Integrated micro-force micro-displacement sensing chip based on TPP and semiconductor laser

Abstract

The invention relates to the technical field of micro-nano sensing, and discloses an integrated micro-force micro-displacement sensing chip based on a TPP and a semiconductor laser, and the chip comprises a high-power semiconductor FP laser, the light-emitting surfaces of the two sides of the high-power semiconductor FP laser are first natural cleavage surfaces, and a second natural cleavage surface forms a first FP resonant cavity; the Gaussian beam reconstruction wavefront reflecting surface is used for forming a second FP resonant cavity with a second natural cleavage surface, close to one side of the high-power semiconductor FP laser, of the high-power semiconductor FP laser, and the cavity length of the second FP resonant cavity is variable; and the first elastic deformation mechanism is connected with the Gaussian beam reconstruction wavefront reflecting surface. The FP laser, the two-photon 3D printing deformable outer cavity and the optimized reflecting surface are integrated, laser wavelength is monitored, force and displacement are precisely measured, high integration, high sensitivity and excellent optical coupling are achieved, and the sensing bottleneck is broken through.

Description

Technical Field

[0001] The present invention relates to the field of micro-nano sensing technology, and in particular to an integrated micro-force and micro-displacement sensing chip based on TPP and semiconductor lasers. Background Art

[0002] Precise force measurement plays a fundamental role in all cutting-edge research fields. At the macroscopic level, precise measurements of gravity in outer space contribute to our understanding of the structure and evolution of the universe. At the microscopic level, accurate understanding of intermolecular forces is crucial for in-depth studies of chemical reaction mechanisms and biomolecular interactions. Currently, key micro-force measurement technologies include atomic force microscopes (AFMs) and specially developed micro- / nano-electromechanical systems (MEMS / NEMS) sensors. AFMs utilize the tip of a microcantilever to detect forces as low as tens of piconewtons. However, these instruments are expensive, complex, and suffer from poor electromagnetic compatibility. In practice, AFMs require sophisticated equipment and specialized operators, limiting their widespread adoption. MEMS / NEMS sensors, despite their tiny size and high sensitivity and response speed, still struggle for applications requiring extremely high precision, such as piconewton-level force measurement. Furthermore, they are susceptible to environmental influences, lacking environmental adaptability and stability.

[0003] Optical micro-force sensors, such as fiber Bragg grating (FBG) sensors, laser interferometers, and confocal optical sensors, are highly sensitive and can detect extremely weak changes in physical quantities. By precisely measuring changes in light parameters such as intensity, phase, and wavelength, they can achieve high-precision measurements of minute forces. Optical signals are immune to electromagnetic interference and can operate stably even in complex electromagnetic environments or those subject to strong electromagnetic interference, ensuring accurate measurement results. Optical sensors also possess excellent spatial resolution and can measure forces in micro- and nanoscale regions by focusing a light beam. They are applicable to research in a wide range of fields, including biomedicine, materials science, and micro- and nano-manufacturing.

[0004] Therefore, the present invention proposes an integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser to solve the shortcomings of the existing technology. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides an integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser, which solves the problems in developing micro-force and micro-displacement sensors with high sensitivity, high integration, miniaturization and low cost.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: an integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser, comprising:

[0007] A high-power semiconductor FP laser, wherein the light-emitting surfaces on both sides of the high-power semiconductor FP laser are respectively a first natural cleavage plane and a second natural cleavage plane, forming a first FP resonant cavity;

[0008] a Gaussian beam reconstruction wavefront reflection surface, wherein the Gaussian beam reconstruction wavefront reflection surface is used to form a second FP resonant cavity with a second natural cleavage plane of the high-power semiconductor FP laser close to the second natural cleavage plane, and the cavity length of the second FP resonant cavity is variable;

[0009] a first elastic deformation mechanism connected to the Gaussian beam reconstructed wavefront reflection surface, and configured to drive the Gaussian beam reconstructed wavefront reflection surface to displace under the action of an external force, thereby changing the cavity length of the second FP resonant cavity;

[0010] A base is used to be fixed to the high-power semiconductor FP laser and connected to the first elastic deformation mechanism.

[0011] Preferably, the sensor chip also includes a carrier, the high-power semiconductor FP laser is arranged on the upper surface of the carrier, and a thin film circuit is provided on the upper surface of the carrier. The thin film circuit is connected to an external power supply and is used to inject current into the high-power semiconductor FP laser, that is, to light up the high-power semiconductor FP laser.

[0012] Preferably, the electrodes of the high-power semiconductor FP laser are connected to the thin-film circuit through gold wire bonding, and the light-emitting end face of the high-power semiconductor FP laser is connected to the coupling optical fiber through a photon wire bonding waveguide, which is used for low-loss output light coupling and input into a spectrometer for spectral analysis; a base is provided on the upper surface of the high-power semiconductor FP laser, and the base is connected to one end of a first elastic deformation mechanism, and the other end of the first elastic deformation mechanism is connected to a Gaussian beam reconstructed wavefront reflection surface, and the first elastic deformation mechanism causes the position of the Gaussian beam reconstructed wavefront reflection surface to displace along the transmission direction of the output light of the high-power semiconductor FP laser.

[0013] Preferably, the output lasing wavelength of the high power semiconductor FP laser is At the same time, it is modulated by the first FP resonant cavity and the second FP resonant cavity; when the external force When acting on the Gaussian beam reconstruction wavefront reflection surface, the first elastic deformation mechanism drives the Gaussian beam reconstruction wavefront reflection surface to displace , so that the cavity length of the second FP resonant cavity is reduced from the initial cavity length becomes The change of the second FP resonant cavity length causes the output lasing wavelength of the high power semiconductor FP laser to Measurable wavelength shift occurs The external force With the displacement The relationship between them conforms to: ,in is the stiffness coefficient of the first elastic deformation mechanism; the measurable wavelength drift With the displacement There is a corresponding relationship between the wavelength shift and the To determine the displacement And the external force .

[0014] Preferably, the Gaussian beam reconstructed wavefront reflection surface has a reflection surface, and after the outgoing beam of the high-power semiconductor FP laser propagates a certain distance, the outgoing beam wavefront morphology is a rotationally non-symmetric characteristic, and the reflection surface of the Gaussian beam reconstructed wavefront reflection surface is therefore specially constructed into a rotationally non-symmetric aspherical structure.

[0015] Preferably, the surface profile of the non-rotationally symmetric aspherical structure is described by the following formula: ;

[0016] in, 、 The equation of the reflecting surface is and The major and minor axis coefficients in the direction, for , The curvature of the surface at is the quadratic constant of the reflection surface equation, 、 、 They are the coefficients of the 4th, 6th and 8th order even terms respectively;

[0017] The specific curved surface profile of the aspheric structure is designed and optimized based on the actual isophase surface morphology of the outgoing light beam from the high-power semiconductor FP laser when it propagates to the location of the reflective surface, so as to ensure that the light beam from the high-power semiconductor FP laser reaching the reflective surface can be accurately reflected back into the high-power semiconductor FP laser with maximum efficiency, thereby effectively coupling into and forming the second FP resonant cavity;

[0018] The coefficient 、 、 、 、 、 、 The value of is obtained by fitting the isophase point data of the light beam emitted by the high-power semiconductor FP laser at a predetermined position.

