Hybrid integrated optical gyroscope chip, preparation method and optical gyroscope

Abstract

The invention relates to the technical field of semiconductor technologies, and discloses a hybrid integrated optical gyroscope chip, a preparation method and an optical gyroscope, the hybrid integrated optical gyroscope chip comprises a multifunctional optical module, a light emitting module, a circuit module, a detector module and an optical fiber which are arranged in a multi-layer stacking manner along a first direction; wherein the light emitting module is provided with a first coupling port, the detector module is provided with a second coupling port, and the multifunctional optical module is provided with a third coupling port and a fourth coupling port. At least one of the following conditions is satisfied: the first coupling port and the third coupling port are connected through a first three-dimensional polymer waveguide; the second coupling port and the third coupling port are connected through a second three-dimensional polymer waveguide; and the fourth coupling port is connected with the optical fiber through a third three-dimensional polymer waveguide. The hybrid integrated optical gyroscope chip is small in size and has excellent thermal mechanical stability and measurement accuracy.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor process, and particularly relates to a hybrid integrated optical gyro chip, a preparation method and an optical gyro. BACKGROUND

[0002] In many military and civilian applications such as aircraft and ship navigation, missile guidance, satellite orientation, geodetic survey, astronomical telescope observation tracking, GPS assisted navigation of vehicles, automatic driving, etc., high-reliability and low-cost inertial measurement devices are needed. The traditional inertial navigation system has long relied on mechanical gyroscopes and fiber-optic gyroscopes, but these technologies have certain limitations. The mechanical gyroscope has the problem that the moving parts are easy to wear out, and the fiber-optic gyroscope is composed of discrete devices, and the system is relatively large in size.

[0003] With the increasing demand for miniaturized and high-reliability navigation systems in modern equipment, the research on small integrated optical gyroscopes has become an inevitable trend. The core idea is to integrate the key optical elements of traditional fiber-optic gyroscopes onto a chip, thereby realizing the miniaturization and high stability of the system. However, the current integrated optical gyroscopes still face multiple technical barriers in heterogeneous material integration. For example, there are significant physical and process differences between different material systems, which can easily lead to interface defects, and the high-temperature process requirements of III-V devices conflict with the thermal budget limitations of silicon-based photonic devices, or the effective utilization rate of traditional device packaging size is insufficient. Therefore, developing a hybrid integrated optical gyro chip with an innovative architecture is one of the current challenges. SUMMARY

[0004] The present application aims to at least partially solve one of the technical problems in the related art. To this end, one object of the present application is to propose a hybrid integrated optical gyro chip, a preparation method and an optical gyro, which is small in size and has excellent thermal mechanical stability.

[0005] In a first aspect of the present application, a hybrid integrated optical gyro chip is proposed, comprising: a multifunctional optical module, a light emitting module, a circuit module, a detector module, and an optical fiber, which are arranged in a multilayer stack along a first direction; The light emitting module is provided with a first coupling port, the detector module is provided with a second coupling port, the multifunctional optical module is provided with a third coupling port and a fourth coupling port, and at least one of the following conditions is satisfied: The first coupling port and the third coupling port are connected by a first three-dimensional polymer waveguide; The second coupling port and the third coupling port are connected by a second three-dimensional polymer waveguide; The fourth coupling port and the optical fiber are connected through a third three-dimensional polymer waveguide. The application connects the coupling ports between different modules through the three-dimensional polymer waveguide, so as to realize the stacking design between different modules. The innovative architecture reduces the overall hybrid integrated optical gyro chip package size to about 10x10x3mm 3 of the super-small specification. Compared with the traditional fiber optic gyroscope (FOG) four-in-one device, the volume is reduced by about 80 times. The three-dimensional polymer waveguide connection of the coupling port helps to improve the alignment accuracy of the coupling port, thereby reducing the coupling loss.

[0006] In some embodiments, the hybrid integrated optical gyro chip further comprises: A diamond substrate is stacked together with the multifunctional optical module, the light emitting module, the circuit module, the detector module and the optical fiber. The diamond substrate exhibits excellent heat dissipation performance, thereby helping to obtain a hybrid integrated optical gyro chip with excellent thermal mechanical stability and small size.

[0007] In some embodiments, the diamond substrate is internally provided with a micro-channel structure for conducting heat inside the optical gyro chip to the external environment. Thus, it helps to further improve the thermal mechanical stability of the hybrid integrated optical gyro chip.

