A time domain sensitivity regulation optical fiber sensing method based on dynamic wavelength time mapping

Abstract

The application discloses a time-domain sensitivity regulation optical fiber sensing method based on dynamic wavelength time mapping. The method in the embodiment of the application is programmable control to the dynamic wavelength tuning process, constructs a nonlinear mapping relationship between the wavelength and the time, forms a time-domain sensitivity window with adjustable position, width and peak value on the time axis, makes the same wavelength change produce an amplified time response in a predetermined time region, and thus realizes active design and engineering regulation of the measurement sensitivity without changing the sensor structure and the intrinsic wavelength sensitivity. The method of the application is suitable for various optical fiber sensing scenes.

Description

Technical Field

[0001] This application relates to the fields of fiber optic sensing, dynamic wavelength modulation, and time-domain measurement laser dynamic tuning, and in particular to a time-domain sensitivity modulation fiber optic sensing method based on dynamic wavelength time mapping. Background Technology

[0002] Fiber optic sensing technology, with its outstanding advantages such as resistance to electromagnetic interference, long transmission distance, high detection sensitivity, small probe size, and ease of distributed network deployment, has been widely applied in many technical fields, including structural health monitoring in civil engineering, online control of industrial processes, status sensing of energy equipment, environmental parameter detection, biomedical detection, and aerospace equipment testing. Current mainstream fiber optic sensors include grating-type sensors such as fiber Bragg gratings, long-period fiber gratings, and tilted fiber gratings, as well as interferometric fiber optic sensors such as Fabry-Perot, Michelson, and Mach-Zehnder. The general sensing mechanism of these sensors is that the measured physical quantity (strain, temperature, pressure, vibration, etc.) causes changes in the characteristic parameters of the sensor's reflection spectrum, transmission spectrum, or interference spectrum, specifically manifested as spectral wavelength shift, phase drift, and fringe period distortion. By analyzing these spectral characteristic changes, the corresponding physical quantity information can be obtained.

[0003] Currently, mainstream fiber optic sensing demodulation systems are all based on wavelength domain resolution mechanisms to achieve signal measurement, mainly including two technical paths: one is to use a broadband light source in conjunction with a spectrometer to complete static spectral acquisition and analysis; the other is to use a tunable narrow-linewidth laser to perform wavelength scanning of the target spectral range, and combine signal processing algorithms such as peak search, correlation matching, phase demodulation, and spectrum analysis to extract sensing feature information, and finally realize the physical quantity calculation. In this type of traditional demodulation framework, the effective resolution and feature recognition of the signal are completed in the wavelength dimension, and the time dimension is only used as an auxiliary recording variable mainly for data acquisition, scanning control, and synchronous data acquisition and equipment scanning. Its role is usually limited to auxiliary coordinates in the process of spectral information acquisition. Existing technologies have not yet treated the wavelength evolution trajectory as a designable object to achieve the engineering control of the measurement response by actively constructing a dynamic mapping relationship between wavelength and time.

[0004] As the requirements for measurement accuracy, dynamic response capability, and adaptive detection performance continue to increase in scenarios such as precision testing of high-end equipment, long-term monitoring of large structures, and acquisition of weak dynamic signals, the technical shortcomings of traditional pure wavelength domain demodulation solutions are gradually becoming apparent. They cannot meet the high-precision, adjustable, universal, and differentiated engineering measurement needs. The specific defects are mainly reflected in the following four aspects:

[0005] First, existing measurement systems lack the ability to actively control the wavelength-time mapping process. Existing fiber optic sensing systems typically use a fixed scan rate or a fixed tuning trajectory to complete spectral acquisition. During the measurement process, the wavelength change rate remains basically constant, making it impossible to construct differentiated time response characteristics for specific measurement intervals, nor can it actively configure the measurement gain according to detection requirements.

[0006] Second, the time dimension resources have not been developed and utilized, and there is a lack of time-domain amplification mechanisms based on dynamic wavelength-time mapping. Traditional demodulation methods directly establish the correspondence between wavelength changes and physical quantity changes, focusing only on steady-state spectral characteristics. They do not utilize the tunable characteristics of wavelength change rates to construct differentiated time responses, and therefore cannot achieve local amplification and active control of the measurement response through wavelength-time mapping without changing the sensor structure and intrinsic wavelength response characteristics.

[0007] Third, existing technologies lack a measurement gain control mechanism independent of specific sensor structures. Different types of fiber optic sensors often rely on their own proprietary demodulation algorithms and signal processing strategies, lacking a general technical framework that can independently enhance and control the measurement response outside the sensor.

[0008] Fourth, multi-point distributed sensor networks lack the ability to configure differentiated sensitivity. In multi-point, distributed fiber optic sensing and monitoring systems, existing technologies generally use uniform and fixed scanning and demodulation parameters to complete the analysis of data from all measurement points. They cannot perform targeted sensitivity enhancement and signal amplification for specific sensor channels or specific detection intervals based on the importance level, signal amplitude range, and measurement accuracy requirements of each monitoring point. This makes it difficult to achieve a balance between high-precision detection in key areas and routine monitoring across the entire region.

[0009] In summary, existing fiber optic sensing demodulation technologies suffer from several technical bottlenecks, including fixed and unadjustable sensitivity, low utilization of time-domain resources, poor algorithm versatility, and a lack of differentiated control capabilities for multi-point detection. These limitations make it difficult to meet the demands for high-precision, programmable, universal, and controllable fiber optic sensing. Therefore, there is an urgent need to develop a time-domain sensitivity-controlled fiber optic sensing method based on a dynamic wavelength-time mapping mechanism. This method involves programmably designing the dynamic wavelength-time mapping trajectory to construct time-domain amplification windows on the time axis, whose position, width, number, and amplification factor can be independently adjusted. By utilizing local variations in the wavelength evolution rate, selective amplification of the measurement response can be achieved. This allows for active design, dynamic configuration, and adaptive control of the measurement gain without altering the sensor structure or intrinsic wavelength response characteristics. Summary of the Invention

[0010] This application provides a fiber optic sensing method for time-domain sensitivity adjustment based on dynamic wavelength-time mapping. By programmably designing and controlling the dynamic wavelength-time mapping trajectory, an adjustable nonlinear mapping relationship is established between wavelength and time, forming a spatial distribution of time-domain amplification factors. This allows for the construction of time-domain amplification windows with adjustable position, width, number, and gain on the time axis. Using these time-domain amplification windows, the same wavelength change can produce differentiated time responses in different time regions, enabling active configuration of measurement gain and sensitivity adjustment. This improves the system's measurement capabilities without altering the sensor structure or its intrinsic wavelength response characteristics.

