A lightweight laser femtosecond micro-engraving waveguide process

Abstract

The present invention belongs to the field of laser processing technology, and specifically relates to a lightweight laser femtosecond micro-engraving waveguide process. By precisely adjusting the energy density, pulse interval and scanning speed of the laser pulse, the modified points on the waveguide path are ensured to be evenly distributed, and the generation of breakpoints and defects is avoided, thereby achieving the continuity of the waveguide path; by finely adjusting the waveguide path, the refractive index on the waveguide path is ensured to change evenly, the transmission efficiency of the waveguide is improved, the loss is reduced, and the overall optical performance of the waveguide is improved; the process flow of the present invention is simple and efficient, does not require complex photomasks and wet etching processes, reduces production costs, improves production efficiency, can effectively solve the problems of discontinuous waveguide paths and unstable optical performance in the prior art, and has broad application prospects.

Description

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

[0002] In modern optical communications and optical interconnects, optical fibers and waveguide devices are widely used in various high-performance systems due to their advantages such as low loss, high bandwidth, and resistance to electromagnetic interference. Traditional waveguide fabrication methods mainly include techniques such as photolithography, ion exchange, and chemical vapor deposition. Although these methods can produce high-quality waveguides, they have some significant limitations during the manufacturing process. For example, photolithography requires complex photomasks and wet etching processes, which are not only costly but also complex, making it difficult to achieve high-precision and high-efficiency production. Methods such as ion exchange and chemical vapor deposition may introduce additional impurities and defects, affecting the optical performance of the waveguide.

[0003] In recent years, femtosecond laser direct writing technology has attracted widespread attention due to its high precision, maskless, non-contact, and three-dimensional processing capabilities. Femtosecond laser direct writing technology can generate nonlinear absorption within transparent or semi-transparent materials, forming local refractive index changes within the material, thereby constructing a three-dimensional waveguide structure. However, existing femtosecond laser direct writing technology still faces some challenges in practical applications, especially in terms of waveguide continuity and optical performance. For example, improper selection of laser pulse parameters may lead to problems such as discontinuity in the waveguide path and uneven refractive index changes, which in turn affect the transmission efficiency and loss of the waveguide.

[0004] The main problems with existing femtosecond laser direct writing technology in the waveguide manufacturing process are the discontinuity of the waveguide path and the instability of optical performance. Specifically,

[0005] Discontinuity of the waveguide path: Improper selection of laser pulse parameters (such as energy density, pulse interval, and scanning speed) may lead to uneven distribution of modified points on the waveguide path, forming breakpoints or defects, which affect the continuity of the waveguide.

[0006] Instability of optical performance: Uneven refractive index variations along the waveguide path can lead to low transmission efficiency and increased loss, thus affecting the overall optical performance of the waveguide. Summary of the Invention

[0007] The purpose of the present invention is to provide a lightweight laser femtosecond micro-engraving waveguide process, which optimizes the continuity and optical performance of the waveguide path by precisely controlling the laser pulse parameters to solve the problems raised in the above background technology.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a lightweight laser femtosecond micro-engraving waveguide process, comprising the following steps:

[0009] Select a transparent or translucent material as the substrate that can withstand femtosecond laser pulses without thermal damage;

[0010] On the selected substrate, a high-precision femtosecond laser is used to emit laser pulses, avoiding ablation of the material surface during the emission of the laser pulses while ensuring nonlinear absorption within the material;

[0011] Adjusting the focusing depth of the femtosecond laser according to the location where the nonlinear absorption occurs so that the laser focus is located at a layer within the material where a refractive index change is expected to occur;

[0012] In combination with the set focus depth, a series of discrete modified points are formed by controlling the number and interval of laser pulses, and the modified points form a predetermined lattice structure inside the material;

[0013] By utilizing the formed lattice structure and continuously changing the position of the laser focus, a continuous waveguide path is constructed, wherein the waveguide path has a predetermined geometric shape, and based on the constructed waveguide path, laser pulse parameters are optimized;

[0014] The waveguide path is adjusted by optimizing the laser pulse parameters to achieve control of the waveguide shape and size. Afterwards, the entire waveguide structure is quality inspected to check whether the continuity and optical performance of the waveguide meet the design standards.

[0015] Based on the results of the quality inspection, the waveguide structures that do not meet the standards are corrected until all waveguides meet the preset performance indicators.

[0016] Preferably, the method of selecting a transparent or translucent material that can withstand femtosecond laser pulses without causing thermal damage as a substrate comprises the following steps:

[0017] On the selected substrate material, measure the initial refractive index n of the material o , and record the thickness d and transmittance T of the material o ;

[0018] Based on the measured parameters, the relationship between the laser pulse energy density E and the refractive index change Δn inside the material is calculated as Δn=kE, where k is the nonlinear coefficient of the material;

[0019] Determine the optimal value of the laser pulse energy density E to ensure that the refractive index change Δn inside the material reaches a predetermined value;

[0020] Under the determined optimal energy density E, the refractive index change Δn inside the material is verified, and the laser parameters are adjusted to optimize the transmission efficiency of the waveguide.

