Light wave modulation method and device

Abstract

The invention discloses a light wave modulation method and equipment. According to an exemplary embodiment, the light wave modulation method comprises the following steps: determining a modulation parameter of a light wave according to target dispersion or determining the modulation parameter of the light wave according to a target spectrum; calculating modulation parameters of ultrasonic waves based on the modulation parameters of the light waves; generating ultrasonic waves, the ultrasonic waves having the modulation parameters calculated for the ultrasonic waves; and modulating light waves through the ultrasonic waves. According to the regulation and control scheme based on the acousto-optic crystal, dispersion control and spectrum control are integrated into a single device, dispersion and spectrum control functions can be achieved through flexible adjustment of ultrasonic parameters, complex light path adjustment is not needed, operation is easy and convenient, work is stable and reliable, the performance limitation of a traditional element is effectively broken through, and the application range is wide. Accurate control of dispersion and spectrum of the ultrashort pulse laser is realized, and a brand new technical path is provided for high-performance regulation and control of the ultrashort pulse laser.

Description

Technical Field

[0001] This application relates to the field of laser technology, and more specifically, various exemplary embodiments relate to optical modulation methods and apparatus. Background Technology

[0002] As a core branch of modern laser technology, ultrashort pulse laser technology has been widely used in precision micro-nano fabrication, ultrafast spectroscopy research, and the medical field due to its unique advantages of short pulse duration and high peak power. Obtaining ideal ultrashort pulses with narrow pulse width, high peak power, and uniform energy distribution is a core prerequisite for ensuring the performance advantages of these applications. Precise dispersion and spectral control are important fundamental conditions for achieving this goal.

[0003] Dispersion has a decisive influence on the temporal characteristics of ultrashort pulses, while the laser spectrum reflects the amplitude, bandwidth, and phase distribution of the laser spectrum. Precise dispersion control technology can optimize the pulse shape, ensuring that the temporal characteristics of ultrashort pulses meet application requirements, while precise spectral modulation technology can optimize the spectral distribution. Especially during laser amplification, dispersion control can broaden the temporal domain of ultrashort pulses by introducing controllable group delay dispersion before amplification to reduce peak power, avoid medium damage and nonlinear effects, and after amplification, use an inverse dispersion compensation system to offset higher-order dispersion errors and calibrate the phase of frequency components to restore narrow pulse characteristics, while maintaining a dynamic balance between nonlinear effects and dispersion in the integrated system. Spectral modulation, on the other hand, can provide a physical basis for pulse compression by broadening the gain spectral width, use filtering elements to suppress amplified spontaneous emission and parametric fluorescence noise to improve pulse contrast, and optimize the spectral shape to ensure uniform energy distribution. Both techniques, starting from temporal phase and frequency domain characteristics respectively, jointly provide crucial guarantees for high-power, narrow-pulse, and highly stable laser output. Summary of the Invention

[0004] The subject matter of the independent claims is provided according to several aspects. Further aspects are defined in the dependent claims. Embodiments that do not fall within the scope of the claims should be interpreted as examples that aid in understanding this disclosure.

[0005] According to a first aspect of this disclosure, a light wave modulation method is provided, which may include: determining modulation parameters of a light wave based on a target dispersion or a target spectrum; calculating modulation parameters of an ultrasonic wave based on the modulation parameters of the light wave; generating an ultrasonic wave having the calculated modulation parameters therefor; and modulating the light wave with the ultrasonic wave.

[0006] According to a second aspect of this disclosure, an optical modulation apparatus is provided, which may include: at least one processor; and

[0007] At least one memory storing instructions, which, when executed by the at least one processor, cause the optical modulation device to perform at least the method according to the first aspect described above.

[0008] According to a third aspect of this disclosure, an optical wave modulation apparatus is provided, which may include: means for determining modulation parameters of an optical wave based on a target dispersion or a target spectrum; means for calculating modulation parameters of an ultrasonic wave based on the modulation parameters of the optical wave; means for generating an ultrasonic wave having modulation parameters calculated therefor; and means for modulating an optical wave by the ultrasonic wave.

[0009] According to a fourth aspect of this disclosure, a computer-readable medium is provided having (computer-executable) instructions stored thereon, which, when executed (or run) by a processor, cause the processor to perform the method described in accordance with the first aspect above.

[0010] According to a fifth aspect of this application, a computer program product is provided, comprising (computer-executable) program instructions that, when executed (or run) by a processor, cause the processor to perform the method described in accordance with the first aspect above.

[0011] The computer program product may include or be embodied in a computer-readable (storage) medium, on which computer-executable computer program instructions and / or programs that can be directly loaded into the internal memory of a computer or its processor are stored. Attached Figure Description

[0012] Figure 1 A schematic diagram of the acousto-optic programmable dispersive filter used in this disclosure is shown;

[0013] Figure 2 A schematic diagram showing the interaction between light pulses and ultrasound in an acousto-optic crystal;

[0014] Figure 3 A schematic diagram illustrating the correspondence between ultrasonic frequency and light wavelength according to an exemplary embodiment of the present disclosure;

[0015] Figure 4 A schematic diagram illustrating the determination of the acousto-optic crystal cutting angle according to an exemplary embodiment of the present disclosure is shown.

[0016] Figure 5 A schematic flowchart of an optical dispersion modulation method according to an exemplary embodiment of the present disclosure is shown;

[0017] Figure 6 A schematic diagram illustrating the relationship between ultrasonic frequency and time according to an exemplary embodiment of the present disclosure;

[0018] Figure 7A schematic flowchart of an optical spectrum modulation method according to an exemplary embodiment of the present disclosure is shown;

[0019] Figure 8 A schematic diagram showing the target spectrum according to an exemplary embodiment of the present disclosure;

[0020] Figure 9 A schematic flowchart of an ultrasonic wave generation method according to an exemplary embodiment of the present disclosure is shown.

[0021] Figure 10 A flowchart illustrating an exemplary method according to an exemplary embodiment of the present disclosure;

[0022] Figure 11 An example block diagram of an example device according to an exemplary embodiment of the present disclosure is shown;

[0023] Figure 12 An example block diagram of an example device according to an exemplary embodiment of the present disclosure is shown.

