Light-weight micro-nano femtosecond waveguide etching process

Abstract

The invention belongs to the technical field of waveguide engraving, and particularly relates to a lightweight micro-nano femtosecond waveguide engraving process, which comprises the following steps of: designing a laser scanning path according to the size and the shape of a required waveguide; adjusting parameters of a femtosecond laser, then scanning the material substrate along a laser scanning path, monitoring the position of a laser focus in real time, and adjusting laser parameters or scanning speed according to monitoring feedback; the controllable local refractive index change is generated in the material substrate by using the ultrashort pulse generated by the femtosecond laser, so that the direct waveguide structure formation without chemical etching is realized. By accurately controlling the position, the intensity and the scanning path of a laser beam, a waveguide element with high consistency and stability can be created on the submicron scale; according to the invention, while the preparation process is simplified, the precision and consistency of the waveguide structure are improved, the production cost is reduced, and the environmental pollution is reduced, so that the application requirements of high-performance photonic devices are met.

Description

Technical Field

[0001] The invention belongs to the technical field of waveguide engraving, and in particular relates to a lightweight micro-nano-femtosecond waveguide engraving process. Background Art

[0002] At present, the preparation of micro-nano waveguides usually adopts traditional methods such as chemical etching or ion beam etching. Although these methods can achieve precise control of waveguide structures, they have some significant shortcomings. First, the chemical etching process is complicated and requires the use of a variety of etching solutions and mask materials, which is not only costly but also seriously pollutes the environment. Secondly, although ion beam etching can achieve high-precision waveguide structures, the equipment is expensive, the operation is complicated, the processing time is long, and the production efficiency is low. In addition, these methods are prone to introduce impurities and defects during the preparation process, affecting the optical performance and stability of the waveguide.

[0003] The main problems of existing technologies are that the preparation process is complicated, the cost is high, the environment is seriously polluted, and it is difficult to achieve high-precision and high-consistency waveguide structures. Especially for micro-nanoscale waveguides, the limitations of traditional methods are more obvious and it is difficult to meet the needs of high-performance photonic devices. Summary of the invention

[0004] The purpose of the present invention is to provide a lightweight micro-nano femtosecond waveguide engraving process, which utilizes the ultrashort pulses generated by a femtosecond laser to produce controllable local refractive index changes inside the material, thereby achieving direct waveguide structure formation without chemical etching, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention adopts the following technical solution: a lightweight micro-nano femtosecond waveguide engraving process, comprising the following steps:

[0006] A material substrate is selected, and a laser scanning path is designed according to the size and shape of the required waveguide to ensure that the laser scanning path covers the target area within the material substrate; the parameters of the femtosecond laser are adjusted to control the femtosecond laser to scan the material substrate along the laser scanning path to cause a refractive index change within the material substrate, and the laser focus position is monitored in real time, and the laser parameters or scanning speed of the femtosecond laser are adjusted according to the monitoring feedback; the laser output of the femtosecond laser is turned off, the external support or fixture on the material substrate is removed, and the material substrate is visually inspected.

[0007] Preferably, the step of selecting a material substrate comprises the following sub-steps:

[0008] Select a material with an optical nonlinear coefficient n2, measure the initial refractive index n0 of the material, and record the temperature and humidity under the measuring conditions;

[0009] Calculate the expected refractive index change Δn using the formula Δn=n2·I·L, where I is the laser intensity and L is the action length of the laser in the material. Adjust the laser parameters of the femtosecond laser based on the calculated Δn.

[0010] Preferably, the step of designing the laser scanning path according to the required size and shape of the waveguide comprises the following sub-steps:

[0011] According to the design specifications of the waveguide, determine the position and direction of the waveguide centerline, marked as path P, using the formula Calculate the offset d(x,y) of each point on path P;

[0012] Based on the calculated offset d(x,y), the node spacing s of path P is adjusted using the formula s = total path length / number of nodes;

[0013] Based on the adjusted path, a detailed laser scanning instruction set is generated to ensure that the coordinates and laser parameters of each node are consistent with the design requirements.

[0014] Preferably, the step of adjusting the femtosecond laser parameters comprises the following sub-steps:

[0015] Determine the initial pulse width τ0 and repetition frequency f0 of the femtosecond laser, and record the initial average power P0. According to the node spacing s of the designed scanning path, calculate the required minimum pulse overlap ratio R using the formula Where v is the laser scanning speed;

[0016] Based on the calculated minimum pulse overlap ratio R, use the formula Adjust the pulse width τ of the femtosecond laser;

[0017] According to the adjusted pulse width τ, use the formula Recalculate the average power P.