[0008] In some embodiments, the diamond substrate comprises opposite first and second surfaces; The circuit module is arranged on the first surface, and the optical fiber is arranged on the surface of the circuit module away from the first surface, and the optical fiber extends along the second direction perpendicular to the first direction; The multifunctional optical module is arranged on the second surface; The light emitting module is arranged on the first surface; The detector module is arranged on the surface of the circuit module away from the first surface. Thus, a hybrid integrated optical gyro chip with compact structure and excellent thermal mechanical stability is obtained.

[0009] In some embodiments, the surface of the circuit module away from the first surface is provided with a V-shaped groove, and the optical fiber is arranged in the V-shaped groove. Thus, it helps to further reduce the size of the hybrid integrated optical gyro chip, and obtain a hybrid integrated optical gyro chip with compact structure.

[0010] In some embodiments, the optical gyro chip has opposite first and second ends in the second direction, the first coupling port is located on an end face of the light emitting module close to the first end, the second coupling port is located on an end face of the detector module close to the first end, the third coupling port is located on an end face of the multifunctional optical module close to the first end, and the fourth coupling port is located on an end face of the multifunctional optical module close to the second end. The reasonable design of the positions of the coupling ports between different modules helps to further improve the packaging size of the hybrid integrated optical gyro chip, so as to obtain a hybrid integrated optical gyro chip with small volume.

[0011] In some embodiments, the first three-dimensional polymer waveguide, the second three-dimensional polymer waveguide, and the third three-dimensional polymer waveguide each comprise a photosensitive polymer material. The refractive index of the photosensitive polymer material matches the optical element and has good thermal mechanical stability after cross-linking and curing, thereby helping to improve the performance of the hybrid integrated optical gyro chip.

[0012] In some embodiments, the first three-dimensional polymer waveguide, the second three-dimensional polymer waveguide, and the third three-dimensional polymer waveguide have a graded refractive index. Thus, the mode field mismatch problem between heterogeneous materials is solved, the coupling loss is reduced, and the coupling efficiency of the optical field is improved.

[0013] In the second aspect of the present application, a preparation method of a hybrid integrated optical gyro chip is provided, comprising: stacking the multifunctional optical module, the light emitting module, the circuit module, the detector module, and the optical fiber; forming a three-dimensional polymer waveguide between at least one of the coupling ports between the light emitting module and the multifunctional optical module, the coupling ports between the detector module and the multifunctional optical module, and the coupling ports between the multifunctional optical module and the optical fiber. Thus, a hybrid integrated optical gyro chip with small volume is obtained.

[0014] In some embodiments, the preparation method of the hybrid integrated optical gyro chip comprises: stacking the diamond substrate and the multifunctional optical module, the light emitting module, the circuit module, the detector module, and the optical fiber. Thus, a hybrid integrated optical gyro chip with small volume and excellent thermal mechanical stability is obtained.

[0015] In some embodiments, the preparation method of the hybrid integrated optical gyro chip comprises: disposing the circuit module on the first surface of the diamond substrate by a mounting technology or a welding technology; disposing the multifunctional optical module on the second surface of the diamond substrate by the mounting technology; The detector module is arranged on the surface of the circuit module far from the first surface by a gold wire bonding or a through silicon via process. The light emitting module is arranged on the first surface of the diamond substrate by a soldering technique or a mounting technique. In this way, a plurality of modules can be arranged in a multi-layer stack by a simple operation, which is helpful to obtain a highly integrated hybrid integrated optical gyro chip.

[0016] In some embodiments, the method for preparing the hybrid integrated optical gyro chip further comprises: etching a V-shaped groove on the surface of the circuit module far from the first surface, and fixing the optical fiber in the V-shaped groove. In this way, the integration of the hybrid integrated optical gyro chip can be further improved.

[0017] In some embodiments, the forming of the three-dimensional polymer waveguide comprises: A photosensitive polymer material is coated on the waveguide coupling ports and the gap region therebetween to be interconnected to form a covering layer. A three-dimensional exposure is performed on the region to be interconnected by using a laser direct writing process. In this way, the interconnection between the coupling ports in a three-dimensional space is realized, and the above method is helpful to improve the alignment accuracy between the coupling ports.

[0018] In a third aspect of the present application, an optical gyro is provided, comprising: The hybrid integrated optical gyro chip as described above; An optical fiber ring connected with the optical fiber; A circuit board, wherein the hybrid integrated optical gyro chip is arranged on the circuit board and electrically connected with the circuit board. In this way, the optical gyro has a small volume and excellent performance. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural schematic diagram of the hybrid integrated optical gyro chip according to an embodiment of the present application.