[0024] The same or substantially the same elements, operations, and steps shown in the various figures may be indicated by the same reference numerals. For clarity, not every element, operation, or step is shown in every figure. Detailed Implementation

[0025] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. It should be understood that this disclosure should not be construed as limiting to the exemplary embodiments described herein, but rather that it can be implemented in various other forms, provided only for a more thorough and complete understanding of the present application. It should also be understood that the accompanying drawings are given by way of example only and are not intended to limit the precise form of the embodiments or to limit the scope of protection of the present application.

[0026] The following embodiments are exemplary. Although the specification refers to "a," "an," or "some" embodiments in various places, this does not necessarily mean that each reference refers to the same embodiment, or that a specific feature applies only to a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments. Moreover, when specific features, structures, or characteristics are described in conjunction with embodiments, whether explicitly described or not, such features, structures, or characteristics will be applied to other embodiments to the extent that those skilled in the art possess the knowledge to do so. It should be understood that although terms such as "first" and "second" may be used to describe various elements, these elements should not be limited by these terms. These terms are merely used to distinguish one element from another.

[0027] In this disclosure, the terms "at least one of A or B", "at least one of A and B", and "A and / or B" mean [A], [B], or [A and B]. In this disclosure, "A, B, and / or C" means [A], [B], [C], [A and B], [A and C], [B and C], or [A, B, and C].

[0028] In the current development of ultrashort pulse laser technology, dispersion control mainly relies on various traditional optical components. Among them, prism pairs, grating pairs, and chirped mirrors, with their mature fabrication processes and well-defined control mechanisms, have become the three most widely used dispersion control devices. However, these three traditional components have significant shortcomings in terms of the flexibility of dispersion control and the adaptability of spectral control, making it difficult to meet the demands of ultrashort pulse lasers towards high power, narrow pulses, and precision. For chirped mirrors, their dispersion characteristics are entirely determined by the solidified factors such as the film structure design and deposition process parameters during fabrication. Once the device is fabricated, its dispersion curve is permanently fixed and cannot be dynamically adjusted according to changes in operating conditions during subsequent practical applications. When the gain medium, pulse parameters, or operating environment of the laser system change, existing chirped mirrors cannot quickly adapt to the new dispersion compensation requirements, necessitating the customization of new devices. This not only increases the cost of use but also seriously affects the system's versatility and debugging efficiency. While prism pairs and grating pairs offer some dispersion tuning capability compared to chirped mirrors, this tuning has significant limitations: firstly, their tuning range only covers up to the third order dispersion, failing to adjust the fourth order and higher-order dispersion during ultrashort pulse laser amplification; secondly, dispersion tuning of these components requires precise changes in the beam incident angle and adjustments to the physical spacing between components through mechanical operations. This process is not only cumbersome, requiring high-precision displacement platforms and calibration equipment, which is time-consuming and labor-intensive, but also prone to introducing additional optical path offsets and system errors during adjustment. Small deviations in the incident angle may cause beam propagation direction shifts, and subtle changes in component spacing may compromise the accuracy of dispersion compensation. These problems all cause considerable inconvenience and reduce the stability and reliability of the entire laser system.

[0029] In the field of spectral control, conventional devices such as prisms, gratings, etalons, and filters can, through their optical properties, filter the center wavelength of a laser and initially limit its spectral width, fulfilling basic spectral modulation requirements. However, these modulation methods are essentially based on the overall characteristics of the spectrum and lack the ability to precisely control spectral details. Specifically, they cannot precisely set the intensity of specific wavelength components in the spectral curve, nor can they achieve differentiated modulation across different wavelength ranges. For example, they cannot attenuate specific bands near the spectral peak. This limitation directly leads to insufficient precision and flexibility in spectral control, failing to meet the refined requirements for the spectral shape and energy distribution of ultrashort pulse lasers in different application scenarios.

[0030] This disclosure proposes an acousto-optic control method based on frequency control, which can be implemented using a programmable dispersion filter, based on the interaction between ultrasonic waves and light waves in an acousto-optic crystal. Those skilled in the art will understand that, for illustrative purposes and not for limitation, the terms "light wave" and "laser" are sometimes used interchangeably, and the technical essence of these terms will be understood by those skilled in the art. This disclosure uses an acousto-optic crystal as the core functional carrier, achieving precise control of the laser through the interaction between ultrasonic waves and light waves within the crystal. At the device design level, by precisely optimizing and controlling the cutting direction of the acousto-optic crystal, a correspondence between ultrasonic wave frequencies and light wave frequencies can be established. Based on this core correlation, by dynamically changing the duration and intensity of the ultrasonic waves corresponding to specific light wave frequencies, precise control of the propagation delay of different frequency components in ultrashort pulse lasers can be achieved, thereby achieving flexible compensation and optimization of dispersion, and selective enhancement or attenuation of the intensity of specific frequency components in the ultrashort pulse spectrum, realizing refined spectral shaping. The disclosed acousto-optic crystal-based modulation scheme integrates dispersion control and spectral control into a single device. Dispersion and spectral control functions can be achieved through flexible adjustment of ultrasonic parameters. It does not require complex optical path adjustment, is simple and convenient to operate, and is stable and reliable. It effectively breaks through the performance limitations of traditional components, realizes precise control of dispersion and spectrum of ultrashort pulse lasers, and provides a new technical path for high-performance modulation of ultrashort pulse lasers.

[0031] Figure 1 A schematic diagram of an acousto-optic programmable dispersive filter 100 for implementing the laser modulation method of this disclosure is shown. Those skilled in the art will understand that... Figure 1 The exemplary structure of the dispersive filter is provided for illustrative purposes only and is not intended to limit the technical solutions of this disclosure. See also Figure 1The acousto-optic dispersion filter 100 may include a connector 120, an adapter circuit 130, a transducer 140, and an acousto-optic crystal 160. These components work collaboratively through signal transmission and physical interaction to achieve programmable control of light waves. The connector 120 serves as the signal input interface of the filter 100, primarily used to receive electrical signals 110 from external devices. The connector 120 may be an SMA (Sub-Miniature Version A) interface to ensure signal integrity and interference resistance during transmission. In some embodiments, the received electrical signal 110 may be a radio frequency signal with a wide frequency range and high control sensitivity to adapt to control scenarios involving different wavelengths of light.