[0018] Preferably, scanning the material substrate along the laser scanning path comprises the following sub-steps:

[0019] Aim the set femtosecond laser at the substrate and calibrate the laser focus position to ensure that the focus is located at the target area inside the substrate;

[0020] Start scanning along the determined path P, set the initial scanning speed v0, and record the actual laser focus position deviation δ during the scanning process. Use the formula

[0021] According to the recorded actual focus position deviation δ, the formula is used Adjust the scanning speed v, where δ max is the maximum deviation allowed;

[0022] Continue scanning at the adjusted scanning speed and monitor the refractive index changes in the substrate in real time. Use the formula Where I is the laser intensity, L is the laser action length, and n0 is the initial refractive index of the substrate.

[0023] Preferably, the real-time monitoring of the laser focus position comprises the following sub-steps:

[0024] During the scanning process, the positioning system is used to monitor the laser focus position in real time and record the real-time coordinates of the focus position (x real ,y real ,z real );

[0025] Compare the recorded real-time coordinates with the planned path coordinates (x pal ,y pal ,z pal ) to compare and calculate the position deviation Δx, Δy, Δz, using the formula Δx=x real -x plan , Δy=y real -y plan , Δz=z real -z plan ;

[0026] According to the calculated position deviation, adjust the position of the laser focus, using the formula x new =x real -Δx,y new =y real -Δy,z new =z real -Δz, continue scanning at the adjusted focus position and update the focus position data in real time.

[0027] Preferably, adjusting the laser parameters or scanning speed of the femtosecond laser according to monitoring feedback comprises the following sub-steps:

[0028] According to the feedback position deviation data, calculate the actual scanning speed v of the laser focus actual , using the formula v actual = path length / actual scanning time;

[0029] Compare the calculated actual scanning speed v actual Calculate the speed deviation Δv from the set scanning speed v, using the formula Δv = v actual -v;

[0030] According to the calculated velocity deviation Δv, adjust the laser parameters, including laser intensity I and pulse repetition frequency f, using the formula and

[0031] Under the adjusted laser parameters, continue scanning and monitor the refractive index change of the waveguide structure in real time. Use the formula

[0032] Preferably, the step of turning off the laser output and removing the external support or fixture on the material substrate comprises the following sub-steps:

[0033] After completing the scanning process, immediately turning off the output of the femtosecond laser, checking the external support or fixture on the substrate, and gradually removing the external support or fixture on the material substrate;

[0034] After removing all external supports or fixtures, make a final inspection of the substrate using the formula where F residual is the residual force on the substrate, m i is the mass of each residue and g is the acceleration due to gravity.

[0035] Preferably, the visual inspection of the material substrate comprises the following sub-steps:

[0036] Perform a preliminary visual inspection of the treated substrate using a microscope to record the overall morphology and position of the waveguide structures;

[0037] Take multiple images of the waveguide structure through a microscope and use the formula Calculate the average brightness of the image I avg , where I i is the brightness of the i-th image, N is the total number of images;

[0038] Based on the acquired image, the edge detection algorithm is used to extract the boundary of the waveguide structure and calculate the actual width W of the waveguide. actual and length L actual , using the formula and where w j and l j are the width and length of the jth boundary point, respectively, and M is the number of boundary points;

[0039] The actual width W will be calculated actual and length L actual The width W in the design specification design and length L design Compare and calculate the deviation ΔW and ΔL, using the formula ΔW=W actual -W design and ΔL=L actual -L design .

[0040] Preferably, the method further comprises: if the visual inspection result meets the preset requirements, placing the material substrate in a protective environment.

[0041] Technical effects and advantages of the present invention: Compared with the prior art, the lightweight micro-nano femtosecond waveguide engraving process proposed by the present invention has the following advantages:

