High-power suitable annular array silicon-based optical phased array chip and optimization method

Abstract

The present invention discloses a high-power applicable annular array silicon-based optical phased array chip and an optimization method. In the present invention, a coupled grating module is used to receive an incident light beam, a cascaded splitter module is used to split the incident light beam into multiple unmodulated detection beams, a phase modulation module is used to phase modulate each unmodulated light beam to generate a phase-modulated detection beam, a two-dimensional antenna annular array module is used to emit all phase-modulated detection beams to the outside of the chip, and a high-power widening waveguide is used as a beam transmission channel; the two-dimensional antenna annular array module adopts an axisymmetric structure, mainly composed of at least one co-centered two-dimensional antenna annular array radially arranged from the inside to the outside, and each two-dimensional antenna annular array is mainly composed of multiple two-dimensional grating antennas evenly arranged along the circumference. The chip of the present invention has high continuous wave optical power carrying capacity, low nonlinear loss and heat accumulation.

Description

Technical Field

[0001] The present invention relates to an integrated optical device, and in particular to a silicon-based optical phased array chip suitable for high-power continuous wave optical input. Background Art

[0002] Optical phased arrays, due to their high integration and controllability, have become a key development direction in lidar technology. However, existing silicon-based optical phased array (OPA) chips suffer from insufficient power handling capacity in applications. This is especially true in continuous wave, high-power input scenarios, where nonlinear waveguide losses and thermal effects significantly increase, reducing the signal-to-noise ratio for distant targets and severely impacting detection performance.

[0003] On the one hand, current silicon-based optical phased array chips are based on a 220nm-thick silicon layer, resulting in a limited waveguide mode area. This results in significant nonlinear losses and thermal effects at high power levels. Extended waveguides based on this platform further limit device integration, significantly restricting power transmission performance in high-power continuous-wave (CW) applications. Silicon-based optical waveguides typically have cross-sectional areas ranging from hundreds of nanometers to micrometers, and their internal optical power density far exceeds that of other optical devices, making them the lowest power threshold element for optical phased arrays in high-power CW applications. High power density significantly enhances the material's intrinsic and nonlinear absorption, while the increased carrier density triggers a localized temperature surge. Given that optical phased arrays rely on precise phase control of multiple waveguides, the failure of any channel can lead to overall wavefront distortion. Optical phased arrays for high-power applications must handle watt-level CW optical inputs in the infrared band, a significant performance requirement that exceeds the power transmission limits of traditional single-mode waveguides. To address this issue, increasing the mode area or introducing a micron-scale silicon layer on the traditional 220nm thick silicon layer can effectively improve the power carrying capacity and stability of the device to a certain extent. However, these methods will also bring about problems such as a significant increase in the size of the device structure and degradation of waveguide performance.

[0004] On the other hand, existing radiating antenna array designs mostly employ uniform or sparse arrays. The limited antenna spacing leads to heat accumulation, along with significant losses and beam quality degradation, in high-power continuous wave (CW) array applications. For example, the traditional periodic array arrangement with equal spacing, equal amplitude and phase, and equal number of rings results in high sidelobe energy in the far-field pattern, reducing the focusing efficiency of the main lobe. Furthermore, it fails to consider the thermal accumulation caused by the superposition of thermal fields from adjacent elements in CW high-power applications. Consequently, it is limited by high sidelobes, poor thermal management, structural rigidity, manufacturing sensitivity, and insufficient dynamic capability. Furthermore, in traditional equally spaced periodic arrays, rectangular antenna array elements are arranged with equal spacing, which offers good symmetry and simple mathematical descriptions. However, as the array scale increases, two major issues remain in high-power applications. First, the uniform distribution of array elements in physical space requires connecting more elements in the center of the array, complicating the waveguide paths and leading to crosstalk between waveguides, which affects beam quality. Second, in highly integrated arrays, the dense and complex waveguides in the center also lead to heat accumulation.

[0005] In summary, these factors collectively restrict the application of optical phased array chips in long-range, high-precision LiDAR systems. Existing silicon-based optical phased array chips still face significant increases in waveguide nonlinear losses and thermal effects when operating under continuous wave, high-power optical input. This further reduces the signal-to-noise ratio for long-range targets, severely impacting detection performance. They are unable to simultaneously meet the requirements for waveguide transmission capability, thermal management, high beam quality, and integration under watt-level high-power input conditions. Summary of the Invention

[0006] To address the problems of insufficient power handling capacity, high nonlinear losses, and heat accumulation in existing silicon-based optical phased array chips, the present invention provides a high-power, ring-shaped silicon-based optical phased array chip and an optimization method. The present silicon-based optical phased array chip boasts high continuous wave optical power input capability, enabling two-dimensional scanning at watt-level high power inputs while also offering advantages such as high sidelobe suppression and high integration. Furthermore, the present optimization method can further improve the thermal uniformity of the silicon-based optical phased array chip, enhancing its thermal management performance.

[0007] The technical solutions adopted in the present invention are as follows:

[0008] 1. A high-power, ring-array silicon-based optical phased array chip

[0009] The annular array silicon-based optical phased array chip includes a coupled grating module, a cascaded splitter module, a phase modulation module, a two-dimensional antenna annular array module, and a high-power stretching waveguide. The coupled grating module is used to receive an incident light beam, the cascaded splitter module is used to split the incident light beam into multiple unmodulated probe beams, the phase modulation module is used to phase modulate each unmodulated light beam to generate a phase-modulated probe beam, the two-dimensional antenna annular array module is used to transmit all phase-modulated probe beams upward to the outside of the chip to achieve two-dimensional beam scanning, and the high-power stretching waveguide is used to serve as the optical channel on the annular array silicon-based optical phased array chip, namely, the beam transmission channel. The two-dimensional antenna annular array module adopts an axisymmetric structure and is mainly composed of at least one co-centered two-dimensional antenna annular array arranged radially from the inside out. Each two-dimensional antenna annular array is mainly composed of multiple two-dimensional grating antennas evenly arranged along the circumference.

[0010] Specifically, the cascaded optical splitter module includes a first-stage optical splitter and two optical splitting cascade networks. The two optical splitting cascade networks are arranged on either side of the two-dimensional antenna ring array module and are symmetrically arranged about the symmetry axis of the two-dimensional antenna ring array module. The input end of the first-stage optical splitter is connected to the output end of the coupled grating module via a high-power stretch waveguide. The two output ends of the first-stage optical splitter are respectively connected to the input ends of the two optical splitting cascade networks via high-power stretch waveguides. The output end of each optical splitting cascade network is connected to the two-dimensional antenna ring array module on the same side via a high-power stretch waveguide.

[0011] Specifically, the phase modulation module includes two phase shifter arrays, and the two phase shifter arrays are respectively arranged above the output ends of two optical splitting cascade networks.

[0012] Specifically, the output end of each optical splitting cascade network includes N branch output waveguides, each phase shifter array includes N phase shifters, and the two-dimensional antenna ring array module includes 2N two-dimensional grating antennas, that is, the two-dimensional antenna ring array module is provided with N two-dimensional grating antennas on both sides of the symmetry axis.