[0032] After the electrical signal 110 is received by connector 120, it can be transmitted to adapter circuit 130 through a dedicated signal transmission line. Adapter circuit 130 is the core signal processing component that realizes the programmable function of the filter. Adapter circuit 130 may have a high-precision signal modulation module and a programmable control chip, enabling precise programming and adjustment of the parameters of the input electrical signal 110. These adjustment parameters may include, for example, the signal frequency, intensity, delay, and phase. In some embodiments, the intensity of the electrical signal can be adjusted by controlling its power, thereby controlling the amplitude of the ultrasonic wave. In some embodiments, adapter circuit 130 can dynamically adjust the combination of various parameters according to the needs of the actual application scenario to ensure optimal performance of the output signal.

[0033] The electrical signal, after being programmed and optimized by the adapter circuit 130, is sent to the transducer 140 in real time. The core function of the transducer 140 is to realize the energy conversion of the electrical signal into mechanical waves. In some embodiments, the transducer 140 can be a piezoelectric transducer closely attached to the acousto-optic crystal 160, such as a piezoelectric ceramic. When the alternating electrical signal acts on the piezoelectric ceramic, the lattice structure inside the ceramic will undergo mechanical vibration. This vibration will be efficiently transmitted to the interior of the acousto-optic crystal 160 through the crystal contact surface, thereby exciting an ultrasonic wave 150 with specific modulation parameters such as frequency, amplitude, duration, and phase corresponding to the electrical signal parameters.

[0034] The acousto-optic crystal 160, as the medium for generating the acousto-optic effect, is a key carrier for realizing light wave manipulation. In some embodiments, the acousto-optic crystal 160 can be made of a crystal material with excellent acousto-optic properties, such as tellurium dioxide (TeO2) crystal. When the ultrasonic wave 150 propagates inside the acousto-optic crystal 160, it causes a periodic change in the refractive index inside the crystal, thereby forming a dynamic acousto-optic grating. When an externally incident light wave 170 is input into the acousto-optic crystal 160 affected by the ultrasonic wave 150, it passes through this periodically changing refractive index region. At this time, the light wave interacts with the acousto-optic grating, i.e., the acousto-optic diffraction effect, thereby realizing the manipulation of the propagation direction, intensity, frequency, and phase of the light wave. In some embodiments, the propagation direction of the ultrasonic wave 150 in the acousto-optic crystal 160 can be the same as the propagation direction of the light wave 170 in the crystal.

[0035] By using the programmable dispersion filter 100, those skilled in the art can embed the laser modulation method proposed in this disclosure into the device. This allows users to operate without needing in-depth knowledge of the underlying principles of acousto-optic effects or mastering complex optical path control techniques. Users simply input the desired target dispersion parameters and target spectral control parameters directly on the computer screen through the device's human-machine interface. The system automatically converts these parameters into control commands for the adapter circuit 130, thereby driving the entire device to precisely control the light wave. In some embodiments, the technical solutions of this disclosure can be implemented using computer programs, which can be stored in the adapter circuit 130. In some embodiments, the adapter circuit 130 may have volatile or non-volatile storage modules to store these computer programs.

[0036] Figure 2 This diagram illustrates the interaction between light pulses and ultrasound waves in an acousto-optic crystal, demonstrating how programmable spatiotemporal distributed ultrasound waves can modulate the dispersion and spectrum of the light pulses. (See also...) Figure 2 Pre-programmed ultrasound waves, whose angular frequency and intensity dynamically change over time, exhibit differentiated angular frequency distributions at different spatial locations within the acousto-optic crystal as they propagate along a specific direction. Figure 2 In the process, the angular frequency of the ultrasound is Ω1 at the initial position, and then successively Ω2, Ω3, Ω4, Ω5 at different positions, until it reaches Ω at the end position. n This is equivalent to constructing a dynamic acousto-optic grating array within the crystal, where the frequency varies with spatial position. The light pulse incident on the acousto-optic crystal is a light signal containing multiple frequency components. Figure 2 In the middle, different wavelengths λ1, λ2, λ3, λ4, λ5...λ nTo distinguish light pulses of different frequencies, those skilled in the art will understand that wavelength and frequency can be directly converted using the electromagnetic wave speed formula c=λf (where c is the speed of light, λ is the wavelength, and f is the frequency). Since the speed of light can reach 1.3×10⁻⁶... 8 m / s, much faster than the speed of ultrasound (4.26 × 10⁻⁶ m / s). 3 Because the speed is m / s, when light and ultrasound travel together in an acousto-optic crystal, the light passes through the crystal in a very short time, while the ultrasound can be considered stationary. Therefore, when this composite light pulse travels along a specific path through the acousto-optic crystal, the light components of different frequencies (corresponding to different wavelengths) within it will interact with the ultrasound waves of specific angular frequencies at different spatial locations within the crystal. For example, a light wave with wavelength λ1 will satisfy the acousto-optic diffraction condition at the location where the ultrasound angular frequency is Ω1, and thus be diffracted out of the crystal by the acousto-optic grating in that region. The remaining light components continue to propagate forward, and when they reach the region where the ultrasound angular frequency is Ω2, the light wave with wavelength λ2 satisfies the matching condition there and is diffracted and separated… and so on, until the wavelength is λ… n The light wave at the end Ω n Diffraction occurs at corresponding positions. This process disperses light of different wavelengths onto different propagation paths outside the crystal. Since the wavelengths of the diffracted light differ at different positions, dispersion occurs. Simultaneously, the diffraction efficiency (i.e., the proportion of light energy diffracted) causes variations in the intensity of light waves of different wavelengths. Therefore, when the diffraction efficiency differs for different wavelengths, the spectrum changes. Based on... Figure 2 The ultrasonic waves and wavelengths shown in this disclosure interact. The optical wave modulation method can include three parts, the first being the calculation of wavelengths λ1, λ2, λ3, λ4, λ5...λ n The angular frequencies of ultrasound waves that interact with light waves are Ω1, Ω2, Ω3, Ω4, Ω5...Ω. n The first step involves calculating the correspondence between light wave frequencies and ultrasonic wave frequencies; the second step involves calculating the modulation parameters of the ultrasonic waves that can generate the target dispersion after given the target dispersion; and the third step involves calculating the modulation parameters of the ultrasonic waves that can generate the target spectrum after given the target spectrum.

