Optical sensor apparatus

Abstract

The present invention relates to an optical sensor apparatus (1) comprising: a laser light source (2) for providing laser light (L); an optical ring resonator (3) which is arranged to receive part of the laser light via a coupler (4), the ring resonator (3) having an optically nonlinear material and / or an optically absorbing material such that a resonance curve (31) of the ring resonator (3) as a function of the wavelength of the laser light (L) to be received is asymmetrical with respect to a resonance wavelength (32), the resonance curve (31) having a side (31a) which rises gradually to the resonance wavelength and a side (31b) which rises steeply to the resonance wavelength (32); a detection device (5) which is designed to detect a portion of the laser light (L) not coupled into the ring resonator (3); a control device (6) which is designed to control the laser power of the laser beam source (2) on the basis of the detected portion of the laser light (L) not coupled into the ring resonator (3), such that laser light (L) coupled into the ring resonator (3) has a laser wavelength (30) which is located on the steeply rising side (31b) of the resonance curve (31).

Description

[0001] Description

[0002] title

[0003] Optical sensor device

[0004] The present invention relates to an optical sensor device.

[0005] State of the art

[0006] Optical gyroscopes are typically based on the Sagnac effect. There are fiber-based and ring-laser-based gyroscopes. Fiber-based gyroscopes rely on light continuously propagating in two opposite directions within a fiber optic cable. Due to the Sagnac effect, the effective length of both light paths varies as the gyroscope rotates. This shifts the phase of the light. After passing through the fiber optic cable, the two light paths meet again, and the light waves superpose. Constructive and destructive interference occurs, resulting in a light wave whose intensity varies proportionally to the rotation rate.

[0007] In ring laser gyroscopes, light propagates in a ring resonator. Ring resonators are closed, circular structures in which light can circulate. Certain modes can exist in ring resonators, which interfere with each other due to the interference of the light after it has passed through the ring. This means that certain frequencies are amplified and others attenuated in a ring resonator. Here, too, the effective path length varies as the system rotates due to the Sagnac effect, thus changing the resonant frequency of the resonator. This ensures that the transmitted intensity varies depending on the rotation rate during rotation. For compact and chip-integrated fiber-based and ring resonator-based gyroscopes, very high-quality manufacturing is required to achieve a high sensitivity comparable to that of larger products.In particular, it is difficult to make the resonance curve of the ring resonator very steep, which increases the sensitivity.

[0008] Feng et al. “Progress of Waveguide Ring Resonators Used in Micro-Optical Gyroscopes,” Photonics, 7, 96 (2020) describes optical gyroscopes.

[0009] The present invention therefore has the object of providing an improved optical sensor device which enables increased sensitivity and / or compactness.

[0010] Disclosure of the invention

[0011] The present invention provides an optical sensor device according to claim 1.

[0012] Preferred further training is the subject of the subclaims.

[0013] Advantages of the invention

[0014] According to the invention, the optical sensor device comprises a laser light source for providing laser light, an optical ring resonator arranged to receive a portion of the laser light via a coupler, wherein the ring resonator comprises an optically nonlinear material and / or an optically absorbing material such that a resonance curve of the ring resonator as a function of the wavelength of the laser light to be received is asymmetric with respect to a resonance wavelength, wherein the resonance curve has a side rising gently towards the resonance wavelength and a side rising steeply towards the resonance wavelength, a detection device configured to detect a portion of the laser light not coupled into the ring resonator, a control device configured to control a laser power of the laser beam source based on the detected portion of the laser light not coupled into the ring resonator in such a way thatthat laser light coupled into the ring resonator has a laser wavelength which is located on the steeply rising side of the resonance curve.,

[0015] This invention is based on a compact sensor design that exploits the nonlinearity of optical materials to increase the slope of the resonance and thus the sensitivity. This allows for the realization of a compact optical, chip-integrated angular rate sensor whose manufacturing quality does not require very high levels of precision.

