Low insertion loss wavelength division multiplexer and control method thereof

Abstract

The application discloses a kind of low insertion loss wavelength division multiplexer and its control method, it is related to wavelength division multiplexer relevant technical field, low insertion loss wavelength division multiplexer includes: input port, input port includes multiple input channels, multiple input channels are used to receive multiple wavelength multiplexing optical signal;At least two filter units, at least two filter units are connected gradually, for multiple wavelength multiplexing optical signal input by multiple input channels is gradually filtered, and multiple wavelength step-by-step filtering signal is output;Output port, output port is used to fit multiple wavelength step-by-step filtering signal, and obtain combined beam multiplexing optical signal.It solves the technical problems that exist in the prior art, such as high insertion loss of wavelength division multiplexer, inaccurate optical signal filtering processing, difficulty in adapting to complex and variable optical signal transmission requirements, and low combined beam multiplexing efficiency, achieving the technical effects of reducing optical signal transmission insertion loss, improving optical signal filtering processing accuracy and flexibility, and improving optical communication system reliability.

Description

Technical Field

[0001] This application relates to the technical field of wavelength division multiplexers and related technologies, specifically to a low insertion loss wavelength division multiplexer and its control method. Background Technology

[0002] Wavelength division multiplexing (WDM) is widely used in backbone networks, metropolitan area networks, and many other fields due to its ability to transmit multiple optical signals of different wavelengths simultaneously in a single optical fiber. However, one of the most prominent problems with traditional WDM multiplexers when processing multi-wavelength multiplexed optical signals is high insertion loss. High insertion loss leads to a significant loss of energy during optical signal transmission, which not only limits the transmission distance but also reduces the overall performance and reliability of the optical communication system. In addition, traditional filtering methods are difficult to accurately classify and process multi-wavelength optical signals, failing to meet the diverse requirements of different services for optical signal quality and transmission characteristics. In complex optical communication network environments, the composition and characteristics of multi-wavelength optical signals are complex and variable, making it difficult for traditional WDM multiplexers to adapt flexibly. This results in low signal processing efficiency, inability to achieve efficient multiplexing, and affects the transmission quality of optical signals.

[0003] Therefore, current related technologies suffer from technical problems such as high insertion loss of wavelength division multiplexers, inaccurate optical signal filtering, difficulty in adapting to complex and ever-changing optical signal transmission requirements, and low beam multiplexing efficiency. Summary of the Invention

[0004] This application provides a low insertion loss wavelength division multiplexer and its control method, which solves the technical problems of high insertion loss, inaccurate optical signal filtering, difficulty in adapting to complex and ever-changing optical signal transmission requirements, and low beam multiplexing efficiency in the prior art. It achieves the technical effects of reducing optical signal transmission insertion loss, improving the accuracy and flexibility of optical signal filtering, and improving the reliability of optical communication systems.

[0005] This application provides a low insertion loss wavelength division multiplexer, comprising: an input port including multiple input channels for receiving multi-wavelength multiplexed optical signals; at least two filtering units connected in stages for filtering the multi-wavelength multiplexed optical signals input through the multiple input channels in stages, and outputting multi-wavelength progressively filtered signals; and an output port for fitting the multi-wavelength progressively filtered signals to obtain a bundled multiplexed optical signal.

[0006] In a possible implementation, the low insertion loss wavelength division multiplexer further includes: each of the at least two filtering units includes a plurality of narrowband filters, wherein the plurality of narrowband filters correspond to the plurality of input channels and respectively receive the multiplexed optical signals of the corresponding channels.

[0007] In a possible implementation, the low insertion loss wavelength division multiplexer further includes: if the at least two-stage filtering units include a first-stage filtering unit and a second-stage filtering unit; filtering the multi-wavelength multiplexed optical signals input from the plurality of input channels by the first-stage filtering unit to obtain a multi-wavelength first-stage filtered signal; inputting the multi-wavelength first-stage filtered signal into the second-stage filtering unit for filtering to obtain a multi-wavelength second-stage filtered signal; and outputting the multi-wavelength second-stage filtered signal as a multi-wavelength progressively filtered signal.

[0008] In a possible implementation, the low insertion loss wavelength division multiplexer further includes: the low insertion loss wavelength division multiplexer includes a filter granularity control unit, the filter granularity control unit being connected to the at least two-stage filter units; the filter granularity control unit is used to set at least two filter granularities according to the number of filter stages of the at least two-stage filter units, and to configure the filter parameters of the at least two-stage filter units according to the at least two filter granularities; wherein each filter granularity includes corresponding filter parameters, the filter parameters including bandwidth, passband center wavelength, sideband rejection ratio, and insertion loss threshold.