[0013] Specifically, for the splitting cascade network, phase shifter array and two-dimensional antenna ring array module located on the same side of the symmetry axis of the two-dimensional antenna ring array module, the number of branch output waveguides, phase shifters and two-dimensional grating antennas is the same and corresponds one to one. A phase shifter is aligned above each branch output waveguide, and the output end of each branch output waveguide is connected to the input end of the corresponding two-dimensional grating antenna through a high-power widened waveguide in a Manhattan routing form.

[0014] Specifically, the two-dimensional grating antenna is mainly composed of three L-shaped grating structures and two grating structure gaps; the horizontal projection shapes of the L-shaped grating structures and the grating structure gaps are both arc-shaped, and the vertical projection shape of the L-shaped grating structure is L-shaped. The three L-shaped grating structures are arranged radially in sequence within the same sector-shaped area located on the horizontal plane, and two adjacent L-shaped grating structures are connected by a grating structure gap; the inner L-shaped grating structure serves as the input end of the two-dimensional grating antenna and is connected to one end of the high-power widening waveguide through a transition waveguide, and the other end of the high-power widening waveguide is connected to the output end of the corresponding branch output waveguide. The horizontal projection shape of the transition waveguide is a truncated sector, the arc side of the transition waveguide is connected to the L-shaped grating structure, and the opposite side of the arc side is connected to the high-power widening waveguide; for two symmetrical two-dimensional grating antennas in the same two-dimensional antenna ring array, the line connecting the centers of the sector-shaped areas corresponding to the two two-dimensional grating antennas is perpendicular to the symmetry axis of the two-dimensional antenna ring array module, thereby forming an axisymmetric structure.

[0015] Specifically, the annular array silicon-based optical phased array chip primarily consists of a silicon substrate layer, a buried layer, a thick silicon layer, a cladding layer, and a phase modulation layer, stacked sequentially from bottom to top. The top surface of the thick silicon layer is etched to form the coupled grating module, cascaded spectrometer module, two-dimensional antenna annular array module, and high-power stretched waveguide. The high-power stretched waveguide is formed through a full-etching process, with a fixed waveguide width selected from 800nm ​​to 1300nm. Compared to single-mode waveguides, this high-power stretched waveguide has a higher power transmission limit and effectively avoids device size increases and chip integration degradation. The phase modulation layer includes a phase modulation module deposited on the top surface of the cladding. Within each phase modulation module, each phase shifter is deposited on the top surface of the cladding above the corresponding branch output waveguide. The incident light beam comprises continuous-wave infrared light with watt-level power.

[0016] Preferably, the optical splitting cascade network is mainly composed of a cascade of multi-stage Y-branch beam splitters or 3dB multimode interference couplers, and the number of cascades is adapted to the number of two-dimensional grating antennas in the two-dimensional antenna ring array module, so that the two-dimensional grating antennas located on one side of the symmetry axis of the two-dimensional antenna ring array module are the same as the number of branch output waveguides of the optical splitting cascade network on the same side.

[0017] Preferably, the curved portion of the optical channel on the annular array silicon-based optical phased array chip adopts an Euler bending waveguide. In the embodiment of the present invention, the equivalent bending radius is 12 μm, providing compact integration of the overall array device; the Euler bending waveguide is formed on the top surface of the thick silicon layer by etching.

[0018] Preferably, the phase shifter is a silicon-based thermo-optical phase shifter, which is formed on the cladding layer by metal evaporation.

[0019] Preferably, the coupling grating module adopts a two-dimensional annular coupling grating; the coupling grating module is formed on the top surface of the thick silicon layer by etching.

[0020] Preferably, each two-dimensional antenna annular array includes the same number of two-dimensional grating antennas.

[0021] Furthermore, the number of the two-dimensional antenna ring arrays, the radial spacing between the rings, and the element spacing of each two-dimensional antenna ring array can be optimized according to the far-field beam sidelobe suppression ratio and heat distribution uniformity through a genetic algorithm.

[0022] The inter-ring radial spacing refers to the radial spacing between two adjacent two-dimensional antenna ring arrays.

[0023] The array element spacing refers to the spacing between two adjacent two-dimensional grating antennas in a two-dimensional antenna ring array.

[0024] The wavelength of the incident light beam is 1550nm, the thickness of the thick silicon layer is 500nm, the etching depth of the high-power broadening waveguide is 500nm, the width of the high-power broadening waveguide is 800nm, the etching depth of the grating structure gap is 500nm, and the etching depth of the L-shaped grating structure is 130nm; N is 32, the number of two-dimensional antenna ring arrays is two, the two-dimensional grating antennas in the two two-dimensional antenna ring arrays are the same, the outer ring aperture is 720μm, and the inner ring aperture is 500μm.

[0025] 2. An optimization method for the above-mentioned annular array silicon-based optical phased array chip

[0026] The optimization method includes the following steps: using a genetic algorithm to establish a fitness function based on the far-field beam sidelobe suppression ratio and thermal distribution uniformity, wherein each individual includes the number of two-dimensional antenna ring arrays, the radial spacing between rings, and the array element spacing of each two-dimensional antenna ring array; after multiple generations of selection, crossover, and mutation operations, the optimal individual is obtained after the termination condition is met; and the ring array silicon-based optical phased array chip is manufactured and obtained based on the number of two-dimensional antenna ring arrays, the radial spacing between rings, and the array element spacing of each two-dimensional antenna ring array in the optimal individual.

[0027] Preferably, the fitness function is set according to the following formula:

[0028] f = SLSR-αp1-βp2-γp3

[0029] Where f represents the fitness, SLSR represents the far-field beam sidelobe suppression ratio, p1 represents the penalty of the outer ring aperture, p2 represents the penalty of the array element spacing, p3 represents the penalty of the radial spacing between rings, α represents the first weight coefficient, β represents the second weight coefficient, and γ represents the third weight coefficient.

[0030] Preferably, the three weight coefficients range from 5 to 10, 2 to 5, and 1 to 3, respectively.

[0031] Preferably, the three penalty amounts are set according to the following formulas:

[0032] p1=max[0,∑(A m -A max ) / A max ]

[0033] p2=max[0,(d min -d e ) / d min ]

[0034] p3=max[0,(1.2A m -A m+1 ) / A m ]

[0035] In the formula, max[ ] represents the maximum value function, A m represents the aperture of the mth ring, A max Indicates the maximum outer ring aperture limit, d e Indicates the minimum element spacing limit, d min Indicates the minimum distance between any two array elements.

[0036] Preferably, the far-field beam sidelobe suppression ratio is obtained by the following process: a radiation pattern is obtained according to the array factor and the far-field distribution of a single antenna, and the far-field beam sidelobe suppression ratio is obtained by extracting it from the radiation pattern according to the following formula:

[0037] SLSR=10log 10 (I main / I side )

[0038] Where, I main Indicates the main lobe peak power, I side Indicates the maximum sidelobe peak power.