[0016] To achieve the steep resonance curve, at least one or a combination of an optically nonlinear and / or an optically strongly absorbing medium is used. Furthermore, an architecture for controlling the power and optionally the phase of a laser is used. It is important that the medium has either a high second or third order susceptibility or a relevant absorption, preferably to create optical bistability. The medium can also be manufactured with intentional defects to increase light absorption. One example is unbonded silicon atoms in a silicon nitride waveguide. Two-photon absorption can occur in the silicon atoms, which does not occur in silicon nitride waveguides, and this causes additional heating of the waveguide.In combination, a system of detectors and laser power control, optionally also phase control, is used to regulate the power in the resonator, which also has an influence on bistability.

[0017] The laser light from a laser light source is coupled into a ring resonator via a coupler. This typically creates an enhanced field and thus a high intensity. The resonator contains any optically nonlinear or optically absorbing material, either in the form of a waveguide, e.g. on an integrated photonic chip, or within a free-space resonator. Any material with a relevant second-order susceptibility such as lithium niobate (also PPLN) or a relevant third-order susceptibility such as silicon or silicon nitride can be considered for the nonlinearity. The material itself as well as the manufacturing method are crucial for the absorption of the material. Depending on the orientation and layer sequence and manufacturing quality of the crystals grown during semiconductor production, they absorb more or fewer photons.

[0018] The transmission of a ring resonator or coupler, i.e., the portion of the laser light that is not coupled into the ring resonator, can be calculated using the coupling rate K, the loss rate y, and the detuning A. While all three define the intensity gain, detuning provides optical bistability and a shift in the resonance frequency. This is composed of effects such as self-phase modulation and thermal modulation. Self-phase modulation causes bistability due to susceptibility, while thermal modulation absorbs photons and converts them into heat. Both cause bistability, which leads to an asymmetric resonance curve when plotted as a function of wavelength.A slope in a nonlinear or steep side of the curve is stronger than in an opposite side, with the sides separated by the resonance wavelength, i.e. the highest point of the resonance curve.

[0019] As mentioned above, in the present invention the transmit power of the ring resonator, i.e. the part of the laser light that is not coupled into the ring resonator, is measured. For this purpose, the resonance frequency of the ring resonator is preferably shifted so that the wavelength of the laser is positioned at the steepest point. This can be made possible by adjusting the wavelength of the laser accordingly. Thus, it is more advantageous to regulate the resonance frequency of the ring resonator with a constantly controlled laser wavelength and laser power. Optionally, this can be done additionally or alternatively using a phase shifter, which can be controlled as a function of the laser power, as described below. The nonlinearity thus makes it possible to achieve a strong signal edge and thus high sensitivity.If a rotation rate acts on the system, the Sagnac effect causes a change in the effective length of the resonator, thus changing the resonant frequency and thus resulting in an effective phase change. This change causes a change in the measured transmission power. Due to the bistability, the change in transmission becomes more pronounced, making the sensor system more sensitive. This is also possible because the steady state is established very quickly in this optical system, allowing phase changes to be measured almost directly as a change in power.

[0020] According to a preferred embodiment of the optical sensor device, a light splitting device is provided, which is arranged and designed to split the laser light into a first light path and a second light path in a predetermined ratio. Thus, the original light path from the laser beam source to the coupler is split into the first and second light paths. The coupler toward the ring resonator is arranged on the first light path. The detection device is configured to detect laser light split in the second light path. This can be achieved by a detector, for example a photodetector, measuring the portion of the laser light deflected into the second light path. For example, the temperature or the current of the laser can be controlled such that the power measured in the second light path is always constant.

[0021] According to a preferred embodiment of the optical sensor device, a light switch is provided which is designed to deflect the laser light into a first light path or a second light path. In this embodiment, the coupler is also arranged on the first light path. The detection device is configured to detect laser light deflected into the second light path. This can in turn be realized by a (photo) detector measuring the portion of the laser power deflected by the light switch onto the second light path and, for example, regulating the temperature or the current of the laser such that the measured power is always constant. The switching time of the light switch to switch light from the first light path to the second light path and vice versa is preferably in the .s range.This makes sense because the oscillation in the ring resonator is in the nanosecond range, and thus faster than the switching time of the light switch. The light switch can in particular be integrated into the coupler. In this way, only a single light path is necessary. According to a preferred embodiment of the optical sensor device, the wavelength is arranged at a steepest point of the resonance curve. This can be controlled by the laser light source itself or by a phase shifter, as described further below. This adjustment leads to a change in the path length with a maximum change in the resonance behavior of the wavelength used. This increases the sensitivity of the optical sensor device.