[0009] In a possible implementation, the low insertion loss wavelength division multiplexer further includes: an insertion loss equalization unit between the at least two filtering units, the insertion loss equalization unit being used to detect the insertion loss index corresponding to the previous filtering unit, the insertion loss index including insertion loss value, bandwidth offset, and center wavelength drift; and performing insertion loss equalization compensation on the filtering parameters of the subsequent filtering unit according to the insertion loss index.

[0010] In a possible implementation, the low insertion loss wavelength division multiplexer further includes: the input terminal of the output port includes a fitting module; the multi-wavelength stepwise filtered signal is fitted according to the fitting module to obtain a bundled multiplexed optical signal, and the bundled multiplexed optical signal is output through the output port.

[0011] In a possible implementation, the low insertion loss wavelength division multiplexer further includes: multiple input channels of the input port are arranged according to a preset wavelength interval, wherein the preset wavelength interval is 100 GHz or 50 GHz.

[0012] This application also provides a control method for a low insertion loss wavelength division multiplexer, comprising: acquiring multi-wavelength multiplexed signals received by multiple input channels according to the input ports of the low insertion loss wavelength division multiplexer; presetting multiple filtering granularities for the multi-stage filtering unit of the low insertion loss wavelength division multiplexer; performing multi-stage filtering on the multi-wavelength multiplexed signals according to the multiple filtering granularities to output multi-wavelength progressively filtered signals; and fitting the multi-wavelength progressively filtered signals according to the output ports of the low insertion loss wavelength division multiplexer to obtain a bundled multiplexed optical signal.

[0013] In a possible implementation, the control method for a low insertion loss wavelength division multiplexer further includes: real-time acquisition of insertion loss indicators of each stage of the multi-stage filtering unit, wherein the insertion loss indicators are obtained by weighting the insertion loss value, bandwidth offset, and center wavelength drift; and activation of the insertion loss equalization unit of the low insertion loss wavelength division multiplexer, wherein the insertion loss equalization unit performs insertion loss compensation on the filtering parameters of the next stage filtering unit according to the insertion loss indicators.

[0014] In a possible implementation, the control method for a low insertion loss wavelength division multiplexer further includes: obtaining the channel spacing of the low insertion loss wavelength division multiplexer; determining the range of each filtering parameter based on the channel spacing of the low insertion loss wavelength division multiplexer, wherein the filtering parameters include bandwidth, passband center wavelength, sideband rejection ratio, and insertion loss threshold; and dividing the range of each filtering parameter according to the number of the multi-stage filtering units to obtain multiple filtering granularities.

[0015] This application proposes a low insertion loss wavelength division multiplexer and its control method. The input port includes multiple input channels for receiving multi-wavelength multiplexed optical signals. At least two stages of filtering units, connected sequentially, are used to filter the multi-wavelength multiplexed optical signals input from the multiple input channels, outputting a multi-wavelength sequentially filtered signal. An output port is used to fit the multi-wavelength sequentially filtered signal to obtain a bundled multiplexed optical signal. This solution addresses the technical problems of high insertion loss, inaccurate optical signal filtering, difficulty in adapting to complex and changing optical signal transmission requirements, and low bundled multiplexing efficiency in existing wavelength division multiplexers. It achieves the technical effects of reducing optical signal transmission insertion loss, improving the accuracy and flexibility of optical signal filtering, and enhancing the reliability of optical communication systems. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments of this disclosure will be briefly described below. Flowcharts are used in this application to illustrate the operations performed by the system according to the embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed precisely in sequence. Instead, various steps can be processed in reverse order or simultaneously as needed. Furthermore, other operations can be added to these processes, or one or more steps can be removed from these processes.

[0017] Figure 1 This is a schematic flowchart of a control method for a low insertion loss wavelength division multiplexer provided in an embodiment of this application. Detailed Implementation

[0018] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application.

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description of this application will be provided in conjunction with the accompanying drawings. The described embodiments should not be considered as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] In the following description, references to "some embodiments" describe a subset of all possible embodiments. However, it is understood that "some embodiments" can be the same or different subsets of all possible embodiments and can be combined with each other without conflict. The terms "first" and "second" are used merely to distinguish similar objects and do not represent a specific ordering of objects. The terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, product, or server that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or modules not explicitly listed or inherent to these processes, products, or devices. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only.