[0039] Preferably, when the main beam points in the direction of (u0, v0), the array factor F(u, v, u0, v0) is expressed by the following formula:

[0040] F(u,v,u0,v0)=∑ M m=1 ∑ Nm N=1 E m,n e^[jkr m ((cosφ m,n (u-u0)+sinφ m,n (v-v0)]

[0041] Where (u0, v0) represents the main lobe direction after phase calibration, and (u, v) represents the main lobe direction before phase calibration; E m,n represents the electric field strength of the nth two-dimensional grating antenna in the mth ring, M represents the number of two-dimensional antenna ring arrays, N m represents the total number of two-dimensional grating antennas in the mth ring, j represents the imaginary unit, k represents the free space wave number, r m represents the radius of the mth ring, that is, the distance from the center of the array to the mth ring; φ m,n represents the azimuth angle of the nth two-dimensional grating antenna in the mth ring.

[0042] The free space wave number k is obtained by the following formula:

[0043] k=2π / λ

[0044] Where λ represents the wavelength of the incident light beam.

[0045] The two direction cosine parameters of the main lobe direction are obtained by the following formulas:

[0046] u=sinφcosθ

[0047] v=sinθcosφ

[0048] Where φ represents the azimuth angle of the main lobe direction, and θ represents the elevation angle of the main lobe direction.

[0049] Furthermore, the optimization method further includes the following steps: in each phase shifter array, the phase shifters are arranged at equal intervals along the symmetry axis, the spacing between adjacent phase shifters is obtained through a simulation method, the total width of the phase shifter array in the symmetry axis direction is calculated based on the number and spacing of the phase shifters, and the maximum outer ring aperture limit is set based on the total width of the phase shifter array in the symmetry axis direction.

[0050] The beneficial effects of the present invention are as follows:

[0051] 1. The annular array silicon-based optical phased array chip provided by the present invention has the advantages of lower nonlinear loss, higher power carrying capacity, higher signal quality and more uniform heat distribution. It can meet the requirements of waveguide transmission capacity, heat management, high beam quality and integration under watt-level high power input.

[0052] 2. In the annular array silicon-based optical phased array chip provided by the present invention, the widened waveguide can stably transmit continuous wave optical input power of more than 1.1W.

[0053] 3. The annular array silicon-based optical phased array chip provided by the present invention combines high-power broadening waveguides and annular array structures, and uses optimization methods to simultaneously reduce sidelobe levels and control heat distribution, thereby improving the overall performance of the chip in high-power scenarios.

[0054] In summary, the present invention proposes a high-power applicable optical phased array chip structure and its optimization method, which has broad application prospects in long-distance, high-power, and high-precision application fields such as integrated optics and lidar. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 Schematic diagram of the annular array silicon-based optical phased array chip provided in Example 1 of the present invention;

[0056] In the figure: 1. Coupled grating module, 2. Cascaded optical splitter module, 3. Phase modulation module, 4. Two-dimensional antenna ring array module, 5. Euler curved waveguide, 6. High-power stretched waveguide;

[0057] Figure 2 A schematic structural diagram of a phase shifter in a ring-shaped silicon-based optical phased array chip provided in Example 1 of the present invention;

[0058] Figure 3 A schematic diagram of a ring-shaped two-dimensional antenna array module in a ring-shaped silicon-based optical phased array chip provided in Example 1 of the present invention;

[0059] Figure 4 A schematic diagram of a two-dimensional radiating antenna in a ring-shaped two-dimensional antenna array module provided in Example 1 of the present invention;

[0060] In the figure: 41, two-dimensional grating antenna, 411, grating structure gap, 412, L-shaped grating structure;

[0061] Figure 5 This is a schematic diagram of the arrangement of two-dimensional radiating antennas optimized using a genetic algorithm in Example 1 of the present invention;

[0062] In the figure: 42, dual-ring two-dimensional antenna ring array module, 421, outer ring antenna array, 422, inner ring antenna array;

[0063] Figure 6 This is the far-field simulation result of the dual-ring two-dimensional antenna ring array module optimized using the genetic algorithm in Example 1 of the present invention;

[0064] Figure 7 1 is a power transmission curve diagram of the widened waveguide compared with the single-mode waveguide in Example 2 of the present invention;

[0065] Figure 8 This is a total insertion loss curve of the widened waveguide compared with the single-mode waveguide in Example 2 of the present invention. DETAILED DESCRIPTION

[0066] The present invention will be explained in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments herein are only used to explain the present invention and are not intended to limit the present invention.

[0067] This invention utilizes a high-continuous-wave transmission broadening waveguide and a ring antenna array optimized for sidelobe suppression and heat distribution uniformity to enhance continuous-wave optical power carrying capacity. This reduces nonlinear losses and heat accumulation in the silicon waveguide and radiating array, improving beam quality and detection performance. It is suitable for high-power beam detection systems such as lidar. The ring-array silicon-based optical phased array chip of this invention enables two-dimensional scanning while also offering advantages such as high sidelobe suppression and high integration.

[0068] A first aspect of the present invention provides a high-power applicable annular array silicon-based optical phased array chip.

[0069] like Figure 1 As shown, the annular array silicon-based optical phased array chip of the present invention includes a coupled grating module 1, a cascaded spectrometer module 2, a phase modulation module 3, a two-dimensional antenna annular array module 4, and a high-power stretching waveguide 6. The coupled grating module 1 is used to receive an incident light beam, the cascaded spectrometer module 2 is used to split the incident light beam into multiple unmodulated probe beams, the phase modulation module 3 is used to phase modulate each unmodulated light beam to generate a phase-modulated probe beam, the two-dimensional antenna annular array module 4 is used to transmit all phase-modulated probe beams upward to the outside of the chip, achieving two-dimensional beam scanning, and the high-power stretching waveguide 6 is used to serve as a beam transmission channel on the annular array silicon-based optical phased array chip.

[0070] Specifically, if Figure 1 and Figure 3 As shown, the two-dimensional antenna annular array module 4 adopts an axisymmetric structure, mainly composed of at least one co-centered two-dimensional antenna annular array arranged radially from the inside to the outside, and each two-dimensional antenna annular array is mainly composed of multiple two-dimensional grating antennas 41 evenly arranged along the circumference. Among them, the two-dimensional antenna annular array module 4 adopts an axisymmetric structure, which means that all two-dimensional grating antennas 41 in the same two-dimensional antenna annular array are arranged axisymmetrically, and all two-dimensional antenna annular arrays share the same symmetry axis, which is the symmetry axis of the two-dimensional antenna annular array module 4. This uniform circular aperture architecture with symmetrical characteristics used in the present invention can break through the physical limitations of traditional array arrangements, while achieving scanning capabilities through annular phase compensation.

[0071] Specifically, the cascaded optical splitter module 2 includes a first-stage optical splitter and two optical splitting cascade networks. The two optical splitting cascade networks are respectively arranged on either side of the two-dimensional antenna ring array module 4 and are symmetrically arranged about the symmetry axis of the two-dimensional antenna ring array module 4. The input end of the first-stage optical splitter is connected to the output end of the coupled grating module 1 via a high-power stretch waveguide 6. The two output ends of the first-stage optical splitter are respectively connected to the input ends of the two optical splitting cascade networks via high-power stretch waveguides 6. The output end of each optical splitting cascade network is connected to the two-dimensional antenna ring array module 4 on the same side via a high-power stretch waveguide 6.

[0072] Specifically, the phase modulation module 3 includes two phase shifter arrays, which are respectively arranged above the output ends of the two optical splitting cascade networks.