[0037] When calculating the correspondence between light wave frequencies and ultrasonic wave frequencies, the refractive indices of the ordinary and extraordinary rays corresponding to different wavelength ranges of light frequency components can be calculated first. For clarity and not limitation, the ordinary ray is referred to as o-ray or incident light, and the extraordinary ray as e-ray or diffracted light in this disclosure. The refractive indices of the ordinary and extraordinary rays corresponding to different wavelength ranges of light frequency components can be calculated based on the refractive index equation of acousto-optic crystals combined with the cutting direction of the acousto-optic crystal. The refractive index of an acousto-optic crystal is determined by the inherent properties of a specific acousto-optic crystal preparation process, and is related to the material, process, and cutting direction of the acousto-optic crystal. Different materials directly affect the molecular arrangement structure inside the crystal, different preparation processes change the purity and defect density of the crystal, and different cutting directions change the propagation path and polarization state of light inside the crystal. These factors work together to ultimately determine that the ordinary and extraordinary rays exhibit different refractive index values ​​in the crystal. After determining the refractive indices of the incident and diffracted light, the relationship between the interacting ultrasonic wave frequencies and light wave frequencies can be calculated based on the refractive indices of the ordinary and extraordinary rays. In some implementations, the correspondence between the interacting ultrasonic waves and light waves in the acousto-optic crystal can be determined based on formula (1):

[0038] (1)

[0039] In equation (1), n1 and n2 are the refractive indices of the incident light and the diffracted light, respectively; ω1, ω2, and Ω are the angular frequencies of the incident light, the diffracted light, and the ultrasound, respectively; c and v are the speed of light in vacuum and the wave speed of ultrasound in an acousto-optic crystal, respectively. Those skilled in the art will understand that angular frequency and frequency can be directly converted using the relationship between angular frequency and frequency ω=2πf (ω is the angular frequency and f is the frequency). Figure 3 The diagram illustrates the correspondence between ultrasonic frequency and light wavelength in an exemplary embodiment of this disclosure. It shows that in an acousto-optic crystal cut at a specific angle, an ultrasonic wave with a frequency of 73 MHz can interact with a light wave with a wavelength of 800 nm. Furthermore, when 73 MHz is used as the adjustable ultrasonic center frequency, the relationships between other adjustable ultrasonic frequencies and the wavelengths of the light waves that can be controlled by that frequency are all... Figure 3 The figure clearly shows that the changing trend of the matching light wavelength is directly observable as the ultrasonic frequency changes, exhibiting a clear correlation between the two. Those skilled in the art will understand that the interval of the adjustable ultrasonic frequency can be determined by the frequency interval of the acousto-optic crystal driving hardware, and the performance parameters of the driving hardware directly limit the adjustment accuracy and range of the ultrasonic frequency.

[0040] In some implementations, the optimal cutting angle of the acousto-optic crystal can be calculated based on the center wavelength of the actual ultrashort pulse laser to be modulated and the center frequency of the ultrasonic driving frequency of the acousto-optic modulator, combined with the correspondence formula between optical frequency and ultrasonic frequency and the refractive index formula of the acousto-optic crystal. This ensures that after cutting the acousto-optic crystal at this angle, the center wavelength of the light wave that can interact with the ultrasonic wave in the acousto-optic crystal and the center frequency of the ultrasonic driving frequency of the actual ultrashort pulse laser to be modulated are the same as the center wavelength of the actual ultrashort pulse laser to be modulated and the center frequency of the ultrasonic driving frequency of the acousto-optic modulator. Figure 4 A schematic diagram illustrates how the acousto-optic crystal cutting angle is determined based on the center wavelength of the ultrashort pulse laser used and the center frequency of the ultrasonic drive frequency of the acousto-optic modulator. See also... Figure 4 When the center wavelength of the ultrashort pulse laser is 800 nm and the center frequency of the ultrasonic drive frequency of the acousto-optic modulator is 73 MHz, the optimal cutting angle of the acousto-optic crystal is 38.76 degrees. In some embodiments, the center wavelength of the ultrashort pulse laser actually used can be determined according to the type of laser emitting the ultrashort pulse laser. Different types of lasers have different gain media and resonant cavity structures, and the center wavelength of the ultrashort pulse laser they emit will also be different.

[0041] Figure 5 A schematic flowchart of an optical dispersion modulation method 500 according to an exemplary embodiment of the present disclosure is shown. See also Figure 5 Firstly, in Operation 510, users can set the target dispersion of the optical pulse according to actual needs. The setting of the target dispersion needs to be combined with the specific application scenario. For example, the requirements for optical pulse dispersion differ significantly in different fields such as laser communication and laser processing. In some implementations, a fourth-order dispersion can be set for the optical pulse. Specifically, users can set the group delay (GD), group velocity dispersion (GVD), third-order dispersion (TOD), and fourth-order dispersion (FOD) to be achieved for the optical pulse. These four dispersion parameters describe the dispersion characteristics of the optical pulse during propagation from different dimensions. The group delay reflects the overall propagation time delay of the optical pulse, the group velocity dispersion describes the group velocity difference of different frequency components, and the third-order and fourth-order dispersions further characterize the higher-order variation laws of dispersion characteristics.

[0042] In operation 520, the delay of the light wave in the crystal can be calculated according to the set target dispersion. The delay to be achieved by the light wave in the crystal can be calculated according to the relationship between the delay of the ultrashort pulse and the angular frequency. The relationship between the delay of the ultrashort pulse and the angular frequency is shown in the following formula (2):

[0043] (2)

[0044] In equation (2), T(ω) is the delay of the light wave, ω is the angular frequency of the light wave, ω0 is the center angular frequency, and GD, GVD, TOD, and FOD are the target dispersions set by the user. By substituting the specific parameter values, the delay time corresponding to different angular frequencies of light waves can be calculated according to equation (2).