[0021] This application provides a low insertion loss wavelength division multiplexer, which includes: The input port includes multiple input channels for receiving multi-wavelength multiplexed optical signals.

[0022] Preferably, the input port is the signal entry point of the entire low insertion loss wavelength division multiplexer (WDM), used to receive multi-wavelength multiplexed optical signals from an external optical communication network and transmit these signals to subsequent filtering units for processing. Multi-wavelength multiplexed optical signals refer to signals transmitted by combining multiple optical signals of different wavelengths into a single optical fiber using wavelength division multiplexing (WDM) technology. The input port includes multiple input channels, each corresponding to multiple independent optical fiber interfaces (such as LC, SC, and other standard optical fiber connectors). Each channel can individually receive one or more multi-wavelength multiplexed optical signals. For example, if the input port contains four input channels, it can simultaneously receive optical signals transmitted from four optical fibers, each of which may have multiplexed multiple wavelengths. Furthermore, the multiple input channels support simultaneous reception of multiple multi-wavelength signals from different terminal devices (such as routers, switches, and servers), significantly improving the input capacity of the WDM. These signals are then aggregated by the WDM and further processed, such as filtered and combined.

[0023] At least two filtering units are connected in stages to filter the multi-wavelength multiplexed optical signals input from the multiple input channels in stages, and output multi-wavelength filtered signals in stages.

[0024] Preferably, the filtering unit uses optical filtering devices (such as fiber Bragg gratings, thin-film filters, arrayed waveguide gratings, etc.) to selectively separate or screen the input multi-wavelength multiplexed optical signal, allowing specific wavelengths of optical signal to pass through while suppressing other wavelengths. A single filtering stage processes wide-band mixed signals, requiring highly complex filtering devices, which may result in high insertion loss (such as signal reflection / coupling loss) and insufficient wavelength isolation (crosstalk between adjacent wavelength signals). Multi-stage filtering units break down the complex filtering task through staged and granular processing, with each stage focusing on coarse screening or fine tuning of a specific wavelength range, thereby reducing the pressure on single-stage devices and improving overall performance (such as reducing insertion loss and increasing isolation).

[0025] Preferably, two-stage filtering units are connected sequentially to filter multi-wavelength multiplexed optical signals input from multiple input channels. Specifically, the first-stage filtering unit uses wide-passband filtering devices (such as coarse wavelength division multiplexer (CWDM) filters) to perform low-resolution filtering on the input signals, decomposing the mixed signals into several wavelength sub-bands to reduce signal mixing and decrease cumulative insertion loss in multi-stage processing. The second-stage filtering unit uses narrow-passband filtering devices (such as dense wavelength division multiplexer (DWDM) filters or fiber Bragg gratings) to perform high-resolution screening on the wavelength sub-bands, extracting single-wavelength or narrow-band signals. In other words, after the multi-wavelength signals enter from the input port, they first pass through the first-stage filtering unit for coarse separation, outputting several wavelength sub-band signals. The sub-band signals then enter the second-stage filtering unit, where they are further decomposed into single-wavelength or narrow-band signals, ultimately outputting multi-wavelength sequentially filtered signals (such as wavelength sequences after each filtering stage), thereby achieving precise wavelength-level separation and meeting high isolation requirements.

[0026] The output port is used to fit the multi-wavelength stepwise filtered signal to obtain a multiplexed optical signal.