[0073] Specifically, the output end of each optical splitting cascade network includes N branch output waveguides, each of which is arranged at equal intervals along the symmetry axis of the two-dimensional antenna ring array module 4. Each phase shifter array includes N phase shifters, each of which is arranged at equal intervals along the symmetry axis of the two-dimensional antenna ring array module 4. The two-dimensional antenna ring array module 4 includes 2N two-dimensional grating antennas 41, that is, the two-dimensional antenna ring array module 4 is provided with N two-dimensional grating antennas 41 on each side of the symmetry axis.

[0074] For the portion of the two-dimensional antenna ring array module 4 located on one side of the symmetry axis, as well as the splitter cascade network and phase shifter array on the same side, the number of branch output waveguides in the splitter cascade network, the phase shifters in the phase shifter array, and the two-dimensional grating antennas 41 in the two-dimensional antenna ring array module 4 are the same and correspond one to one. Phase shifters (such as Figure 2 As shown), the phase shifter is used to phase modulate the unmodulated light beam of the corresponding branch output waveguide arranged below itself, and the branch output waveguide is connected to the corresponding two-dimensional grating antenna 41 through a high-power widening waveguide 6 in the form of Manhattan routing, and then the phase-modulated detection light beam generated by its own corresponding phase shifter is output to the corresponding two-dimensional grating antenna 41 through the high-power widening waveguide 6.

[0075] Specifically, if Figure 4As shown, the two-dimensional grating antenna 41 is primarily composed of three L-shaped grating structures 412 and two grating structure gaps 411. The two-dimensional periodic arrangement of the L-shaped grating structures 412 can control the outgoing light field in the vertical direction (z direction), enhancing directivity and optimizing beam divergence characteristics, thereby reducing energy loss. The grating gaps 411 further achieve precise wavefront control by adjusting the phase distribution, making them suitable for high-precision optical phased array systems. The grating structure optimizes the divergence of the optical waveguide and free-space light through mode matching. The adjustability of the grating period, duty cycle, and gap size allows the antenna's operating frequency and radiation angle characteristics to be customized according to the requirements of the annular array, adapting to different array structures. The horizontal projections of the L-shaped grating structure 412 and the grating structure gap 411 are both arc-shaped, and the vertical projection of the L-shaped grating structure 412 is L-shaped. Three L-shaped grating structures 412 are arranged sequentially along the radial direction of the fan-shaped region within the same fan-shaped horizontal region, with two adjacent L-shaped grating structures 412 connected by a grating structure gap 411. The L-shaped grating structure 412 located at the innermost side of the fan-shaped region is connected to the high-power stretch waveguide 6 via a transition waveguide. The horizontal projection of the transition waveguide is a truncated fan-shaped shape, with the arc side of the transition waveguide connected to the inner L-shaped grating structure 412, and the opposite side of the arc side connected to the high-power stretch waveguide 6. The truncated fan-shaped shape consists of three straight sides and one arc side, and the two straight sides adjacent to the arc side are collinear with the two side sides of the horizontal projection of the fan-shaped region.

[0076] Specifically, for two symmetrical two-dimensional grating antennas 41 in the same two-dimensional antenna ring array, the line connecting the centers of the sector-shaped areas to which the two two-dimensional grating antennas 41 belong is perpendicular to the symmetry axis of the two-dimensional antenna ring array module 4 .

[0077] Further, if Figure 2 As shown, the annular silicon-based optical phased array chip primarily consists of a silicon substrate layer, a buried layer, a thick silicon layer (Si waveguide layer), a cladding layer (SiO2 cladding), and a phase modulation layer (metal electrode layer), stacked from bottom to top. The top surface of the thick silicon layer is etched to form the coupled grating module 1, the cascaded optical splitter module 2, the two-dimensional antenna annular array module 4, and the high-power stretched waveguide 6. The high-power stretched waveguide 6 is formed by a full-etch process. Within the same annular silicon-based optical phased array chip, the high-power stretched waveguide 6 has a fixed waveguide width, ranging from 800nm ​​to 1300nm. Compared to single-mode waveguides, the high-power stretched waveguide 6 has a higher power transmission limit and effectively avoids device size increases and chip integration degradation. The phase modulation layer includes a phase modulation module 3 deposited on the top surface of the cladding, and phase shifters deposited on the top surface of the cladding above the corresponding branch output waveguides.

[0078] Preferably, the thickness of the thick silicon layer is 500 nm. The high-power stretched waveguide 6 utilizes a waveguide stretching design to effectively expand the mode field area and reduce the power density per unit area, thereby significantly reducing nonlinear losses and having a higher power transmission limit than a single-mode waveguide.

[0079] Preferably, the incident light beam comprises continuous wave light in the infrared band with a power in the watt range.

[0080] Preferably, the incident light beam comprises continuous wave light having a wavelength of 1500 nm at a power level in the watt range.

[0081] Preferably, the optical splitting cascade network is mainly composed of a cascade of multi-stage Y-branch beam splitters or 3dB multimode interference couplers, and the number of cascades is adapted to the number of two-dimensional grating antennas 41 in the two-dimensional antenna ring array module 4, so that the two-dimensional grating antennas 41 located on one side of the symmetry axis of the two-dimensional antenna ring array module 4 are the same as the number of branch output waveguides of the optical splitting cascade network on the same side.

[0082] Preferably, the curved portion of the optical channel on the annular array silicon-based optical phased array chip adopts an Euler curved waveguide 5 , and the Euler curved waveguide 5 is formed on the top surface of the thick silicon layer by etching.

[0083] Preferably, the phase shifter is a metal thermo-optical phase shifter, which is formed on the cladding by metal evaporation.

[0084] Preferably, the coupling grating module 1 adopts a two-dimensional annular coupling grating; the coupling grating module 1 is formed on the top surface of the thick silicon layer by etching.

[0085] Preferably, each two-dimensional antenna annular array includes the same number of two-dimensional grating antennas 41 .

[0086] Furthermore, the number of two-dimensional antenna annular arrays, the radial spacing between rings, and the element spacing within each two-dimensional antenna annular array can be optimized using a genetic algorithm based on the far-field beam sidelobe suppression ratio and thermal distribution uniformity. The radial spacing between rings refers to the radial spacing between two adjacent two-dimensional antenna annular arrays. The element spacing refers to the circumferential spacing between two adjacent two-dimensional grating antennas 41 within the two-dimensional antenna annular array. The circumferential spacing refers to the distance along the circumference of the two-dimensional antenna annular array.

[0087] As a preferred embodiment of the present invention, when the wavelength of the incident light beam is 1550 nm, the thickness of the thick silicon layer is 500 nm, the etching depth of the high-power stretched waveguide 6 is 500 nm, the width of the high-power stretched waveguide 6 is 800 nm, the etching depth of the grating structure gap 411 is 500 nm, and the etching depth of the L-shaped grating structure 412 is 130 nm. N is 32, the number of two-dimensional antenna ring arrays is 2, and the two-dimensional grating antennas 41 in the two two-dimensional antenna ring arrays are identical, with an outer ring aperture of 720 μm and an inner ring aperture of 500 μm. This array provides a sidelobe suppression ratio exceeding 10.2 dB and effectively addresses heat accumulation issues and modal crosstalk between thick silicon stretched waveguides under high-power continuous wave conditions through spacing control, while ensuring that heat in the designed phase shifter array is properly controlled.