[0020] Figure 2 is a structural schematic diagram of the diamond substrate according to an embodiment of the present application.

[0021] Figure 3 is a structural schematic diagram of the hybrid integrated optical gyro chip according to an embodiment of the present application.

[0022] Figure 4 is a structural schematic diagram of the hybrid integrated optical gyro chip according to an embodiment of the present application.

[0023] Figure 5 is a structural schematic diagram of the hybrid integrated optical gyro chip according to an embodiment of the present application.

[0024] Figure 6is a structural schematic diagram of a hybrid integrated optical gyro chip according to an embodiment of the present application.

[0025] Figure 7 is a structural schematic diagram of a hybrid integrated optical gyro chip according to an embodiment of the present application.

[0026] Figure 8 is a structural schematic diagram of a circuit module according to an embodiment of the present application.

[0027] Figure 9 is a structural schematic diagram of a hybrid integrated optical gyro chip according to an embodiment of the present application.

[0028] Figure 10 is a structural schematic diagram of a hybrid integrated optical gyro chip according to an embodiment of the present application.

[0029] Reference signs 1: multifunctional optical module 2: light emitting module 3: circuit module 4: detector module 5: optical fiber 6: diamond substrate 7: first three-dimensional polymer waveguide 8: second three-dimensional polymer waveguide 9: third three-dimensional polymer waveguide 10: V-shaped groove 6-1: first surface 6-2: second surface A: first coupling port B: second coupling port C: third coupling port D: fourth coupling port DETAILED DESCRIPTION Embodiments of the present application are described in detail below, and the embodiments described below are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0030] The present application is based on the following findings and recognitions of the inventor: As described above, the integrated optical gyro chip in the related art has some drawbacks, specifically, in the design of a conventional optical system, an aspherical lens assembly is one of the key optical elements, however, it has specific physical limitations, due to its optical characteristics, the aspherical lens assembly must reserve a millimeter-level optical path space when constructing an optical path, the reserved optical path space occupies more than 40% of the total volume of the package, the strict optical alignment requirements force the device layout to reserve a large amount of redundant space, resulting in insufficient effective utilization of the device package size, and the integrated optical gyro chip obtained has a large volume.

[0031] Based on the above recognitions, the inventor considers developing a new waveguide structure to solve the problem of insufficient effective utilization of the package size of the conventional integrated optical gyro chip, and innovatively designs the layout between the modules to further reduce the package volume of the integrated optical gyro chip.

[0032] Therefore, in a first aspect of the present application, a hybrid integrated optical gyro chip is provided, with reference toFigure 1 , including multi-functional optical module 1, light emitting module 2, circuit module 3, detector module 4, optical fiber 5 arranged in a multi-layer stack along the first direction, the multi-layer stack allows the above-mentioned modules to be arranged compactly in three-dimensional space, greatly compressing the overall size of the hybrid integrated optical gyroscope chip, thereby helping to shorten the signal transmission path between different modules, reducing signal loss and delay, and improving the detection accuracy and response speed of the gyroscope, ensuring more accurate and real-time measurement. The stacking method and order of the above-mentioned multi-functional optical module 1, light emitting module 2, circuit module 3, detector module 4, and optical fiber 5 are not limited here, and can be stacked according to the size of different modules in practice to achieve the smallest volume.

[0033] In some embodiments, with reference to Figure 1 , the hybrid integrated optical gyroscope chip further comprises: a diamond substrate 6, which is arranged in a multi-layer stack with the multi-functional optical module 1, the light emitting module 2, the circuit module 3, the detector module 4, and the optical fiber 5. There are differences in thermal expansion characteristics between integrated heterogeneous materials (InP, Si, LiNbO3, etc.) in the integrated optical gyroscope chip, and the expansion or contraction of different materials is not the same, which will generate thermal stress at the interface. If the thermal stress cannot be effectively dispersed in time, it may cause the stress distribution inside the chip to be disordered, affect the stability of optical signal transmission, and cause the optical gyroscope precision to decrease, and at the same time, it may cause micro-cracks in the chip, greatly shortening the service life of the chip; in addition, III-V devices in the integrated optical gyroscope chip rely on high-temperature processes (such as epitaxial growth at 600-1200°C) to achieve high-efficiency carrier transport and high-gain optical properties, but silicon-based photonic devices have limited temperature tolerance and will have problems such as crystal defects and uneven refractive index if baked for a long time above 400°C. Therefore, if the excess heat cannot be effectively dissipated, it will affect the performance of the optical gyroscope chip. In this application, a diamond substrate is innovatively added, which has excellent thermal conductivity and excellent heat dissipation performance, and is used to conduct heat inside the optical gyroscope chip to the external environment. Thus, the hybrid integrated optical gyroscope chip obtained by the present application has excellent thermal mechanical stability.