[0011] The embodiments of this application adopt the following technical solutions:

[0012] In a first aspect, embodiments of this application provide a time-domain sensitivity-adjustable fiber optic sensing method based on dynamic wavelength-time mapping, comprising the following steps:

[0013] Step S1: Set the corresponding measurement target parameters according to the type of physical quantity being measured, the measurement accuracy requirements, the target detection area, and the response speed requirements;

[0014] Step S2: Design a time-domain sensitivity window based on the measurement target parameters. The time-domain sensitivity window is a time-domain control unit used to limit the sensitivity enhancement range within a local time interval during wavelength scanning. The time-domain sensitivity window includes at least one or more of the following parameters: window position parameter, window width parameter, window gain parameter, and window number parameter.

[0015] Step S3: Based on the parameters of the time-domain sensitivity window, by configuring the wavelength evolution rate corresponding to different time regions, a dynamic wavelength time mapping trajectory is designed to form a non-uniform mapping relationship between the output wavelength of the light source and time.

[0016] Step S4: Generate a corresponding driving signal based on the dynamic wavelength time mapping trajectory, and drive the light source to output a dynamic wavelength scanning light wave that follows the dynamic wavelength time mapping trajectory;

[0017] Step S5: Inject the dynamic wavelength scanning light wave into the fiber optic sensing unit, and acquire the corresponding time-domain observation through the photoelectric detection unit and the signal acquisition unit.

[0018] Step S6: Based on the dynamic wavelength-time mapping relationship, the acquired time-domain observations are analyzed to complete the calculation of the measured physical quantity, and the parameters of the time-domain sensitivity window and the dynamic wavelength-time mapping trajectory are optimized based on the calculation results.

[0019] The dynamic wavelength time mapping trajectory is a designable evolution trajectory of the output wavelength of the light source with respect to time, and its corresponding local wavelength evolution rate can be independently configured in different time regions; the time domain sensitivity window includes the time region in the dynamic wavelength time mapping trajectory where the local wavelength evolution rate is reduced, which is used to form a time domain amplification effect in the time region.

[0020] The above-mentioned at least one technical solution adopted in the embodiments of this application can achieve the following beneficial effects: The fiber optic sensing method based on dynamic wavelength time mapping provided in the embodiments of this application establishes an adjustable nonlinear mapping relationship between wavelength and time by programmably designing the dynamic wavelength time mapping trajectory, so that different time regions correspond to different wavelength time mapping gains, thereby forming a time-domain sensitivity window with adjustable position, width, number and gain on the time axis.

[0021] Unlike existing fiber optic sensing demodulation methods that primarily rely on the intrinsic wavelength sensitivity of the sensor, this application achieves local enhancement and active modulation of the measurement response by controlling the dynamic wavelength time mapping trajectory without altering the sensor structure or its intrinsic wavelength response characteristics. Utilizing the time-domain amplification effect formed by the local wavelength evolution slowdown region, the same wavelength change can correspond to a larger change in time response, thereby improving the detection capability of weak signals and the measurement resolution.

[0022] Furthermore, the time-domain sensitivity window in this application can be independently configured according to actual measurement needs. Its window position, window width, window gain, number of windows, and window distribution can all be programmable, realizing differentiated sensitivity configurations for different measurement areas, different sensing channels, and different detection targets, thereby improving the system engineering adaptability and measurement flexibility.

[0023] Furthermore, the dynamic wavelength-time mapping mechanism proposed in this application is independent of specific fiber optic sensor structures and is compatible with various fiber optic sensors such as fiber Bragg gratings, long-period fiber gratings, tilted fiber gratings, Fabry-Perot interferometers, Michelson interferometers, and Mach-Zehnder interferometers, providing a unified time-domain sensitivity control framework for different types of fiber optic sensing systems.

[0024] Therefore, this application achieves active design, dynamic configuration and adaptive control of measurement gain without changing the sensor structure and intrinsic sensitivity parameters. It has the advantages of strong versatility, high programmability, good engineering adaptability and easy multi-point expansion. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0026] Figure 1 This is a flowchart illustrating the time-domain sensitivity modulation fiber optic sensing method based on dynamic wavelength-time mapping, as described in an embodiment of this application.

[0027] Figure 2 This is a schematic diagram of the dynamic wavelength time mapping trajectory corresponding to the programmable time-domain amplification window in an embodiment of this application;

[0028] Figure 3 This is a schematic diagram illustrating the mechanism of the time-domain amplification effect generated by dynamic wavelength time mapping in an embodiment of this application;

[0029] Figure 4 This is a schematic diagram of the programmable time-domain magnification window distribution in an embodiment of this application;

[0030] Figure 5 This is a schematic diagram of the system structure of the fiber optic sensing method for time-domain sensitivity modulation based on dynamic wavelength time mapping, as described in this application. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] As mentioned earlier, mainstream fiber optic sensing demodulation systems are all based on wavelength domain resolution mechanisms to achieve signal measurement. Behind the above technical path lies a technical premise that has long been accepted in the field: the time dimension is merely an auxiliary coordinate in the process of acquiring spectral information, and its role is limited to data acquisition triggering, scanning control and measurement synchronization. It does not have, nor should it be, given the function of actively controlling the measurement response.

[0033] The industry's inherent perception that the time dimension is unavailable is not arbitrary, but rather determined and reinforced by the physical rate bottleneck of existing fiber optic sensing and demodulation equipment:

[0034] First, traditional spectrometers employ a mechanically rotating grating dispersive structure, limiting their scanning rate to the tens of Hz range. At this rate, the spectral acquisition process itself is time-consuming, and the temporal information cannot contain any meaningful transient characteristics. Consequently, the industry naturally regards this time merely as a passive window of waiting for the spectral scan to complete.

[0035] Secondly, even when using scanning lasers or scanning FP etalon solutions, the highest scanning rate of commercially available mainstream fiber optic sensor demodulators (including high-end products from companies like LUNA) does not exceed 5-10 kHz. Limited by this rate, the change of wavelength over time is essentially a quasi-static process in engineering, and the time dimension serves only as an index label for wavelength measurement results, rather than being further refined or manipulated as an independent signal dimension.