[0088] A second aspect of the present invention provides an optimization method for the above-mentioned annular array silicon-based optical phased array chip.

[0089] The optimization method of the present invention comprises the following steps: using a genetic algorithm to establish a fitness function according to the far-field beam sidelobe suppression ratio and the heat distribution uniformity, wherein each individual includes the number of two-dimensional antenna ring arrays, the radial spacing between rings, and the array element spacing of each two-dimensional antenna ring array; after multiple generations of selection, crossover, and mutation operations, an optimal individual is obtained after a termination condition is met; and a ring array silicon-based optical phased array chip is manufactured and obtained according to the number of two-dimensional antenna ring arrays, the radial spacing between rings, and the array element spacing of each two-dimensional antenna ring array in the optimal individual.

[0090] Preferably, the fitness function is set according to the following formula:

[0091] f = SLSR-αp1-βp2-γp3

[0092] Where f represents the fitness, SLSR represents the far-field beam sidelobe suppression ratio, p1 represents the penalty of the outer ring aperture, p2 represents the penalty of the array element spacing, p3 represents the penalty of the radial spacing between rings, α represents the first weight coefficient, β represents the second weight coefficient, and γ represents the third weight coefficient.

[0093] Among them, the three penalty amounts are set according to the following formulas:

[0094] p1=max[0,∑(A m -A max ) / A max ]

[0095] p2=max[0,(d min -d e ) / d min ]

[0096] p3=max[0,(1.2Am -A m+1 ) / A m ]

[0097] In the formula, max[ ] represents the maximum value function, A m represents the aperture of the mth two-dimensional antenna ring array, A max Indicates the maximum outer ring aperture limit, d e Indicates the minimum element spacing limit, d min Indicates the minimum distance between any two array elements;

[0098] The far-field beam sidelobe suppression ratio is obtained by the following process: the radiation pattern is obtained based on the array factor and the far-field distribution of a single antenna, and the far-field beam sidelobe suppression ratio is extracted from the radiation pattern according to the following formula:

[0099] SLSR=10log 10 (I main / I side )

[0100] Where, I main Indicates the main lobe peak power, I side Indicates the maximum sidelobe peak power.

[0101] When the main beam points in the direction of (u0, v0), the array factor F(u, v, u0, v0) is expressed by the following formula:

[0102] F(u,v,u0,v0)=∑ M m=1 ∑ Nm N=1 E m,n e^[jkr m ((cosφ m,n (u-u0)+sinφ m,n (v-v0)]

[0103] Where (u0, v0) represents the main lobe direction after phase calibration, and (u, v) represents the main lobe direction before phase calibration; E m,n represents the electric field strength of the n-th two-dimensional grating antenna 41 in the m-th ring, M represents the number of two-dimensional antenna ring arrays, N m represents the total number of two-dimensional grating antennas 41 in the mth ring, j represents the imaginary unit, k represents the free space wave number, r m represents the radius of the mth ring, that is, the distance from the center of the array to the mth ring; φ m,n represents the azimuth angle of the nth two-dimensional grating antenna in the mth ring.

[0104] The free space wave number k is obtained by the following formula:

[0105] k=2π / λ

[0106] Where λ represents the wavelength of the incident light beam.

[0107] The two direction cosine parameters of the main lobe direction are obtained by the following formulas:

[0108] u=sinφcosθ

[0109] v=sinθcosφ

[0110] Where φ represents the azimuth angle of the main lobe direction, and θ represents the elevation angle of the main lobe direction.

[0111] Furthermore, the optimization method of the present invention also includes the following steps: in each phase shifter array, the phase shifters are arranged at equal intervals along the symmetry axis, the spacing between adjacent phase shifters is obtained by simulation, the width of the phase shifter array in the symmetry axis direction is calculated based on the number and spacing of the phase shifters, and the maximum outer ring aperture is set based on the width of the phase shifter array in the symmetry axis direction.

[0112] Specifically, device fabrication includes two electron beam exposures and inductively coupled plasma etchings, wherein the first exposure and etching are used to define the waveguide structure, and the second exposure and etching are used to form the grating overlay structure in the optical coupling unit and the two-dimensional grating antenna.

[0113] Preferably, the manufacturing process of the annular array silicon-based optical phased array chip is specifically as follows:

[0114] Performing a first electron beam exposure and inductively coupled plasma etching on the top surface of the thick silicon layer, with the etching depth being full, to form a main waveguide structure; the main waveguide structure includes a coupled grating module 1, a cascaded optical splitter module 2, a grating structure gap 411 in a two-dimensional antenna ring array module 4, an Euler bending waveguide 5, and a high-power broadening waveguide 6;

[0115] A second electron beam exposure and inductively coupled plasma etching is performed on the top surface of the thick silicon layer. The etching depth is shallow, and the shallow etching depth is less than the full etching depth, to form a grating overlay structure. The overlay depth (i.e., the shallow etching depth) is optimized based on the coupling efficiency and the upward radiation efficiency of the antenna array element. The grating overlay structure includes the coupled grating module 1 and the L-shaped grating structure 412 in the two-dimensional antenna ring array module 4.

[0116] forming a cladding layer on top of the thick silicon layer;

[0117] A deposition process is performed on the top surface of the cladding layer to form a phase modulation layer mainly composed of the phase modulation modules 3 .

[0118] Optionally, the deposition process uses processes such as photolithography, metal evaporation or lift-off.

[0119] The specific embodiments of the present invention are as follows: Example

[0120] In this embodiment, the wavelength of the incident light beam is 1500 nm. Figure 1 As shown, the ring-shaped silicon-based optical phased array chip includes a coupled grating module 1, a cascaded optical splitter module 2, a phase modulation module 3, a two-dimensional antenna ring array 4, an Euler bend waveguide 5, and a high-power stretch waveguide 6. These device structures are fabricated using silicon-on-insulator (SOI) material with a silicon layer thickness of 500 nanometers and integrated into a single chip. The chip measures 3 mm × 2.5 mm and includes a total of 64 two-dimensional grating antennas 41.

[0121] The coupling grating module 1 uses a two-dimensional annular coupling grating, which is formed on the top surface of the thick silicon layer by etching. The incident direction of the incident light beam and the transmission direction of the light beam in the coupling grating module 1 are both aligned with the symmetry axis of the two-dimensional antenna ring array module 4.

[0122] Cascaded optical splitter module 2 is primarily composed of 63 1×2 multimode interference coupler beam splitters cascaded in multiple stages. Except for the first-stage beam splitters, the remaining multimode interference coupler beam splitters and input and output waveguides are divided into two groups, symmetrically arranged about the x-axis. Except for the first-stage beam splitters, the remaining multimode interference coupler beam splitters extend along the y-direction.