[0022] According to a preferred embodiment of the optical sensor device, the ring resonator has a phase shifter configured to shift the phase of the laser light coupled into the ring resonator. The phase shifter can be either a thermal phase shifter, which shifts the temperature and thus the phase, or an electro-optical phase shifter, which shifts the refractive index of the waveguide material and thus the phase. By appropriately adjusting the phase control of the laser light, the frequency or wavelength of the laser light can be changed, particularly as a function of the laser power, so that the wavelength used can be optimally adjusted to the steepest point in the resonance curve in order to achieve increased sensitivity.

[0023] According to a preferred embodiment of the optical sensor device, a temperature sensor is provided for detecting the ambient temperature. The control device is designed to control the phase shifter based on the detected ambient temperature. Depending on the measured value, the phase can then be shifted so that the operating point is preferably always located at the steepest edge during transmission. This allows temperature fluctuations to be compensated, so that the sensitivity of the optical sensor device is maintained even with fluctuations in the ambient temperature.

[0024] According to a preferred embodiment of the optical sensor device, a variable attenuator is provided, which is arranged between the laser beam source and the coupler. In this way, an additional attenuator in the form of the variable attenuator can be used, which regulates the laser power. This is more stable than temperature or current control, since the wavelength can also change. The variable attenuator can be arranged on-chip between the laser light source and the coupler. The control device is configured to control the variable attenuator to control the laser power. In addition, this detector can be used as a reference sensor to correctly interpret the power changes at the other detectors. This can be chip-integrated, e.g.after the coupler, for example via the optical resistor using graphene layers, or be positioned macroscopically behind the laser light source.

[0025] According to a preferred embodiment of the optical sensor device, the detection device is configured to detect laser light coupled out of the ring resonator via a further coupler. The control device is designed to control the laser power based on a detected amount of the laser light coupled out of the ring resonator. In this way, additional control for the optical power in the resonator is used. Since the non-linearity depends on the power in the resonator, reliable operation can be guaranteed. For this purpose, a portion of the power in the resonator can be coupled out and detected. The laser light source can then be adjusted so that the power in the resonator remains constant. In this way, a defined portion of the light in the resonator can be coupled out and measured via a further coupling point.It is advantageous if this additional coupler is designed to be broadband and thus couples an equal power component of the light from the resonator regardless of the wavelength.

[0026] According to a preferred embodiment of the optical sensor device, the control device is designed to control the phase shifter based on the detected light quantity of the laser light coupled out of the ring resonator. Thus, the wavelength of the laser light coupled into the ring resonator or the resonance condition of the ring resonator can be adjusted via additional phase shifters, thereby ensuring high sensitivity. According to a preferred embodiment of the optical sensor device, the ring resonator has a slotted waveguide having a slotted region between a first conductor core and a second conductor core, wherein the optically nonlinear material and / or the optically absorbing material is arranged in the slotted region. In this way, the material can have a higher nonlinearity.The other waveguides can have a different shape to realize a sensitive sensor region in the ring resonator, while at the same time ensuring efficient light guidance in the other paths.

[0027] According to a preferred embodiment of the optical sensor device, the ring resonator is arranged on a photonic integrated circuit. Furthermore, a chip coupler is provided, which is designed to couple the laser light provided by the laser light source onto the photonic integrated circuit. This enables a particularly compact design.

[0028] According to a preferred embodiment of the optical sensor device, the ring resonator and the laser light source are heterogeneously or homogeneously integrated on a photonic integrated circuit. This enables a particularly compact design without the need for a chip coupler.