[0036] It is precisely because of the aforementioned rate ceiling of tens of Hz to several kHz that those skilled in the art have formed and solidified the following technical biases through long-term practice:

[0037] Spectral measurements must be resolved in the wavelength domain; time is merely a carrier of the spectrum, and manipulation of the time axis will not change the measurement sensitivity.

[0038] The wavelength scanning rate should be kept constant to ensure the accuracy and repeatability of wavelength calibration; variable speed scanning is considered to introduce distortion and is an error source that needs to be calibrated and eliminated.

[0039] The sensitivity of a sensor is determined by its physical structure (such as grating reflectivity, interference cavity length, etc.), and there is no need to actively adjust the sensitivity at the demodulation end.

[0040] The aforementioned technical biases have prevented existing technologies from overcoming the following technical bottlenecks: measurement sensitivity is fixed and cannot be adjusted; multi-point distributed sensor networks cannot achieve differentiated sensitivity configurations; and the ability to detect weak signals is limited by the intrinsic response of the sensor and cannot be enhanced through system-level adjustments.

[0041] It is evident that existing technologies, limited by the physical bottleneck of equipment speed, have long been subject to an industry-wide technical bias that the time dimension cannot be used for sensitivity control. This has led to a lack of motivation for those skilled in the art to consider the technical path of controlling measurement sensitivity by designing wavelength-time mapping trajectories. This application breaks this bias by elevating the time dimension from a passive auxiliary coordinate to an active control resource, thereby realizing a system-side programmable design for fiber optic sensing measurement gain.

[0042] Specifically, this application employs pulsed high-current drive combined with fine current waveform modulation within ultrashort pulses to complete a full wavelength scan within a time window of hundreds of nanoseconds (ns), achieving an ultra-high equivalent scan rate on the order of 2 MHz. At this rate, the time resolution is improved by several orders of magnitude, and the wavelength change exhibits a finely controllable transient evolution process on the time axis. Based on this, this application proposes for the first time a time-domain magnification factor... As a core design variable, by actively reducing the local scan rate (rather than eliminating distortion) within a specific time interval, the same sensor wavelength change produces an amplified time response shift on the time axis, thereby achieving programmable active configuration and differentiated control of measurement sensitivity without changing the intrinsic structure of the sensor.

[0043] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0044] This application provides a time-domain sensitivity-adjustable fiber optic sensing method based on dynamic wavelength-time mapping, such as... Figure 1 The diagram illustrates a flowchart of a time-domain sensitivity-tuned fiber optic sensing method based on dynamic wavelength-time mapping, as shown in this application. The method includes at least the following steps S1 to S6:

[0045] Step S1: Set the corresponding measurement target parameters according to the type of physical quantity being measured, the measurement accuracy requirements, the target detection area, and the response speed requirements.

[0046] The types of physical quantities being measured include temperature, strain, pressure, vibration, refractive index, or gas concentration. When the fiber optic sensing unit contains multiple sensors or a sensor network, independent measurement target parameters are set for each sensing channel or each measuring point, including different accuracy requirements and different response speed requirements for different measuring points. For example, in a multi-point sensing network, the first measuring point is set to a high-precision mode (strain accuracy ±1με), the second measuring point is set to a conventional monitoring mode (strain accuracy ±10με), and the third measuring point is set to a high-speed dynamic mode (response speed ≥10kHz).

[0047] Step S2: Design a time-domain sensitivity window based on the measurement target parameters. The time-domain sensitivity window is a time-domain control unit used to limit the sensitivity enhancement range within a local time interval during wavelength scanning. The time-domain sensitivity window includes at least one or more of the following parameters: window position parameter, window width parameter, window gain parameter, and window number parameter.

[0048] When sensitivity enhancement is required for a single specific wavelength range, a single time-domain sensitivity window can be designed:

[0049] The window position parameter is set to the time domain position corresponding to the target sensor reflection peak. For example, when the sensor reflection peak is expected to appear at the 50μs of the scanning cycle during wavelength scanning, the window position is set to the interval between the 48μs and 52μs.

[0050] The window width parameter is set to 4μs for example, which corresponds to the mapping width of the 3dB bandwidth of the target sensor's reflectance spectrum on the time axis.

[0051] An example setting of the window gain parameter is 10x, which corresponds to a reduction in the wavelength scan rate to 1 / 10 of the normal scan rate within that time region.

[0052] The number of windows parameter is set to 1.

[0053] In some embodiments, the time-domain sensitivity window further includes a window shape parameter, wherein the window shape can be set to one of Gaussian, plateau, spike, or any continuous distribution form.

[0054] For example, when the measured signal is a continuously changing physical quantity (such as a slowly changing temperature), a plateau-shaped window is used to ensure uniform sensitivity within the window's coverage area, facilitating accurate signal amplitude calculation. When the measured signal is a weak peak-type signal (such as weak vibration), a Gaussian or peak-shaped window is used to maximize sensitivity in the central region of the window, suitable for peak detection. When the window shape is Gaussian, the window gain parameter can further include peak gain and full width at half maximum (FWHM) parameters.

[0055] Step S3: Based on the parameters of the time-domain sensitivity window, by configuring the wavelength evolution rate corresponding to different time regions, a dynamic wavelength time mapping trajectory is designed to form a non-uniform mapping relationship between the output wavelength of the light source and time.

[0056] This step generates a preset driving current waveform using a programmable signal source (such as an arbitrary waveform generator, AWG). The timing structure of this driving current waveform corresponds to the time-domain sensitivity window parameters. The design time resolution of the dynamic wavelength time mapping trajectory reaches the nanosecond to microsecond level. Preferably, the transient wavelength evolution process of the light source is precisely controlled by a high-speed programmable driving signal (such as an arbitrary waveform generator with a sampling rate ≥ 2.5 GS / s) to achieve a high-resolution configuration with a time-domain sensitivity window position accuracy better than 100 ns and a width accuracy better than 200 ns. The dynamic wavelength time mapping relationship is implemented using any one or a combination of piecewise linear functions, polynomial functions, exponential functions, trigonometric functions, and spline functions.

[0057] Within the normal time range, the driving current changes linearly with time, causing the output wavelength of the light source to change at a constant rate, i.e., dλ / dt = constant. However, within the time range corresponding to the time-domain sensitivity window in the embodiment of the application, the rate of change of the driving current with time decreases, causing the rate of change of the output wavelength of the light source to decrease from a first rate to a second rate. For example, if the normal scan rate is set to 0.01 nm / μs, the scan rate within the window range is reduced to 0.001 nm / μs (corresponding to a 10-fold gain). The position and width of the window range after the scan rate reduction correspond to the window position and window width designed in step S2.