[0045] In operation 530, the duration of ultrasound waves at various frequencies within the crystal can be calculated. To calculate the duration of ultrasound waves within the crystal, the diffraction position z(ω) of the light wave in the acousto-optic crystal to achieve the target dispersion can be calculated first based on formula (3).

[0046] (3)

[0047] In equation (3), c represents the speed of light, and n o (ω) represents the refractive index of the ordinary ray, n e (ω) represents the refractive index of the acousto-optic crystal, and L represents the length of the acousto-optic crystal. By determining the diffraction position z(ω) of the light wave within the acousto-optic crystal, we can ascertain which wavelengths of light need to diffract at which positions within the crystal to achieve dispersion towards the target after passing through the crystal. For example, at... Figure 2 In this process, a light wave with wavelength λ1 diffracts at the initial position, a light wave with wavelength λ2 diffracts at the first subsequent position, a light wave with wavelength λ3 diffracts at the second subsequent position, and so on. Correspondingly, an ultrasonic wave with a specific frequency that can interact with the light wave of that wavelength should also be able to interact with the light wave at that position. Therefore, after obtaining the correspondence between the wavelength of the light wave and the frequency of the ultrasonic wave, the spatial distribution of the ultrasonic wave within the acousto-optic crystal can be obtained by combining the diffraction position of the light wave. That is, the position of ultrasonic waves of each frequency in the crystal when the light wave passes through the acousto-optic crystal, thus providing a reference for the subsequent calculation of the time variation law of the ultrasonic wave. Then, in operation 540, the time variation of the ultrasonic wave frequency can be calculated based on the spatial distribution of the ultrasonic wave within the acousto-optic crystal. In some embodiments, the distribution of different ultrasonic frequencies over time can be calculated by measuring the wave velocity of the ultrasonic wave in the crystal and combining it with the spatial distribution of the ultrasonic wave. In some implementations, the distribution of different ultrasonic rates over time can be represented by the duration of ultrasonic waves at different frequencies. The length of the duration directly affects the duration of the acousto-optic interaction, which in turn affects the delay of each wavelength of light and ultimately the dispersion modulation effect. In this way, ultrasonic waves can be continuously generated in an acousto-optic crystal according to a specific duration and frequency, thereby forming an acousto-optic grating in the crystal that can interact with light waves and achieve the target dispersion. Figure 6This illustrates a set of ultrasonic frequency variations over time calculated using an optical dispersion modulation method according to an exemplary embodiment of the present disclosure. For example... Figure 6 As shown, in order to achieve the target dispersion set for the light pulse, the frequency of the ultrasonic wave can be gradually increased from 68 MHz over time, reaching approximately 78 MHz at 24 μs. Those skilled in the art will understand that when controlling the dispersion of light frequency, the time and duration distribution of the frequency allocation can be determined based on the frequency intervals of the acousto-optic crystal driver hardware. The performance of the driver hardware directly determines the fineness of the frequency adjustment, thus affecting the accuracy of the dispersion control.

[0048] Another important aspect of the optical wave modulation method disclosed herein is that, given a target spectrum, the modulation parameters of the ultrasonic waves that can generate the target spectrum are calculated. Spectral modulation and dispersive modulation together constitute the core of the optical wave modulation method disclosed herein, and the two achieve the control of the optical pulse from the two dimensions of spectral characteristics and dispersive characteristics, respectively. Figure 7 A schematic flowchart of an optical spectrum modulation method 700 according to an exemplary embodiment of the present disclosure is shown. Figure 7 As shown, in operation 710, the target spectrum to be achieved can be determined first. The determination of the target spectrum needs to be combined with specific application requirements. For example, in fields such as laser amplification, spectral analysis, and laser display, there are different requirements for the spectral shape and intensity distribution of the light pulse. An exemplary target spectrum is shown below. Figure 8 As shown, the target spectrum is the spectrum obtained by punching holes in the ultrashort pulse laser spectrum. In this target spectrum, the center wavelength of the hole is approximately 800 nm, the hole depth is approximately 0.5 nm, and the hole width is approximately 10 nm. This punched spectrum can effectively avoid distortion of the amplified laser spectrum in laser amplification scenarios and has significant application value. Next, in operation 720, the center wavelength and diffraction efficiency at the center wavelength can be determined based on the target spectrum. For example, to achieve... Figure 8The target spectrum shown has a center wavelength of 800 nm, and the diffraction efficiency of the center wavelength can be set to 80%. In operation 730, other wavelengths of the light wave and their corresponding diffraction efficiencies can be determined. For example, the diffraction efficiency of the light wave at a wavelength of 780 nm can be determined to be 72%. In some embodiments, the diffraction efficiency can be reduced proportionally to reduce power consumption. For example, the diffraction efficiency of the center wavelength of 800 nm can be set to 40%, while the diffraction efficiency at a wavelength of 780 nm can be reduced to 36%, and the reduction in diffraction efficiency can be compensated by amplifying the laser afterwards. Then in operation 740, the amplitude of the ultrasonic wave can be calculated based on the wavelength and diffraction efficiency. In some embodiments, the amplitude of the ultrasonic wave can be determined by the ultrasonic power, which is related to the power of the input electrical signal. The magnitude of the ultrasonic power directly affects the amplitude intensity of the ultrasonic wave, and thus affects the intensity of the acoustic-optic interaction, which is ultimately reflected in the change of diffraction efficiency. The relationship between the radio frequency power required for the diffraction efficiency of the laser wavelength in the overall ultrasonic range can be determined based on the parameters and attenuation coefficient of the acousto-optic crystal, as shown in the following formula (4). The relationship between ultrasonic power and diffraction efficiency is:

[0049] (4)

[0050] In formula (4), η(ω) represents the diffraction efficiency; P represents the ultrasonic power; P0 represents the power when the diffraction efficiency is 100%; sinc is the Singer function; and Δk is the e-wave vector of the diffracted light in the acousto-optic interaction. Incident light wave vector and ultrasonic vector The projection of the vector difference onto the direction of sound wave propagation. It can be calculated using the following equation (5):

[0051] (5)

[0052] in, Let be the unit vector in the direction of the ultrasonic wave vector. Based on formula (4), the method disclosed herein can calculate the amplitude of the ultrasonic wave frequency corresponding to the optical wavelength based on the relative intensity of the target spectrum wavelength and the intensity of the incident spectrum. In some embodiments, the amplitude of the ultrasonic wave can be a normalized number between (0,1), representing the relationship between the power of the ultrasonic wave and the power P0 at 100% diffraction efficiency. The normalized amplitude representation can more intuitively reflect the proportional relationship between the ultrasonic wave power and the maximum diffraction efficiency power, facilitating subsequent parameter adjustment and control.