[0029] According to a preferred embodiment of the optical sensor device, the coupler is designed as an evanescent coupler or a multimode interferometer. These couplers can be integrated on a chip-based basis and thus guarantee compactness. Furthermore, they represent particularly reliable optical components.

[0030] According to a preferred embodiment of the optical sensor device, the ring resonator and the coupler are implemented by an arrangement of beam splitters and free-space mirrors. In this way, an optical sensor device can be realized with simple and relatively inexpensive components.

[0031] According to a preferred embodiment of the optical sensor device, the ring resonator has a "horserace" configuration, similar to the shape of an elongated hole, or a spiral configuration. Thus, the ring resonator has an extended sensing area, which increases sensitivity due to the larger surface area.

[0032] Short description of the drawings

[0033] The present invention is explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawing.

[0034] They show:

[0035] Fig. 1 A is a schematic representation of an optical sensor device according to an embodiment of the present invention;

[0036] Fig. 1 B is a schematic representation of a resonance curve of a ring resonator in an optical sensor device according to an embodiment of the present invention;

[0037] Fig. 2 is a schematic representation of an optical

[0038] Sensor device according to another embodiment of the present invention;

[0039] Fig. 3 is a schematic representation of an optical

[0040] Sensor device according to another embodiment of the present invention; and

[0041] Fig. 4 is a schematic representation of an optical

[0042] Sensor device according to another embodiment of the present invention;

[0043] In the figures, identical reference numerals denote identical or functionally identical elements. Fig. 1A shows a schematic representation of an optical sensor device 1 according to an embodiment of the present invention.

[0044] The optical sensor device 1 shown in Fig. 1 comprises a laser light source 2 for providing laser light L. The laser light source 2 can be any form of laser suitable for the application. Compact laser light sources 2 are preferred, which also have a narrow linewidth and oscillate with a small number of modes, preferably with a single mode. For example, DFB lasers or diode-pumped fiber lasers with Bragg gratings or similar devices are used.

[0045] The optical sensor device 1 further comprises an optical ring resonator 3, which is arranged to receive a portion of the laser light via a coupler 4. In certain embodiments, the coupler 4 is designed as an evanescent coupler. In further embodiments, the coupler 4 is designed as a multimode interferometer. The ring resonator 3 comprises an optically nonlinear material and / or an optically absorbing material such that a resonance curve 31 of the ring resonator 3, as a function of the wavelength of the laser light L to be received, is asymmetric with respect to a resonance wavelength 32. A detection device 5, which is configured to detect a portion of the laser light L not coupled into the ring resonator 3. Thus, a photodetector 5 is provided, which detects the laser light L that is not coupled into the ring resonator and passes through the coupler.The transmission of a ring resonator 3, i.e. the part of the laser light L which is not coupled into the ring resonator, can be given as follows.

[0046] T = | / c / [(y + K) / 2 - rA]- 11 2 where the coupling rate K, the loss rate y, and the detuning A are included in the formula. This transmitted laser light L is detected by the photodetector 5.

[0047] The optical sensor device 1 further comprises a control device 6, which is designed to control a laser power of the laser beam source 2 based on the detected portion of the laser light L not coupled into the ring resonator 3 such that the laser light L coupled into the ring resonator has a laser wavelength located on the steeply rising side 31b of the resonance curve 31. The resonance curve 31 with the steeply rising side 31b is explained in more detail in the following Fig. 1B.

[0048] Fig. 1 B shows a schematic representation of a resonance curve 31 of a ring resonator 3 in an optical sensor device according to an embodiment of the present invention.

[0049] The resonance curve 31 shown in Fig. 1B is plotted as intensity on the vertical axis 33 as a function of the wavelength 34. The resonance curve 31 has a side 31a that rises gently toward the resonance wavelength 32, which represents the highest point in the resonance curve 31, and a side 31b that rises steeply toward the resonance wavelength 32. In this embodiment of the optical sensor device 1, the wavelength 30 of the laser light L coupled into the ring resonator 3 is arranged at a steepest point of the resonance curve 31.