[0123] Phase modulation module 3 includes two phase shifter arrays, and the phase shifters use silicon-based thermo-optical phase shifters. Through thermal simulation, power boundary conditions are applied to the device heating electrodes to solve the temperature field distribution, obtain the thermal distribution model of the overall area of ​​the waveguide and phase shifter, and introduce optical simulation to solve the light field changes, and then obtain high-performance thermo-optical phase shifter parameters under high temperature conditions. The optimized size of each thermo-optical phase shifter is 200μm×2μm, with a spacing of 50μm, which avoids heat accumulation in high-power scenarios caused by dense electrodes, and provides heat dissipation characteristics and stable 2π phase shifting capabilities. Figure 2 As shown, each thermo-optical phase shifter uses 200nm thick metal as the conductive material and is deposited on the silicon dioxide cladding using photolithography and metal evaporation processes (corresponding to Figure 2 metal electrode layer in the ).

[0124] The two-dimensional antenna ring array 4 forms a circularly symmetrical structure by distributing two-dimensional grating antennas 41 at equal angles on concentric rings. Figure 4As shown, the grating structure gap 411 is 0.56μm, the period of the L-type grating structure 412 is 1.26μm, the duty cycle is 0.476, providing an upward radiation efficiency higher than 50%, and the overall size of the L-type grating structure 41 is 10.7μm×6μm, its 1dB bandwidth exceeds 100nm and the 3dB envelope is 21.4°×18.7°.

[0125] like Figure 3 As shown in the figure, this uniform circular aperture architecture with symmetric characteristics can achieve scanning capability through annular phase compensation. For a circular optical phased array structure composed of m concentric rings (the number of array elements in the mth concentric ring is N m , the corresponding ring radius R m ), all radiating elements (two-dimensional grating antenna 41) are set to isotropic point sources. Under this condition, when the main beam points in the direction of (u0, v0), the expression of the array factor F(u, v, u0, v0) is expressed as:

[0126] F(u,v,u0,v0)=∑ M m=1 ∑ Nm N=1 E m,n e^[jkr m ((cosφ m,n (u-u0)+sinφ m,n (v-v0)]

[0127] Where (u0, v0) represents the main lobe direction after phase calibration, and (u, v) represents the main lobe direction before phase calibration; E m,n represents the electric field strength of the n-th two-dimensional grating antenna 41 in the m-th ring, M represents the number of two-dimensional antenna ring arrays, N m represents the total number of two-dimensional grating antennas 41 in the mth ring, j represents the imaginary unit, k represents the free space wave number, r m represents the radius of the mth ring, that is, the distance from the center of the array to the mth ring, φ m,n represents the azimuth angle of the nth two-dimensional grating antenna in the mth ring.

[0128] In this embodiment, a dynamic optimization scheme based on a genetic algorithm is used. Through multi-parameter joint control (sidelobe suppression ratio, number of rings, radial spacing and array element spacing) and multi-objective collaborative optimization (far-field beam sidelobe suppression ratio and thermal uniformity), that is, the array structure is dynamically optimized using a genetic algorithm, and mandatory constraints are set based on the process limitations of minimum unit spacing and maximum aperture size. This significantly improves the beam performance and robustness under high-power continuous waves.

[0129] In this embodiment, the fitness function includes the far-field beam sidelobe suppression ratio, determined by the array factor formula, and the thermal distribution uniformity, determined by the number of rings, radial spacing, and element spacing. The initial population size is set to 100, with a crossover probability of 0.6 and a mutation rate of 0.002. 64 units are selected and combined with random heuristic individuals to balance search space diversity and early convergence efficiency. Each generation is evaluated using the fitness function.

[0130] For each generation of individuals in the population, the fitness is calculated through the following process:

[0131] The radiation pattern is obtained based on the array factor and the far-field distribution of a single antenna. The far-field beam sidelobe suppression ratio is extracted from the radiation pattern according to the following formula:

[0132] SLSR=10log 10 (I main / I side )

[0133] Where, I main Indicates the main lobe peak power, I side Indicates the maximum sidelobe peak power.

[0134] Calculate the fitness according to the fitness function:

[0135] f = SLSR-αp1-βp2-γp3

[0136] Wherein, f represents the fitness, SLSR represents the far-field beam sidelobe suppression ratio, p1 represents the penalty for the outer ring aperture, p2 represents the penalty for the array element spacing, p3 represents the penalty for the radial spacing between rings, α represents the first weight coefficient, β represents the second weight coefficient, and γ represents the third weight coefficient. In this embodiment, the three weight coefficients are set to 5, 3, and 2, respectively.

[0137] The three penalty amounts are set according to the following formulas:

[0138] p1=max[0,∑(A m -A max ) / A max ]

[0139] p2=max[0,(d min -d e ) / d min ]

[0140] p3=max[0,(1.2A m -A m+1 ) / A m ]

[0141] In the formula, max[ ] represents the maximum value function, A mrepresents the aperture of the mth ring, A max Indicates the maximum outer ring aperture limit, d e Indicates the minimum element spacing limit, d min Indicates the minimum distance between any two array elements.

[0142] The maximum outer ring aperture is set according to the total width of the phase shifter array in the x direction, and is set to 1100 μm in this embodiment. The minimum element spacing is set according to the crosstalk simulation between units, and is set to 30 μm in this embodiment. The ring expansion rule in this embodiment is set as follows: the outer ring radial spacing is greater than 1.2 times the inner ring aperture, that is, N k+1 ≥1.2N k , ensuring that the power density of multiple rings is evenly distributed and preventing heat accumulation caused by too small a spacing between multiple rings.

[0143] The optimization results are as follows Figure 5 As shown, in the dual-ring two-dimensional antenna ring array module 42, the outer ring antenna array 421 has an aperture of 720μm, the inner ring antenna array 422 has an aperture of 500μm, the radial spacing is 110μm, and the minimum array element spacing within the ring is 49μm, providing good array element uniformity, thereby providing good thermal management performance and simple output waveguide wiring complexity.

[0144] The parameter combination corresponding to the optimal individual is simulated with high precision in the far field beam. The results are as follows: Figure 6 As shown, the far-field spot at the center has a sidelobe suppression ratio greater than 10.2dB. This indicator shows that the array effectively reduces radiation interference in non-main beam directions, providing high directivity and low signal interference capabilities for the output beam system, meeting the beam detection requirements of applications such as LiDAR.

[0145] High-power stretched waveguide 6. In this embodiment, the high-power stretched waveguide 6 is based on a 500nm thick silicon layer and utilizes a waveguide stretching design to effectively expand the mode field area and reduce the power density per unit area, thereby significantly reducing nonlinear losses and having a higher power transmission upper limit compared to a single-mode waveguide.

[0146] It is worth explaining that in high-power scenarios, the two main nonlinear losses suffered by silicon materials include two-photon absorption (TPA) and free carrier absorption (FCA). Both will greatly limit the average power level that the silicon waveguide can stably transmit, and the loss increases with the high-order power of the light intensity per unit area. After the input power exceeds a certain threshold, the nonlinear loss in the waveguide increases and causes more serious thermal effects or device damage. At the same time, the widened waveguide based on the traditional 220nm thick silicon layer platform will lead to a significant increase in the size of the device structure and performance degradation. The waveguide structure design of the present invention is comprehensively optimized in terms of nonlinear loss, device size, coupling efficiency, manufacturing process, etc.