[0021] Preferably, the method of emitting laser pulses on the selected substrate using a high-precision femtosecond laser comprises the following steps:

[0022] First, determine the repetition frequency f and pulse width τ of the laser pulse, record the absorption coefficient α of the material, and calculate the peak power P of the laser pulse inside the material. peak , using the formula P peak =E / (τ·A), where A is the laser spot area;

[0023] Utilize peak power P peak , determine the upper limit of the laser pulse energy density E to avoid ablation of the material surface, using the formula E max =P peak ·τ·A;

[0024] At the determined upper limit E max The laser pulse energy density E is adjusted to ensure nonlinear absorption inside the material while avoiding thermal damage.

[0025] Preferably, adjusting the focus depth of the femtosecond laser according to the position where the nonlinear absorption occurs comprises the following steps:

[0026] Measure the material thickness d and the initial position z of the laser focus o , and record the refractive index gradient of the material Calculate the focal depth z of the laser focus inside the material f , using the formula where Δn is the refractive index change;

[0027] Using focus depth z f Adjust the focusing system of the femtosecond laser so that the laser focus is precisely located at the layer inside the material where the refractive index change is expected to occur;

[0028] After adjusting the focus depth z f Under the given conditions, verify the position of the laser focus and make fine adjustments if necessary.

[0029] Preferably, the focus depth is set in combination with the number and interval of laser pulses to form a series of discrete modified points, comprising the following steps:

[0030] Determine the number of laser pulses N and the pulse interval t, and record the laser spot diameter D. Calculate the distance s between adjacent modified points using the formula s = v·t, where v is the laser scanning speed;

[0031] The interval t of the laser pulses is adjusted using the step distance s to ensure that the modified points are evenly distributed inside the material to form a predetermined lattice structure;

[0032] Under the adjusted pulse interval t, the laser pulse parameters are fine-tuned as needed to optimize the uniformity and density of the lattice structure.

[0033] Preferably, the method of utilizing the formed lattice structure to construct a continuous waveguide path by continuously changing the position of the laser focus comprises the following steps:

[0034] Determine the predetermined geometry of the waveguide path, record the total length L of the path and the radius of curvature R of the path, and calculate the moving speed v of the laser focus on the path using the formula where t total is the time required to complete the path;

[0035] Using the moving speed v, the scanning speed of the laser is adjusted to ensure that the laser focus moves continuously and evenly along the path, forming a continuous waveguide path;

[0036] Under the adjusted scanning speed v, fine-tune the laser parameters as needed.

[0037] Preferably, the step of optimizing laser pulse parameters based on the constructed waveguide path comprises the following steps:

[0038] Measuring the initial transmission efficiency η of the waveguide path o and loss coefficient α o ;

[0039] Calculate the effect of laser pulse energy density E on transmission efficiency η using the formula η=η o exp(-α o L), where L is the length of the waveguide path, the laser pulse energy density E is adjusted using the formula to maximize the transmission efficiency η and minimize the loss coefficient α o ;

[0040] Under the adjusted laser pulse energy density E, the laser parameters are optimized.

[0041] Preferably, the adjusting the waveguide path by optimizing the laser pulse parameters comprises the following steps:

[0042] Determine the predetermined geometry and dimensions of the waveguide path, record the width and height h of the waveguide, and calculate the scanning path length L of the laser focus on the waveguide path scan , using the formula L scan =L+2h, where L is the total length of the waveguide path;

[0043] Using the scan path length L scan , adjust the repetition frequency f of the laser pulse to ensure that the laser focus is evenly distributed on the waveguide path, using the formula f = L scant, where v is the laser scanning speed and t is the pulse interval;

[0044] Under the adjusted repetition frequency f, the laser parameters are fine-tuned as needed to achieve control of the waveguide shape and size.

[0045] Preferably, the quality inspection of the entire waveguide structure comprises the following steps:

[0046] Measure the transmittance T and reflectance R of the waveguide, and record the total loss α of the waveguide. Calculate the transmission efficiency η of the waveguide using the formula

[0047] The transmission efficiency η is used to evaluate the continuity and optical performance of the waveguide to ensure that it meets the design standards. Based on the evaluation results, the overall performance of the waveguide is verified and optimized and adjusted as needed.