[0050] The coupling rate and the loss rate define the intensity gain of the resonance curve 31. The detuning creates the optical bistability and a shift in the resonance frequency. This is composed of effects such as self-phase modulation and thermal modulation. Self-phase modulation causes bistability due to susceptibility, while thermal modulation absorbs photons and converts them into heat. Both cause bistability, as shown in Fig. 1B. It can be seen that the slope in the nonlinear resonance curve 32, particularly on the steeply rising side 31b, is steeper than in a linear curve 33 drawn for comparison, which represents a symmetrical resonance curve 35 in the absence of the optically nonlinear and / or optically absorbing material in the ring resonator 3.In the present invention, the power of the laser light L transmitted by the ring resonator 3 is measured by the photodetector 5. For this purpose, the resonance frequency or resonance wavelength 32 of the ring resonator 3 is shifted so that the wavelength of the coupled laser light 30 is positioned at the steepest point possible, as shown in Fig. 1B.

[0051] The nonlinearity thus allows a strong signal edge and thus high sensitivity to be achieved. If a rotation rate acts on the system, the Sagnac effect causes a change in the effective length of the resonator, thus changing the resonance frequency 32 and thus resulting in an effective phase change. Due to this change, the measured power of the transmission at the photodetector 5 in Fig. 1 A changes. Due to the bistability, the change in transmission becomes stronger and thus the optical sensor device 1 becomes more sensitive. This is also possible because the steady state is established very quickly in this optical system, and thus phase changes can be measured almost directly in a power change.

[0052] Fig. 2 shows a schematic representation of an optical sensor device 1 according to a further embodiment of the present invention.

[0053] The optical sensor device 1 of Fig. 2 is based on the optical sensor device 1 of Fig. 1 and can be combined with one another. The optical sensor device 1 shown in Fig. 2 has a light splitting device 71, which is arranged and designed to split the laser light L into a first light path 11 and a second light path 12 in a predetermined ratio. The coupler 4 is arranged on the first light path 11. The detection device 5 is configured to detect laser light L split in the second light path. This means that, in addition to a first photodetector 5a, which detects the laser light not coupled into the ring resonator 3 in the first light path 11, a second photodetector 5b is provided, which detects the laser light branched into the second light path 12. The second photodetector 5b is connected to the control device 6 (shown in Fig. for clarity).2 omitted) and configured to control the laser power of the laser light source 2 based on the measured light quantity at the second photodetector 5b. Fig. 3 shows a schematic representation of an optical sensor device 1 according to another embodiment of the present invention.

[0054] The optical sensor device 1 of Fig. 3 is based on the optical sensor device 1 of Fig. 1 and can be combined with each other. Furthermore, the optical sensor device shown in Fig. 3 can be considered an alternative embodiment to the optical sensor device 1 of Fig. 2. However, the optical sensor directions shown in Fig. 2 and Fig. 3 can still be combined with each other.

[0055] The optical sensor device 1 shown in Fig. 3 has a light switch 72, which is designed to deflect the laser light into a first light path or a second light path. In contrast to the light splitting device 71, the light switch 71 deflects the entire incoming light quantity of the laser light L emitted by the laser light source 2 onto the first or second light path.

[0056] The detection device 5 is configured to detect laser light deflected into the second light path. For this purpose, both light paths 11, 12 are combined on a photodetector 5, which, depending on the switching state of the light switch 72, detects the laser light L propagated in the first light path 11 and not coupled into the ring resonator 3 via the coupler 4, or the laser light L propagating via the second light path 12. The photodetector 5 is connected to the control device 6 (omitted from Fig. 2 for the sake of clarity) and configured to control the laser power of the laser light source 2 based on the amount of light measured at the photodetector 5, also depending on the setting of the light switch. Since the oscillation of the ring resonator 3 is in the ns range, the light switch 72 can be switched in the .s range in order to monitor the power of the laser light source 2 and adjust it accordingly.