[0058] When designing multiple time-domain sensitivity windows, this step involves designing dynamic wavelength time-mapping trajectories across multiple low scan rate regions. Specifically, multiple locally slope-reducing segments are set on the drive current waveform, with the position, width, and slope change amplitude of each segment corresponding one-to-one with the position, width, and gain parameters of each window. The slope change amplitudes of each segment can be the same or different to achieve differentiated gain configurations for different measurement points.

[0059] Step S4: Generate a corresponding driving signal based on the dynamic wavelength time mapping trajectory, and drive the light source to output a dynamic wavelength scanning light wave that follows the dynamic wavelength time mapping trajectory.

[0060] Step S5: Inject dynamic wavelength scanning light waves into the fiber optic sensing unit, and acquire corresponding time-domain observations through the photoelectric detection unit and signal acquisition unit.

[0061] Step S6: Based on the dynamic wavelength-time mapping relationship, the acquired time-domain observations are analyzed to complete the calculation of the measured physical quantity, and the parameters of the time-domain sensitivity window and the dynamic wavelength-time mapping trajectory are optimized based on the calculation results.

[0062] The feedback optimization in this embodiment includes one or more of the following adjustment methods:

[0063] Window position adjustment: When the change of the measured physical quantity obtained by the solution exceeds the expected range, indicating that there is a deviation between the window position and the actual time domain position of the target reflection peak, the window position parameter is corrected according to the actual peak arrival time offset, so that the window center is aligned with the actual signal position.

[0064] Window width adjustment: When the signal-to-noise ratio of the detected signal is lower than the preset threshold, the window width is increased to provide sensitivity enhancement over a wider time range and improve the signal acquisition probability; when the system response speed needs to be improved, the window width is appropriately reduced to reduce the time overhead of the sensitivity enhancement area.

[0065] Window gain adjustment: When the signal amplitude is weak and needs to be further amplified, increase the window gain parameter (i.e., further reduce the local scan rate) to enhance the time domain amplification effect; when the signal amplitude is too large and close to the upper limit of the acquisition unit range, decrease the window gain parameter.

[0066] Window number adjustment: When an unforeseen weak signal feature is detected in a non-window region, a new time-domain sensitivity window is added to cover the signal.

[0067] Dynamic wavelength time mapping trajectory adjustment: Based on the overall distribution of real-time measurement results, the global shape of the trajectory is fine-tuned to optimize the time allocation and sensitivity configuration of each region.

[0068] In this embodiment, feedback optimization is performed continuously in an iterative manner. During system operation, after each measurement, the window parameters and mapping trajectory are updated based on the solution results, so that the time-domain sensitivity distribution automatically adapts to the dynamic changes and long-term drift of the measured physical quantity, achieving adaptive control.

[0069] It is worth noting that the dynamic wavelength time mapping trajectory in this embodiment is a designable evolution trajectory of the output wavelength of the light source with respect to time, and its corresponding local wavelength evolution rate can be independently configured in different time regions; the time domain sensitivity window includes the time region in the dynamic wavelength time mapping trajectory where the local wavelength evolution rate is reduced, which is used to form a time domain amplification effect in the time region.

[0070] The schematic diagram of the programmable dynamic wavelength time mapping trajectory in this embodiment is shown below. Figure 2 (a)- Figure 2 As shown in (d). Figure 2 (a)- Figure 2 The upper part of (d) shows the curve of the output wavelength (λ) of the light source changing with time (t), and the lower part shows the corresponding wavelength change rate (dλ / dt) changing with time. By programmably designing the wavelength-time mapping trajectory, different forms of time-domain sensitivity enhancement regions can be formed on the time axis, thereby realizing the construction and control of the time-domain magnification window. Figure 2 (a)- Figure 2 (d) lists four typical dynamic wavelength time mapping methods.

[0071] (a) Conventional linear scan.

[0072] Figure 2 (a) presents the traditional linear wavelength scanning method. In this method, the wavelength changes approximately linearly with time, and the wavelength change rate (dλ / dt) remains constant, thus there is a fixed mapping relationship between time and wavelength. For the same wavelength change Δλ, the corresponding time change Δt remains constant, without producing a local time-domain amplification effect or forming a local sensitivity enhancement region.

[0073] (b) Single sensitivity window.

[0074] Figure 2 (b) illustrates a single local low scan rate window structure. While maintaining a monotonic change in the overall wavelength, the wavelength change rate is reduced within a predetermined time interval, decreasing (|dλ / dt|) in the local region. Since the mapping ratio of time to wavelength (dt / dλ) increases accordingly, the same wavelength change corresponds to a larger change in time response within this time interval, thus forming a single time-domain magnification window and a single local sensitivity enhancement region.

[0075] (c) Double low scan rate window.

[0076] Figure 2 (c) shows the dynamic wavelength time-mapping trajectory with two local low scan rate regions. By setting multiple local wavelength variation mitigation regions at different time positions, multiple independent time-domain magnification windows can be formed on the time axis. Each window can correspond to different measurement targets, different sensing channels, or different regions of interest, thereby achieving multi-region sensitivity enhancement.

[0077] (d) Programmable sensitivity window distribution.

[0078] Figure 2 (d) illustrates the multi-window dynamic wavelength-time mapping trajectory. By finely designing the wavelength-time mapping trajectory, multiple independent control windows can be formed during a single scan. The position, width, number, and enhancement level of each window can be configured independently, thereby constructing a programmable time-domain sensitivity distribution and realizing differentiated measurement gain configuration and adaptive detection capability.

[0079] In practical applications, the dynamic wavelength-time mapping relationship can be implemented using any programmable function, including piecewise linear functions, polynomial functions, exponential functions, trigonometric functions, spline functions, or combinations thereof. It can also be generated through digital control circuits, analog circuits, or a combination of hardware and software.

[0080] The core of dynamic wavelength time mapping lies in adjusting the wavelength change rate. Changing the time-to-wavelength mapping ratio This allows for the construction of a time-domain magnification window with adjustable position, width, number, and enhancement level on the time axis, and further enables the active design and dynamic control of measurement sensitivity.