[0042] The present invention uses ultrashort pulses generated by femtosecond lasers to produce controllable local refractive index changes inside the material, thereby achieving direct waveguide structure formation without chemical etching. By precisely controlling the position, intensity, and scanning path of the laser beam, a waveguide element with high consistency and stability can be created at the submicron scale; the present invention can simplify the preparation process while improving the accuracy and consistency of the waveguide structure, reducing production costs and environmental pollution, thereby meeting the application requirements of high-performance photonic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 The present invention is a flow chart of a lightweight micro-nano femtosecond waveguide engraving process. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The present invention provides a lightweight micro-nano femtosecond waveguide engraving process, such as Figure 1As shown, the purpose is to select a material substrate and design a laser scanning path according to the size and shape of the required waveguide to ensure that the path covers the target area in the substrate; adjust the parameters of the femtosecond laser, and then scan the material substrate along the laser scanning path to change the refractive index in the material substrate, and monitor the laser focus position in real time, and adjust the laser parameters or scanning speed based on the monitoring feedback; turn off the laser output of the femtosecond laser, remove the external support or fixture on the material substrate, and perform a visual inspection of the material substrate. While simplifying the preparation process, it can improve the accuracy and consistency of the waveguide structure, reduce production costs, and reduce environmental pollution, thereby meeting the application requirements of high-performance photonic devices.

[0047] In this embodiment, the above-mentioned lightweight micro-nano femtosecond waveguide engraving process includes the following steps:

[0048] S1: Selecting a transparent material as a substrate, the material having a refractive index change characteristic that can be induced by a femtosecond laser; further comprising the following sub-steps:

[0049] S11: Select materials with specific optical nonlinear coefficient n2, which determines the sensitivity of the material to femtosecond laser response; common materials include silicon dioxide (SiO2), phosphate glass, borate glass, etc. These materials can produce obvious refractive index changes under the action of femtosecond laser, which is suitable for the engraving of micro-nano waveguides.

[0050] S12: Measure the initial refractive index n0 of the material selected in step S11, and record the temperature and humidity under the measurement conditions to ensure the consistency of the measurement environment; the purpose of this step is to obtain accurate initial refractive index data to provide a basis for subsequent calculations.

[0051] S13: Calculate the expected refractive index change Δn using the formula Δn = n2·I·L, where I is the laser intensity and L is the length of the laser action in the material. This calculation is based on the initial refractive index n0 obtained in step S12; by adjusting the laser parameters, the refractive index change inside the material can be controlled. The calculation of the expected refractive index change helps optimize the laser parameters and ensure the accurate formation of the waveguide structure.

[0052] S14: According to the Δn calculated in step S13, the laser parameters are adjusted to ensure that the refractive index change inside the material during the actual processing meets the design requirements while maintaining the physical integrity of the material.

[0053] By accurately selecting materials and measuring the initial refractive index, combined with the calculation of the expected refractive index change and the adjustment of laser parameters, a high-precision and high-consistency waveguide structure can be achieved at the submicron scale. This makes the prepared waveguide have excellent optical properties and stability. Compared with traditional chemical etching and ion beam etching methods, the present invention uses femtosecond lasers to directly form waveguide structures inside the material, which simplifies the preparation process, reduces production costs, and reduces environmental pollution.

[0054] S2: designing a laser scanning path according to the size and shape of the required waveguide to ensure that the laser scanning path covers the target area within the substrate selected in step S1; further comprising the following sub-steps:

[0055] S21: According to the design specifications of the waveguide, determine the position and direction of the waveguide centerline, marked as path P; use computer-aided design (CAD) software to accurately mark the position and direction of the waveguide centerline and generate a path diagram. The purpose of this step is to ensure that the design of the waveguide meets the actual application requirements. By accurately determining the position and direction of the waveguide centerline, it can be ensured that the geometric shape and size of the waveguide structure meet the design requirements, providing an accurate basis for the subsequent laser scanning path design.

[0056] S22: Calculate the offset d(x,y) of each point on path P using the formula Ensure that path P can accurately cover the target area; by calculating the offset, it can be ensured that the laser focus can accurately move along the designed path to cover the target area in the substrate. The purpose of this step is to ensure the accuracy and reliability of the path. Calculating the offset of each point on the path can effectively reduce the path deviation, ensure that the laser focus can accurately cover the target area during the scanning process, and improve the accuracy and consistency of the waveguide structure.

[0057] S23: Based on the offset d(x,y) calculated in step S22, adjust the node spacing s of path P, using the formula s = total path length / number of nodes to ensure the smoothness and continuity of the path; by adjusting the node spacing, the smoothness and continuity of the path can be ensured to avoid path discontinuity or excessive overlap caused by too large or too small node spacing. The purpose of this step is to optimize the path to make it more in line with actual processing requirements.