[0034] In some embodiments, the thickness of the diamond substrate is 300-400 μm, and can be 300 μm, 310 μm, 320 μm, 330 μm, 340 μm, 350 μm, 360 μm, 370 μm, 380 μm, 390 μm, 400 μm, etc. The diamond substrate has a high thermal conductivity when the thickness is within the above range, and the thermal conductivity is as high as 2000-2600 W / (m·K). The thermal conductivity of the diamond substrate can be significantly improved with the increase of the thickness. When the thickness is greater than 300 μm, the grain size increases, the grain boundary density decreases, and the thermal conductivity can reach a maximum value, which is more than 3 times of that of a traditional brass / aluminum nitride substrate. The excellent thermal conductivity can quickly conduct the heat generated in the chip to the external environment, significantly reduce the temperature of the chip, and effectively eliminate the heat crosstalk phenomenon.

[0035] In some embodiments, referring to Figure 2 , the diamond substrate is internally provided with a micro-channel structure. The diamond has excellent thermal conductivity (>2000 W / mK). The micro-channel structure constructed based on the characteristics of the diamond can become the core support of the efficient thermal management of the entire chip as a heat dissipation system of the hybrid integrated optical gyro chip. When the optical gyro chip is working, heat is continuously generated, and the micro-channel structure helps to further improve the heat dissipation efficiency of the diamond substrate, thereby further improving the thermal mechanical stability of the hybrid integrated optical gyro chip.

[0036] In some embodiments, the circuit module includes a silicon circuit. The silicon circuit is continuously optimized in terms of integration, performance, power consumption, and cost, and becomes the core component of various electronic devices. The silicon circuit can be combined with an advanced package to allow the circuit to be closely integrated with the optical path, optimize the use of space, reduce the size of the overall system, and integrate multiple electrical functional modules (such as a detector module, a light-emitting module, etc.) required by the optical gyro on one chip, thereby reducing the number of external components and simplifying the system design. Thus, it helps to make the entire integrated optical gyro system smaller and more suitable for the needs of modern portable and compact devices.

[0037] In some embodiments, the multifunctional optical module is specially designed and integrates key optical functional elements such as a beam splitter, a beam combiner, and a modulator.

[0038] In some embodiments, referring to Figure 3 , the light-emitting module 2 is provided with a first coupling port A, the detector module 4 is provided with a second coupling port B, the multifunctional optical module 1 is provided with a third coupling port C, and referring to Figure 4 , the multifunctional optical module 1 is further provided with a fourth coupling port D. Further, referring to Figure 5, the first coupling port A and the third coupling port C are connected by a first three-dimensional polymer waveguide 7, the second coupling port B and the third coupling port C are connected by a second three-dimensional polymer waveguide 8, referring to Figure 6 , the fourth coupling port D and the optical fiber 5 are connected by a third three-dimensional polymer waveguide 9. The coupling ports between different modules are connected by three-dimensional polymer waveguides, which realizes the interconnection of optical signals between the above-mentioned stacked modules, and the connection of the coupling ports by the three-dimensional polymer waveguide helps to improve the alignment accuracy of the coupling ports, thereby reducing the coupling loss.

[0039] In some embodiments, referring to Figure 7 , the diamond substrate 6 includes opposite first and second surfaces 6-1 and 6-2, the circuit module 3 and the light emitting module 2 are both disposed on the first surface 6-1, the detector module 4 is disposed on the surface of the circuit module 3 away from the first surface 6-1, the optical fiber 5 is disposed on the surface of the circuit module 3 away from the first surface 6-1, the optical fiber 5 extends along a second direction, and the second direction is perpendicular to the first direction, and the multifunctional optical module 1 is disposed on the second surface 6-2. The hybrid integrated optical gyro chip adopts a highly integrated design, integrates a multifunctional optical module, a light emitting module, a circuit module, a detector module, and an optical fiber, and obtains a hybrid integrated optical gyro chip with multiple layers stacked. The chip layout is compact and has excellent thermal mechanical stability.