[0027] Preferably, the output port is the signal output hub of the wavelength division multiplexer, used to recombine the discrete wavelength signals or sub-band signals output by the multi-stage filtering units into a single multi-wavelength multiplexed optical signal (i.e., a bundled multiplexed optical signal) through optical devices for transmission in a single optical fiber. The output port is also used to fit the multi-wavelength filtered signals, that is, to calibrate and match the optical parameters of the signals output by the multi-stage filtering to ensure that the signal quality is not compromised during bundle combining. Specifically, this includes power equalization (adjusting the optical power of each wavelength signal to avoid strong signals suppressing weak signals), phase synchronization (compensating for the phase difference generated by different wavelength signals during filtering), and mode matching (ensuring that the spot patterns of each wavelength signal are consistent and reducing mode mismatch loss during bundle combining), finally obtaining the bundled multiplexed optical signal. The key device for bundle combining is the optical coupler / bundler, and common types and working mechanisms are shown in Table 1. Table 1 Optical Coupler / Beam Combiner Data Sheet fused tapered fiber coupler Multiple optical fibers are fused together using a fused taper process, and evanescent field coupling is used to achieve multi-wavelength signal mixing with low insertion loss (<0.5dB). Coarse Wavelength Division Multiplexing (CWDM) systems for low-cost scenarios Arrayed waveguide grating (AWG) By utilizing the phase delay characteristics of waveguide arrays, signals of different wavelengths can be focused onto the same output port, supporting high-density wavelength combining (such as wavelengths above 80). Dense wavelength division multiplexing (DWDM) systems for long-distance transmission Thin-film filter (TFF) combiner Based on the light reflection / transmission characteristics of multilayer dielectric films, beams are combined layer by layer (e.g., first combine λ1+λ2, then combine λ3+the former two). Medium-scale wavelength beam combining, requiring flexible configuration scenarios Furthermore, the low insertion loss wavelength division multiplexer also includes a plurality of narrowband filters in each of the at least two filtering units, wherein the plurality of narrowband filters correspond to the plurality of input channels and respectively receive the multiplexed optical signals of the corresponding channels.

[0028] Preferably, the entire filtering module of the low insertion loss wavelength division multiplexer is composed of multiple levels (such as 2-level, 3-level, etc.) of filtering units connected in series. Each level of filtering unit undertakes different stages of filtering tasks (such as coarse filtering, fine filtering), and achieves fine separation or multiplexing of multi-wavelength signals through step-by-step processing. Each filtering unit integrates a narrowband filter that corresponds one-to-one with the number of input channels. For example, if there are N input channels, then each level of filtering unit has at least N narrowband filters, where N is a positive integer. Narrowband filters are optical devices that only allow optical signals within a specific wavelength range to pass through, and have high selectivity, such as thin-film filters and fiber Bragg gratings. The multi-wavelength multiplexed optical signal transmitted by each input channel will be directly connected to the corresponding numbered narrowband filter, ensuring that the signals of each channel do not interfere with each other during the filtering process and maintaining the independence of the signals.

[0029] Furthermore, the low insertion loss wavelength division multiplexer also includes, if the at least two-stage filtering unit includes a first-stage filtering unit and a second-stage filtering unit; filtering the multi-wavelength multiplexed optical signals input from the multiple input channels according to the first-stage filtering unit to obtain a multi-wavelength first-stage filtered signal, inputting the multi-wavelength first-stage filtered signal into the second-stage filtering unit for filtering to obtain a multi-wavelength second-stage filtered signal; and outputting the multi-wavelength second-stage filtered signal as a multi-wavelength progressively filtered signal.

[0030] Preferably, at least two stages of filtering units (such as a first-stage filtering unit and a second-stage filtering unit) are used to process the multi-wavelength multiplexed optical signal step by step, achieving fine separation or multiplexing of the optical signal. The optical signals transmitted through multiple input channels contain multiple optical carriers of different wavelengths. Specifically, the first-stage filtering unit uses a wide-spectrum or medium-precision narrowband filter to perform preliminary wavelength screening on the input multi-wavelength multiplexed signal, allowing optical signals within the target wavelength range to pass through while filtering out stray light or interference signals deviating from the target wavelength, outputting the main target wavelength in each channel signal, i.e., the multi-wavelength first-stage filtered signal. The second-stage filtering unit uses a narrow-bandwidth, high-selectivity narrowband filter to perform secondary filtering on the multi-wavelength first-stage filtered signal output by the first-stage filtering unit, allowing the target wavelength to pass through while filtering out interference from other wavelengths to the maximum extent, outputting the highly purified target wavelength in each channel signal, i.e., the multi-wavelength second-stage filtered signal, and outputting it as a multi-wavelength progressively filtered signal, which is a pure wavelength signal after two stages of filtering, thereby reducing insertion loss and crosstalk and improving filtering accuracy and reliability.

[0031] Furthermore, the low insertion loss wavelength division multiplexer also includes a filter granularity control unit connected to the at least two filter stages. The filter granularity control unit is used to set at least two filter granularities based on the number of filter stages of the at least two filter stages, and to configure the filter parameters of the at least two filter stages according to the at least two filter granularities. Each filter granularity includes corresponding filter parameters, including bandwidth, passband center wavelength, sideband rejection ratio, and insertion loss threshold.