[0048] Preferably, the method of correcting the waveguide structure that does not meet the standards according to the results of the quality inspection until all waveguides meet the preset performance indicators includes the following steps:

[0049] Based on the quality inspection results, identify the waveguide structures that do not meet the standards in the waveguide and record the locations and defect types of these parts;

[0050] Based on the defect information, analyze the cause of the defect and use the formula ΔE=E opt -E actual , where E opt is the optimized laser pulse energy density, E actual is the actual laser pulse energy density used;

[0051] Using the analysis results, adjust the laser pulse parameters, including energy density E, pulse interval t, and scanning speed v, to eliminate or reduce defects;

[0052] Under the adjusted parameter conditions, the waveguides are re-processed and the continuity and optical performance of the waveguides are verified until all waveguides meet the preset performance indicators.

[0053] Technical effects and advantages of the present invention: Compared with the existing technology, the lightweight laser femtosecond micro-engraving waveguide process proposed in the present invention has the following advantages:

[0054] The present invention ensures uniform distribution of modified points on the waveguide path by precisely adjusting the energy density, pulse interval and scanning speed of the laser pulse, avoids the generation of breakpoints and defects, and thus achieves continuity of the waveguide path; through fine adjustment of the waveguide path, it ensures uniform variation of the refractive index on the waveguide path, improves the transmission efficiency of the waveguide, reduces loss, and thus enhances the overall optical performance of the waveguide; the process flow of the present invention is simple and efficient, does not require complex photomasks and wet etching processes, reduces production costs, improves production efficiency, can effectively solve the problems of discontinuous waveguide paths and unstable optical performance in the prior art, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a flow chart of a lightweight laser femtosecond micro-engraving waveguide process of the present invention. DETAILED DESCRIPTION

[0056] 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 embodiments described are only part of the embodiments of the present invention, not all of the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0057] The present invention provides Figure 1 A lightweight laser femtosecond micro-engraving waveguide process shown includes the following steps:

[0058] Step 1: Select a transparent or translucent material that can withstand femtosecond laser pulses without thermal damage as a substrate. For example, silica (SiO2) glass is selected as the substrate material because silica glass has good optical transparency and mechanical stability, which is suitable for femtosecond laser micromachining. On the selected substrate material, use an Abbe refractometer to measure the initial refractive index n of the substrate material. o , use a micrometer to measure the thickness of the substrate material, use a UV-visible spectrometer to measure the transmittance of the substrate material, and record the thickness d and transmittance T of the material o ; Assume that the measured initial refractive index is n o =1.45, d=1, T o =90%, nonlinear coefficient is k=10 -10 m 2 / J.

[0059] Based on the measured parameters, the relationship between the laser pulse energy density E and the refractive index change Δn inside the material is calculated. Δn=kE, where k is the nonlinear coefficient of the material. For example, if the refractive index change inside the material is expected to reach Δn=10 -3 , then the required laser pulse energy density E is:

[0060]

[0061] Determine the optimal value of the laser pulse energy density E to ensure that the refractive index change Δn inside the material reaches the predetermined value; Based on the above calculation, the optimal value of the laser pulse energy density is determined to be E opt =10 7 J / m 2 This value can ensure that the refractive index change inside the material reaches the predetermined value while avoiding thermal damage to the material surface.

[0062] Under the conditions of the determined optimal energy density E, the refractive index change Δn inside the material is verified, and the laser parameters are adjusted to optimize the transmission efficiency of the waveguide. opt Under these conditions, a femtosecond laser is used to perform preliminary processing inside the substrate material, and then an ellipsometer is used to measure the refractive index change inside the material. Assuming that the actual refractive index change measured is Δn actual =0.95×10 -3 .

[0063] According to the actual measured refractive index change, adjust the laser pulse energy density E. For example, if the actual refractive index change is lower than the expected value, the laser pulse energy density can be appropriately increased. Assume that the adjusted energy density is E new =1.05×10 7 J / m 2 After adjusting the energy density E new Under these conditions, the waveguide was re-processed and the transmission efficiency and loss of the waveguide were verified through experiments.

[0064] Step 2: Using a high-precision femtosecond laser to emit laser pulses on the selected substrate, the process avoids ablation of the material surface while ensuring nonlinear absorption within the material; further including:

[0065] First, determine the repetition frequency f and pulse width τ of the laser pulse, record the absorption coefficient α of the material, and calculate the peak power P of the laser pulse inside the material. peak , using the formula P peak =E / (τ·A), where A is the laser spot area;

[0066] Utilize peak power P peak, determine the upper limit of the laser pulse energy density E to avoid ablation of the material surface, using the formula E max =P peak ·τ·A;

[0067] At the determined upper limit E max The laser pulse energy density E is adjusted to ensure nonlinear absorption inside the material while avoiding thermal damage.

[0068] By precisely controlling the repetition frequency, pulse width, and energy density of the laser pulses, we ensure that the laser pulses produce nonlinear absorption within the material while avoiding ablation of the material surface. This helps to preserve the integrity and optical properties of the material surface.