[0040] In some embodiments, referring to Figure 8 , the surface of the circuit module 3 away from the first surface 6-1 is provided with a V-shaped groove 10, and the optical fiber 5 is disposed in the V-shaped groove 10. The V-shaped groove not only provides stable mechanical positioning for the optical fiber, but also further reduces the volume of the hybrid integrated optical gyro chip, thereby obtaining a hybrid integrated optical gyro chip with higher integration.

[0041] In some embodiments, referring to Figure 9 , the hybrid integrated optical gyro chip has opposite first and second ends in the second direction, the first coupling port A is located on the end face of the light emitting module 2 close to the first end, the second coupling port B is located on the end face of the detector module 4 close to the first end, the third coupling port C includes two independent coupling ports C-1 and C-2, both of which are located on the end face of the multifunctional optical module 1 close to the first end, referring to Figure 10 , the fourth coupling port D includes two independent coupling ports D-1 and D-2, both of which are located on the end face of the multifunctional optical module 1 close to the second end. The reasonable design of the positions of the coupling ports between different modules helps to further improve the packaging size of the hybrid integrated optical gyro chip, thereby obtaining a hybrid integrated optical gyro chip with small volume.

[0042] In some embodiments, the first three-dimensional polymer waveguide 7, the second three-dimensional polymer waveguide 8, and the third three-dimensional polymer waveguide 9 are all made of a photosensitive polymer material. In terms of optical performance, the refractive index of such a photosensitive polymer matches the optical element, which can ensure that the reflection, scattering and other losses of light are minimized when the light is transmitted in the above-mentioned three-dimensional polymer waveguide, so that the optical signal can be more efficiently and stably transmitted in the three-dimensional polymer waveguide, thereby improving the optical performance of the hybrid integrated optical gyroscope chip. On the other hand, the cross-linked and cured photosensitive polymer has good thermal mechanical stability in the temperature range of 20-150°C, so that it can maintain stable optical and mechanical properties in the working environment, maintain the integrity of the three-dimensional polymer waveguide structure, and thus maintain the stability of light transmission, which helps to improve the working reliability of the hybrid integrated optical gyroscope chip in complex environments.

[0043] In some embodiments, with reference to Figures 5 to 7 The working principle of the hybrid integrated optical gyroscope chip is as follows: the optical signal generated by the light emitting module 2 is first transmitted to the multifunctional optical module 1 via the first three-dimensional polymer waveguide 7. After being processed by the precisely designed beam combiner / splitter and electro-optical modulator inside the multifunctional optical module 1, the optical signal is split into two paths and enters the optical fiber 5 for loop propagation via the third three-dimensional polymer waveguide 9. After loop transmission, the two beams of optical signal are returned to the multifunctional optical module 1 via the third three-dimensional polymer waveguide 9 and form interference, and finally the signal detection is completed by the detector module 4 via the second three-dimensional polymer waveguide 8. This architecture highly integrates all core functional components of a traditional fiber optic gyroscope into a single chip and supports any length of sensitive loop configuration from short range (a few meters) to ultra long range (kilometer level), which can be flexibly adjusted according to different requirements of detection sensitivity for specific application scenarios.

[0044] In some embodiments, the first three-dimensional polymer waveguide, the second three-dimensional polymer waveguide, and the third three-dimensional polymer waveguide have a graded refractive index. In a hybrid integrated optical gyroscope chip, different optical materials (i.e. heterogeneous materials) have different optical properties. When the optical signal propagates between different modules, the mode field distribution may not match. However, the graded refractive index waveguide can realize the continuous change of the refractive index inside the waveguide. At the interconnection between different modules, the graded refractive index waveguide can serve as a transition structure to gradually adjust the distribution of the optical field. This helps the optical signal to adapt to the characteristics of different materials, thereby effectively solving the mode field mismatch problem between heterogeneous materials and reducing the coupling loss, thereby improving the coupling efficiency of the optical field.

[0045] In a second aspect of the present application, a preparation method of a hybrid integrated optical gyroscope chip is provided, comprising: S10: stacking the multifunctional optical module, the light emitting module, the circuit module, the detector module, and the optical fiber.

[0046] In this step, the above modules are stacked according to the size and actual needs. For example, the multifunctional optical module, the light-emitting module, the detector module, the circuit module, and the optical fiber can be stacked in sequence. Different modules can be connected by mounting technology or welding technology.