[0032] Preferably, the filter granularity control unit dynamically adjusts the filtering accuracy (granularity) and parameters by matching the filter unit stages, thereby achieving a balance between the wavelength separation accuracy of the optical signal and transmission loss. Here, filter granularity refers to the filter's precision in selecting optical signal wavelengths. Each filter granularity includes corresponding filter parameters, including bandwidth, passband center wavelength, sideband rejection ratio, and insertion loss threshold. Specifically, bandwidth refers to the wavelength range that the filter allows the optical signal to pass through (e.g., center wavelength ±50GHz). The first stage (coarse granularity) sets a wider bandwidth (e.g., 100GHz) to ensure the complete passage of the target wavelength signal, while the second stage (fine granularity) sets a narrower bandwidth (e.g., 50GHz). (GHz), allowing only the target wavelength and signals within its extremely narrow range to pass through; the passband center wavelength refers to the center wavelength of the filter's passband. The center wavelengths of each stage of the filter must be strictly aligned with the target wavelength to ensure that the signal does not deviate from the target channel during multi-stage filtering; the sideband rejection ratio refers to the filter's ability to suppress wavelengths outside the passband. The larger the value, the better the suppression effect. The first stage has a low sideband rejection ratio (e.g., 20dB), while the second stage has a high sideband rejection ratio (e.g., 35dB); the insertion loss threshold refers to the upper limit of the filter's power loss on the optical signal. The smaller the value, the lower the loss. The first stage allows a higher insertion loss threshold (e.g., 1.5dB), while the second stage sets a lower insertion loss threshold (e.g., 1.0dB).

[0033] Preferably, the filter granularity control unit is directly connected and interacts with at least two levels of filter units (such as the first level and the second level). Based on the preset number of filter levels, it dynamically configures the filter parameters of each filter unit. By setting different granularities (such as coarse granularity for the first level and fine granularity for the second level), it minimizes the insertion loss of each filter level while ensuring wavelength separation accuracy, achieving the dual goals of high-precision filtering and low-loss transmission. The filter granularity control unit is used to set at least two filter granularities based on the number of filter levels of at least two filter units, and configure the filter parameters of at least two filter units according to these two granularities. That is, if there are first and second level filter units (a total of 2 levels), the filter granularity control unit needs to set at least two different filter granularities (such as granularity A and granularity B), corresponding to the filtering requirements of different levels. This allows the first level filter unit to use a coarser granularity (such as a wider bandwidth) to perform preliminary screening of multi-wavelength signals, while the second level filter unit uses a finer granularity (such as a narrower bandwidth) to further refine the filtering of the signal output from the first level, ensuring that the wavelength accuracy meets the transmission requirements.

[0034] Furthermore, the low insertion loss wavelength division multiplexer also includes an insertion loss equalization unit between the at least two filtering units. The insertion loss equalization unit is used to detect the insertion loss index corresponding to the previous filtering unit. The insertion loss index includes insertion loss value, bandwidth offset, and center wavelength drift. The insertion loss equalization unit compensates for the filtering parameters of the subsequent filtering unit based on the insertion loss index.

[0035] Preferably, in a multi-stage filtering module, each stage of filtering introduces a certain insertion loss, which may be accompanied by bandwidth shift or center wavelength drift. This loss can accumulate stage by stage, leading to power attenuation or wavelength misalignment in the final output signal, affecting communication quality. An insertion loss equalization unit is then introduced between two filtering stages to monitor the deviation of the preceding stage in real time and dynamically adjust the parameters of the subsequent stage to achieve error compensation. Specifically, the insertion loss equalization unit first performs real-time detection of the actual performance of the preceding filtering stage to obtain insertion loss indicators, including the insertion loss value (energy loss of the optical signal after passing through the preceding filter) and bandwidth shift (energy loss of the preceding filter). The system detects the deviation between the actual passband width and the design value of the filter and the center wavelength drift (the magnitude of the deviation of the center wavelength of the passband of the preceding filter from the target value). Then, based on the deviation detected by the preceding stage, the insertion loss equalization unit dynamically adjusts the filtering parameters of the subsequent filtering unit to compensate for the error introduced by the preceding stage. This includes insertion loss compensation (reducing the insertion loss threshold of the subsequent filtering unit), bandwidth offset compensation (reducing the bandwidth parameters of the subsequent filtering unit), and center wavelength drift compensation (dynamically adjusting the passband center wavelength of the subsequent filtering unit to shift it in the opposite direction to offset the error of the preceding stage). Finally, the overall high performance is achieved through subsequent stage compensation, balancing cost and performance indicators.