[0081] The schematic diagram of the mechanism of the time-domain amplification effect generated by the dynamic wavelength time mapping in the embodiments of this application is shown below. Figure 3 As shown. Figure 3 Taking conventional linear wavelength time mapping and dynamic wavelength time mapping as examples, this paper illustrates the differences in time response corresponding to the same wavelength change under different mapping trajectories.

[0082] Under conventional linear scanning conditions, the wavelength λ and time t approximately satisfy a linear relationship, and the wavelength change rate (dλ / dt) remains constant. Therefore, the mapping ratio between time and wavelength remains essentially unchanged. For the same wavelength change Δλ, the corresponding time change Δt is a fixed value.

[0083] In this embodiment, by designing the dynamic wavelength time mapping trajectory, a local wavelength change mitigation region is constructed within a predetermined time interval, such as... Figure 3The shaded area is shown in the figure. Within this region, the rate of wavelength change, dλ / dt, decreases, causing a change in the mapping ratio between time and wavelength.

[0084] To describe this mapping enhancement effect, this embodiment defines a time-domain magnification factor. :

[0085] (1)

[0086] in, The time-domain amplification factor is configured by adjusting the local wavelength evolution rate, thereby achieving active configuration of the time-domain amplification factor and forming a time-domain sensitivity window distribution in the form of a single window, a double window, or a multi-window on the time axis. For time, The instantaneous output wavelength of the light source; This is the wavelength-time mapped gain.

[0087] Accordingly, for the wavelength change The corresponding time response change It can be represented as:

[0088] (2)

[0089] From the above relationship, it can be seen that when the rate of change of local wavelength decreases, the time-domain amplification factor... Increase, therefore the same amount of wavelength change This will produce a larger change in time response on the time axis. .exist Figure 3 middle and This represents two different wavelength positions, and the difference between them is... - Under dynamic wavelength-time mapping conditions, the time interval corresponding to the same wavelength difference expands from the reference time position under conventional mapping conditions to a larger time response variation. This results in a time-domain amplification effect. Indicates the reference time position under normal scanning conditions. This indicates the time position corresponding to the use of a low scan rate window.

[0090] This embodiment demonstrates that the core of this application is not to change the wavelength sensitivity of the sensor itself, but rather to alter the scale of the spectral response on the time axis by adjusting the dynamic wavelength time mapping trajectory, thereby transforming the originally fixed spectral changes into designable and controllable time-domain response changes. This time-domain amplification mechanism constitutes the theoretical basis for time-domain sensitivity control and provides a physical basis for subsequently constructing time-domain sensitivity windows with adjustable position, width, and peak value.

[0091] In practical applications, the position parameter of the time-domain sensitivity window defines the time axis point corresponding to sensitivity adjustment. The width parameter of the time-domain sensitivity window defines the range of sensitivity adjustment coverage on the time axis. The peak value parameter of the time-domain sensitivity window defines the maximum gain value of sensitivity adjustment. The number parameter of the time-domain sensitivity window sets one or more sensitivity adjustment intervals. The shape parameter of the time-domain sensitivity window allows the sensitivity distribution to be set to any continuous distribution form, such as Gaussian, plateau, or spike.

[0092] In some embodiments, a low scan rate region is constructed within a preset time interval of wavelength scanning, wherein the slope of wavelength-time change in the low scan rate region is less than the slope of change in conventional linear scanning; by adjusting the wavelength scan rate The magnitude of the value changes the mapping ratio between wavelength and time. To establish a variable wavelength-time correspondence; for the same fixed wavelength variation By reducing the local scan rate Increase the wavelength change Corresponding time change The low scan rate region is implemented by any one or more combinations of a single local slope reduction form, a scan rate approaching zero form, a scan direction switching form, or a multi-region rate combination form.

[0093] When the local scan rate When the mapping ratio decreases, Increase, therefore for the same amount of wavelength change This allows for a larger change in time response. This means that the sensor response observed on the time axis is amplified, thereby improving measurement resolution and sensitivity.

[0094] By constructing a low scan rate region within a predetermined time interval, the rate of wavelength change over time is significantly reduced within this region, such as... Figure 3 The shaded area is shown in the image. As the scan rate decreases, the mapping ratio of wavelength to time changes, resulting in a larger time shift corresponding to a unit change in wavelength. The mathematical relationship can be expressed as:

[0095] (3)

[0096] In some embodiments, a time-domain sensitivity calculation parameter system is constructed based on the established dynamic wavelength-time mapping relationship. The inherent intrinsic wavelength sensitivity parameters of the sensor are coupled with the time amplification factor parameters generated by the dynamic mapping. By adjusting the driving waveform of the dynamic wavelength-tuned light source, the real-time value of the scanning rate is continuously adjusted to match the time amplification factor at different times. Based on the variable scanning rate, non-uniformly distributed time-domain sensitivity parameters are set on the time axis, and the window position, window width, window gain, number of windows, and window shape parameters of the time-domain sensitivity window are configured independently or jointly. Within the time interval corresponding to the time-domain sensitivity window, a locally reduced or zeroed scanning rate is configured. The scanning rate parameters outside the window are configured as conventional linear scanning rate parameters. The local zeroed scanning rate configuration is achieved by changing the direction of wavelength scanning. The time-domain sensitivity can be expressed as the rate of change of the time response corresponding to the measured physical quantity X.

[0097] (4)

[0098] in, Indicates the intrinsic wavelength sensitivity of the sensor. This represents the time amplification factor determined by the dynamic wavelength time mapping. Since different time positions correspond to different scan rates, It can change continuously over time, thus allowing the time-domain sensitivity to form a designable distribution structure on the time axis.

[0099] By adjusting the driving waveform of the dynamically tuned light source, the following parameters of the time-domain sensitivity window can be controlled independently or in combination:

[0100] 1. Window position: determines the timing and location of the sensitivity enhancement;

[0101] 2. Window width: Determines the coverage area of ​​the enhanced region on the timeline;

[0102] 3. Window gain: determines the maximum sensitivity enhancement factor;

[0103] 4. Number of windows: Allows for the creation of single or multiple sensitivity enhancement regions;

[0104] 5. Window shape: can be Gaussian, plateau, spike, or other continuous distribution forms.

[0105] As a preferred embodiment, the time axis points corresponding to sensitivity adjustment are limited by configuring the position parameters of the time domain sensitivity window.

[0106] By modifying the timing nodes of the modulation waveform output by the programmable signal source, the corresponding point on the time axis is limited to the time domain sensitivity window, so that the sensitivity control area is aligned with the time domain interval corresponding to the measured spectral change, thus completing the fixed-point locking of the target monitoring period.