[0019] The present invention also provides a method for preparing an integrated micro-force and micro-displacement sensor chip based on TPP and a semiconductor laser, comprising:

[0020] S1. Providing a high-power semiconductor FP laser (4), wherein the high-power semiconductor FP laser (4) has two opposing natural cleavage planes, wherein one of the natural cleavage planes is a second natural cleavage plane (14) designated as a first laser end face for forming an external cavity, and the other natural cleavage plane is a first natural cleavage plane (12) designated as a second laser end face for light output;

[0021] S2. Using a two-photon polymerization process, a base (5), a first elastic deformation mechanism (6), and the Gaussian beam reconstruction wavefront reflection surface (7) are integrally manufactured on the high-power semiconductor FP laser (4) or relative to the high-power semiconductor FP laser (4), so that the base (5) is fixed to the high-power semiconductor FP laser (4), the first elastic deformation mechanism (6) connects the base (5) and the Gaussian beam reconstruction wavefront reflection surface (7), and the Gaussian beam reconstruction wavefront reflection surface (7) and the first laser end face of the high-power semiconductor FP laser (4) together constitute the second FP resonant cavity (15);

[0022] S3. Using a two-photon polymerization process, manufacture a photonic wire bonding waveguide to optically couple the second laser end face of the high-power semiconductor FP laser to a coupling optical fiber.

[0023] Preferably, the high-power semiconductor FP laser in step S1 is formed by stacking, from bottom to top, a substrate, a buffer layer, a slab-coupled waveguide layer, a lower confinement layer, a multi-quantum well layer, an upper confinement layer, a corrosion barrier layer, a waveguide layer, and a contact layer, including:

[0024] S11, sequentially growing a buffer layer, a planar coupling waveguide layer, and a lower confinement layer on the substrate by metal organic compound vapor deposition, then growing a multi-quantum well layer on the lower confinement layer, growing an upper confinement layer on the multi-quantum well layer, and then growing a corrosion barrier layer on the upper confinement layer;

[0025] S12, depositing InP on the corrosion barrier layer, and then sequentially growing the corrosion barrier layer, the waveguide layer, and the contact layer;

[0026] S13, corroding the waveguide layer and the contact layer to form a ridge, etching electrical isolation to achieve partitioning, and growing a front metal electrode in the ridge area above the contact layer;

[0027] S14, thinning and polishing the back side of the substrate, evaporating the back electrode and heating to obtain an alloy, and cleaving the chip to obtain the high-power semiconductor quantum well FP laser.

[0028] Preferably, the step of manufacturing the base, the first elastic deformation mechanism and the Gaussian beam reconstruction wavefront reflection surface by using a two-photon polymerization process in step S2 includes:

[0029] S21, fixing the high-power semiconductor FP laser on a processing stage, and applying a photosensitive resin on the upper surface of the high-power semiconductor FP laser and a predetermined processing area near the end face of the first laser;

[0030] S22. Utilizing optical imaging and image recognition algorithms, accurately identifying a predetermined printing position on the high-power semiconductor FP laser, and reconstructing a preset three-dimensional digital model of the wavefront reflection surface based on the base, the first elastic deformation mechanism, and the Gaussian beam, aligning and using a focused laser beam to selectively induce a polymerization reaction within the photosensitive resin via a two-photon absorption effect, thereby constructing the three-dimensional structure in a point-by-point, line-by-line, and layer-by-layer scanning exposure manner;

[0031] S23. After the exposure is completed, the unpolymerized photosensitive resin is removed by a development operation and cleaned to reveal and obtain the base, the first elastic deformation mechanism and the Gaussian beam reconstruction wavefront reflection surface integrated with the high-power semiconductor FP laser.

[0032] Preferably, the step of manufacturing the photon wire bonding waveguide by using a two-photon polymerization process in step S3 includes:

[0033] S31, aligning the second laser end face of the high-power semiconductor FP laser with the input end of the coupling optical fiber, fixing the two on a common substrate, and then applying a photosensitive resin to a predetermined processing area between the second laser end face and the input end of the coupling optical fiber;

[0034] S32. Using a high-power objective lens observation system in combination with an image recognition algorithm, identify the optical port positions and normal directions of the second laser end face and the input end of the coupling optical fiber, and accordingly plan the three-dimensional path and geometric shape required for the photonic wire bonding waveguide;

[0035] S33, using a focused laser beam to selectively initiate a polymerization reaction within the photosensitive resin through a two-photon absorption effect according to the planned path and geometric shape, thereby completing exposure and forming of the photonic wire bonding waveguide;

[0036] S34. After the exposure is completed, the unpolymerized photosensitive resin is removed by a development process to reveal and obtain the photon wire bonding waveguide connecting the second laser end face of the high-power semiconductor FP laser and the input end of the coupling optical fiber.

[0037] The present invention provides an integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser. It has the following beneficial effects:

[0038] 1. This invention utilizes a sensing solution that integrates a high-power semiconductor FP laser with a two-photon polymerization 3D-printed deformable external cavity. This solution achieves the technical effect of precisely detecting minute displacements and external forces by monitoring changes in the laser's lasing wavelength. Compared to existing sensing systems that rely on discrete components and complex optical coupling, this invention addresses the limitations of low integration, difficult system calibration, and potentially poor alignment stability.

[0039] 2. This invention utilizes a reflective surface manufacturing solution that combines optimized laser output wavefront reconstruction with two-photon polymerization 3D printing technology. This allows for the precise manufacture of complex curved reflectors that match the laser beam wavefront, significantly improving optical feedback efficiency and laser operating stability. Compared to existing designs that commonly use standard flat or spherical reflectors, this invention addresses the shortcomings of low optical coupling efficiency and poor sensor signal quality caused by beam mode mismatch.

[0040] 3. This invention utilizes two-photon polymerization technology to in-situ integrate the base, elastic deformation mechanism, and wavefront reconstruction reflector, among other key sensing microstructures, onto the laser chip. This results in a highly integrated, highly aligned, and mechanically superior all-in-one sensing device. Compared to traditional micro-nano device manufacturing processes that rely on separate machining of multiple components followed by precise assembly, this invention addresses the drawbacks of complex processes, the susceptibility to assembly errors, and the difficulty in achieving device miniaturization and high-precision alignment.

[0041] 4. This invention utilizes a high-power semiconductor FP laser coupled with a deformable external resonant cavity customized using two-photon polymerization technology to form a dual-cavity system. This sensing scheme directly inverts external force or displacement by monitoring laser output wavelength drift, achieving high-sensitivity, high-resolution measurement, and simplified signal demodulation. Compared to existing sensing mechanisms that rely on changes in light intensity, capacitance, or other indirect physical quantity conversions, this invention addresses the potential for nonlinear responses, susceptibility to environmental noise, and relatively complex signal processing.