[0036] Furthermore, the low insertion loss wavelength division multiplexer also includes a fitting module at the input of the output port; the fitting module fits the multi-wavelength stepwise filtered signal to obtain a bundled multiplexed optical signal, which is output through the output port.

[0037] Preferably, the fitting module is a signal processing unit integrated at the front end of the output port. It is used to perform waveform fitting and reconstruction on the optical signal after multi-stage filtering to ensure that the signal can still maintain good transmission quality after filtering. Specifically, the input signal is a multiplexed optical signal containing multiple wavelengths. After being processed by at least two stages of filtering units, each wavelength signal may experience waveform distortion (signal edge smoothing, amplitude attenuation, or phase shift), noise introduction (accumulated noise), and inter-wavelength crosstalk (interference caused by adjacent wavelength signals). The fitting module compensates for the waveform distortion caused by filtering through algorithms (such as raised cosine filtering, equalization filtering, etc.) to restore the original shape of the signal; adjusts the power of each wavelength signal to make the amplitude of signals of different wavelengths consistent; reduces noise and improves the signal-to-noise ratio through filtering or digital signal processing (DSP) technology; ensures that the center frequency of each wavelength signal is accurate and avoids wavelength shift caused by filtering; and then recombines the fitted multi-wavelength signal into a multiplexed optical signal for transmission in a single optical fiber.

[0038] Furthermore, the low insertion loss wavelength division multiplexer also includes multiple input channels of the input port arranged according to a preset wavelength interval, wherein the preset wavelength interval is 100 GHz or 50 GHz.

[0039] Preferably, the input port of the low insertion loss wavelength division multiplexer includes multiple independent input channels, which are arranged according to a preset wavelength spacing. The wavelength spacing refers to the difference in the center wavelength of the optical signals carried by adjacent input channels, and the unit is frequency (GHz) or wavelength (nm). The preset wavelength spacing is 100GHz or 50GHz, which represents the standard wavelength spacing commonly used in optical communication and corresponds to different spectrum resource allocation densities. The frequency difference between adjacent wavelengths in the 100GHz spacing is 100GHz, which corresponds to a wavelength spacing of approximately 0.8nm; the frequency difference between adjacent wavelengths in the 50GHz spacing is 50GHz, which corresponds to a wavelength spacing of approximately 0.4nm, resulting in higher spectrum utilization.

[0040] This application also provides a control method for a low insertion loss wavelength division multiplexer, such as... Figure 1 As shown, the method includes: Step S100: Obtain multi-wavelength multiplexed signals received from multiple input channels according to the input ports of the low insertion loss wavelength division multiplexer; Step S200: Preset multiple filtering granularities for the multi-stage filtering unit of the low insertion loss wavelength division multiplexer, and perform multi-stage filtering on the multi-wavelength multiplexed signals according to the multiple filtering granularities to output multi-wavelength step-by-step filtered signals; Step S300: Fit the multi-wavelength step-by-step filtered signals according to the output ports of the low insertion loss wavelength division multiplexer to obtain a bundled multiplexed optical signal.

[0041] Preferably, multiple input channels of the low insertion loss wavelength division multiplexer (WDM) receive multiple multi-wavelength multiplexed optical signals through optical couplers or optical splitters, ensuring that the multi-wavelength signals enter the WDM intact and without distortion. Based on the number of filtering stages, multiple filtering granularities are preset for the multi-stage filtering units of the low insertion loss WDM. Then, the multi-wavelength multiplexed signals are filtered in multiple stages according to these granularities. Specifically, the multi-wavelength signals from each input channel enter the corresponding first-stage filtering unit. The filter, with coarse-grained parameters, allows the target wavelength group to pass through, filters out obviously non-target wavelengths, and outputs a multi-wavelength first-stage filtered signal. Next, the sub-band signals output from the first stage enter the second-stage filtering unit, corresponding to a fine-grained filter. The filter further filters according to fine-grained parameters, allowing only single wavelengths to pass through, and outputs a multi-wavelength progressively filtered signal. Finally, the multi-wavelength progressively filtered signal is fitted according to the output port of the low insertion loss WDM, including power equalization, waveform reconstruction, and phase synchronization, ultimately outputting a bundled multiplexed optical signal while ensuring low insertion loss, high precision, and flexibility.