[0058] S24: Based on the path adjusted in step S23, a detailed laser scanning instruction set is generated to ensure that the coordinates and laser parameters of each node (such as pulse width and energy density) are consistent with the design requirements, thereby ensuring the precise forming of the waveguide structure. The purpose of this step is to convert the design path into an actual laser scanning operation to ensure high-quality preparation of the waveguide structure. Generating a detailed laser scanning instruction set can ensure that the coordinates and laser parameters of each node are consistent with the design requirements, thereby achieving precise forming of the waveguide structure and improving the optical performance and stability of the waveguide.

[0059] By accurately determining the position and direction of the waveguide centerline, calculating the offset of each point on the path, adjusting the node spacing of the path, and generating a detailed laser scanning instruction set, it is ensured that the geometric shape and size of the waveguide structure meet the design requirements and improve the accuracy and consistency of the waveguide. By adjusting the node spacing of the path, the smoothness and continuity of the path are ensured, the path deviation is reduced, and the uniformity and stability of the waveguide structure are improved. A detailed laser scanning instruction set is generated to ensure that the coordinates and laser parameters of each node are consistent with the design requirements, so as to achieve precise shaping of the waveguide structure and improve the optical performance and stability of the waveguide.

[0060] S3: Adjusting the parameters of the femtosecond laser, including but not limited to pulse width, repetition frequency and average power, to meet the scanning path requirements designed in step S2; further comprising the following sub-steps:

[0061] S31: Before starting to adjust the parameters of the femtosecond laser, you first need to determine the initial pulse width τ0 and repetition frequency f0 of the femtosecond laser, and record the initial average power P0; under different materials and different processing requirements, the optimal working parameters of the femtosecond laser will be different. By recording the initial parameters, it can be used as a reference for subsequent adjustments. Determining the initial parameters can provide a clear starting point for subsequent parameter adjustments, which helps to quickly find the optimal working parameters and ensure the processing quality of the waveguide structure.

[0062] S32: Based on the node spacing s of the scan path designed in step S2, calculate the required minimum pulse overlap ratio R using the formula Where v is the laser scanning speed; the pulse overlap rate refers to the overlap degree of the heat-affected zone generated by two adjacent pulses in the material. By calculating the minimum pulse overlap rate, it can be ensured that there is enough overlap between adjacent pulses during the laser scanning process to avoid unprocessed areas or over-processing.

[0063] S33: Based on the minimum pulse overlap ratio R calculated in step S32, adjust the pulse width τ of the femtosecond laser to ensure that the pulse overlap ratio meets the design requirements, using the formula Adjusting the pulse width will affect the energy distribution and action time of the pulse, and thus affect the refractive index change inside the material. By adjusting the pulse width, ensuring that the pulse overlap rate meets the design requirements, precise control of the internal structure of the material can be achieved.

[0064] S34: Based on the pulse width τ adjusted in step S33, recalculate the average power P to ensure that the laser energy density is moderate, using the formula Ensure that the refractive index changes inside the material are uniform and controllable. The purpose of adjusting the average power is to ensure that the laser energy density is moderate, so that neither material ablation or damage will occur due to excessive power, nor insufficient refractive index changes will occur due to too low power. By recalculating the average power, ensure that the refractive index changes inside the material are uniform and controllable. Recalculating the average power can ensure that the laser energy density is moderate, so that the refractive index changes inside the material are uniform and controllable, avoid material damage or insufficient processing, and improve the stability and reliability of the waveguide structure.

[0065] S4: using the femtosecond laser set in step S3, scanning the substrate selected in step S1 along the path determined in step S2, so that the refractive index changes in the material substrate; further comprising the following sub-steps:

[0066] S41: Align the femtosecond laser set up in step S3 to the substrate selected in step S1, and calibrate the laser focus position to ensure that the focus is located in the target area inside the substrate; use a high-precision alignment system to ensure that the laser focus position accurately falls on the target area inside the substrate. Calibrating the laser focus position is a key step to ensure that the laser energy is concentrated and effectively acts on the target area.

[0067] S42: Start scanning along the path P determined in step S2, set the initial scanning speed v0, and record the actual laser focus position deviation δ during the scanning process, using the formula After alignment and calibration are completed, start scanning along the path determined in step S2. Set an initial scanning speed and record the actual deviation of the laser focus position in real time during the scanning process. The purpose of this step is to ensure that the laser focus can move accurately along the designed path to avoid processing errors caused by position deviation.

[0068] S43 adjusts the scanning speed v according to the actual focus position deviation δ recorded in step S42, using the formula where δ max is the maximum allowable deviation to ensure the accuracy of the scanning path; a feedback control system is used to dynamically adjust the scanning speed according to the deviation to ensure that the laser focus always moves accurately along the designed path. The purpose of this step is to eliminate position deviation and improve the accuracy of the scanning path by adjusting the scanning speed in real time.