[0042] 5. This invention utilizes an integrated optical sensing solution that deeply integrates a high-power semiconductor FP laser, a two-photon 3D-printed deformable external cavity, and an optimized wavefront reconstruction reflective surface. This solution achieves the technical effect of constructing a miniaturized, high-precision, and highly sensitive micro-force and micro-displacement sensing system. Compared to existing solutions that simply combine or discretely apply these technical elements, failing to fully exploit their synergistic advantages, this invention addresses these shortcomings in terms of increasing integration, optimizing optical coupling efficiency, and breaking through sensing performance bottlenecks. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A perspective view of the device of the present invention;

[0044] Figure 2 Schematic diagram of the micro-force and micro-displacement test of the present invention;

[0045] Figure 3 Schematic diagram of the slope of the fitted straight line of the present invention;

[0046] Figure 4 The spring stress diagram of the present invention is shown in FIG. Figure 1 ;

[0047] Figure 5 The spring stress diagram of the present invention is shown in FIG. Figure 2 ;

[0048] Figure 6 Schematic diagram of the mode field distribution of the TE fundamental mode of the laser of the present invention;

[0049] Figure 7 Schematic diagram of the structure of the high-power semiconductor quantum well FP laser of the present invention;

[0050] Figure 8 Schematic diagram of the second elastic deformation mechanism of the present invention.

[0051] Among them, 1. spectrometer; 2. coupling optical fiber; 3. photon wire bonding waveguide; 4. high-power semiconductor FP laser; 5. base; 6. first elastic deformation mechanism; 7. Gaussian beam reconstruction wavefront reflection surface; 8. thin film circuit; 9. carrier; 10. gold wire bonding; 11. external power supply; 12. first natural cleavage plane; 13. first FP resonant cavity; 14. second natural cleavage plane; 15. second FP resonant cavity; 16. first reflection spectrum; 17. second reflection spectrum; 18. first fitting straight line; 19. rectangular cross-section width; 20. rectangular cross-section thickness; 21. natural length; 22. spring radius; 23. second fitting straight line; 24. equal phase point; 25. reflection surface morphology; 26. second elastic deformation mechanism. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0053] See also Figure 1-6 The embodiment of the present invention provides an integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser, comprising:

[0054] A high-power semiconductor FP laser 4, wherein the light-emitting surfaces on both sides of the high-power semiconductor FP laser 4 are respectively a first natural cleavage plane 12 and a second natural cleavage plane 14 forming a first FP resonant cavity 13;

[0055] Specifically, a high-power semiconductor FP laser 4 is used as the light source of the chip. The high-power semiconductor FP laser 4 has two opposite light-emitting surfaces, namely a first natural cleavage surface 12 and a second natural cleavage surface 14. The two natural cleavage surfaces themselves constitute a Fabry-Perot (FP) resonant cavity, namely a first FP resonant cavity 13. In a specific embodiment, the physical length of the first FP resonant cavity 13 ( ) can be 500µm;

[0056] The Gaussian beam reconstruction wavefront reflection surface 7 is arranged opposite to the second natural cleavage surface 14 of the high-power semiconductor FP laser 4, and together they form a second Fabry-Perot resonant cavity, i.e., a second FP resonant cavity 15. The cavity length of the second FP resonant cavity 15 is variable. In a specific embodiment, its initial static cavity length ( The surface profile of the Gaussian beam reconstruction wavefront reflection surface 7 is specially designed to optimize the reflection efficiency.

[0057] One end of the first elastic deformation mechanism 6 is connected to the Gaussian beam reconstruction wavefront reflection surface 7, and the other end is connected to the base 5. Its main function is to drive the Gaussian beam reconstruction wavefront reflection surface 7 to displace along the transmission direction of the output light of the high-power semiconductor FP laser 4 when an external force is applied to the Gaussian beam reconstruction wavefront reflection surface 7, thereby accurately changing the cavity length of the second FP resonant cavity 15.

[0058] a Gaussian beam reconstruction wavefront reflection surface 7, wherein the Gaussian beam reconstruction wavefront reflection surface 7 is used to form a second FP resonant cavity 15 with a second natural cleavage plane 14 of the high-power semiconductor FP laser 4 close to the second natural cleavage plane 14 of the high-power semiconductor FP laser 4, and the cavity length of the second FP resonant cavity 15 is variable;

[0059] a first elastic deformation mechanism 6, connected to the Gaussian beam reconstruction wavefront reflection surface 7, and configured to drive the Gaussian beam reconstruction wavefront reflection surface 7 to displace under the action of an external force, thereby changing the cavity length of the second FP resonant cavity 15;

[0060] a base 5, the base 5 being used to be fixed to the high-power semiconductor FP laser 4 and connected to the first elastic deformation mechanism 6;

[0061] Specifically, the base 5 is directly fixed to the upper surface of the high-power semiconductor FP laser 4 and connected to one end of the first elastic deformation mechanism 6 to provide a stable support and positioning reference for the elastic mechanism and the reflective surface.

[0062] The sensor chip further includes a carrier 9, the high-power semiconductor FP laser 4 is arranged on the upper surface of the carrier 9, and a thin film circuit 8 is provided on the upper surface of the carrier 9. The thin film circuit 8 is connected to an external power supply 11 and is used to inject current into the high-power semiconductor FP laser 4, that is, to light up the high-power semiconductor FP laser 4;

[0063] Specifically, the high-power semiconductor FP laser 4 is arranged on the upper surface of the carrier 9, and the thin film circuit 8 is arranged on the upper surface of the carrier 9, and is connected to the electrode of the high-power semiconductor FP laser 4 through gold wire bonding 10; the external power supply 11 is connected to the thin film circuit 8, and is used to inject current into the high-power semiconductor FP laser 4 to achieve electric pumping lighting of the high-power semiconductor FP laser.

[0064] The electrodes of the high-power semiconductor FP laser 4 are connected to the thin-film circuit 8 via gold wire bonding 10, and the light-emitting end face of the high-power semiconductor FP laser 4 is connected to the coupling optical fiber 2 via a photon wire bonding waveguide 3, for low-loss output light coupling and input into the spectrometer 1 for spectral analysis; a base 5 is provided on the upper surface of the high-power semiconductor FP laser 4, and the base 5 is connected to one end of a first elastic deformation mechanism 6, and the other end of the first elastic deformation mechanism 6 is connected to a Gaussian beam reconstruction wavefront reflection surface 7, and the first elastic deformation mechanism 6 causes the position of the Gaussian beam reconstruction wavefront reflection surface 7 to shift along the transmission direction of the output light of the high-power semiconductor FP laser 4;

[0065] Specifically, in the optical coupling output section, the output end face of the high-power semiconductor FP laser 4 is connected to the external coupling optical fiber 2 via a photonic wire bonding waveguide 3. The photonic wire bonding waveguide 3 is used to low-loss transmit the optical output of the high-power semiconductor FP laser 4 to the coupling optical fiber 2, and further input it into the spectrometer 1 for spectral analysis.

[0066] See also Figure 2-Figure 6In this embodiment, the mechanism by which the integrated micro-force and micro-displacement sensor chip achieves its sensing function, along with the optimized design of its core optical components, form the basis for highly sensitive micro-force and micro-displacement measurement. This mechanism relies on a precisely controlled dual Fabry-Perot (FP) resonant cavity system modulating the output characteristics of the high-power semiconductor FP laser 4.