[0147] The light intensity I in the silicon waveguide is affected by linear loss, two-photon absorption, and free-carrier absorption during continuous wave light propagation. The total loss equation can be expressed as:

[0148] dI / dz=-αI-β TPA I 2 -β FCA I 3

[0149] Where I represents the distribution of optical power on the cross section along the waveguide propagation direction z, and the specific value is I=P / A eff , P is the input continuous wave optical power, A eff is the mode area of ​​the waveguide, α is the linear propagation loss coefficient, β TPA and β FCA are the nonlinear coefficients corresponding to two-photon absorption and free-carrier absorption effects, respectively.

[0150] It can be seen from the total loss equation that the two nonlinear effects of TPA and FCA are caused by the high local light intensity of the waveguide cross section. In the case of high-power continuous wave light input, both will significantly limit the optical power that can be stably transmitted in the silicon waveguide. Since thick silicon waveguides and waveguide widening designs can reduce the optical power density per unit area, it is possible to reduce optical loss and signal distortion by alleviating nonlinear effects including TPA and FCA. Therefore, in high-power and long-distance transmission, the high-power widened waveguide 6 in the present invention can ensure that high-power continuous wave light can be stably transmitted while maintaining a high transmission efficiency. However, directly increasing the thickness of the silicon layer or widening the waveguide on the traditional design platform will lead to a decrease in device integration, thereby degrading the integration area of ​​the on-chip system. Silicon waveguides for high-power applications need to be comprehensively designed and their performance verified through specific experiments.

[0151] Based on this, this example uses a 500nm-thick silicon layer as the chip design platform, with waveguide widths of 800nm ​​and 1300nm, respectively. By introducing an unconventional thick silicon layer platform and a waveguide stretching strategy, the waveguide mode area is expanded to ~2.67 and ~4.33 times that of the single-mode waveguide baseline design, respectively, to meet the requirements of high-power transmission and integration.

[0152] Euler bending waveguide 5, this embodiment uses a compact Euler bending waveguide, that is, a bending waveguide optimized by Euler bending. The bending parts between all devices are connected by Euler bending optimized bending waveguides, providing low loss and high-order mode suppression characteristics. This embodiment uses a maximum curvature radius R max A thick silicon curved waveguide optimized for a 500μm Euler curve has an equivalent bending radius of 12μm and an insertion loss of less than 0.01dB within a 50nm bandwidth at a central wavelength of 1550nm.

[0153] In this embodiment, device fabrication involves two electron beam exposure and inductively coupled plasma etching steps. The first exposure and etching step forms the main structure, with an etching depth of 500 nm. The second exposure and etching step forms the L-shaped grating structure in the coupled grating module 1 and the two-dimensional grating antenna 41, with an etching depth of 130 nm. This embodiment achieves high coupling efficiency and antenna element upward radiation efficiency by selecting an optimized overlay depth of 130 nm.

[0154] Example 2

[0155] This embodiment verifies the power boosting effect of the high-power stretched waveguide 6 through experiments.

[0156] The experimental process is as follows: The experimental system uses a cascaded structure of a tunable laser (TL) and an erbium-doped fiber amplifier (EDFA). A precision power control module stably adjusts the continuous wave output power from 0 to 1.1 W. Polarization control is used to ensure the coupling efficiency of the grating, and a power meter is used to simultaneously monitor the input and output power to accurately estimate the total insertion loss.

[0157] In this example, the three test waveguides were fixed at 1mm in length and fabricated using a standard CMOS process, involving two electron beam exposures and inductively coupled plasma etching. The first exposure and etching process defined the waveguide structure, while the second formed the input coupling grating structure. The system used an optical power meter to quantify the input and output optical power and calculate the total insertion loss. The waveguide transmission power was calculated as the power transmitted within the waveguide after compensating for the insertion loss of the single-sided coupling grating. The single-mode waveguides fabricated on a thick silicon platform were 300nm wide, with a mode field area similar to that of an existing 220nm silicon layer. The three waveguides used identical coupling gratings and were integrated on the same chip. The experimental instruments and parameter settings for the three waveguides were consistent, demonstrating the significant significance of this comparative experiment.

[0158] The experimental results are as follows Figure 7 and Figure 8 As shown in the figure, the overall insertion loss and growth rate of the single-mode waveguide are greater than those of the stretched waveguide. When the input power reaches 800mW or above, the single-mode waveguide can no longer maintain high-power continuous-wave optical transmission, quantifying the limitation of its limited cross-sectional area on power carrying capacity. At the same time, the total insertion loss of the two groups of stretched waveguides increases more slowly. This is consistent with theory because the light intensity per unit area is reduced at the same input power, thereby weakening the nonlinear effect.

[0159] No structural damage was observed for the 800nm ​​and 1300nm widened waveguides at a continuous wave optical input power of 1.1W, corresponding to a higher upper power threshold; no structural damage was observed for the coupled grating at a continuous wave optical input power of 1.1W, also corresponding to a higher upper power threshold.

[0160] In summary, the two sets of 500nm silicon layer widened waveguides have significant applicability in high-power scenarios. The 1300nm widened waveguide has a higher power transmission threshold, but the propagation loss introduced by the manufacturing process and the mode mismatch loss caused by the sidewall roughness jointly lead to its increased loss in the 0.2W-0.8W input power range. In comparison, the 800nm ​​widened waveguide has more stable loss characteristics and is preferred and used in the high-power applicable two-dimensional optical phased array chip in Example 1.

[0161] In summary, the ring array design of the present invention introduces annular symmetry, breaking the uniform spacing and strict periodicity of traditional arrays. This addresses the problems of traditional rectangular arrays, where the uniform distribution of array elements in physical space requires more elements to be connected in the center of the array, resulting in complex waveguide paths, crosstalk between waveguides, and poor beam quality. Furthermore, the dense and complex waveguides in the center of the array can lead to heat accumulation in highly integrated arrays. Its key advantages lie in the following: Instead of being concentrated in the center, the array elements of the ring array are distributed across different ring layers. The distance between array elements in each ring layer is more evenly distributed. Compared to traditional arrays, the array elements are not densely packed in the center, thus providing excellent thermal uniformity under high-power continuous wave conditions. Furthermore, by adding more rings or increasing the number of elements per ring, the ring array can be effectively expanded without sacrificing system performance. Compared to traditional equally spaced array layouts, the ring array avoids the problem of dense and overlapping wiring, thereby reducing wiring complexity and signal interference. The even distribution of array elements makes wiring simple and efficient, meeting the requirements of high-power, large-scale integration.

[0162] The present invention has been described in detail above, and has been elaborated in detail through specific embodiments and corresponding principles used in the present invention. The above embodiments are only intended to facilitate understanding of the present invention and its core features for certificate transfers. It should be noted that those skilled in the art may make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications are also within the scope of protection of the claims of the present invention.