[0069] S44: Continue scanning at the scanning speed adjusted in step S43, and monitor the refractive index change in the substrate in real time, using the formula Where I is the laser intensity, L is the laser action length, and n0 is the initial refractive index of the substrate, ensuring that the refractive index change meets the design requirements. By monitoring the refractive index change, it can be ensured that the refractive index change inside the material meets the design requirements. The purpose of this step is to ensure that the refractive index change of the waveguide structure is uniform and controllable through real-time monitoring.

[0070] By real-time monitoring of the refractive index changes within the substrate, it is possible to ensure that the refractive index changes within the material meet the design requirements, avoid under- or over-processing, and improve the optical performance and stability of the waveguide structure.

[0071] S5: During step S4, the laser focus position is monitored in real time to ensure that it moves accurately along the path planned in step S2; further comprising the following sub-steps:

[0072] S51: During the scanning process in step S4, a high-precision positioning system (such as a laser interferometer or a high-resolution camera) is used to monitor the laser focus position in real time and record the real-time coordinates of the focus position (x real ,y real ,z real ); The purpose of this step is to ensure that the position information of the laser focus can be obtained in real time, providing basic data for subsequent deviation calculation and position adjustment. By using a high-precision positioning system to monitor the laser focus position in real time, it is possible to ensure that accurate focus position data is obtained, providing reliable data support for subsequent deviation calculation and position adjustment.

[0073] S52: Compare the real-time coordinates recorded in step S51 with the path coordinates planned in step S2 (x pal ,y pal ,z pal ) to compare and calculate the position deviation Δx, Δy, Δz, using the formula Δx=x real -x plan , Δy=y real -y plan , Δz=z real -z plan The purpose of this step is to evaluate the degree of deviation between the actual position of the laser focus and the planned path by calculating the position deviation. By calculating the position deviation, the degree of deviation between the actual position of the laser focus and the planned path can be evaluated in real time, providing a basis for subsequent position adjustments and ensuring that the laser focus always moves along the planned path.

[0074] S53: According to the position deviation calculated in step S52, adjust the position of the laser focus using the formula x new =x real -Δx,ynew =y real -Δy,z new =z real -Δz, ensure that the focus always moves along the planned path; the purpose of this step is to eliminate position deviation and ensure the accuracy of the scanning path by adjusting the position of the laser focus in real time. By adjusting the position of the laser focus according to the position deviation, the position deviation can be eliminated, ensuring that the laser focus always moves along the planned path, and improving the accuracy and consistency of the waveguide structure.

[0075] S54: Continue scanning at the focus position adjusted in step S53, and update the focus position data in real time to ensure the high precision and stability of the focus position during the entire scanning process. The purpose of this step is to ensure that the laser focus position always maintains high precision and stability during the entire scanning process to avoid processing errors caused by position deviation. By updating the focus position data in real time, it can be ensured that the laser focus position always maintains high precision and stability during the entire scanning process, thereby improving the uniformity and stability of the waveguide structure.

[0076] S6: adjusting the laser parameters or scanning speed according to the feedback from step S5 to ensure the consistency and stability of the waveguide structure; further comprising the following sub-steps:

[0077] S61: Based on the position deviation data fed back in step S5, calculate the actual scanning speed v of the laser focus actual , using the formula v actual = path length / actual scanning time; actual scanning speed refers to the real speed at which the laser focus moves on the substrate. The actual scanning speed can be calculated by analyzing the position deviation data. The purpose of this step is to ensure that the actual movement state of the laser focus can be accurately grasped, providing basic data for subsequent speed deviation calculations.

[0078] S62: Compare the actual scanning speed v calculated in step S61 actual Calculate the speed deviation Δv from the scanning speed v set in step S4, using the formula Δv = v actual -v; Speed ​​deviation refers to the difference between the actual scanning speed and the set scanning speed. The purpose of this step is to evaluate the speed change during the scanning process by calculating the speed deviation, so as to provide a basis for subsequent parameter adjustment.

[0079] S63: According to the velocity deviation Δv calculated in step S62, adjust the laser parameters, including laser intensity I and pulse repetition frequency f, using the formula and Ensure the consistency of the waveguide structure; by adjusting the laser intensity and pulse repetition frequency, the processing inconsistency caused by speed deviation can be compensated to ensure the consistency of the waveguide structure. The purpose of this step is to eliminate the influence of speed deviation and improve the processing quality of the waveguide structure by dynamically adjusting the laser parameters.