[0069] By adjusting the laser pulse energy density to ensure sufficient nonlinear absorption within the material, the desired refractive index change is achieved. This helps construct high-quality waveguide paths. By precisely controlling the laser pulse parameters, the continuity and uniformity of the waveguide path are optimized, improving transmission efficiency and reducing losses.

[0070] This embodiment simplifies the waveguide manufacturing process by precisely controlling laser pulse parameters, reduces unnecessary tests and adjustments, and improves production efficiency and yield.

[0071] Through the above specific implementation methods, the femtosecond laser micromachining process can be effectively controlled and optimized to ensure the high quality and high performance of the waveguide.

[0072] Step 3: Based on the location where nonlinear absorption occurs, adjust the focusing depth of the femtosecond laser so that the laser focus is located at the level within the material where the refractive index change is expected to occur; further including:

[0073] Measure the material thickness d and the initial position z of the laser focus o , and record the refractive index gradient of the material Calculate the focal depth z of the laser focus inside the material f , using the formula Where Δn is the change in refractive index. Through this formula, the specific position of the laser focus inside the material can be determined.

[0074] Use a micrometer to measure the thickness of the substrate material and record the value. Ensure the measurement is accurate for subsequent calculations and adjustments. Use a microscope or laser positioning system to measure the initial position of the laser focus on the material surface and record the value. Ensure the measurement accuracy of the initial position to avoid errors in subsequent adjustments. Obtain the refractive index gradient of the substrate material through experiments or by consulting relevant literature, and record this value. The refractive index gradient reflects the change in the refractive index within the material with position and is crucial for accurately adjusting the depth of focus.

[0075] Using focus depth z f Adjust the focusing system of the femtosecond laser so that the laser focus is precisely located at the level within the material where the refractive index change is expected to occur. This adjustment can be done manually or with an automated focus system. Ensure that the laser focus position is stable and accurate during the adjustment process.

[0076] After adjusting the focus depth z f Verify the laser focus position under the adjusted focus depth and make fine adjustments as needed. At the adjusted focus depth, use a microscope or other high-precision measuring tool to verify the actual laser focus position. Ensure that the laser focus is exactly at the calculated focus depth. If the verification results show that the laser focus position deviates from the expected value, make fine adjustments based on the deviation. Ensure the laser focus position is accurate through repeated verification and fine-tuning.

[0077] By precisely measuring the material thickness, the initial position of the laser focus, and the material's refractive index gradient, combined with the refractive index change, the laser's focal depth within the material can be accurately calculated. This ensures the laser focus is precisely located at the layer within the material where the refractive index change is expected, enabling highly accurate waveguide path construction.

[0078] Precise focus depth control helps create a uniform and continuous refractive index variation within the material, thereby improving the quality of the waveguide path. This not only ensures the continuity of the waveguide path but also enhances the waveguide's optical performance, such as transmission efficiency and loss. By precisely adjusting the laser focus position, excessive laser focus on the material surface is avoided, reducing thermal damage to the material surface. This helps protect the material's surface integrity and extend its service life.

[0079] This embodiment simplifies the waveguide path construction process by precisely controlling and verifying the position of the laser focus, reduces unnecessary tests and adjustments, and improves production efficiency and yield.

[0080] Step 4: Combined with the set focus depth, by controlling the number and interval of laser pulses, a series of discrete modified points are formed, and the modified points form a predetermined lattice structure inside the material;

[0081] Determine the number of laser pulses based on the waveguide path length and the desired density of modified dots. Ensure that the number of pulses is sufficient to form a continuous and uniform lattice structure. Determine the interval between laser pulses based on the laser scanning speed and the desired dot spacing. The pulse spacing should be moderate—neither too dense nor too sparse—to ensure uniform distribution of modified dots within the material. Measure the laser spot diameter using a microscope and record this value. The laser spot diameter determines the size of each modified dot and significantly influences the uniformity and density of the lattice structure.

[0082] First, determine the number of laser pulses N and the pulse interval t, and record the laser spot diameter D. Calculate the distance s between adjacent modified points using the formula s = v·t, where v is the laser scanning speed. This formula determines the distance between each modified point, ensuring uniform distribution within the material. The laser scanning speed is determined based on the performance of the femtosecond laser and the design of the waveguide path. The scanning speed should be moderate to ensure stability and uniformity of the laser focus within the material. The laser scanning speed and pulse interval are used to calculate the distance between adjacent modified points.

[0083] The step distance s is used to adjust the interval t of the laser pulse to ensure that the modified points are evenly distributed inside the material to form a predetermined lattice structure; under the adjusted pulse interval t, the laser pulse parameters are fine-tuned as needed to optimize the uniformity and density of the lattice structure.