Claims

1. A method for optimizing a high-power ring array silicon-based optical phased array chip, characterized in that: The following steps are involved: A genetic algorithm is used to establish a fitness function based on the far-field beam sidelobe suppression ratio and thermal distribution uniformity, where the thermal distribution uniformity is determined by the number of rings, radial spacing, and array element spacing. Each individual includes the number of two-dimensional antenna ring arrays, the radial spacing between rings, and the array element spacing of each two-dimensional antenna ring array. After multiple generations of selection, crossover, and mutation operations, an optimal individual is obtained after a termination condition is met. The ring array silicon-based optical phased array chip is manufactured and obtained based on the number of two-dimensional antenna ring arrays, the radial spacing between rings, and the array element spacing of each two-dimensional antenna ring array in the optimal individual. The fitness function is set according to the following formula: f = SLSR-αp1-βp2-γp3 Where f represents fitness, SLSR represents far-field beam sidelobe suppression ratio, p1 represents the penalty for outer ring aperture, p2 represents the penalty for element spacing, p3 represents the penalty for radial spacing between rings, α represents the first weight coefficient, β represents the second weight coefficient, and γ represents the third weight coefficient; the ranges of the three weight coefficients are 5-10, 2-5, and 1-3, respectively. The three penalty amounts are set according to the following formulas: p1=max[0,∑(A m -A max ) / A max ] p2=max[0,(d min -d e ) / d min ] p3=max[0,(1.2A m -A m+1 ) / A m ] In the formula, max[ ] represents the maximum value function, A m represents the aperture of the mth ring, A max Indicates the maximum outer ring aperture limit, d e Indicates the minimum element spacing limit, d min Indicates the minimum distance between any two array elements; The optimization method further includes the following steps: in each phase shifter array, the phase shifters are arranged at equal intervals along the symmetry axis, the spacing between adjacent phase shifters is obtained through thermal simulation and optical simulation methods, the total width of the phase shifter array along the symmetry axis is calculated based on the number and spacing of the phase shifters, and a maximum outer ring aperture limit is set based on the total width of the phase shifter array along the symmetry axis; The annular array silicon-based optical phased array chip includes: A coupled grating module (1) for receiving an incident light beam; A cascaded optical splitting module (2) is used to split an incident light beam into multiple unmodulated detection light beams; A phase modulation module (3) is used to perform phase modulation on each unmodulated light beam to generate a phase-modulated detection light beam; A two-dimensional antenna ring array module (4) is used to transmit all phase-modulated detection beams to the outside of the chip; it adopts an axisymmetric structure and is mainly composed of at least one co-centered two-dimensional antenna ring array arranged radially from the inside to the outside, and each two-dimensional antenna ring array is mainly composed of a plurality of two-dimensional grating antennas (41) uniformly arranged along the circumference; A high power stretched waveguide (6) for use as an optical channel; The coupled grating module (1), the cascaded optical splitter module (2), the two-dimensional antenna ring array module (4) and the high-power widening waveguide (6) are formed on the top surface of the thick silicon layer by etching, the high-power widening waveguide (6) is formed by full etching, the thickness of the thick silicon layer is 500nm, and the waveguide width of the high-power widening waveguide (6) is selected from 800nm; The cascade optical splitter module (2) includes a first-stage optical splitter and two optical splitting cascade networks, the two optical splitting cascade networks are symmetrically arranged on both sides of the two-dimensional antenna ring array module (4), the input end of the first-stage optical splitter is connected to the output end of the coupling grating module (1), the two output ends of the first-stage optical splitter are respectively connected to the input ends of the two optical splitting cascade networks, and the output end of each optical splitting cascade network is connected to the two-dimensional antenna ring array module (4) on the same side; the phase modulation module (3) includes two phase shifter arrays, the two phase shifter arrays are respectively arranged above the output ends of the two optical splitting cascade networks; The incident light beam includes continuous wave light in the infrared band with a power of the order of watts.

2. The method for optimizing a high-power, applicable annular silicon-based optical phased array chip according to claim 1, characterized in that: The far-field beam sidelobe suppression ratio is obtained by the following process: a radiation pattern is obtained according to the array factor and the far-field distribution of a single antenna, and the far-field beam sidelobe suppression ratio is extracted from the radiation pattern according to the following formula: SLSR=10log 10 (I main / I side ) Where, I main Indicates the main lobe peak power, I side Indicates the maximum sidelobe peak power.

3. The method for optimizing a high-power, applicable annular silicon-based optical phased array chip according to claim 1, characterized in that: For the optical splitting cascade network, phase shifter array and two-dimensional antenna ring array module (4) located on the same side, the number of branch output waveguides, phase shifters and two-dimensional grating antennas (41) is the same and corresponds one to one, and the phase shifters are arranged above the branch output waveguides in a corresponding aligned manner, and the branch output waveguides and the corresponding two-dimensional grating antennas (41) are connected through high-power widening waveguides (6) in a Manhattan routing form.

4. The method for optimizing a high-power, applicable annular silicon-based optical phased array chip according to claim 1, characterized in that: The two-dimensional grating antenna (41) is mainly composed of three L-shaped grating structures (412) and two grating structure gaps (411); the horizontal projection shapes of the L-shaped grating structure (412) and the grating structure gap (411) are both arc-shaped, and the vertical projection shape of the L-shaped grating structure (412) is L-shaped. The three L-shaped grating structures (412) are arranged radially in sequence within the same sector area, and two adjacent L-shaped grating structures (412) are connected through a grating structure gap (411); the L-shaped grating structure (412) located on the inner side is connected to the high-power broadening waveguide (6) through a transition waveguide, and the horizontal projection shape of the transition waveguide is a truncated sector; for two symmetrical two-dimensional grating antennas (41) in the same two-dimensional antenna ring array, the line connecting the centers of the two sector areas is perpendicular to the symmetry axis of the two-dimensional antenna ring array module (4).

5. The method for optimizing the annular silicon-based optical phased array chip according to claim 1, characterized in that: The annular array silicon-based optical phased array chip mainly consists of a silicon substrate layer, a buried layer, a thick silicon layer, a cladding layer and a phase modulation layer stacked in sequence from bottom to top; the phase modulation layer includes a phase modulation module (3) deposited on the top surface of the cladding layer, and the phase shifter is deposited above the corresponding branch output waveguide.

6. The method for optimizing the annular silicon-based optical phased array chip according to claim 5, characterized in that: The annular array silicon-based optical phased array chip meets at least one of the following characteristics: The optical splitting cascade network is mainly formed by cascading multiple stages of Y-branch beam splitters or 3dB multimode interference couplers, and the number of cascades is adapted to the number of two-dimensional grating antennas (41) in the two-dimensional antenna ring array module (4); The curved portion of the optical channel on the annular array silicon-based optical phased array chip adopts an Euler curved waveguide (5); the Euler curved waveguide (5) is formed on the top surface of the thick silicon layer by etching; The phase shifter adopts a silicon-based thermo-optical phase shifter; The coupling grating module (1) adopts a two-dimensional annular coupling grating; Each two-dimensional antenna annular array includes the same number of two-dimensional grating antennas (41).

7. The method for optimizing the annular silicon-based optical phased array chip according to claim 1, characterized in that: The wavelength of the incident light beam is 1550 nm, the etching depth of the grating structure gap (411) is 500 nm, and the etching depth of the L-shaped grating structure (412) is 130 nm; N is 32, the number of the two-dimensional antenna ring arrays is two, the two-dimensional grating antennas (41) in the two two-dimensional antenna ring arrays are identical, the outer ring aperture is 720 μm, and the inner ring aperture is 500 μm.

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