[0067] Specifically, the optical system core of the sensor chip includes two interacting FP resonant cavities. One is the first FP resonant cavity 13 inherent to the high-power semiconductor FP laser 4. The first FP resonant cavity 13 is composed of two opposite natural cleavage planes of the high-power semiconductor FP laser 4, namely the first natural cleavage plane 12 and the second natural cleavage plane 14. The first FP resonant cavity 13 has a certain physical cavity length, which is recorded as The second is a second FP resonant cavity 15 formed externally. The second FP resonant cavity 15 is composed of the second natural cleavage surface 14 of the high-power semiconductor FP laser 4 and the Gaussian beam reconstruction wavefront reflection surface 7 arranged outside and opposite to it. The initial static cavity length of this second FP resonant cavity 15 when it is not subjected to external force or displacement is recorded as For example, in one specific design, the initial static cavity length Can be set to 75µm.

[0068] In general, the final output laser wavelength of the high power semiconductor FP laser 4 is recorded as , is not solely determined by the internal first FP resonant cavity 13, but is modulated by the dual-cavity system consisting of this first FP resonant cavity 13 and the external second FP resonant cavity 15. This dual-cavity coupling effect makes the lasing mode selection of the high-power semiconductor FP laser 4 highly sensitive to changes in the parameters of the external resonant cavity (i.e., the second FP resonant cavity 15), especially small changes in its cavity length.

[0069] When there is an external force When the force is applied to the Gaussian beam reconstruction wavefront reflection surface 7, the first elastic deformation mechanism 6 connected to the Gaussian beam reconstruction wavefront reflection surface 7 will produce corresponding elastic deformation due to the force. This elastic deformation will drive the Gaussian beam reconstruction wavefront reflection surface 7 to undergo a slight displacement along the optical axis direction (i.e., the laser emission direction) of the high-power semiconductor FP laser 4. The displacement amount is recorded as .

[0070] This displacement The effective optical cavity length of the second FP resonant cavity 15 is directly changed from the initial cavity length becomes the new cavity length ( ). The external force The resulting displacement The relationship between , within the elastic working limit of the first elastic deformation mechanism 6, can usually be approximated as a linear relationship, that is: Here, represents the equivalent stiffness coefficient of the first elastic deformation mechanism 6, which mainly depends on the material properties and geometric configuration of the elastic mechanism.

[0071] This change in the length of the second FP resonant cavity 15 will cause a corresponding change in the effective reflection spectrum or mode loss spectrum of the entire dual-cavity coupling system. As a direct result, the output lasing wavelength of the high-power semiconductor FP laser 4 A corresponding wavelength shift will occur which can be precisely measured and is recorded as In a specific exemplary scenario, when an external force causes a displacement Changes, such as When the lasing wavelength changes from 0 to -100nm, It may change linearly from 1539.876nm to 1539.784nm. This laser wavelength and displacement The relationship between the two usually shows good linearity, and the displacement sensing sensitivity (i.e. ) can be accurately characterized by the slope of the straight line obtained by linear fitting of the experimental data. For example, the sensitivity value can be 0.0184 nm / nm.

[0072] Therefore, the wavelength shift of the output light of the high power semiconductor FP laser 4 can be analyzed by an external spectrum analysis device, such as a spectrometer 1. Real-time monitoring and high-precision measurement are performed, and the wavelength drift obtained in advance through experimental calibration or theoretical calculation is combined With the displacement The characteristic response relationship between the two can accurately infer the small displacement of the Gaussian beam reconstructed wavefront reflection surface 7. After further determining the displacement Then, if the stiffness coefficient of the first elastic deformation mechanism 6 is If it is known or has been obtained through calibration, then the relationship between force and displacement can be calculated based on the above equation , calculate the external force that causes the displacement size.

[0073] The first elastic deformation mechanism 6 is specifically implemented as a rectangular cross-section cylindrical helical compression spring. The structural parameters of the spring, such as the width of the rectangular cross section of the spring wire, are described as follows. 19. Rectangular section thickness 20. Effective working turns of the spring , the number of turns is 1, and the natural length of the spring when it is not stressed 21, can be precisely controlled and the spring radius can be achieved through two-photon polymerization (TPP) micro-nano manufacturing process 22. Through the finite element simulation analysis (FEM) method, the spring with specific geometric parameters and material properties can be analyzed under different external forces. Stress distribution and deformation under action Based on such simulation data or experimentally measured data, the force can be fitted and displacement The relationship curve between the spring constant and the spring constant is obtained for the specific spring design. For example, in one possible spring design, the spring constant is It can be 83.4pN / nm. Based on this stiffness coefficient And the aforementioned displacement sensing sensitivity , we can further deduce the micro-force measurement sensitivity of the sensor chip (Right now ), for example, the sensitivity of this micro-force measurement can reach the order of 0.22nm / nN.

[0074] To ensure the efficient and stable operation of the wavelength modulation-based sensing mechanism and achieve highly sensitive measurements, the light beam emitted from the high-power semiconductor FP laser 4 must be efficiently coupled back into itself to form a high-quality second FP resonant cavity 15. This is the fundamental reason for the optimized design of the Gaussian beam reconstruction wavefront reflection surface 7.

[0075] In general, the wavefront morphology of the light beam emitted from a high-power semiconductor FP laser, especially an edge-emitting laser such as the high-power semiconductor FP laser 4 described in this embodiment, often exhibits non-rotational symmetry after propagating a certain distance. This asymmetry is mainly due to the different limiting capabilities of the internal resonant cavity structure of the high-power semiconductor FP laser 4 on the light field in the plane parallel to the PN junction and perpendicular to the PN junction, as well as the anisotropy of the properties of the active region gain medium itself. Typically, the light beam emitted by the high-power semiconductor FP laser 4 has different waist radii, different far-field divergence angles, and possible astigmatism in the horizontal and vertical directions. For example, the near-field mode spot size of its output light field in the horizontal direction may be larger, and the corresponding far-field divergence angle is smaller; while the near-field mode spot size in the vertical direction may be smaller, and the corresponding far-field divergence angle is larger.

[0076] The electric field distribution of this asymmetric Gaussian beam Under certain conditions, it can be approximately described by the following formula: ;

[0077] in: is the light field at the initial position (e.g. The amplitude of the vibration at and The beams are At the laser light-emitting end face, Direction and The beam waist radius in the direction; and The propagation distance of the beam is Chuyan Direction and The spot radius of the direction; is the wave number of the light beam in the propagation medium; is the distance along the main direction of beam propagation; and Beam edges Direction and The Rayleigh length in the direction characterizes the collimation area of ​​the Gaussian beam; and The propagation distance of the beam is Chuyan Direction and The radius of curvature of the directional equivalent wavefront.