[0107] As a preferred embodiment, the range of sensitivity adjustment on the time axis is limited by configuring the width parameter of the time domain sensitivity window.

[0108] By adjusting the duration of the low scan rate segment on the modulation waveform, the range of sensitivity control on the time axis is limited, and the time domain span corresponding to the window is shortened or extended as needed to adapt to the time domain distribution range corresponding to the spectral bandwidth of the measured physical quantity. Preferably, in this embodiment, the maximum gain value of sensitivity control is limited by configuring the peak parameter of the time domain sensitivity window.

[0109] By changing the decrease in wavelength scanning rate within the corresponding time period of the window, the maximum gain value of sensitivity adjustment is limited. The lower the scanning rate, the greater the corresponding window gain, thus achieving quantitative setting of the maximum sensitivity index of the window.

[0110] As a preferred embodiment, the number of time-domain sensitivity windows is configured to set one or more sensitivity control ranges.

[0111] Within a single modulated waveform, one or more mutually separated low scan rate sections are set, and correspondingly, one or more independent sensitivity control intervals are set to meet the requirements for synchronous partitioned sensitivity control of multi-point spectral signals.

[0112] As a preferred embodiment, the sensitivity distribution can be set to any continuous distribution form such as Gaussian, plateau, or spike by configuring the shape parameter of the time-domain sensitivity window.

[0113] Edit the rate change curve of the modulation waveform according to the preset distribution rules, and set the sensitivity distribution shape corresponding to the window to any continuous distribution form such as Gaussian, plateau, or spike. Gaussian corresponds to a smooth and gradual change in scanning rate, plateau corresponds to a constant low value of scanning rate within the interval, and spike corresponds to a rate change pattern of rapid rate drop in short period and rapid recovery in other periods.

[0114] In a preferred embodiment, in step S4, a corresponding driving signal is generated based on the dynamic wavelength time-mapping trajectory designed in step S3, and then loaded onto the dynamic wavelength time-mapping light source to achieve the output of a predetermined wavelength scanning trajectory. For example, the light source can be a tunable semiconductor laser, which can be any one of a distributed feedback laser, a vertical-cavity surface-emitting laser, or a Fabry-Perot laser, with a working wavelength range of 0.8 μm to 2 μm.

[0115] In this embodiment, a temperature control structure is provided simultaneously. An external constant temperature platform or thermoelectric cooler is used in conjunction with a thermistor and a PID controller to form a temperature control loop, thereby implementing constant temperature control of the semiconductor laser and stabilizing the laser output wavelength.

[0116] In a preferred embodiment, step S2 involves designing time-domain sensitivity window parameters based on the target measurement requirements. These window parameters include: window position; window width; window gain; number of windows; and window distribution. These parameters can be configured independently or in combination.

[0117] In a preferred embodiment, step S3 involves establishing a dynamic wavelength time-mapping trajectory based on the time-domain sensitivity window parameters. By adjusting the local wavelength change rate, trajectory shape, duration, and mapping distribution corresponding to the dynamic wavelength time-mapping trajectory, the target time-domain amplification factor is constructed. The dynamic wavelength time-mapping trajectory can correspond to a single-window, dual-window, or multi-window time-domain amplification structure.

[0118] In a preferred embodiment, in step S6, the time-domain sensitivity window parameters are optimized based on the time-domain observations and the calculated results of the measured parameters obtained in step S5. The optimization includes: window position adjustment; window width adjustment; window gain adjustment; window number adjustment; and dynamic wavelength time mapping trajectory adjustment. Iterative optimization improves measurement accuracy, dynamic range, or local measurement capability. This embodiment also provides a method for constructing and controlling a time-domain magnification window, illustrating how the present invention forms an adjustable time-domain magnification distribution structure on the time axis through dynamic wavelength time mapping trajectory design.

[0119] The schematic diagram of the programmable time-domain magnification window distribution in this embodiment is shown below. Figure 4 As shown in the figure. The horizontal axis represents time (t), and the vertical axis represents the time-domain magnification factor. The dashed line in the figure represents the mapping relationship under conventional linear scanning conditions, where the wavelength change rate remains essentially constant. It is approximately a constant. The solid line represents the time-domain magnification window constructed using the dynamic wavelength-time mapping of this invention.

[0120] In this embodiment, a single-window, dual-window, or multi-window amplification structure can be formed on the time axis by adjusting the dynamic wavelength time mapping trajectory. Each amplification window corresponds to a different time-domain amplification region, and its position, width, gain, and number can all be configured independently. Specifically:

[0121] Window position: Used to determine the time interval during which the time-domain magnification occurs;

[0122] Window width: Used to determine the time range covered by the time-domain magnification effect;

[0123] Window gain: Used to determine the degree of time-domain magnification for the corresponding region;

[0124] Number of windows: Used to construct one or more independent magnified regions;

[0125] Window shape: used to describe the distribution of the time-domain magnification factor.

[0126] By independently or jointly adjusting the above parameters, a time-domain magnification window distribution structure suitable for different measurement needs can be formed.

[0127] When the time-domain magnification window and the sensor's intrinsic wavelength sensitivity work together, a designable time-domain sensitivity distribution can be further formed, enabling active configuration and dynamic control of measurement sensitivity.

[0128] The time-domain sensitivity-adjustable fiber optic sensing method based on dynamic wavelength-time mapping in this application embodiment is applicable to the following system, which specifically includes:

[0129] Dynamic wavelength time mapping construction unit: used to generate a predetermined dynamic wavelength time mapping trajectory and generate the corresponding driving signal.

[0130] The building unit includes: an arbitrary waveform generator or other programmable signal source; a constant current source or DC bias power supply; a bias combining unit for superimposing the DC bias with the AC modulation signal; a dynamic wavelength tuned light source; and a temperature stabilization control unit.

[0131] The bias combining unit can be a bias tee, an RF biaser, an analog adder circuit, or other driving structures capable of superimposing DC and modulated signals; the frequency range of the modulated signal can be from 0.01Hz to 6GHz, but is not limited thereto; the dynamic wavelength tuned light source can be a DFB laser, a VCSEL laser, an FP laser, or other tunable semiconductor laser, with its center wavelength located in the 0.8μm to 2μm band; the temperature stability control can be achieved through an external constant temperature platform, or through a thermoelectric cooler, a thermistor, and PID control.