[0084] Adjust the laser pulse interval based on the calculated distance between adjacent modified sites. Ensure the pulse interval is appropriate to form the desired lattice structure. This adjustment can be made manually or using an automated control system. Using a microscope or other high-precision measurement tool, verify the distribution of the modified sites within the material using the adjusted pulse interval. Ensure the modified sites are evenly distributed, forming the desired lattice structure.

[0085] Based on the verification results, if the distribution of modified points is found to be uneven or the density does not meet the requirements, the laser pulse parameters such as energy density, pulse interval, and scanning speed can be fine-tuned. Through repeated verification and fine-tuning, the modified points are ensured to be evenly distributed within the material, forming a high-quality lattice structure.

[0086] By precisely controlling the number and spacing of laser pulses and adjusting the laser scanning speed, the modified dots are evenly distributed within the material. This helps form a continuous and uniform lattice structure, improving the quality of the waveguide path. Fine-tuning the laser pulse parameters optimizes the density of the lattice structure, ensuring that the size and spacing of each modified dot meet design requirements. This not only improves the uniformity of the lattice structure but also enhances the stability and reliability of the waveguide path. Evenly distributed modified dots help form a continuous waveguide path, reducing breakpoints and defects. This improves the continuity of the waveguide path and ensures efficient transmission of optical signals within the waveguide.

[0087] This embodiment simplifies the construction process of the lattice structure by accurately controlling and verifying the laser pulse parameters, reduces unnecessary experiments and adjustments, and improves production efficiency and yield.

[0088] Step 5: Utilizing the formed lattice structure, by continuously changing the position of the laser focus, a continuous waveguide path is constructed, wherein the waveguide path has a predetermined geometric shape, and based on the constructed waveguide path, the laser pulse parameters are optimized; further comprising:

[0089] According to the actual application requirements, determine the predetermined geometric shape of the waveguide path. Common geometric shapes include straight lines, curves, rings, etc. Determine the predetermined geometric shape of the waveguide path, record the total length L of the path and the curvature radius R of the path, calculate the moving speed v of the laser focus on the path, and use the formula where t total is the time required to complete the path; using this formula, we can determine the speed at which the laser focus moves along the path, ensuring that it moves continuously and evenly along the path.

[0090] Using the moving speed v, the laser scanning speed is adjusted to ensure that the laser focus moves continuously and evenly along the path, forming a continuous waveguide path; ensure that the scanning speed is moderate to form a continuous waveguide path. This adjustment can be achieved by manual adjustment or using an automatic control system.

[0091] Verify path continuity: Use a microscope or other high-precision measurement tool to verify the continuity and geometry of the waveguide path at the adjusted scanning speed. Ensure that the laser focus moves continuously and evenly along the path to form a high-quality waveguide path.

[0092] Fine-tune the laser parameters as needed at the adjusted scanning speed v. Based on the verification results, if the waveguide path continuity or geometry is found to not meet the requirements, fine-tune the laser parameters, such as the laser pulse energy density, pulse interval, and scanning speed. Repeated verification and fine-tuning ensure that the waveguide path continuity and geometry meet the design requirements.

[0093] By precisely controlling the laser focus's movement speed, we ensure that it moves continuously and evenly along the path, forming a continuous waveguide path. This helps reduce breakpoints and defects in the path and improves the continuity of the waveguide path.

[0094] By adjusting the laser's scanning speed, the waveguide path geometry is ensured to meet design requirements. Whether it's a straight line, curved line, or circular path, the predetermined geometry is precisely formed, improving the stability and reliability of the waveguide path. A continuous and uniform waveguide path helps improve the transmission efficiency of optical signals within the waveguide and reduce losses. This not only enhances the waveguide's optical performance but also ensures efficient transmission of optical signals.

[0095] Further comprising: measuring the initial transmission efficiency η of the waveguide path o and loss coefficient α o ;

[0096] Calculate the effect of laser pulse energy density E on transmission efficiency η using the formula η=η o exp(-α o L), where L is the length of the waveguide path, the laser pulse energy density E is adjusted using the formula to maximize the transmission efficiency η and minimize the loss coefficient α o Use a spectrometer or optical power meter to measure the initial transmission efficiency of the waveguide path. Transmission efficiency reflects the ability of optical signals to propagate within the waveguide and is an important indicator for evaluating waveguide performance. Determine the initial loss coefficient of the waveguide path through experiments or theoretical calculations. The loss coefficient reflects the attenuation of optical signals during propagation within the waveguide and has a significant impact on the waveguide's optical performance.

[0097] Optimize the laser parameters under the adjusted laser pulse energy density E. Based on the calculated results, adjust the laser pulse energy density to maximize transmission efficiency and minimize the loss factor. Find the optimal values ​​by gradually increasing or decreasing the laser pulse energy density and observing the changes in transmission efficiency and loss factor. Remeasure the transmission efficiency and loss factor of the waveguide path under the adjusted laser pulse energy density to ensure that the optimized waveguide path has higher transmission efficiency and lower loss.