[0047] In some embodiments, the diamond substrate and the above-mentioned multifunctional optical module, light-emitting module, circuit module, detector module, and optical fiber can be stacked. The stacking method is not limited. For example, the circuit module and the light-emitting module can be arranged on the first surface of the diamond substrate by mounting technology or welding technology. The multifunctional optical module can be arranged on the second surface of the diamond substrate by mounting technology. The mounting technology is suitable for different sizes and types of modules. The mounting technology has high precision, which helps to ensure the accuracy of optical signal transmission and improve the performance of the optical gyroscope chip. The welding technology can firmly combine different modules and withstand certain mechanical stress and vibration, ensuring reliable circuit connection and stable signal transmission of the optical gyroscope chip under complex working conditions.

[0048] Further, the detector module can be arranged on the surface of the circuit module away from the first surface by gold wire bonding or through silicon via technology. The gold wire bonding technology can quickly establish an electrical connection between the detector module and the circuit module, adapt to different sizes and layouts, and be easy to operate during subsequent adjustment and maintenance. The gold wire has excellent conductivity, which can reduce the resistance and loss of electrical signal transmission, ensure the accurate and efficient transmission of electrical signals collected by the detector module to the circuit module for processing, and improve the signal processing accuracy of the optical gyroscope chip. The through silicon via technology can construct a short and straight signal transmission path, greatly reducing signal transmission delay and crosstalk. For high-frequency and high-speed signal transmission of the detector module, it can ensure signal integrity and improve the working speed and response performance of the optical gyroscope chip.

[0049] In some embodiments, a V-shaped groove is obtained on the surface of the circuit module away from the first surface by etching, and the optical fiber is fixed in the V-shaped groove. Specifically, micro-nano processing technology (such as photolithography-etching cooperative technology) can be used. First, photoresist is coated on the surface of the circuit module. After photolithography exposure, the V-shaped groove pattern is transferred to the photoresist layer. Then, according to the photoresist mask pattern, the surface of the circuit module is selectively removed by etching technology. By accurately controlling the etching parameters, such as etching gas type, flow rate, power, or chemical solution concentration, temperature, etching time, etc., a V-shaped groove structure meeting the geometric parameter requirements can be processed.

[0050] S20: Forming a three-dimensional polymer waveguide at at least one of between the coupling port of the light-emitting module and the multi-functional optical module, between the coupling port of the detector module and the multi-functional optical module, and between the coupling port of the multi-functional optical module and the optical fiber.

[0051] In this step, after the stacking of the different modules is completed, a three-dimensional polymer waveguide is formed at the corresponding coupling port, so that the signals between the different modules are interconnected. Specifically, a photosensitive polymer material is coated on the waveguide coupling port, and is placed in a photonic wire bonding device for automatic image recognition and waveguide positioning. The system automatically plans an exposure route, sets the exposure intensity and time for exposure to obtain a three-dimensional polymer waveguide. After the exposure is completed, the sample is taken out of the device and developed to remove the unexposed part of the photosensitive polymer material, and finally the target three-dimensional polymer waveguide is obtained. This method can achieve a three-dimensional spatial alignment accuracy of sub-micron (±0.5 μm), which is an order of magnitude higher than the traditional mechanical alignment method.

[0052] For example, the photosensitive polymer material can be IP-Dip, which does not need to be baked and cured, and does not need to use quartz glass cover. The lens can be directly immersed in the photosensitive polymer material, which can effectively avoid aberration.

[0053] In some embodiments, before the photosensitive polymer material is coated on the waveguide coupling port, the coupling port can also be pretreated. The coupling port is cleaned with acetone, alcohol or the like, thereby effectively removing dust particles, organic residues or impurities generated during the processing on the surface of the port, so as to improve the surface cleanliness of the port, reduce the optical loss caused by interface scattering and adhesion pollution, and at the same time, the cleaned surface can enhance the bonding force between the photosensitive polymer and the waveguide port, so as to ensure that the coupling interface between the three-dimensional polymer waveguide and the chip waveguide is more stable, thereby further improving the optical transmission efficiency and the long-term reliability of the device.

[0054] In some embodiments, femtosecond laser can be used for two-photon polymerization. The laser focus is accurately focused inside the polymer volume. The micro area where the focus point is located absorbs two photon energies to trigger the polymerization reaction, forming a solidified polymer "wire". Through the computer-controlled three-dimensional scanning system, the laser focus point "writes" a three-dimensional free curve waveguide along the designed trajectory in space. This method does not rely on traditional masks, but is "direct writing", similar to 3D printing, but the precision can reach sub-micron.