[0080] S64: Continue scanning under the laser parameters adjusted in step S63 and monitor the refractive index change of the waveguide structure in real time, using the formula Ensure the stability and consistency of the waveguide structure. By monitoring the refractive index change in real time, it can be ensured that the refractive index change inside the material meets the design requirements to avoid under- or over-processing. The purpose of this step is to ensure the stability and consistency of the waveguide structure through real-time monitoring.

[0081] S7: After completing steps S4 to S6, turning off the laser output and removing any external support or fixture on the material substrate; further comprising the following sub-steps:

[0082] S71: After completing the scanning process from S4 to S6, immediately turn off the output of the femtosecond laser to ensure that the laser no longer acts on the substrate. The purpose of this step is to prevent the laser from continuing to act on the substrate when it is unnecessary, thereby avoiding additional thermal effects or damage to the substrate.

[0083] S72: After turning off the laser output, carefully check the external supports or fixtures on the substrate and record the location and type of the devices. The purpose of this step is to ensure that all external supports or fixtures are correctly identified to provide accurate information for subsequent removal work.

[0084] S73: According to the information recorded in step S72, the external support or fixture on the material substrate is gradually removed. Appropriate tools and methods are used to ensure that the removal process is smooth and does not damage the substrate. The purpose of this step is to ensure that the substrate is not damaged during the removal of the external device and maintain its integrity and surface quality.

[0085] S74: After removing all external supports or fixtures, perform a final inspection of the substrate to ensure that the substrate surface is flat and free of residues, using the formula Among them, F residual is the residual force on the substrate, m i is the mass of each residue, g is the gravitational acceleration, and ensures that the substrate is completely released and stress-free. The purpose of this step is to ensure that the substrate still maintains good surface quality and stress-free state after removing the external device. By performing a final inspection on the substrate to ensure that the substrate surface is flat and free of residue, the integrity and surface quality of the substrate can be guaranteed, avoiding residues or stress affecting the performance of the waveguide structure.

[0086] S8: visually inspecting the substrate after the processing in step S7 to confirm that the waveguide structure meets the design specifications; further comprising the following sub-steps:

[0087] S81: Perform a preliminary visual inspection using a high-resolution microscope on the substrate treated in step S7. Record the overall morphology and position of the waveguide structure to ensure that the basic features of the waveguide structure are clearly visible. The purpose of this step is to preliminarily confirm the appearance and position of the waveguide structure and provide a basis for subsequent detailed inspection;

[0088] S82: Take multiple images of the waveguide structure through a microscope and use the formula Calculate the average brightness of the image I avg , where I i is the brightness of the i-th image, N is the total number of images, and ensures that the image quality meets the inspection requirements; the purpose of this step is to ensure that the captured image quality is high, can clearly show the details of the waveguide structure, and provide reliable image data for subsequent dimensional measurement. By taking multiple images and calculating the average brightness, it is possible to ensure that the image quality is high, can clearly show the details of the waveguide structure, and provide reliable image data for subsequent dimensional measurement.

[0089] S83: Based on the image obtained in step S82, use the edge detection algorithm to extract the boundary of the waveguide structure and calculate the actual width W of the waveguide actaal and length L actual , using the formula and where w j and l j are the width and length of the jth boundary point, respectively, and M is the number of boundary points; the purpose of this step is to accurately extract the boundary of the waveguide structure through the edge detection algorithm to ensure that the measured dimension data is accurate and reliable. By using the edge detection algorithm to extract the boundary of the waveguide structure, the actual width and length of the waveguide can be accurately calculated to ensure that the measured dimension data is accurate and reliable, providing a basis for subsequent dimension comparison.

[0090] S84: The actual width W calculated in step S83 is actual and length L actual The width W in the design specification design and length L design Compare and calculate the deviation ΔW and ΔL, using the formula ΔW=W actual -W design and ΔL=L actual -L design, to ensure that the size of the waveguide structure meets the design requirements. The purpose of this step is to ensure that the size of the waveguide structure meets the design requirements and verify the processing quality of the waveguide structure by comparing the actual size with the design specifications. By comparing the actual width and length with the design specifications and calculating the deviation, it is possible to ensure that the size of the waveguide structure meets the design requirements, verify the processing quality of the waveguide structure, and ensure the performance and reliability of the waveguide structure.