[0042] Furthermore, a control method for a low insertion loss wavelength division multiplexer also includes: real-time acquisition of insertion loss indicators of each stage of the multi-stage filtering unit, wherein the insertion loss indicators are obtained by weighting the insertion loss value, bandwidth offset, and center wavelength drift; and activation of the insertion loss equalization unit of the low insertion loss wavelength division multiplexer, wherein the insertion loss equalization unit performs insertion loss compensation on the filtering parameters of the next stage filtering unit according to the insertion loss indicators.

[0043] Preferably, the insertion loss, bandwidth offset, and center wavelength drift of each stage of the multi-stage filtering unit are collected in real time. Then, according to different application scenarios (e.g., high-speed transmission is more sensitive to center wavelength drift, while bandwidth offset affects channel isolation), different weights are assigned to the three indicators (e.g., 50% for insertion loss, 30% for bandwidth offset, and 20% for center wavelength drift), and then they are weighted and calculated to obtain the insertion loss index, so as to facilitate real-time evaluation of the performance degradation of the filtering unit. Then, the insertion loss equalization unit of the low insertion loss wavelength division multiplexer is started, and the filtering parameters of the subsequent stage filtering unit are compensated for insertion loss according to the insertion loss index, as shown in Table 2. Table 2. Correspondence Table of Insertion Loss Indicators and Insertion Loss Compensation The insertion loss value is too high. Increase the gain of the subsequent filtering unit (e.g., through reverse compensation using an adjustable optical attenuator); optimize the steepness of the filter curve to reduce in-band loss. Bandwidth offset Adjust the passband width of the subsequent filtering unit (e.g., by widening or narrowing the bandwidth using an adjustable filter); match the bandwidth after the offset of the previous stage to avoid channel crosstalk. Center wavelength drift Fine-tune the center wavelength of the subsequent filter unit (e.g., through temperature control or voltage tuning); align the center wavelengths of the passbands of the preceding and following stages to ensure smooth signal transmission. Furthermore, a control method for a low insertion loss wavelength division multiplexer also includes: obtaining the channel spacing of the low insertion loss wavelength division multiplexer; determining the range of each filtering parameter based on the channel spacing of the low insertion loss wavelength division multiplexer, wherein the filtering parameters include bandwidth, passband center wavelength, sideband rejection ratio, and insertion loss threshold; and dividing the range of each filtering parameter according to the number of the multi-stage filtering units to obtain multiple filtering granularities.

[0044] Preferably, the channel spacing of the low insertion loss wavelength division multiplexer (WDM) is obtained, which is the difference in center frequencies between adjacent optical channels. Common values ​​are 100 GHz (approximately 0.8 nm) or 50 GHz (approximately 0.4 nm). Based on the channel spacing of the WDM, the range of each filtering parameter (bandwidth, passband center wavelength, sideband rejection ratio, and insertion loss threshold) is determined. For example, the bandwidth usually needs to be less than 50% of the channel spacing (e.g., a 50 GHz spacing corresponds to a bandwidth ≤ 0.2 nm) to avoid crosstalk between adjacent channels; the tolerance is usually required to be within 5% of the channel spacing (e.g., ±0.02 nm) to ensure that the signal is located in the center of the passband; the sideband rejection ratio is inversely proportional to the channel spacing, and the smaller the spacing, the higher the requirement (e.g., 50 GHz spacing ≥ 30 dB, 100 GHz spacing ≥ 25 dB); the insertion loss threshold is not directly related to the channel spacing, but when filtering in multiple stages, the loss of each stage needs to be controlled (e.g., single stage ≤ 0.5 dB) to avoid cumulative exceedance. Finally, within the range of various filtering parameters, different levels of filtering granularity are allocated based on the number of multi-level filtering units. For example, the first level (coarse granularity) has a wider parameter range, which quickly separates the target wavelength group (e.g., bandwidth 0.4nm, sideband suppression ratio 25dB). The second level (fine granularity) has a narrower parameter range, which accurately locates a single wavelength (e.g., bandwidth 0.1nm, sideband suppression ratio 35dB).

[0045] Although this application makes various references to the low insertion loss wavelength division multiplexer according to the embodiments of this application, the various units included therein are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of each functional unit are only for easy distinction between each other and are not intended to limit the scope of protection of this invention.