[0078] If a conventional plane mirror or a simple rotationally symmetric spherical mirror is used as the external reflector constituting the second FP resonant cavity 15, i.e., the Gaussian beam reconstruction wavefront reflection surface 7, then due to the inherent asymmetric divergence characteristics of the laser beam and possible wavefront distortion (such as astigmatism), only a small portion of the paraxial light near the center of the beam can be effectively reflected and coupled back into the resonant cavity (i.e., the first FP resonant cavity 13) of the high-power semiconductor FP laser 4. Most of the off-axis light is lost due to angle mismatch or mode mismatch, resulting in a poor match between the overall mode field distribution of the reflected light and the intrinsic mode of the high-power semiconductor FP laser 4 itself, thus causing low optical coupling efficiency. This inefficient coupling not only significantly increases the round-trip loss of the second FP resonant cavity 15 but may also adversely affect the operating characteristics of the laser 4, such as increasing its lasing threshold current, reducing its output power, and even affecting the stability of its lasing mode, thereby reducing the overall sensitivity and accuracy of the sensor.

[0079] To overcome this technical challenge and maximize optical feedback efficiency, in this embodiment, the reflective surface of the Gaussian beam reconstruction wavefront reflector 7 is specially designed and constructed as a non-rotationally symmetric aspheric structure. The core design concept is to ensure that the three-dimensional surface profile of the Gaussian beam reconstruction wavefront reflector 7 accurately matches or highly approximates the actual phase plane shape of the output beam of the high-power semiconductor FP laser 4 when it propagates to the location of the reflective surface.

[0080] The surface profile of the non-rotationally symmetric aspherical structure , that is, the surface height changes with the transverse coordinate in the Cartesian coordinate system with the intersection of the optical axis and the surface as the origin. and The changing relationship shows the reflection surface morphology 25 reconstructed based on the equal phase point 24, and the surface equation of the reflection surface is reconstructed by fitting the equal phase point 24: ;

[0081] in, 、 The equation of the reflecting surface is and The major and minor axis coefficients in the direction, for , The curvature of the surface at is the quadratic constant of the reflection surface equation, 、 、 These are the 4th, 6th, and 8th order even-order coefficients. These higher-order coefficients are used to further refine the basic quadratic surface, allowing the reflective surface to more accurately fit complex or non-ideal wavefront shapes and effectively compensate for possible higher-order aberrations.

[0082] In a possible implementation, the coefficients of the above aspheric equations (e.g. 、 、 、 、 、 、 The determination of the precise value of , etc.) is a process based on detailed analysis and optimization calculation of the actual output beam characteristics of the high-power semiconductor FP laser 4.

[0083] This process usually includes: first, through precise optical simulation tools or high-resolution wavefront sensing experimental technology, the three-dimensional light field distribution data of the outgoing light beam of the high-power semiconductor FP laser 4 is obtained when it propagates in free space to the predetermined Gaussian beam reconstruction wavefront reflection surface 7 design position, especially its isophase surface data. Then, a series of representative spatial coordinate points are extracted from the calculated or measured isophase surface. Finally, a nonlinear surface fitting algorithm is used to fit the coordinate data of these sampling points as target data to fit the above-mentioned aspheric equation, and a set of coefficient values ​​that can best describe the shape of the isophase surface is obtained through an iterative optimization process. For example, when the initial cavity length of the second FP resonant cavity 15 is An example set of aspheric coefficients that might be obtained through such a fitting process, with a diameter of 75µm, is: .

[0084] By using this non-rotationally symmetric aspheric surface, customized based on the wavefront characteristics of the actual output light beam from the high-power semiconductor FP laser 4, as the Gaussian beam reconstruction wavefront reflection surface 7, it is possible to ensure that the majority of the energy of the light beam emitted from the high-power semiconductor FP laser 4 and reaching the Gaussian beam reconstruction wavefront reflection surface 7 can be accurately reflected back into the first FP resonant cavity 13 of the high-power semiconductor FP laser 4 in a manner that approximates the original path, and is effectively coupled into, thereby forming the second FP resonant cavity 15 with high quality. This optimized design not only significantly improves the efficiency of optical feedback and effectively reduces the round-trip loss of the external resonant cavity, but also helps to maintain the stable lasing of the high-power semiconductor FP laser 4 in the desired single longitudinal mode or a few specific longitudinal modes, and enhances the response sensitivity of the output wavelength of the high-power semiconductor FP laser 4 to changes in the cavity length of the external resonant cavity 15. This provides a solid optical foundation and performance guarantee for achieving high-precision and high-stability micro-force and micro-displacement sensing.

[0085] See also Figure 7 In this embodiment, the preparation method of the integrated micro-force and micro-displacement sensor chip mainly includes the preparation of a high-power semiconductor FP laser 4, and then the integration of key optical and mechanical microstructures using two-photon polymerization (TPP) technology. The specific technical implementation method is as follows:

[0086] In this embodiment, the steps of providing a high-power semiconductor FP laser 4 are described in detail. The preparation of the high-power semiconductor FP laser 4 is the basis for the entire sensor chip manufacturing. Its typical structural form is a multi-layer heterojunction structure.

[0087] During the fabrication process, semiconductor materials are first grown epitaxially. Specifically, on a selected suitable substrate, such as an indium phosphide (InP) substrate, precise epitaxial growth techniques such as metal organic chemical vapor deposition (MOCVD) are used to sequentially grow the materials according to the pre-designed device structure and the required thickness of each functional layer. These functional layers typically include, from the substrate upwards: a buffer layer, which improves the crystal quality of the subsequent epitaxially grown layers; a slab-coupled waveguide layer, which controls the waveguide mode and enables effective mode coupling; a lower confinement layer, which limits the distribution of carriers and optical fields within the active region; a multiple quantum well (MQW) active layer, which is the core region for laser generation and amplification; an upper confinement layer, which works in conjunction with the lower confinement layer to effectively confine carriers and optical fields within the MQW active layer; and a first etch barrier layer, which provides a selective etch stop during subsequent etching processes.

[0088] Subsequently, deposition continues on top of the first corrosion barrier layer to form the upper structure. This process includes depositing another layer of indium phosphide (InP) material, followed by the sequential growth of a second corrosion barrier layer, a waveguide layer (which will be used to form a ridge waveguide structure in subsequent processes), and a heavily doped contact layer (which is intended to form a low-resistance ohmic contact).

[0089] Next, the chip undergoes microfabrication. Using standard semiconductor process lithography and etching techniques, the upper waveguide layer and contact layer are patterned and etched to form a ridge waveguide structure with a specific width and height. Simultaneously, precisely controlled etching and other methods are used to achieve electrical isolation and partitioning within the device, enabling precise control of current injection into specific areas of the active region. After the ridge waveguide structure is fabricated, a front-facing metal electrode is grown on the contact layer at the top of the ridge waveguide using metallization processes such as electron beam evaporation and photolithographic lift-off.