[0091] S9: If the visual inspection result of step S8 meets the preset requirements, the material substrate is placed in a protective environment to prevent it from being damaged by external factors, which specifically includes the following steps:

[0092] S91: After the visual inspection results in step S8 meet the preset requirements, select a protective environment suitable for storing the substrate. The environment should have constant temperature, humidity and dustproof conditions to ensure that the substrate is not affected by external factors during storage. The purpose of this step is to provide a stable storage environment for the substrate to ensure its long-term stability and reliability.

[0093] S92: Measure the temperature T in the protective environment env and humidity H env , ensure that they meet the requirements of the base storage, using the formula and Where T min and T max are the upper and lower limits of the temperature range, H min and H max The upper and lower limits of the humidity range; the purpose of this step is to ensure that the temperature and humidity in the protective environment are within the appropriate range to avoid degradation of substrate performance due to improper environmental conditions. By measuring the temperature and humidity in the protective environment and ensuring that they meet the requirements for substrate storage, degradation of substrate performance due to improper environmental conditions can be avoided and the storage quality of the substrate can be ensured.

[0094] S93: Carefully place the substrate in a protective environment, ensuring that the substrate is placed stably to avoid any damage caused by physical contact;

[0095] S94: After step S93 is completed, record the placement time and position of the substrate, using the formula t place =t start +Δt, where t start is the time to start placement, and Δt is the time required for the placement process, ensuring that the storage information of the substrate is fully recorded to facilitate subsequent management and traceability.

[0096] By choosing a protective environment with constant temperature, humidity and dustproof conditions, it is possible to ensure that the substrate is not affected by external factors during storage, maintaining its long-term stability and reliability. By measuring the temperature and humidity in the protective environment and ensuring that they meet the requirements for substrate storage, it is possible to avoid degradation of substrate performance due to improper environmental conditions and ensure the storage quality of the substrate. By carefully placing the substrate and ensuring that the substrate is placed smoothly and avoiding any damage caused by physical contact, the integrity and surface quality of the substrate can be ensured, avoiding damage caused by improper placement. By recording the placement time and location of the substrate, the storage information of the substrate is ensured to be fully recorded, which is convenient for subsequent management and traceability, ensuring the traceability and management convenience of the substrate during storage.

[0097] In summary, the present invention uses ultrashort pulses generated by femtosecond lasers to produce controllable local refractive index changes inside the material, thereby achieving direct waveguide structure formation without chemical etching. By precisely controlling the position, intensity, and scanning path of the laser beam, waveguide elements with high consistency and stability can be created at the submicron scale; the present invention can simplify the preparation process while improving the accuracy and consistency of the waveguide structure, reducing production costs and environmental pollution, thereby meeting the application requirements of high-performance photonic devices.

[0098] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A lightweight micro-nano femtosecond waveguide engraving process, characterized in that: The following steps are involved: Selecting a material substrate and designing a laser scanning path according to the size and shape of the required waveguide to ensure that the laser scanning path covers the target area within the material substrate; Adjusting the parameters of the femtosecond laser, controlling the femtosecond laser to scan the material substrate along the laser scanning path, causing the refractive index in the material substrate to change, and monitoring the laser focus position in real time, and adjusting the laser parameters or scanning speed of the femtosecond laser according to the monitoring feedback; The laser output of the femtosecond laser is turned off, the external support or fixture on the material substrate is removed, and the material substrate is visually inspected.

2. A lightweight micro-nano-femtosecond waveguide engraving process according to claim 1, characterized in that: The method of selecting a material substrate comprises the following sub-steps: Select a material with an optical nonlinear coefficient n2, measure the initial refractive index n0 of the material, and record the temperature and humidity under the measuring conditions; Calculate the expected refractive index change Δn using the formula Δn=n2·I·L, where I is the laser intensity and L is the action length of the laser in the material. Adjust the laser parameters of the femtosecond laser based on the calculated Δn.

3. A lightweight micro-nano femtosecond waveguide engraving process according to claim 2, characterized in that: The step of designing a laser scanning path according to the required size and shape of the waveguide comprises the following sub-steps: According to the design specifications of the waveguide, determine the position and direction of the waveguide centerline, marked as path P, using the formula Calculate the offset d(x,y) of each point on path P; Based on the calculated offset d(x,y), the node spacing s of path P is adjusted using the formula s = total path length / number of nodes; Based on the adjusted path, a laser scanning instruction set is generated to ensure that the coordinates and laser parameters of each node are consistent with the design requirements.