[0098] After determining the optimal laser pulse energy density, we further optimized other laser parameters, such as pulse interval, scanning speed, and repetition rate. Through multiple experiments and verifications, we ensured that all parameters were optimal for achieving the best performance of the waveguide path. Based on the experimental results, we fine-tuned the laser parameters to ensure the optimal transmission efficiency and loss coefficient of the waveguide path.

[0099] By precisely adjusting the laser pulse energy density, the transmission efficiency of the waveguide path can be significantly improved. The optimized waveguide path can transmit optical signals more efficiently, reduce signal loss, and improve overall performance.

[0100] By optimizing laser pulse energy density and other parameters, the loss coefficient of the waveguide path can be effectively reduced. A lower loss coefficient means less attenuation of the optical signal within the waveguide, allowing for longer transmission distances, making it suitable for long-distance optical communications and high-precision optical systems. The optimized waveguide path offers greater stability and reliability. The continuous and uniform waveguide path reduces fluctuations and noise in signal transmission, improving the overall stability of the system.

[0101] Step 6: Through the parameter optimization process, the waveguide path is adjusted to achieve control of the waveguide shape and size. After that, the entire waveguide structure is quality inspected to check whether the waveguide continuity and optical performance meet the design standards;

[0102] The waveguide path is adjusted through a parameter optimization process, which includes the following steps:

[0103] Determine the predetermined geometric shape and size of the waveguide path according to actual application requirements. Common geometric shapes include straight lines, curves, rings, etc. Record the width and height h of the waveguide and calculate the scanning path length L of the laser focus on the waveguide path. scan , using the formula L scan =L+2h, where L is the total length of the waveguide path; through this formula, the scanning path length of the laser focus on the waveguide path can be determined to ensure that the laser focus is evenly distributed on the waveguide path.

[0104] Using the scan path length L scan , adjust the repetition frequency f of the laser pulse to ensure that the laser focus is evenly distributed on the waveguide path, using the formula f = L scan t, where v is the laser scanning speed and t is the pulse interval;

[0105] Fine-tune laser parameters such as pulse energy density, pulse interval, and scanning speed as needed under the adjusted repetition rate f. Ensure the waveguide shape and dimensions meet design requirements through repeated verification and fine-tuning to achieve control of the waveguide shape and dimensions. Use a microscope or other high-precision measurement tool to verify the waveguide shape and dimensions. Ensure that the waveguide width and height are uniform, without obvious defects or discontinuities.

[0106] By precisely calculating the scanning path length of the laser focus and adjusting the repetition frequency of the laser pulses, it is possible to ensure that the laser focus is evenly distributed along the waveguide path. This helps to precisely control the shape and size of the waveguide, ensuring that the geometry of the waveguide path meets the design requirements.

[0107] By fine-tuning the laser parameters, the uniformity of the waveguide path can be optimized. A uniform waveguide path helps improve the transmission efficiency of optical signals within the waveguide, reduce signal loss, and improve overall performance.

[0108] Perform quality inspection on the entire waveguide structure, including the following steps:

[0109] Use a spectrometer or optical power meter to measure the transmittance T and reflectance R of the waveguide, and record the total loss α of the waveguide to calculate the transmission efficiency η of the waveguide using the formula Through this formula, the transmission efficiency of the waveguide can be evaluated to ensure that it meets the design standards.

[0110] Transmittance reflects the intensity of the light signal after passing through the waveguide and is an important indicator for evaluating waveguide transmission efficiency. Reflectivity reflects the reflection of the light signal at the waveguide entrance and has a significant impact on the waveguide's optical performance. Total loss reflects the attenuation of the light signal during propagation within the waveguide and is an important parameter for evaluating waveguide performance.

[0111] Using the transmission efficiency η, a microscope or other high-precision measurement tool is used to evaluate the waveguide's continuity and optical performance to ensure they meet design specifications. Based on the evaluation results, the overall waveguide performance is verified and optimized and adjusted as needed. If the waveguide's continuity or optical performance does not meet the requirements, further optimization and adjustment can be performed. For example, adjustments to the laser pulse energy density, pulse interval, and scanning speed can be made to improve the waveguide's transmission efficiency and reduce losses.

[0112] Step 7: Based on the quality inspection results, correct the waveguide structure that does not meet the standards until all waveguides meet the preset performance indicators. This further includes:

[0113] Based on the quality inspection results, identify any substandard waveguide structures and record the locations and defect types of these areas. For example, record breakpoints, discontinuities, or high-loss areas in the waveguide path. Also record the defect types, such as surface ablation, internal bubbles, and uneven refractive index variations. Ensure detailed records to facilitate subsequent analysis and resolution.