[0090] Finally, back-side processing and preparatory work before packaging are performed. The back side of the substrate with the front-side structure is thinned to reduce the device thickness and polished to obtain a flat surface. Then, a back-side metal electrode is formed on the back side of the thinned and polished substrate through an evaporation process. To ensure good ohmic contact between the metal electrode and the semiconductor material, alloying processes such as rapid thermal annealing (RTA) are usually required. After completing all the above steps, the entire wafer is cleaved according to the predetermined chip size and divided into individual laser chip strips or independent laser units. The cleavage planes naturally formed during this cleavage process constitute the first natural cleavage plane 12 and the second natural cleavage plane 14 of the high-power semiconductor FP laser 4. These two opposing natural cleavage planes with a certain reflectivity together constitute the first FP resonant cavity 13 within the high-power semiconductor FP laser 4. One of the cleavage surfaces, such as the second natural cleavage surface 14, is designed to be used as the first laser end face of the second FP resonant cavity 15 together with the external Gaussian beam reconstruction wavefront reflection surface 7; and the other cleavage surface, such as the first natural cleavage surface 12, can be used as the light output end face of the high-power semiconductor FP laser 4, that is, the second laser end face.

[0091] In this embodiment, the TPP integrated manufacturing steps for the base 5, the first elastic deformation mechanism 6, and the Gaussian beam reconstructed wavefront reflection surface 7 are described in detail. After obtaining the fabricated high-power semiconductor FP laser 4, two-photon polymerization (TPP) laser direct writing 3D printing technology is used to in-situ and integrally manufacture the base 5, the first elastic deformation mechanism 6, and the Gaussian beam reconstructed wavefront reflection surface 7 at a specific location on the high-power semiconductor FP laser 4.

[0092] Specifically, the prepared high-power semiconductor FP laser chip 4 is first precisely secured to the processing stage 9 of the two-photon polymerization 3D printing device using a suitable fixture or adhesive. Subsequently, liquid photosensitive resin (also known as photoresist) is applied by drop coating or spin coating to the top surface of the high-power semiconductor FP laser 4 and the intended processing area near its second natural cleavage plane 14, which is intended to serve as the external cavity mirror. Ensure that all areas to be processed are completely and evenly covered with the photosensitive resin.

[0093] Next, precise alignment and processing parameter setting are performed before exposure. The pre-designed three-dimensional digital models of the base 5, the first elastic deformation mechanism 6, and the Gaussian beam reconstructed wavefront reflection surface 7 are imported into the TPP equipment's control software system. Utilizing the TPP equipment's integrated high-magnification objective lens and high-resolution camera system, combined with precision imaging methods such as confocal imaging or layer-by-layer photography, and supplemented by image recognition algorithms tailored to specific structures on the laser chip, the actual spatial position and posture of the fixed high-power semiconductor FP laser 4 are accurately identified and located. This step is crucial to ensure that the three-dimensional microstructure subsequently printed using TPP technology is accurately positioned at the predetermined location on the laser chip and maintains the designed relative relationship with relevant laser components (such as the second natural cleavage plane 14). After precise positioning is achieved, various TPP equipment processing parameters, such as the output power of the femtosecond laser, the scanning speed of the laser focus within the photosensitive resin, and the scanning path planning strategy, are set based on factors such as the optical and chemical properties of the selected photosensitive resin, the desired structural accuracy, and processing efficiency.

[0094] Next, the two-photon polymerization exposure process is performed. A high-numerical aperture (NA) objective lens focuses an ultrafast femtosecond laser beam onto a diffraction-limited volume (i.e., a voxel) within the photosensitive resin. At this laser focus, due to the extremely high instantaneous photon density, the photosensitive resin molecules are able to simultaneously absorb two incident photons, thereby becoming excited and initiating a localized chemical polymerization reaction. A control system drives the laser focus or sample stage, precisely scanning the photosensitive resin point by point, line by line, and layer by layer according to the geometry defined by the previously imported 3D digital model. Due to the nonlinear nature of two-photon absorption, the light intensity is only sufficient at the laser focus to effectively initiate polymerization in the photosensitive resin. In areas outside the focus, even if laser light passes through, the light intensity is insufficient to trigger two-photon absorption, and the photosensitive resin in these areas remains unpolymerized, in a liquid or gel state. In this way, the designed three-dimensional microstructure is precisely constructed step by step at the predetermined position of the high-power semiconductor FP laser chip 4, including the base 5 firmly fixed to the upper surface of the laser, the first elastic deformation mechanism 6 connected to the base 5 at one end and having a specifically designed elastic coefficient, and the Gaussian beam reconstruction wavefront reflection surface 7 connected to the elastic mechanism at the other end and having a specific aspheric profile.

[0095] Finally, development and post-processing steps are performed. After the two-photon polymerization exposure process is complete, the laser chip with the exposed structure is removed from the TPP apparatus and immersed in a specific developer. The developer is selected based on the chemical properties of the photosensitive resin used; its function is to dissolve and completely remove the portions of the photosensitive resin that have not been polymerized by laser exposure. The three-dimensional microstructures that have been laser-exposed and polymerized are insoluble in the developer and are thus completely preserved, thereby initially revealing the designed morphology. To prevent these delicate three-dimensional microstructures, especially those with high aspect ratios or cantilever structures, from collapsing, deforming, or being damaged during the drying process with traditional solvents (such as isopropyl alcohol (IPA)) due to excessive surface tension, a preferred strategy is to use a special cleaning agent with low surface tension, such as methyl nonafluorobutyl ether, for the final cleaning and drying steps. Through the above steps, the base 5, the first elastic deformation mechanism 6, and the Gaussian beam reconstruction wavefront reflection surface 7 are precisely aligned and integrated with the high-power semiconductor FP laser 4.

[0096] In this embodiment, the TPP fabrication steps for the photonic wire-bonded waveguide 3 are described in detail. To achieve efficient optical coupling between the high-power semiconductor FP laser 4 and external optical components, such as the coupling fiber 2, two-photon polymerization (TPP) technology can also be used to fabricate the polymer photonic wire-bonded waveguide 3.

[0097] Specifically, the optical components to be connected are first aligned and fixed. The components that need to be optically interconnected through the PWB waveguide, that is, the partially processed sensor chip with an integrated laser module 4, and the end of a coupling optical fiber 2 for optical signal input / output, are adjusted to a predetermined relative position and posture through a high-precision positioning platform and then firmly fixed on a common substrate or a special fixture. This step requires ensuring that an appropriate gap that meets the requirements of the PWB manufacturing process is maintained between the light output end face of the high-power semiconductor FP laser 4 and the input end face of the coupling optical fiber (2). Subsequently, a special photosensitive resin specifically used for PWB waveguide production is applied to the predetermined processing area between the laser light output end face and the optical fiber input end face to ensure that the entire three-dimensional path where the waveguide needs to be formed is completely covered by the photosensitive resin.

[0098] Secondly, the optical ports are precisely identified and the waveguide paths are planned. Leveraging the high-magnification objective lens magnification and observation system integrated into the TPP device, methods such as confocal imaging or layer-by-layer photography can be employed. Combined with image recognition algorithms designed for specific waveguide structures or end-face features (such as the core and ridge waveguide edges), key parameters such as the precise spatial positions of the light-emitting end face of the high-power semiconductor FP laser 4 and the input end face of the coupling fiber 2 (primarily the core position), the dimensions of the effective optical ports, and the normal directions of their respective end faces can be accurately identified. Based on this precise identification information and in accordance with design principles for optimizing optical coupling efficiency, the TPP device's control software plans the three-dimensional spatial path and geometry of the PWB waveguide 3 connecting the two optical ports. This path and shape can be designed to be linear, tapered, curved, or even more complex free-form surface combinations, depending on specific requirements.