[0053] Through the aforementioned embodiments, modulation parameters for the modulated ultrasonic waves can be obtained. These modulation parameters may include frequency, amplitude, duration, and phase. Then, an optical modulation device, such as [insert optical modulation device here], can be used based on these modulation parameters. Figure 1The dispersive filter 100 controls and processes the input electrical signal to generate ultrasonic waves with the aforementioned modulation parameters in the acousto-optic crystal. Figure 9 A schematic flowchart of an ultrasonic wave generation method 900 according to an exemplary embodiment of the present disclosure is shown. Figure 9 As shown, in operation 910, ultrasonic waves with specific modulation parameters can be generated. In some embodiments, an adapter circuit and transducer can be programmed to process the input electrical signal to generate ultrasonic waves with specific modulation parameters. Next, in operation 920, the generated ultrasonic waves can be input into an acousto-optic crystal to drive it to form an acousto-optic grating. In operation 930, the ultrasonic waves interact with the input light waves in the acousto-optic crystal, and the diffraction of the light waves by the acousto-optic grating formed by the ultrasonic waves achieves the modulation of the light wave's dispersion and spectral characteristics. In operation 940, after the acousto-optic interaction, a light pulse with the target dispersion and target spectrum can be generated, ultimately realizing the complete process from parameter setting to light pulse modulation.

[0054] Figure 10 A flowchart illustrating an exemplary method 1000 according to an exemplary embodiment of the present disclosure is shown. The exemplary method 1000 can be... Figure 1 The dispersive filter 100 in the middle is executed. See also Figure 10 The exemplary method 1000 may include: operation 1310, determining the modulation parameters of a light wave based on the target dispersion or the target spectrum; operation 1320, calculating the modulation parameters of an ultrasonic wave based on the modulation parameters of the light wave; operation 1330, generating an ultrasonic wave having the modulation parameters calculated therefor; and operation 1340, modulating the light wave with the ultrasonic wave.

[0055] In some embodiments, the modulation of the light wave by the ultrasonic wave may include: inputting the ultrasonic wave and the light wave into an acousto-optic crystal, and modulating the light wave by the acousto-optic crystal subjected to the ultrasonic wave.

[0056] In some embodiments, calculating the modulation parameters of the ultrasonic wave based on the modulation parameters of the light wave may include: determining the correspondence between the frequency of the light wave and the frequency of the ultrasonic wave, wherein the ultrasonic wave is used to modulate the light wave having the corresponding frequency.

[0057] In some implementations, determining the modulation parameters of the light wave based on the target dispersion may include: determining the correspondence between the frequency and the delay of the light wave based on the target group delay, the target group velocity dispersion, the target third-order dispersion, and the target fourth-order dispersion.

[0058] In some embodiments, calculating the modulation parameters of the ultrasonic wave based on the modulation parameters of the light wave may include: calculating the duration of the ultrasonic wave at a corresponding frequency based on the frequency of the light wave and the delay corresponding to that frequency.

[0059] In some embodiments, calculating the duration of ultrasound at a corresponding frequency based on the frequency of the light wave and the corresponding delay may include: calculating the diffraction position of the light wave in the acousto-optic crystal based on the frequency of the light wave and the corresponding delay; obtaining the spatial distribution of ultrasound within the acousto-optic crystal based on the diffraction position of the light wave; obtaining the temporal distribution of ultrasound within the acousto-optic crystal based on the spatial distribution of ultrasound within the acousto-optic crystal; and obtaining the duration of ultrasound at a corresponding frequency based on the temporal distribution of ultrasound within the acousto-optic crystal.

[0060] In some implementations, determining the modulation parameters of the light wave based on the target spectrum may include: determining the correspondence between the frequency of the light wave and the diffraction efficiency based on the target spectrum.

[0061] In some implementations, calculating the modulation parameters of the ultrasonic wave based on the modulation parameters of the light wave may include: calculating the frequency and amplitude of the ultrasonic wave based on the frequency of the light wave and the corresponding diffraction efficiency.

[0062] Figure 11 A block diagram of an example device 1100 according to an exemplary embodiment is shown. Device 1100 may be implemented as at least a portion of the dispersive filters 100 discussed above. Reference Figure 11 The device 1100 includes, for example, at least one processor 1112 and at least one memory 1114 storing instructions 1116. When the instructions 1116 are executed by the at least one processor 1112, the device 1110 causes at least the above-mentioned instructions to be executed. Figure 10 The method described. In one example, the at least one memory 1114 and instructions 1116 (e.g., computer program code, software) are configured to cause the device 1100 to perform any of the methods described above, via the at least one processor 1112.

[0063] Processor 1112 may include, or be configured as, one or more circuits configured to perform stages of the method according to the disclosed exemplary embodiments. In this disclosure, the term "circuit" may refer to one or more of the following: (a) a hardware-only circuit implementation, such as an implementation solely in analog and / or digital circuitry; (b) a combination of hardware circuitry and software, if applicable, such as: (i) a combination of analog and / or digital hardware circuitry with software / firmware, and (ii) any portion of a hardware processor with software (including digital signal processors, software, and memory, which work together to enable a device such as a user equipment to perform various functions); (c) hardware circuitry and / or a processor, such as a microprocessor or a portion thereof, which requires software (e.g., firmware) for operation, but which may be absent when not required for operation. This definition of circuitry applies to all uses of the term in this disclosure (including any claims). As a further example, when used in this disclosure, the term circuitry also encompasses: an implementation solely of hardware circuitry or a processor (or multiple processors), a portion of hardware circuitry or a processor, and an implementation of its accompanying software and / or firmware.