[0114] According to the recorded defect location and type, analyze the cause of the defect. Common causes include insufficient or too high laser pulse energy density, improper pulse interval, too fast or too slow scanning speed, etc. Based on the defect information, analyze the cause of the defect using the formula ΔE=E opt -E actual , where E opt is the optimized laser pulse energy density, E actual is the actual laser pulse energy density used; through this formula, we can analyze the impact of laser pulse energy density on waveguide defects and find out the specific causes of the defects.

[0115] Using the analysis results, adjust the laser pulse parameters, including energy density E, pulse interval t, and scanning speed v, to eliminate or reduce defects. If the energy density is insufficient, increase it appropriately; if it is too high, reduce it appropriately.

[0116] Adjust the laser pulse interval to ensure that the modified points are evenly distributed within the material. If the pulse interval is too small, the modified points may overlap; if it is too large, discontinuities may appear between the modified points. Adjust the laser scanning speed (v) to ensure that the laser focus moves continuously and evenly along the waveguide path. If the scanning speed is too fast, the modified points may be unevenly distributed; if it is too slow, the processing time may increase, affecting production efficiency.

[0117] Under the adjusted parameters, re-process the waveguides and verify their continuity and optical performance until all waveguides meet the preset performance specifications. Use a microscope or other high-precision measurement tools to verify the waveguide's continuity and optical performance. Ensure that the waveguide's transmission efficiency and loss coefficient meet the design specifications. Based on the verification results, if the waveguide's continuity or optical performance is still insufficient, further fine-tune the laser parameters until all waveguides meet the preset performance specifications.

[0118] By precisely analyzing and adjusting the laser pulse parameters, defects in the waveguide, such as breakpoints, discontinuous areas, and high-loss regions, can be effectively eliminated or reduced. This helps improve the waveguide's continuity and optical performance.

[0119] The optimized waveguide path has higher transmission efficiency and lower loss coefficient. This not only improves the optical performance of the waveguide, but also ensures efficient transmission of optical signals, making it suitable for various high-performance optical systems.

[0120] Through detailed defect analysis and parameter adjustment, the stability and reliability of the waveguide path can be ensured. The continuous and uniform waveguide path reduces fluctuations and noise in signal transmission and improves the overall stability of the system.

[0121] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A lightweight laser femtosecond micro-engraving waveguide process, characterized in that: The following steps are involved: Select a transparent or translucent material as the substrate that can withstand femtosecond laser pulses without thermal damage; On the selected substrate, a high-precision femtosecond laser is used to emit laser pulses, avoiding ablation of the material surface during the emission of the laser pulses while ensuring nonlinear absorption within the material; Adjusting the focusing depth of the femtosecond laser according to the location where the nonlinear absorption occurs so that the laser focus is located at a layer within the material where a refractive index change is expected to occur; In combination with the set focus depth, a series of discrete modified points are formed by controlling the number and interval of laser pulses, and the modified points form a predetermined lattice structure inside the material; By utilizing the formed lattice structure and continuously changing the position of the laser focus, a continuous waveguide path is constructed, wherein the waveguide path has a predetermined geometric shape, and based on the constructed waveguide path, laser pulse parameters are optimized; The waveguide path is adjusted by optimizing the laser pulse parameters to achieve control of the waveguide shape and size. Afterwards, the entire waveguide structure is quality inspected to check whether the continuity and optical performance of the waveguide meet the design standards. Based on the results of the quality inspection, the waveguide structures that do not meet the standards are corrected until all waveguides meet the preset performance indicators; The method of adjusting the focus depth of the femtosecond laser according to the position where the nonlinear absorption occurs comprises the following steps: measuring the thickness d of the material and the initial position z of the laser focus; o , and record the refractive index gradient of the material Calculate the focal depth z of the laser focus inside the material f , using the formula where Δn is the refractive index change; using the depth of focus z f Adjust the focusing system of the femtosecond laser so that the laser focus is precisely located at the layer inside the material where the refractive index change is expected to occur; at the adjusted focusing depth z f Under the given conditions, verify the position of the laser focus and make fine adjustments as needed; The adjustment of the waveguide path by optimizing the laser pulse parameters comprises the following steps: determining the predetermined geometric shape and size of the waveguide path, recording the width and height h of the waveguide, and calculating the scanning path length L of the laser focus on the waveguide path. scan , using the formula L scan = L + 2h, where L is the total length of the waveguide path; using the scanning path length L scan , adjust the repetition frequency f of the laser pulse to ensure that the laser focus is evenly distributed on the waveguide path, using the formula f = L scan ·t, where v is the laser scanning speed and t is the pulse interval; the laser parameters are fine-tuned as needed under the adjusted repetition frequency f to achieve control of the waveguide shape and size.