[0132] Fiber optic sensing measurement unit: used to convert the measured physical quantity into a spectral response change. Fiber Bragg gratings and their extended forms (long-period fiber gratings, tilted fiber gratings, chirped gratings, etc.); interferometric sensors (Fabry-Perot, Mach-Zehnder, and Michelson types, etc.); and other fiber optic sensors capable of generating changes in reflection, transmission, or interference spectra. The fiber optic sensing unit can employ a single-point structure or a multi-point sensing network.

[0133] Time-domain observation acquisition unit: used to acquire the time-domain response signal under dynamic wavelength time mapping conditions. It includes: an optical path coupling structure, a photodetector, a signal acquisition device, and a data preprocessing module. The optical path coupling structure can be an optical fiber coupler, an optical circulator, or other equivalent optical path structures; a reflection unit or independent triggering channel can be provided for synchronous triggering and power monitoring; the reflection unit can be a mirror with a reflectivity greater than 4%; a delay fiber can be provided to construct a single-point or multi-point time-division multiplexing system; the bandwidth of the photodetector needs to be greater than the bandwidth of the modulation waveform of the dynamically wavelength tuned light source, for example, greater than 10 GHz.

[0134] The signal acquisition unit is connected to the photoelectric detection unit and is used for high-speed sampling, storage, and preprocessing of the time-domain signal. The signal acquisition unit can be a digital oscilloscope, a high-speed data acquisition card, or other equivalent device. The data preprocessing module can be implemented by a hardware FPGA, or the host computer software can set a signal-to-noise ratio optimization algorithm to perform signal quality processing according to actual needs. The optimization algorithm can be, for example, cumulative averaging.

[0135] The time-domain sensitivity control unit is used to construct a time-domain sensitivity window based on the dynamic wavelength-time mapping relationship. It includes: a time-domain amplification factor calculation module; a window parameter configuration module; a time-domain observation analysis module; and a sensitivity control module. It can be programmed and controlled using LabVIEW software.

[0136] Feedback optimization unit: Used to dynamically optimize window parameters based on real-time measurement results. Includes: window position adjustment module; window width adjustment module; window gain adjustment module; and mapping trajectory optimization module.

[0137] like Figure 5 As shown, the system that can be used to implement the time-domain sensitivity control fiber optic sensing method based on dynamic wavelength time mapping in this application embodiment includes an arbitrary waveform generator 1, a constant current source 2, a bias combining unit 3, a temperature controller 4, a dynamic wavelength time mapping light source 5, a coupler 6, a reflection unit 7, a delay fiber 8, a fiber optic sensing unit 9, a photodetector 10, a signal acquisition unit 11, a time-domain observation extraction unit 12, and a time-domain amplification window construction and control unit 13.

[0138] Specifically, the arbitrary waveform generator 1 is used to generate a preset dynamic modulation signal. The arbitrary waveform generator needs to have nanosecond-level time resolution or GHz-level bandwidth to construct a dynamic wavelength time mapping trajectory. The modulation signal can be a linear waveform, a waveform with a local low scan rate, a waveform containing changes in scan direction, a multi-window waveform, or any combination thereof. The constant current source 2 is used to provide the DC bias current required for the operation of the semiconductor laser 5.

[0139] The bias combining unit 3 is used to superimpose the modulation signal output from the arbitrary waveform generator 1 with the DC bias signal output from the constant current source 2, and output the result to the semiconductor laser 5 through the combined output terminal 303. The bias combining unit 3 can employ a bias tee, an RF biaser, an analog adder circuit, or other driving structures capable of combining DC and modulation signals. The bias combining unit 3 must ensure that the analog signal bandwidth matches the waveform generator to ensure that the output signal is not distorted. In this embodiment, the bias tee used can operate in a frequency range of 0.01Hz to 6GHz, with a maximum DC blocking voltage of 50V, a maximum output power of 2W, a maximum input DC current of 2A, and an RF-DC port isolation greater than 30dB. However, the above parameters are only one implementation method and do not constitute a limitation of the present invention.

[0140] The temperature controller 4 is used to maintain the stable operating temperature of the semiconductor laser 5. The temperature control method can employ an external constant temperature platform or a closed-loop temperature control system consisting of a thermoelectric cooler, a thermistor, and a PID controller. The semiconductor laser 5, driven by the bias combining unit 3, performs dynamic wavelength tuning and establishes a predetermined wavelength-time mapping relationship. The semiconductor laser 5 can be a distributed feedback laser, a vertical-cavity surface-emitting laser, a Fabry-Perot laser, or other tunable semiconductor lasers, with a center wavelength ranging from 0.8 μm to 2 μm, including but not limited to the 1310 nm, 1550 nm, and 1650 nm bands.

[0141] The dynamic wavelength time-mapping light source 5 is used to respond to the drive signal output by the bias combining unit 3, outputting a dynamic scanning optical signal that satisfies a predetermined wavelength time-mapping trajectory, and establishing a corresponding dynamic wavelength time-mapping relationship. The dynamic wavelength time-mapping light source 5 can be implemented using a distributed feedback laser (DFB), a vertical-cavity surface-emitting laser (VCSEL), a Fabry-Perot laser (FP), an external cavity tunable laser, or other light sources with dynamic wavelength tuning capabilities. The light source with dynamic wavelength tuning capabilities must be able to follow the ns-level waveform changes under the action of the drive signal, ensuring that the wavelength tuning rate is consistent with the time-mapping relationship. The optical signal output by the dynamic wavelength time-mapping light source 5 is input to the fiber optic sensing unit 9 via a coupler 6. The coupler 6 can be a 2×2 fiber optic coupler, an optical circulator, or other equivalent optical path structure. In this embodiment, one output 601 of the coupler 6 can be connected to the reflection unit 7 as a synchronization trigger, power monitoring, or reference channel, and the other output 602 is connected to the fiber optic sensing unit 9 via a delay fiber 8. The delay fiber 8 can be a common single-mode fiber, and its length can be configured according to the system timing requirements, or it can be omitted. The fiber optic sensing unit 9 can be a single-point sensor or a multi-point sensing network composed of series, parallel, wavelength division multiplexing, or time division multiplexing.

[0142] The reflection unit 7 can be a reflective device such as a mirror, FBG, Faraday mirror, or Fresnel end face. The reflectivity intensity should be such that the reflected signal can be triggered and captured by the acquisition unit, for example, greater than 4%.