[0046] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A low insertion loss wavelength division multiplexer, characterized in that, The low insertion loss wavelength division multiplexer includes: An input port, comprising multiple input channels, wherein the multiple input channels are used to receive multi-wavelength multiplexed optical signals; At least two filtering units are connected in stages to filter the multi-wavelength multiplexed optical signals input from the multiple input channels in stages and output multi-wavelength filtered signals in stages. The output port is used to fit the multi-wavelength stepwise filtered signal to obtain a multiplexed optical signal. If the at least two-stage filtering unit includes a first-stage filtering unit and a second-stage filtering unit; The first-stage filtering unit filters the multi-wavelength multiplexed optical signals input from the multiple input channels to obtain a multi-wavelength first-stage filtered signal. The multi-wavelength first-stage filtered signal is then input into the second-stage filtering unit for further filtering to obtain a multi-wavelength second-stage filtered signal. The multi-wavelength second-stage filtered signal is output as a multi-wavelength step-by-step filtered signal. The low insertion loss wavelength division multiplexer includes a filter granularity control unit, which is connected to the at least two-stage filter units. The filter granularity control unit is used to set at least two filter granularities according to the number of filter levels of the at least two filter units, and to configure the filter parameters of the at least two filter units according to the at least two filter granularities. Each filtering granularity includes corresponding filtering parameters, which include bandwidth, passband center wavelength, sideband rejection ratio, and insertion loss threshold.

2. The low insertion loss wavelength division multiplexer as described in claim 1, characterized in that, Each of the at least two-stage filtering units includes multiple narrowband filters, wherein the multiple narrowband filters correspond to the multiple input channels and respectively receive the multiplexed optical signals of the corresponding channels.

3. The low insertion loss wavelength division multiplexer as described in claim 1, characterized in that, An insertion loss equalization unit is provided between the at least two filtering units. The insertion loss equalization unit is used to detect the insertion loss index corresponding to the previous filtering unit. The insertion loss index includes insertion loss value, bandwidth offset, and center wavelength drift. The insertion loss is compensated by equalizing the insertion loss of the filtering parameters of the next-stage filtering unit based on the insertion loss index.

4. The low insertion loss wavelength division multiplexer as described in claim 3, characterized in that, The input terminal of the output port includes a fitting module; The fitting module fits the multi-wavelength stepwise filtered signal to obtain a multiplexed optical signal, which is then output through the output port.

5. The low insertion loss wavelength division multiplexer as described in claim 1, characterized in that, The multiple input channels of the input port are arranged according to a preset wavelength interval, which is 100GHz or 50GHz.

6. A control method for a low insertion loss wavelength division multiplexer, characterized in that, The control method is applied to the low insertion loss wavelength division multiplexer according to any one of claims 1 to 5, and the method includes: Based on the input port of the low insertion loss wavelength division multiplexer, the multi-wavelength multiplexed signal received by multiple input channels is obtained; Multiple filtering granularities are preset for the multi-stage filtering unit of the low insertion loss wavelength division multiplexer. The multi-wavelength multiplexed signal is filtered in multiple stages according to the multiple filtering granularities to output a multi-wavelength filtered signal. The multi-wavelength stepwise filtered signal is fitted to the output port of the low insertion loss wavelength division multiplexer to obtain a bundled multiplexed optical signal.

7. The control method as described in claim 6, characterized in that, The method involves performing multi-level filtering on the multi-wavelength multiplexed signal according to the multiple filtering granularities, including: The insertion loss index of each filtering unit in the multi-stage filtering unit is collected in real time. The insertion loss index is obtained by weighting the insertion loss value, bandwidth offset, and center wavelength drift. The insertion loss equalization unit of the low insertion loss wavelength division multiplexer is activated, and the insertion loss equalization unit compensates for the insertion loss of the filtering parameters of the next stage filtering unit according to the insertion loss index.

8. The control method as described in claim 6, characterized in that, The method for presetting multiple filter granularities for the multi-stage filtering unit of the low insertion loss wavelength division multiplexer includes: Obtain the channel spacing of the low insertion loss wavelength division multiplexer; Based on the channel spacing of the low insertion loss wavelength division multiplexer, the range of each filtering parameter is determined, wherein the filtering parameters include bandwidth, passband center wavelength, sideband rejection ratio and insertion loss threshold; Within the range of each filtering parameter, the filtering is divided according to the number of the multi-level filtering units to obtain multiple filtering granularities.

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