

4. The sensor unit (100) according to any one of the above claims, the sensor unit further comprising at least one light source (165) and / or a laser light source, the at least one light source and / or the laser light source being configured to send light into the waveguide (105), in particular wherein, There is additionally provided a further light source (170) and / or a further laser light source, the further light source and / or the further laser light source being configured to send light into the at least one further waveguide (155, 157), in particular wherein the light source (165) or the further light source (170) is configured to emit light of different wavelengths, in particular wherein the light source (165) and / or the laser light source can be used or is used as a pump light source, and the further light source (170) and / or the further laser light source can be used or is used as a signal light source, and / or wherein the light source (170) can be used or is used as a pump light source and a signal light source.

5. The sensor unit (100) according to any one of the above claims, wherein, The ring resonator (115) is configured to generate a quantum state using three-wave mixing, four-wave mixing and / or the Kerr effect.

6. The sensor unit (100) according to any one of the above claims, wherein, The waveguide (105) has at least second sub-waveguides (105a, 105b) between which the ring resonator (115) is arranged.

7. The sensor unit (100) according to any one of the preceding claims, the sensor unit having at least one grating coupler (175) for coupling light into the waveguide (105) or for outputting light from the output end (135) to at least one detector (145a) of the detection unit (145).

8. The sensor unit (100) according to any one of the above claims, the sensor unit having at least one phase-shifting element (180) for changing the state guided on the waveguide (105), the further waveguide (157) and / or the Mach-Zehnder interferometer (120) and / or for changing the resonance condition of the ring resonator (115), in particular wherein, The at least one phase-shifting element (180) can be controlled based on the signal of the temperature sensor (185), and / or wherein the detection unit (145) is configured to infer the rotational speed from the frequency of the measured floating signal.

9. The sensor unit (100) according to any one of the above claims, wherein, At least the waveguides (105, 105a, 105b) and / or the ring resonator (120) are at least partially shaped as a tab waveguide having a tab region and / or a slot waveguide having a slot region and / or are formed of silicon and / or silicon nitride.

10. The sensor unit (100) according to claim 9, wherein, At least one multimode interferometer is adjacent to the tab region and / or the slot region, in particular wherein the tab region and / or the slot region are arranged between two multimode interferometers.

11. A method (300) for operating a sensor unit (100) according to any one of the preceding claims, wherein, The method (300) has the following steps: - transmitting (310) light into at least the waveguide (105) by means of light; and - analyzing the received light received by at least the detector (145a) to obtain a sensor signal (147).

12. The method (300) according to claim 11, the method having the step of adjusting the phase-shifting element (180) using at least the detection signal and / or the sensor signal (147) of the detector (145a) and / or the signal of the at least one light source (165, 170), and / or wherein, In the transmitting step (310), the light is emitted as pulsed light or as continuous light.

13. A control unit (400) configured to perform and / or control the steps (310, 320) of the method (300) according to claim 11 or 12 in a corresponding device (410, 420).

14. A computer program product having program code for performing and / or controlling the steps (310, 320) of the method (300) according to claim 11 or 12 when the program product is implemented on a control unit (400).

15. A machine-readable storage medium on which the computer program product according to claim 14 is stored.

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