[0099] Next, the TPP exposure and shaping process for the PWB waveguide is executed. The high-precision motion control system within the TPP system drives the laser focus, performing precise scanning exposure within the applied photosensitive resin according to the previously planned three-dimensional path and geometry. The laser beam output by the femtosecond laser is focused to the starting point of the waveguide to be formed. The laser focus then moves along the planned path within the photosensitive resin, selectively polymerizing the resin through two-photon absorption, thus completing the exposure and shaping of the entire polymer waveguide structure in three dimensions.

[0100] Finally, development and post-processing are performed. After the exposure process of the PWB waveguide is completed, it also needs to go through a development process. The component with the exposed PWB structure is immersed in a suitable developer to wash away the photosensitive resin portion that has not been laser-polymerized, while the PWB photon wire bonding waveguide 3 composed of a polymeric material that precisely connects the light-emitting end face of the high-power semiconductor FP laser 4 and the input end face of the coupling optical fiber 2 is retained. The PWB waveguide manufactured in situ using TPP technology can accurately adapt to the actual position and shape of the two optical ports to be connected and can be designed into a gradient structure with mode conversion function.

[0101] See also Figure 8 The embodiment of the present invention further provides a solution in which the second elastic deformation mechanism 26 is a possible alternative to the first elastic deformation mechanism 6. All other preparation processes and measurement principles are the same.

[0102] Working principle: Output lasing wavelength of high power semiconductor FP laser 4 It is modulated by both its own first FP resonant cavity 13 and the external second FP resonant cavity 15. This multi-cavity structure makes the laser's lasing wavelength very sensitive to changes in the cavity length of the external resonant cavity (the second FP resonant cavity 15).

[0103] When there is external force When applied to the Gaussian beam reconstruction wavefront reflection surface 7, the first elastic deformation mechanism 6 will deform, driving the Gaussian beam reconstruction wavefront reflection surface 7 to produce a small displacement along the transmission direction of the laser output light. .external force and displacement They follow Hooke's law, that is: ,in is the equivalent stiffness coefficient of the first elastic deformation mechanism 6. When the direction points to the high power semiconductor FP laser 4, the displacement is a negative value; on the contrary, when the direction of the external force deviates from the high-power semiconductor FP laser 4, is a positive value; this displacement The length of the second FP resonant cavity 15 is directly changed from the initial cavity length becomes The change of the cavity length of the second FP resonant cavity 15 will cause the change of the effective reflection spectrum of the entire dual cavity system, which will lead to the change of the output lasing wavelength of the high power semiconductor FP laser 4. A precisely measurable wavelength shift occurs ; Among them, the spectrum line 15 shows the first FP resonant cavity 13 when acting alone, the first reflection spectrum line 16 illustrates the second FP resonant cavity The reflection spectrum of the first and second cavities is shown in Figure 15 when the two cavities act alone, while the second reflection spectrum line 17 is the overall reflection spectrum when the two cavities act together. The laser usually lases at the wavelength with the highest reflectivity (or the lowest equivalent loss) in the overall reflection spectrum. For example, in a certain state, the lasing wavelength may be 1539.876nm. When the external force causes When changes occur, such as From 0 to -100nm, the laser wavelength It may change linearly from 1539.876nm to 1539.784nm. This laser wavelength and displacement The relationship between is usually linear and its sensitivity (i.e. ) can be accurately characterized by the slope of the first fitting straight line 18, such as 0.0184 nm / nm.

[0104] Therefore, the drift of the laser output lasing wavelength is monitored in real time by an external spectrometer 1. , you can use the pre-calibrated and The corresponding relationship can accurately infer the displacement of the Gaussian beam reconstructed wavefront reflection surface 7. Furthermore, in combination with the known or pre-calibrated stiffness coefficient of the first elastic deformation mechanism 6 , you can use the formula Calculate the external force applied to the Gaussian beam reconstructed wavefront reflection surface 7 Taking the first elastic deformation mechanism 6 as a rectangular cross-section cylindrical helical compression spring as an example, its structural parameters such as the rectangular cross-section width 19. Rectangular section thickness 20. Number of turns , the number of turns is 1, the natural length 21 and spring radius 22, etc., can be precisely controlled by TPP process; through finite element simulation analysis (FEM), different external forces can be calculated Stress distribution and deformation of the spring under action Based on simulation, by fitting and The second fitting straight line 23 in the relationship between the spring and the spring constant can be obtained. ,For example pN / nm. Based on this, the micro-force measurement sensitivity of the sensor chip can be calculated. , for example 0.22nm / nN.

[0105] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser, characterized in that: include: A high-power semiconductor FP laser (4), wherein light-emitting surfaces on both sides of the high-power semiconductor FP laser (4) are respectively a first natural cleavage plane (12) and a second natural cleavage plane (14) forming a first FP resonant cavity (13); A Gaussian beam reconstruction wavefront reflection surface (7), wherein the Gaussian beam reconstruction wavefront reflection surface (7) is used to form a second FP resonant cavity (15) with a second natural cleavage surface (14) close to one side of the high-power semiconductor FP laser (4), and the cavity length of the second FP resonant cavity (15) is variable; a first elastic deformation mechanism (6), the first elastic deformation mechanism (6) being connected to the Gaussian beam reconstruction wavefront reflection surface (7) and being used for driving the Gaussian beam reconstruction wavefront reflection surface (7) to displace under the action of an external force, thereby changing the cavity length of the second FP resonant cavity (15); A base (5) is used to be fixed to the high-power semiconductor FP laser (4) and connected to the first elastic deformation mechanism (6).

2. The integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser according to claim 1, characterized in that: The sensor chip further includes a carrier (9), the high-power semiconductor FP laser (4) is arranged on the upper surface of the carrier (9), and a thin film circuit (8) is provided on the upper surface of the carrier (9). The thin film circuit (8) is connected to an external power supply (11) and is used to inject current into the high-power semiconductor FP laser (4), that is, to light up the high-power semiconductor FP laser (4).

3. The integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser according to claim 2, characterized in that: The electrodes of the high-power semiconductor FP laser (4) are connected to the thin film circuit (8) through gold wire bonding (10), and the light-emitting end face of the high-power semiconductor FP laser (4) is connected to the coupling optical fiber (2) through a photon wire bonding waveguide (3), so as to couple the output light with low loss and input the output light into the spectrometer (1) for spectral analysis; a base (5) is provided on the upper surface of the high-power semiconductor FP laser (4), and the base (5) is connected to one end of a first elastic deformation mechanism (6), and the other end of the first elastic deformation mechanism (6) is connected to a Gaussian beam reconstruction wavefront reflection surface (7), and the first elastic deformation mechanism (6) causes the position of the Gaussian beam reconstruction wavefront reflection surface (7) to shift along the transmission direction of the output light of the high-power semiconductor FP laser (4).