[0057] Alternatively, the light splitting device 71 or the light switch 72 can also be implemented in the coupler 4. Thus, only one coupler 4 is required as a component, and only one light supply to the photodiode 5 is necessary. Fig. 4 shows a schematic representation of an optical sensor device 1 according to a further embodiment of the present invention.

[0058] The optical sensor device 1 of Fig. 4 is based on the optical sensor devices 1 of Figs. 1 to 3 and can also be combined with these.

[0059] In this embodiment, the ring resonator has a phase shifter 80, which is designed to shift a phase of the laser light L coupled into the ring resonator 3. The phase shifter 80 can be either a thermal phase shifter 80, which shifts the temperature and thus the phase, or an electro-optical phase shifter, which shifts the refractive index of the waveguide material and thus the phase. By appropriately adjusting the control of the phase of the laser light L, the frequency or wavelength of the laser light L can be changed, so that the wavelength used can be optimally adjusted to the steepest point in the resonance curve 31 in order to achieve increased sensitivity. In addition, a further phase shifter 81 is arranged between the light splitting device 71, or, in certain embodiments the light switch 72, and the coupler 4, with which the laser light L can also be phase-shifted and thus frequency-shifted by controlling it with the control device 6 in order to set the wavelength of the laser light to the steepest point of the resonance curve 31 of the ring resonator 3 (connection of the control device 6 to the phase shifter 81 not shown in Fig. 4 for the sake of clarity).

[0060] Furthermore, the optical sensor device 1 has a temperature sensor 82 for detecting the ambient temperature. The control device 6 is designed to control the phase shifter 80 based on the detected ambient temperature.

[0061] Furthermore, in this embodiment of the optical sensor device 1, a variable attenuator 9 is provided, which is arranged between the laser light source 2 and the coupler 4. In further embodiments, the variable attenuator 9 is arranged in a chip-integrated manner downstream of the coupler 4. The control device 6 is configured to control the variable attenuator 9 to control the laser power. Furthermore, the control device 6 is configured to control all phase shifters 80.

[0062] In this embodiment of the optical sensor device 1, the detection device 5 is configured to detect laser light coupled out of the ring resonator 3 via a further coupler 41. This is achieved using a third photodiode 5c, which sends a corresponding electrical signal to the control device 6. The control device 6 is configured to control the laser power based on a detected light quantity of the laser light L coupled out of the ring resonator 3. Furthermore, the control device 6 is configured to control the phase shifter 80 based on the detected light quantity of the laser light coupled out of the ring resonator 3.

[0063] Furthermore, Fig. 4 shows that some components, such as the ring resonator 3, are arranged on a photonic integrated circuit 10. A chip coupler 21 arranged between the laser light source 2 and the light splitting device 71 is designed to couple the laser light L provided by the laser light source 2 onto the photonic integrated circuit 10. In further embodiments, the laser light source 2 is also heterogeneously or homogeneously integrated on the photonic integrated circuit 10, so that no chip coupler 21 is necessary.

[0064] Although the present invention has been fully described above using the preferred embodiment, it is not limited thereto but can be modified in many ways.

[0065] In further embodiments, the ring resonator 3 has a slotted waveguide having a slotted region between a first conductor core and a second conductor core, wherein the optically nonlinear material and / or the optically absorbing material is arranged in the slotted region. This can increase the nonlinearity of the ring resonator 3 and thus improve the sensitivity of the optical sensor device 1. Even if the ring resonator 3 is shown as a ring by way of example, it is not limited to this shape. In further embodiments, the ring resonator has a "horse-race" or spiral arrangement. The ring resonator thus has an extended sensor area, which increases the sensitivity due to the larger surface area.

[0066] In further embodiments, the laser light source 2 is manufactured chip-integrated and integrated with the photonic integrated circuit 10 via homo- or heterogeneous integration.

[0067] In further embodiments, the ring resonator 3 and the coupler 4 are implemented by an arrangement of beam splitters and free-space mirrors instead of fiber optic components. Thus, the optical sensor device 1 can be implemented using simple and relatively inexpensive optical components.