[0064] The memory 1114 can be implemented using any suitable data storage technology. The memory 1114 may be at least partially external to the device 1100, but may be accessible to the device 1100.

[0065] Instruction 1116 may be contained in a computer-readable medium or a non-transitory computer-readable medium. The term non-transitory, as used herein, is in contrast to the limitation of data storage persistence (e.g., RAM versus ROM) and is a limitation concerning the medium itself (i.e., tangible rather than signal).

[0066] Device 1100 may include a user interface 1118, which includes at least one of, for example, a keyboard, microphone, touchscreen, display, speaker, etc. User interface 1118 can be used to control device 1100 by a user. User interface 1118 may be external to device 1100. For example, device 1100 may be connected to another device, such as a computer, via a wireless or wired connection, and device 1100 may be controlled by a user via the computer.

[0067] In some embodiments, at least some of the methods described herein can be performed by a device including means for performing various operations or steps in the described methods. Means for performing the method steps described herein may include software and / or hardware components of device 1100. For example, at least one processor 1112, memory 1114, and computer program code may form means for performing the methods described herein and any embodiments thereof. The term “means” as used herein may be interpreted in the singular form, meaning a single element, or in the plural form, meaning a combination of single elements. Therefore, the term “means for performing A, B, C” should be interpreted to encompass devices in which only one means performs A, B, C; or in which separate means perform A, B, C; or in which partially or entirely overlapping means perform A, B, C. Furthermore, the terms “apparatus for performing A, apparatus for performing B, apparatus for performing C” should be interpreted to cover devices in which only one apparatus performs A, B, or C; or in which separate apparatuses perform A, B, or C; or in which some or all overlapping apparatuses perform A, B, or C.

[0068] Figure 12 An example block diagram of an example device 1200 according to an exemplary embodiment of the present disclosure is shown. The example device 1200 may be, for example, at least a portion of the dispersive filter 100 described above.

[0069] like Figure 12 As shown, the example device 1200 may include: a device 1210 for determining modulation parameters of a light wave based on a target dispersion or a target spectrum; a device 1220 for calculating modulation parameters of an ultrasonic wave based on the modulation parameters of the light wave; a device 1230 for generating an ultrasonic wave having the modulation parameters calculated therefor; and a device 1240 for modulating the light wave using the ultrasonic wave.

[0070] In some embodiments, the modulation of the light wave by the ultrasonic wave may include: inputting the ultrasonic wave and the light wave into an acousto-optic crystal, and modulating the light wave by the acousto-optic crystal subjected to the ultrasonic wave.

[0071] In some embodiments, calculating the modulation parameters of the ultrasonic wave based on the modulation parameters of the light wave may include: determining the correspondence between the frequency of the light wave and the frequency of the ultrasonic wave, wherein the ultrasonic wave is used to modulate the light wave having the corresponding frequency.

[0072] In some implementations, determining the modulation parameters of the light wave based on the target dispersion may include: determining the correspondence between the frequency and the delay of the light wave based on the target group delay, the target group velocity dispersion, the target third-order dispersion, and the target fourth-order dispersion.

[0073] In some embodiments, calculating the modulation parameters of the ultrasonic wave based on the modulation parameters of the light wave may include: calculating the duration of the ultrasonic wave at a corresponding frequency based on the frequency of the light wave and the delay corresponding to that frequency.

[0074] In some embodiments, calculating the duration of ultrasound at a corresponding frequency based on the frequency of the light wave and the corresponding delay may include: calculating the diffraction position of the light wave in the acousto-optic crystal based on the frequency of the light wave and the corresponding delay; obtaining the spatial distribution of ultrasound within the acousto-optic crystal based on the diffraction position of the light wave; obtaining the temporal distribution of ultrasound within the acousto-optic crystal based on the spatial distribution of ultrasound within the acousto-optic crystal; and obtaining the duration of ultrasound at a corresponding frequency based on the temporal distribution of ultrasound within the acousto-optic crystal.

[0075] In some implementations, determining the modulation parameters of the light wave based on the target spectrum may include: determining the correspondence between the frequency of the light wave and the diffraction efficiency based on the target spectrum.

[0076] In some implementations, calculating the modulation parameters of the ultrasonic wave based on the modulation parameters of the light wave may include: calculating the frequency and amplitude of the ultrasonic wave based on the frequency of the light wave and the corresponding diffraction efficiency.

[0077] It should be understood that the apparatus according to the embodiments of this disclosure is not limited to the examples described above. The modules in the illustrated example apparatuses can be connected or coupled together in any suitable manner, and the arrows between the modules are only used to indicate the direction of data or signals of interest, but do not indicate that the direction of data or signals between modules can only be in the direction of the arrows.

[0078] Some exemplary embodiments also provide computer program code or instructions that, when executed by one or more processors, cause a device or apparatus to perform the methods described above. The computer program code for performing the methods of the example embodiments can be written in any known or future-developed programming language, such as Java, C++, C, and Assembler. The computer program code can be provided to one or more processors or controllers of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that, when executed by the processor or controller, it causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote computer or server.

[0079] Some example embodiments also provide a computer program product or computer-readable medium in which computer program code or instructions are stored, which, when executed by a processor, cause the associated means to perform the methods, steps, or functions described above. A computer-readable medium can be any tangible medium that may contain or store a program for use by or in connection with an instruction execution system, means, or apparatus. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, means, or apparatuses, or any suitable combination thereof. More specific examples of machine-readable storage media will include electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0080] As stated above and reiterated below, this disclosure includes, but is not limited to, the following exemplary embodiments.

[0081] An exemplary embodiment provides a light wave modulation device, comprising: means for determining modulation parameters of a light wave based on target dispersion and target spectrum; means for calculating modulation parameters of an ultrasonic wave based on the modulation parameters of the light wave; means for generating an ultrasonic wave having the modulation parameters calculated therefor; and means for modulating the light wave by the ultrasonic wave.

[0082] In some embodiments, the modulation of the light wave by the ultrasonic wave may include: inputting the ultrasonic wave and the light wave into an acousto-optic crystal, and modulating the light wave by the acousto-optic crystal subjected to the ultrasonic wave.