4. The integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser according to claim 1, characterized in that: The output lasing wavelength of the high-power semiconductor FP laser (4) At the same time, it is modulated by the first FP resonant cavity (13) and the second FP resonant cavity (15); when the external force When acting on the Gaussian beam reconstruction wavefront reflection surface (7), the first elastic deformation mechanism (6) drives the Gaussian beam reconstruction wavefront reflection surface (7) to displace , so that the cavity length of the second FP resonant cavity (15) is reduced by the initial cavity length becomes The change of the cavity length of the second FP resonant cavity (15) causes the output lasing wavelength of the high-power semiconductor FP laser (4) to be Measurable wavelength shift occurs The external force With the displacement The relationship between them conforms to: ,in is the stiffness coefficient of the first elastic deformation mechanism (6); the measurable wavelength drift With the displacement There is a corresponding relationship between the wavelength shift and the To determine the displacement And the external force .

5. The integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser according to claim 1, characterized in that: The Gaussian beam reconstruction wavefront reflection surface (7) has a reflection surface. After the outgoing beam of the high-power semiconductor FP laser (4) propagates a certain distance, the outgoing beam wavefront morphology is a rotationally non-symmetrical characteristic. Therefore, the reflection surface of the Gaussian beam reconstruction wavefront reflection surface (7) is specially constructed into a rotationally non-symmetrical aspherical structure.

6. The integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser according to claim 5, characterized in that: The surface profile of the non-rotationally symmetric aspherical structure is described by the following formula: ； in, 、 The equation of the reflecting surface is and The major and minor axis coefficients in the direction, for , The curvature of the surface at is the quadratic constant of the reflection surface equation, 、 、 They are the coefficients of the 4th, 6th and 8th order even terms respectively; The specific curved surface profile of the aspheric structure is designed and optimized based on the actual phase surface morphology of the outgoing light beam of the high-power semiconductor FP laser (4) when it propagates to the position of the reflecting surface, and is intended to ensure that the light beam from the high-power semiconductor FP laser (4) reaching the reflecting surface can be accurately reflected back into the high-power semiconductor FP laser (4) with maximum efficiency, thereby effectively coupling into and forming the second FP resonant cavity (15); The coefficient 、 、 、 、 、 、 The value is obtained by fitting the isophase point data of the light beam emitted by the high-power semiconductor FP laser (4) at a predetermined position.

7. A method for preparing an integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser, applied to the chip according to any one of claims 1 to 6, characterized in that: include: S1. Providing a high-power semiconductor FP laser (4), wherein the high-power semiconductor FP laser (4) has two opposing natural cleavage planes, wherein one of the natural cleavage planes is a second natural cleavage plane (14) designated as a first laser end face for forming an external cavity, and the other natural cleavage plane is a first natural cleavage plane (12) designated as a second laser end face for light output; S2. Using a two-photon polymerization process, a base (5), a first elastic deformation mechanism (6), and the Gaussian beam reconstruction wavefront reflection surface (7) are integrally manufactured on the high-power semiconductor FP laser (4) or relative to the high-power semiconductor FP laser (4), so that the base (5) is fixed to the high-power semiconductor FP laser (4), the first elastic deformation mechanism (6) connects the base (5) and the Gaussian beam reconstruction wavefront reflection surface (7), and the Gaussian beam reconstruction wavefront reflection surface (7) and the first laser end face of the high-power semiconductor FP laser (4) together constitute the second FP resonant cavity (15); S3. Using a two-photon polymerization process, a photon wire bonding waveguide (3) is manufactured to optically couple the second laser end face of the high-power semiconductor FP laser (4) to a coupling optical fiber (2).

8. The method for preparing an integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser according to claim 7, characterized in that: The high-power semiconductor FP laser (4) in step S1 is formed by stacking a substrate, a buffer layer, a planar coupling waveguide layer, a lower confinement layer, a multi-quantum well layer, an upper confinement layer, a corrosion barrier layer, a waveguide layer and a contact layer from bottom to top, including the following steps: S11, sequentially growing a buffer layer, a planar coupling waveguide layer, and a lower confinement layer on the substrate by metal organic compound vapor deposition, then growing a multi-quantum well layer on the lower confinement layer, growing an upper confinement layer on the multi-quantum well layer, and then growing a corrosion barrier layer on the upper confinement layer; S12, depositing InP on the corrosion barrier layer, and then sequentially growing the corrosion barrier layer, the waveguide layer, and the contact layer; S13, corroding the waveguide layer and the contact layer to form a ridge, etching electrical isolation to achieve partitioning, and growing a front metal electrode in the ridge area above the contact layer; S14, thinning and polishing the back side of the substrate, evaporating the back electrode and heating to obtain an alloy, and cleaving the chip to obtain the high-power semiconductor quantum well FP laser.

9. The method for preparing an integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser according to claim 7, characterized in that: The steps of manufacturing the base (5), the first elastic deformation mechanism (6) and the Gaussian beam reconstruction wavefront reflection surface (7) by using a two-photon polymerization process in step S2 include: S21, fixing the high-power semiconductor FP laser (4) on a processing platform, and applying a photosensitive resin on the upper surface of the high-power semiconductor FP laser (4) and a predetermined processing area near the end face of the first laser; S22, using optical imaging and image recognition algorithms to accurately identify a predetermined printing position on the high-power semiconductor FP laser (4), and based on a preset three-dimensional digital model of the base (5), the first elastic deformation mechanism (6) and the Gaussian beam reconstruction wavefront reflection surface (7), align and use a focused laser beam to selectively initiate a polymerization reaction inside the photosensitive resin through a two-photon absorption effect, and construct the three-dimensional structure in a point-by-point, line-by-line, and layer-by-layer scanning exposure manner; S23. After the exposure is completed, the unpolymerized photosensitive resin is removed by a development operation and cleaned to reveal and obtain the base (5), the first elastic deformation mechanism (6) and the Gaussian beam reconstruction wavefront reflection surface (7) integrated with the high-power semiconductor FP laser (4).

10. The method for preparing an integrated micro-force and micro-displacement sensor chip based on TPP and semiconductor laser according to claim 7, characterized in that: The step of manufacturing the photon wire bonding waveguide (3) by using a two-photon polymerization process in step S3 includes: S31, aligning the second laser end face of the high-power semiconductor FP laser (4) with the input end of the coupling optical fiber (2), and fixing the two on a common substrate, and then applying photosensitive resin to a predetermined processing area between the second laser end face and the input end of the coupling optical fiber (2); S32, using a high-power objective lens observation system in combination with an image recognition algorithm to identify the optical port position and normal direction of the second laser end face and the input end of the coupling optical fiber (2), and accordingly planning the three-dimensional path and geometric shape required for the photonic wire bonding waveguide (3); S33, according to the planned path and geometric shape, using a focused laser beam to selectively initiate a polymerization reaction inside the photosensitive resin through a two-photon absorption effect, thereby completing the exposure and forming of the photon wire bonding waveguide (3); S34, after the exposure is completed, the unpolymerized photosensitive resin is removed by a development process to reveal and obtain the photon wire bonding waveguide (3) connecting the second laser end face of the high-power semiconductor FP laser (4) and the input end of the coupling optical fiber (2).

Images