[0055] In some embodiments, in a two-photon polymerization writing process, the refractive index of the polymer is related to the degree of polymerization (conversion rate), and the degree of polymerization depends on the local laser dose. If the laser power or scanning speed is gradually changed during the scanning process, a cured polymer with a gradually changing refractive index can be obtained, the target gradient refractive index distribution is discretized, and is divided into several layers, each layer has a different degree of polymerization, thereby having a different refractive index. When the number of layers is sufficient and the refractive index change is small enough, the whole is equivalent to a three-dimensional polymer waveguide with a gradually changing refractive index. By designing a three-dimensional polymer waveguide with a gradually changing refractive index, the mode field mismatch problem between heterogeneous materials can be effectively solved, and the coupling loss is expected to be controlled below 0.5 dB.

[0056] Specifically, the implementation mode of the three-dimensional polymer waveguide with a gradually changing refractive index can be: 1. Layered writing: in a direct writing process, different refractive indexes are formed at different depths / regions by changing the laser dose or exposure parameters; 2. Multi-material superposition: depositing or photoetching different refractive index polymer thin layers layer by layer; 3. Step structure: forming a “step refractive index”, which is approximately a gradually changing refractive index on the scale of an optical waveguide.

[0057] In a third aspect of the present application, an optical gyroscope is provided, comprising: The hybrid integrated optical gyroscope chip described above; An optical fiber ring connected to the optical fiber; A circuit board, wherein the hybrid integrated optical gyroscope chip is arranged on the circuit board and electrically connected to the circuit board. Thus, the optical gyroscope has a small volume and excellent performance.

[0058] The optical gyroscope described above is highly integrated, has a significantly reduced volume, and can adapt to application scenarios with limited space, such as unmanned aerial vehicles and mechanical arms. At the same time, the optical gyroscope has excellent performance, can ensure accurate signals in complex environments, and high integration can help reduce signal transmission loss. The optical gyroscope can play a key role in fields such as aerospace (e.g., satellite attitude control, real-time sensing of satellite spin and orbit adjustment angular velocity changes), intelligent transportation (inertial navigation of autonomous vehicles, continuous provision of vehicle motion state data when GPS signals are disturbed), and industrial detection (vibration monitoring of high-precision equipment, capturing of small vibration angular velocities of equipment, and auxiliary fault prediction). The optical gyroscope provides reliable angular velocity measurement support for accurate sensing and stable operation of various systems, and helps to improve the intelligent and automated level of equipment.

[0059] The hybrid integrated optical gyroscope chip or the optical gyroscope in the present application has at least the following advantages: 1. High-precision optical coupling performance: The three-dimensional polymer waveguide structure constructed by the laser-assisted direct writing process realizes sub-micron (±0.5 μm) accurate alignment, and through the innovative graded refractive index design, effectively solves the mode field mismatch problem between the light-emitting module and the silicon circuit, and controls the coupling loss below 2 dB. Compared with the loss level of more than 3 dB of the traditional lens coupling scheme, the present technology not only improves the coupling efficiency by 1.5 times, but also significantly simplifies the packaging process, reduces the production steps by more than 50%, and greatly improves the production efficiency.

[0060] 2. In terms of thermal mechanical stability: The three-dimensional polymer waveguide used in the present technology has the characteristics of thermal stress self-adaptation, and its thermal expansion coefficient (CTE≈50ppm / ℃) can effectively buffer the thermal expansion difference between InP (4.5ppm / ℃), Si (2.6ppm / ℃) and LiNbO3 (14ppm / ℃) and other heterogeneous materials.

[0061] 3. Heat dissipation system design: The diamond substrate with micro-channel structure exhibits excellent heat dissipation performance. Its ultra-high thermal conductivity of more than 2000W / mK combined with the micro-channel structure realizes efficient heat management at the chip level. Most notably, the volume ratio of the diamond substrate is controlled to be within 5%, compared with the volume ratio of 30% of the traditional discrete TEC module, the space utilization is improved by 6 times. This compact and efficient diamond substrate provides key support for the miniaturization of the system.

[0062] 4. System integration: The present scheme successfully replaces the traditional lens system which accounts for 40% of the volume through photonic wire bonding technology (PWB). This innovation reduces the overall chip packaging size to about 10x10x3mm 3 , which is much smaller than the size of about 40x40x15mm 3 of the traditional fiber optic gyroscope (FOG) four-in-one device, and the volume is reduced by about 80 times.