4. A lightweight micro-nano femtosecond waveguide engraving process according to claim 3, characterized in that: The step of adjusting the femtosecond laser parameters comprises the following sub-steps: Determine the initial pulse width τ0 and repetition frequency f0 of the femtosecond laser, and record the initial average power P0. According to the node spacing s of the designed scanning path, calculate the required minimum pulse overlap ratio R using the formula Where v is the laser scanning speed; Based on the calculated minimum pulse overlap ratio R, use the formula Adjust the pulse width τ of the femtosecond laser; According to the adjusted pulse width τ, use the formula Recalculate the average power P.

5. A lightweight micro-nano-femtosecond waveguide engraving process according to claim 4, characterized in that: The step of scanning the material substrate along the laser scanning path comprises the following sub-steps: Aim the set femtosecond laser at the substrate and calibrate the laser focus position to ensure that the focus is located at the target area inside the substrate; Start scanning along the determined path P, set the initial scanning speed v0, and record the actual laser focus position deviation δ during the scanning process. Use the formula According to the recorded actual focus position deviation δ, the formula is used Adjust the scanning speed v, where δ max is the maximum deviation allowed; Continue scanning at the adjusted scanning speed and monitor the refractive index changes in the substrate in real time. Use the formula Where I is the laser intensity, L is the laser action length, and n0 is the initial refractive index of the substrate.

6. A lightweight micro-nano-femtosecond waveguide engraving process according to claim 5, characterized in that: The real-time monitoring of the laser focus position includes the following sub-steps: During the scanning process, the positioning system is used to monitor the laser focus position in real time and record the real-time coordinates of the focus position (x real ,y real ,z real ); The recorded real-time coordinates (x real ,y real ,z real ) and the planned path coordinates (x pal ,y pal ,z pal ) to compare and calculate the position deviation Δx, Δy, Δz, using the formula Δx=x real -x plan , Δy=y real -y plan , Δz=z real -z plan ; According to the calculated position deviation, adjust the position of the laser focus, using the formula x new =x real -Δx,y new =y real -Δy,z new =z real -Δz, continue scanning at the adjusted focus position and update the focus position data in real time.

7. A lightweight micro-nano-femtosecond waveguide engraving process according to claim 6, characterized in that: The step of adjusting the laser parameters or scanning speed of the femtosecond laser according to the monitoring feedback comprises the following sub-steps: According to the feedback position deviation data, calculate the actual scanning speed v of the laser focus actial , using the formula v actual = path length / actual scanning time; Compare the calculated actual scanning speed v actual Calculate the speed deviation Δv from the set scanning speed v, using the formula Δv = v actual -v; According to the calculated velocity deviation Δv, adjust the laser parameters, including laser intensity I and pulse repetition frequency f, using the formula and Under the adjusted laser parameters, continue scanning and monitor the refractive index change of the waveguide structure in real time. Use the formula 8. A lightweight micro-nano-femtosecond waveguide engraving process according to claim 7, characterized in that: The step of shutting down the laser output and removing the external support or fixture on the material substrate comprises the following sub-steps: After completing the scanning process, immediately turning off the output of the femtosecond laser, checking the external support or fixture on the substrate, and gradually removing the external support or fixture on the material substrate; After removing all external supports or fixtures, make a final inspection of the substrate using the formula Among them, F residual is the residual force on the substrate, m i is the mass of each residue and g is the acceleration due to gravity.

9. A lightweight micro-nano-femtosecond waveguide engraving process according to claim 8, characterized in that: The visual inspection of the material substrate comprises the following sub-steps: Perform a preliminary visual inspection of the treated substrate using a microscope to record the overall morphology and position of the waveguide structures; Take multiple images of the waveguide structure through a microscope and use the formula Calculate the average brightness of the image I avg , where I i is the brightness of the i-th image, N is the total number of images; Based on the acquired image, the edge detection algorithm is used to extract the boundary of the waveguide structure and calculate the actual width W of the waveguide. actual and length L actual , using the formula and where w j and l j are the width and length of the jth boundary point, respectively, and M is the number of boundary points; The actual width W will be calculated actual and length L actual The width W in the design specification design and length L design For comparison, calculate the deviations ΔW and ΔL using the formula: ΔW = W actual -W design and ΔL = L actual -L design .

10. The lightweight micro-nano-femtosecond waveguide engraving process according to claim 1, characterized in that: After visually inspecting the material substrate, the method further comprises: If the visual inspection result meets the preset requirements, the material substrate is placed in a protective environment.

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