Claims

Claims 1. An optical sensor device (1) comprising a laser light source (2) for providing laser light (L), an optical ring resonator (3) arranged to receive a portion of the laser light via a coupler (4), wherein the ring resonator (3) comprises an optically non-linear material and / or an optically absorbing material such that a resonance curve (31) of the ring resonator (3) is asymmetrical with respect to a resonance wavelength (32) as a function of the wavelength of the laser light (L) to be received, wherein the resonance curve (31) has a side (31a) rising gently towards the resonance wavelength and a side (31b) rising steeply towards the resonance wavelength (32), a detection device (5) configured to detect a portion of the laser light (L) not coupled in the ring resonator (3), a control device (6) configured toto control a laser power of the laser beam source (2) based on the detected portion of the laser light (L) not coupled into the ring resonator (3) such that laser light (L) coupled into the ring resonator (3) has a laser wavelength (30) which is arranged on the steeply rising side (31 b) of the resonance curve (31).

2. Optical sensor device (1) according to claim 1, wherein a light splitting device (71) is provided which is arranged and designed to split the laser light (L) into a first light path (11) and a second light path (12) in a predetermined ratio, wherein the coupler (4) is arranged on the first light path (11), wherein the detection device (5) is set up to detect laser light (L) split in the second light path (12).

3. Optical sensor device (1) according to claim 1, wherein a light switch (72) is provided which is designed to deflect the laser light into a first light path (11) or a second light path (12), wherein the coupler (4) is arranged on the first light path (11), wherein the detection device (5) is configured to detect laser light (L) deflected into the second light path (12), wherein the light switch (72) is integrated in particular in the coupler (4).

4. Optical sensor device (1) according to one of the preceding claims, wherein the wavelength (30) is arranged at a steepest point of the resonance curve (31).

5. Optical sensor device (1) according to one of the preceding claims, wherein the ring resonator has a phase shifter (80) which is configured to shift a phase of the laser light (L) coupled into the ring resonator (3).

6. Optical sensor device (1) according to claim 5, wherein a temperature sensor (82) is provided for detecting the ambient temperature, wherein the control device (6) is designed to control the phase shifter (80) based on the detected ambient temperature.

7. Optical sensor device (1) according to one of the preceding claims, wherein a variable attenuator (9) is provided, which is arranged, in particular chip-integrated, between the laser light source (2) and the coupler (4), wherein the control device (6) is designed to control the variable attenuator (9) to control the laser power.

8. Optical sensor device (1) according to one of the preceding claims, wherein the detection device (5) is configured to detect laser light coupled out of the ring resonator (3) via a further coupler (4), wherein the control device (6) is configured to control the laser power based on a detected light quantity of the laser light (L) coupled out of the ring resonator (3).

9. Optical sensor device (1) according to claim 8, wherein the control device (6) is designed to control the phase shifter (80) based on the detected light quantity of the laser light coupled out of the ring resonator (3).

10. Optical sensor device (1) according to one of the preceding claims, wherein the ring resonator (3) comprises a slot waveguide having a slot region between a first conductor core and a second conductor core, wherein the optically non-linear material and / or the optically absorbing material is arranged in the slot region.

11. Optical sensor device (1) according to one of the preceding claims, wherein the ring resonator (3) is arranged on a photonic integrated circuit (10), wherein a chip coupler (21) is provided which is designed to couple the laser light (L) provided by the laser light source (2) onto the photonic integrated circuit (10).

12. Optical sensor device (1) according to one of the preceding claims, wherein the ring resonator (3) and the laser light source (2) are heterogeneously or homogeneously integrated on a photonic integrated circuit (10).

13. Optical sensor device (1) according to one of the preceding claims, wherein the coupler (4) is designed as an evanescent coupler or a multimode interferometer.

14. Optical sensor device (1) according to one of the preceding claims, wherein the ring resonator (3) and the coupler (4) are realized by an arrangement of beam splitters and free-space mirrors.

15. Optical sensor device (1) according to one of the preceding claims, wherein the ring resonator (3) has a horse-race or spiral arrangement.

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