[0083] In some embodiments, calculating the modulation parameters of the ultrasonic wave based on the modulation parameters of the light wave may include: determining the correspondence between the frequency of the light wave and the frequency of the ultrasonic wave, wherein the ultrasonic wave is used to modulate the light wave having the corresponding frequency.

[0084] In some implementations, determining the modulation parameters of the light wave based on the target dispersion may include: determining the correspondence between the frequency and the delay of the light wave based on the target group delay, the target group velocity dispersion, the target third-order dispersion, and the target fourth-order dispersion.

[0085] In some embodiments, calculating the modulation parameters of the ultrasonic wave based on the modulation parameters of the light wave may include: calculating the duration of the ultrasonic wave at a corresponding frequency based on the frequency of the light wave and the delay corresponding to that frequency.

[0086] In some embodiments, calculating the duration of ultrasound at a corresponding frequency based on the frequency of the light wave and the corresponding delay may include: calculating the diffraction position of the light wave in the acousto-optic crystal based on the frequency of the light wave and the corresponding delay; obtaining the spatial distribution of ultrasound within the acousto-optic crystal based on the diffraction position of the light wave; obtaining the temporal distribution of ultrasound within the acousto-optic crystal based on the spatial distribution of ultrasound within the acousto-optic crystal; and obtaining the duration of ultrasound at a corresponding frequency based on the temporal distribution of ultrasound within the acousto-optic crystal.

[0087] In some implementations, determining the modulation parameters of the light wave based on the target spectrum may include: determining the correspondence between the frequency of the light wave and the diffraction efficiency based on the target spectrum.

[0088] In some implementations, calculating the modulation parameters of the ultrasonic wave based on the modulation parameters of the light wave may include: calculating the frequency and amplitude of the ultrasonic wave based on the frequency of the light wave and the corresponding diffraction efficiency.

[0089] Furthermore, although the operations are described in a specific order, this should not be construed as requiring such operations to be performed in the specific order or sequence shown, or requiring all of the operations shown to achieve the desired result. In some cases, multitasking and parallel processing can be advantageous. Similarly, although several specific implementation details are included in the foregoing discussion, these details should not be construed as limiting the scope of this disclosure, but rather as descriptions of features specific to particular embodiments. Certain features described in the context of a single embodiment may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0090] The basic principles of this disclosure have been described above in conjunction with embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0091] The block diagrams of devices, apparatuses, devices, and systems disclosed herein are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0092] Furthermore, in the apparatus, devices, and methods disclosed herein, the components or steps can be disassembled and / or recombined. Such disassembly and / or recombination should be considered equivalent solutions to this disclosure.

[0093] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0094] The above description has been given for illustrative and descriptive purposes and is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

[0095] Although the subject matter has been described in language specific to structural features and / or methodological actions, it should be understood that the subject matter defined in the appended claims is not limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as examples of implementing the claims.

Claims

1. A method for modulating light waves, comprising: determining modulation parameters of the light waves according to a target dispersion or determining modulation parameters of the light waves according to a target spectrum; calculating modulation parameters of ultrasonic waves based on the modulation parameters of the light waves; generating ultrasonic waves with the calculated modulation parameters; modulating the light waves by the ultrasonic waves.

2. The optical wave modulation method as claimed in claim 1, wherein, The modulating the light waves by the ultrasonic waves comprises: inputting the ultrasonic waves and the light waves into an acousto-optic crystal, and modulating the light waves by the acousto-optic crystal under the action of the ultrasonic waves.

3. The optical wave modulation method as claimed in claim 2, wherein, The calculating modulation parameters of ultrasonic waves based on the modulation parameters of the light waves comprises: determining a correspondence between a frequency of the light waves and a frequency of the ultrasonic waves, the ultrasonic waves being used to modulate the light waves with the corresponding frequency.

4. The optical wave modulation method as claimed in claim 3, wherein, The determining modulation parameters of the light waves according to a target dispersion comprises: determining a correspondence between a frequency of the light waves and a time delay according to a target group delay, a target group velocity dispersion, a target third-order dispersion and a target fourth-order dispersion.

5. The optical wave modulation method as claimed in claim 4, wherein, The calculating modulation parameters of ultrasonic waves based on the modulation parameters of the light waves comprises: calculating a duration of the ultrasonic waves with the corresponding frequency based on the frequency of the light waves and a time delay corresponding to the frequency.

6. The optical wave modulation method as claimed in claim 5, wherein, The calculating a duration of the ultrasonic waves with the corresponding frequency based on the frequency of the light waves and a time delay corresponding to the frequency comprises: calculating a diffraction position of the light waves in the acousto-optic crystal based on the frequency of the light waves and the time delay corresponding to the frequency; obtaining a spatial distribution of the ultrasonic waves in the acousto-optic crystal based on the diffraction position of the light waves in the acousto-optic crystal; obtaining a time distribution of the ultrasonic waves in the acousto-optic crystal based on the spatial distribution of the ultrasonic waves in the acousto-optic crystal; obtaining the duration of the ultrasonic waves with the corresponding frequency based on the time distribution of the ultrasonic waves in the acousto-optic crystal. 7.The method for modulating laser according to claim 3, wherein The determining modulation parameters of the light waves according to a target spectrum comprises: determining a correspondence between a frequency of the light waves and a diffraction efficiency according to a target spectrum. 8.The method for modulating light waves according to claim 7, wherein The calculating modulation parameters of ultrasonic waves based on the modulation parameters of the light waves comprises: calculating a frequency and an amplitude of the ultrasonic waves based on the frequency of the light waves and the corresponding diffraction efficiency. 9.An apparatus for modulating light waves, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus for modulating light waves to perform at least the method of any one of claims 1-8. 10.An apparatus for modulating light waves, comprising: means for determining modulation parameters of the light waves according to a target dispersion or determining modulation parameters of the light waves according to a target spectrum; means for calculating modulation parameters of ultrasonic waves based on the modulation parameters of the light waves; means for generating ultrasonic waves with the calculated modulation parameters; means for modulating the light waves by the ultrasonic waves. 11.A computer readable medium comprising program instructions that, when executed, implement the method of any one of claims 1 to 8. 12.A computer program product comprising instructions that, when executed by a processor, perform the method of any one of claims 1-8.

Images