[0143] The fiber optic sensing unit 9 may include, but is not limited to, fiber Bragg gratings and their extended forms (including long-period gratings, tilted gratings, chirped gratings, etc.), Fabry-Perot interferometers, Mach-Zehnder interferometers, Michelson interferometers, and other fiber optic sensors capable of generating changes in reflection spectrum, transmission spectrum, or interference spectrum.

[0144] The optical signal output from the fiber optic sensing unit 9 is returned via coupler 6 and then fed into the photodetector 10 through the output terminal 604 of coupler 6. The photodetector 10 converts the optical signal into an electrical signal, and its bandwidth must be higher than the frequency of the dynamic wavelength tuning waveform (e.g., >1 GHz or ≥ the highest frequency of the modulation signal). The converted electrical signal is input to the signal acquisition unit 11 for high-speed sampling and storage. The sampling rate of the signal acquisition unit 11 must satisfy Nyquist's theorem, at least twice the highest frequency of the photoelectric signal, and is recommended to be 5–10 GS / s or higher to ensure accurate capture of the time-domain response. It can be a digital oscilloscope, a high-speed data acquisition card, or other equivalent device.

[0145] The time-domain observation extraction unit 12 is connected to the signal acquisition unit 11 and is used to preprocess the acquired time-domain signal and extract time-domain observations. The time-domain observations include, but are not limited to: peak position; extreme point position; phase characteristics; fringe shift; characteristic time interval; zero-crossing position; and other time-domain characteristic parameters that can characterize spectral changes. The time-domain sensitivity engineering processing unit 12 can be implemented by a computer, host computer software, embedded processor, digital signal processor, or other hardware and software combinations.

[0146] The time-domain amplification window construction and control unit 13 is connected to the time-domain observation extraction unit 12, and is used to construct a time-domain amplification window according to the dynamic wavelength-time mapping relationship, and to configure and control the window parameters. The window parameters include: window position; window width; window gain; number of windows; and window distribution form.

[0147] In this embodiment, the time-domain amplification window construction and control unit 13 can also perform feedback control on the arbitrary waveform generator 1 according to the current measurement results, dynamically adjust the shape, amplitude, duration and local scan rate of the driving waveform, thereby realizing closed-loop optimization of the dynamic wavelength time mapping trajectory and the time-domain amplification window parameters.

[0148] The system structure described in this embodiment is only a typical implementation of the present invention. The dynamic wavelength tuned light source, optical path structure, sensor type, acquisition device, and processing platform can all be implemented using other equivalent technical means. As long as an adjustable time-domain sensitivity window can be constructed through dynamic wavelength time mapping, and the measurement sensitivity can be controlled using this window, it falls within the protection scope of the present invention.

[0149] This invention constructs a dynamic wavelength-time mapping relationship, forming a time-domain sensitivity window with adjustable position, width, and gain on the time axis. This transforms the fixed wavelength sensitivity, originally determined by the sensor structure, into an actively designable time-domain sensitivity distribution, thereby enhancing and optimizing measurement sensitivity without altering the sensor's intrinsic characteristics. This invention is applicable to fiber Bragg gratings, interferometric sensors, special gratings, and single-point or multi-point sensor networks, offering advantages such as simple structure, wide applicability, high flexibility, and convenient engineering implementation.

[0150] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A time-domain sensitivity-tunable fiber optic sensing method based on dynamic wavelength-time mapping, characterized in that, Includes the following steps: Step S1: Set the corresponding measurement target parameters according to the type of physical quantity being measured, the measurement accuracy requirements, the target detection area, and the response speed requirements; Step S2: Design a time-domain sensitivity window based on the measurement target parameters. The time-domain sensitivity window is a time-domain control unit used to limit the sensitivity enhancement range within a local time interval during wavelength scanning. The time-domain sensitivity window includes at least one or more of the following parameters: window position parameter, window width parameter, window gain parameter, and window number parameter. Step S3: Based on the parameters of the time-domain sensitivity window, by configuring the wavelength evolution rate corresponding to different time regions, a dynamic wavelength time mapping trajectory is designed to form a non-uniform mapping relationship between the output wavelength of the light source and time. Step S4: Generate a corresponding driving signal based on the dynamic wavelength time mapping trajectory, and drive the light source to output a dynamic wavelength scanning light wave that follows the dynamic wavelength time mapping trajectory; Step S5: Inject the dynamic wavelength scanning light wave into the fiber optic sensing unit, and acquire the corresponding time-domain observation through the photoelectric detection unit and the signal acquisition unit. Step S6: Based on the dynamic wavelength-time mapping relationship, the acquired time-domain observations are analyzed to complete the calculation of the measured physical quantity, and the parameters of the time-domain sensitivity window and the dynamic wavelength-time mapping trajectory are optimized based on the calculation results. The dynamic wavelength time mapping trajectory is a designable evolution trajectory of the output wavelength of the light source with respect to time, and its corresponding local wavelength evolution rate can be independently configured in different time regions; the time domain sensitivity window includes the time region in the dynamic wavelength time mapping trajectory where the local wavelength evolution rate is reduced, which is used to form a time domain amplification effect in the time region.

2. The method as described in claim 1, characterized in that, The dynamic wavelength time mapping trajectory in step S3 forms a local wavelength evolution slowdown region within a predetermined time interval, and the wavelength time mapping gain of the local wavelength evolution slowdown region satisfies the following constraint: ； in, The time-domain amplification factor is configured by adjusting the local wavelength evolution rate, thus achieving active configuration of the time-domain amplification factor. For time, The instantaneous output wavelength of the light source; This is the wavelength-time mapped gain.

3. The method as described in claim 1, characterized in that, The dynamic wavelength time mapping trajectory is constructed within a timescale of nanoseconds to microseconds, and step S3 includes: The transient wavelength evolution process of the light source is controlled by a high-speed programmable drive signal, so that the local wavelength evolution rate in different time regions can be independently configured on the time scale from nanosecond to microsecond.

4. The method as described in claim 1, characterized in that, The feedback optimization in step S6 includes: adjusting the window position parameter, adjusting the window width parameter, adjusting the window gain parameter, adjusting the number of windows parameter, and adjusting the dynamic wavelength time mapping trajectory.

5. The method as described in claim 1, characterized in that, The light source in step S4 is a tunable semiconductor laser, which can be any one of a distributed feedback laser, a vertical cavity surface-emitting laser, or a Fabry-Perot laser, and the operating wavelength range of the tunable semiconductor laser is 0.8 μm to 2 μm.

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