[0063] In the description of the present application, it should be understood that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0064] In the description of the specification, the description using the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the particular feature, structure, material or characteristic being described is included in at least one embodiment or example of the present application. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily referred to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Furthermore, the terms "comprise", "comprising", "include", "including", "contain", "containing" or variations thereof are used inclusively and do not exclude the additional inclusion of unrecited features, structures, materials, or characteristics.

[0065] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be interpreted as limiting the present application, and ordinary skilled people in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A hybrid integrated optical gyroscope chip, characterized in that, include: A multi-functional optical module, light-emitting module, circuit module, detector module, and optical fiber are arranged in a multi-layered stacked manner along the first direction; The light-emitting module is provided with a first coupling port, the detector module is provided with a second coupling port, and the multifunctional optical module is provided with a third coupling port and a fourth coupling port, and at least one of the following conditions is satisfied: The first coupling port and the third coupling port are connected by a first three-dimensional polymer waveguide; The second coupling port and the third coupling port are connected by a second three-dimensional polymer waveguide; The fourth coupling port and the optical fiber are connected via a third three-dimensional polymer waveguide.

2. The optical gyroscope chip according to claim 1, characterized in that, Also includes: The diamond substrate, together with the multifunctional optical module, the light-emitting module, the circuit module, the detector module, and the optical fiber, are arranged in a multi-layer stacked configuration. The diamond substrate has a microfluidic structure inside, which is used to conduct heat from inside the optical gyroscope chip to the external environment.

3. The optical gyroscope chip according to claim 2, characterized in that, The diamond substrate includes opposing first and second surfaces; The circuit module is disposed on the first surface, and the optical fiber is disposed on the surface of the circuit module away from the first surface. The optical fiber extends along a second direction, which is perpendicular to the first direction. The multifunctional optical module is disposed on the second surface; The light-emitting module is disposed on the first surface; The detector module is disposed on the surface of the circuit module away from the first surface.

4. The optical gyroscope chip according to claim 3, characterized in that, A V-groove is provided on the surface of the circuit module away from the first surface, and the optical fiber is disposed in the V-groove.

5. The optical gyroscope chip according to claim 4, characterized in that, The optical gyroscope chip has a first end and a second end opposite to each other in the second direction. The first coupling port is located on the end face of the light-emitting module near the first end, the second coupling port is located on the end face of the detector module near the first end, the third coupling port is located on the end face of the multifunctional optical module near the first end, and the fourth coupling port is located on the end face of the multifunctional optical module near the second end.

6. The optical gyroscope chip according to claim 1, characterized in that, At least one of the following conditions must be met: The first three-dimensional polymer waveguide, the second three-dimensional polymer waveguide, and the third three-dimensional polymer waveguide all comprise photosensitive polymer materials; The first three-dimensional polymer waveguide, the second three-dimensional polymer waveguide, and the third three-dimensional polymer waveguide have a graded refractive index.

7. A method for fabricating a hybrid integrated optical gyroscope chip as described in any one of claims 1 to 6, characterized in that, include: The multi-functional optical module, light-emitting module, circuit module, detector module, and optical fiber are stacked in multiple layers. A three-dimensional polymer waveguide is formed at least at one of the following locations: between the coupling ports of the light-emitting module and the multifunctional optical module, between the coupling ports of the detector module and the multifunctional optical module, and between the coupling port of the multifunctional optical module and the optical fiber.

8. The method for fabricating a hybrid integrated optical gyroscope chip according to claim 7, characterized in that, The diamond substrate and the multifunctional optical module, the light-emitting module, the circuit module, the detector module, and the optical fiber are stacked in multiple layers.

9. The method for fabricating a hybrid integrated optical gyroscope chip according to claim 7, characterized in that, The formation of the three-dimensional polymer waveguide includes: A photosensitive polymer material is applied to the waveguide coupling ports and their gap regions to be interconnected, forming a cover layer; The three-dimensional polymer waveguide is formed by three-dimensional exposure in the areas that need to be interconnected using a laser direct writing process.

10. An optical gyroscope, characterized in that, include: The hybrid integrated optical gyroscope chip according to any one of claims 1 to 6; Fiber optic ring, used to connect to optical fibers; The circuit board, wherein the hybrid integrated optical gyroscope chip is disposed on the circuit board and electrically connected to the circuit board.

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