2. A lightweight laser femtosecond micro-engraving waveguide process according to claim 1, characterized in that: The method of selecting a transparent or translucent material as a substrate that can withstand femtosecond laser pulses without causing thermal damage comprises the following steps: On the selected substrate material, measure the initial refractive index n of the material o , and record the thickness d and transmittance T of the material H ; Based on the measured parameters, the relationship between the laser pulse energy density E and the refractive index change Δn inside the material is calculated as Δn=kE, where k is the nonlinear coefficient of the material; Determine the optimal value of the laser pulse energy density E to ensure that the refractive index change Δn inside the material reaches a predetermined value; Under the determined optimal energy density E, the refractive index change Δn inside the material is verified, and the laser parameters are adjusted to optimize the transmission efficiency of the waveguide.

3. A lightweight laser femtosecond micro-engraving waveguide process according to claim 2, characterized in that: The method of emitting laser pulses on the selected substrate using a high-precision femtosecond laser comprises the following steps: First, determine the repetition frequency f and pulse width τ of the laser pulse, record the absorption coefficient α of the material, and calculate the peak power P of the laser pulse inside the material. peak , using the formula P peak =E / (τ·A), where A is the laser spot area; Utilize peak power P peak , determine the upper limit of the laser pulse energy density E to avoid ablation of the material surface, using the formula E max =P peak ·τ·A; At the determined upper limit E max The laser pulse energy density E is adjusted to ensure nonlinear absorption inside the material while avoiding thermal damage.

4. A lightweight laser femtosecond micro-engraving waveguide process according to claim 3, characterized in that: The focus depth is set in combination with the number and interval of laser pulses to form a series of discrete modified points, including the following steps: Determine the number of laser pulses N and the pulse interval t, and record the laser spot diameter D. Calculate the distance s between adjacent modified points using the formula s = v·t, where v is the laser scanning speed; The interval t of the laser pulses is adjusted using the step distance s to ensure that the modified points are evenly distributed inside the material to form a predetermined lattice structure; Under the adjusted pulse interval t, the laser pulse parameters are fine-tuned as needed to optimize the uniformity and density of the lattice structure.

5. A lightweight laser femtosecond micro-engraving waveguide process according to claim 4, characterized in that: The method of constructing a continuous waveguide path by continuously changing the position of the laser focus using the formed lattice structure includes the following steps: Determine the predetermined geometry of the waveguide path, record the total length L of the path and the radius of curvature R of the path, and calculate the moving speed v of the laser focus on the path using the formula where t total is the time required to complete the path; Using the moving speed v, the scanning speed of the laser is adjusted to ensure that the laser focus moves continuously and evenly along the path, forming a continuous waveguide path; Under the adjusted scanning speed v, fine-tune the laser parameters as needed.

6. A lightweight laser femtosecond micro-engraving waveguide process according to claim 5, characterized in that: The method of optimizing laser pulse parameters based on the constructed waveguide path comprises the following steps: Measuring the initial transmission efficiency η of the waveguide path o and loss coefficient α o ; Calculate the effect of laser pulse energy density E on transmission efficiency η using the formula η=η o exp(-α o L), where L is the length of the waveguide path, the laser pulse energy density E is adjusted using the formula to maximize the transmission efficiency η and minimize the loss coefficient α o ; Under the adjusted laser pulse energy density E, the laser parameters are optimized.

7. The lightweight laser femtosecond micro-engraving waveguide process according to claim 6, characterized in that: The quality inspection of the entire waveguide structure includes the following steps: Measure the transmittance T and reflectance R of the waveguide, and record the total loss α of the waveguide. Calculate the transmission efficiency η of the waveguide using the formula The transmission efficiency η is used to evaluate the continuity and optical performance of the waveguide to ensure that it meets the design standards. Based on the evaluation results, the overall performance of the waveguide is verified and optimized and adjusted as needed.

8. The lightweight laser femtosecond micro-engraving waveguide process according to claim 7, characterized in that: The method comprises the following steps: correcting the waveguide structures that do not meet the standards according to the results of the quality inspection until all waveguides meet the preset performance indicators; Based on the quality inspection results, identify the waveguide structures that do not meet the standards in the waveguide and record the locations and defect types of these parts; Based on the defect information, analyze the cause of the defect and use the formula ΔE=E opt -E actual , where E opt is the optimized laser pulse energy density, E actual is the actual laser pulse energy density used; Using the analysis results, adjust the laser pulse parameters, including energy density E, pulse interval t, and scanning speed v, to eliminate or reduce defects; Under the adjusted parameter conditions, the waveguides are re-processed and the continuity and optical performance of the waveguides are verified until all waveguides meet the preset performance indicators.

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