Unidirectional optical fiber transmission system

Abstract

The invention relates to the technical field of optical fiber transmission, and discloses a unidirectional optical fiber transmission system, which comprises a first optical splitter, a second optical splitter, a third optical splitter, a first optical fiber, a second optical fiber, a first filter, a second filter, a first detection module, a second detection module, an optical switching module and a control module, when the first optical splitter receives optical signals and outputs the optical signals to the first optical fiber and the second optical fiber respectively, the control module controls the optical switching module to gate the second optical splitter to receive the optical signals transmitted by the first optical fiber according to detection results of the first detection module and / or the second detection module, or controls the optical switching module to gate the second optical splitter to receive the optical signals transmitted by the second optical fiber. Gating a third optical splitter to receive the optical signal transmitted by the second optical fiber; according to the technical scheme, the misjudgment rate is effectively reduced, and the accuracy and response speed of link switching are improved.

Description

Technical Field

[0001] The present invention relates to the field of optical transmission technology, and in particular to a unidirectional optical fiber transmission system. Background Art

[0002] With the rapid development of communication networks, fiber-optic communication systems have become a mainstream means of information transmission, widely used in scenarios such as metropolitan area networks (MANs), data centers, and long-distance backbone networks. In actual deployments, to ensure optical line stability and service continuity, optical line protection mechanisms are often required. These mechanisms enable timely failover to a backup link in the event of a primary link failure, thereby improving system reliability and interference mitigation. To reduce fiber resource utilization, some solutions attempt to implement primary / backup protection using unidirectional fiber transmission architectures. These architectures employ two fiber paths in a single direction to transmit the same signal, with detection and switching between them. However, these systems still face numerous challenges in determining link status, controlling switchover delays, and mitigating false switchovers. Existing unidirectional fiber transmission solutions often lack efficient monitoring and selection mechanisms, hindering timely identification of fiber link failures or degradation. This results in an inability to quickly switch to a backup path when a link degrades or is interrupted, compromising overall system reliability and transmission quality. Summary of the Invention

[0003] The embodiment of the present invention provides a unidirectional optical fiber transmission system to solve the above technical problems.

[0004] An embodiment of the present invention provides a unidirectional optical fiber transmission system, including a first optical splitter, a second optical splitter, a third optical splitter, a first optical fiber, a second optical fiber, a first filter, a second filter, a first detection module, a second detection module, an optical switching module, and a control module, wherein a first output end of the first optical splitter is connected to one end of the first optical fiber, a second output end of the first optical splitter is connected to one end of the second optical fiber, the other end of the first optical fiber is connected to an input end of the second optical splitter, a first output end of the second optical splitter is connected to the input end of the first filter, a second output end of the second optical splitter is connected to a first switching end of the optical switching module, the other end of the second optical fiber is connected to the input end of the third optical splitter, a first output end of the third optical splitter is connected to the input end of the second filter, a second output end of the third optical splitter is connected to a second switching end of the optical switching module, an output end of the first filter is connected to the input end of the first detection module, and an output end of the second filter is connected to the input end of the second detection module; and the control module is connected to the output end of the first detection module, the output end of the second detection module, and the control end of the optical switching module, respectively. When the first optical splitter receives an optical signal and outputs the optical signals to the first optical fiber and the second optical fiber respectively, the control module controls the optical switching module to enable the second optical splitter to receive the optical signal transmitted by the first optical fiber, or to enable the third optical splitter to receive the optical signal transmitted by the second optical fiber, based on the detection results of the first detection module and / or the second detection module.

[0005] Optionally, when receiving an optical signal, the first optical splitter generates a first optical signal and a second optical signal in the same ratio, and outputs the first optical signal to the first optical fiber, and outputs the second optical signal to the second optical fiber.

[0006] Optionally, the second optical splitter generates a third optical signal and a fourth optical signal according to a preset ratio based on the first optical signal, so as to output the third optical signal to the optical switching module and output the fourth optical signal to the first filter.

[0007] Optionally, the first filter filters the fourth optical signal and outputs a fifth optical signal to the first detection module. The first detection module detects the power of the fifth optical signal and outputs the detection result to the control module. When the detection result of the fifth optical signal is abnormal, the control module controls the optical switching module to select the third optical splitter.

[0008] Optionally, the first filter filters the fourth optical signal according to a wavelength range, so that the fifth optical signal is within a preset wavelength range.

[0009] Optionally, the third optical splitter generates a sixth optical signal and a seventh optical signal according to a preset ratio based on the second optical signal, so as to output the sixth optical signal to the optical switching module and output the seventh optical signal to the second filter.

[0010] Optionally, the second filter filters the seventh optical signal and outputs an eighth optical signal to the second detection module. The second detection module detects the power of the eighth optical signal and outputs the detection result to the control module. When the detection result of the eighth optical signal is abnormal, the control module controls the optical switching module to select the second optical splitter.

[0011] Optionally, the first filter filters the seventh optical signal according to a wavelength range, so that the eighth optical signal is within a preset wavelength range.

[0012] Optionally, the control module is also used to periodically sample and perform sliding average calculation on the power value output by the first detection module to construct a time trend graph of the link signal; when the power value continues to show a downward trend, the control module issues a link degradation warning signal and enters a pre-switching preparation state.

[0013] Optionally, the control module collects the power output value of the first detection module once per second, and calculates the power average using a sliding window of a preset time period; if the power average continuously decreases and is lower than a first threshold, an early warning signal is output; if the power average drops to below a second threshold, the optical switching module is controlled to perform a link switching operation.

[0014] The technical effect of the embodiments of the present invention is that by installing optical splitters, filters, and detection modules on the primary and backup optical fiber paths, and intelligently controlling the optical switching module based on the detection results to achieve link switching, the control module can automatically switch to the backup optical fiber path when the primary optical fiber link fails or the signal quality degrades, ensuring the continuous and stable transmission of the optical signal. This optical fiber transmission system has a simple structure, rapid response, and low resource utilization, significantly improving the reliability of the transmission link and the fault tolerance of the system. It is particularly suitable for scenarios where optical fiber resources are scarce or high reliability is required. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0016] Figure 1 This is a first structural diagram of a unidirectional optical fiber transmission system provided in Example 1 of the present invention; In the figure: 101, first optical splitter; 102, first optical fiber; 103, second optical fiber; 104, first filter; 105, second optical splitter; 106, third optical splitter; 107, second filter; 108, first detection module; 109, optical switching module; 110, second detection module; 111, control module. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0018] It should be understood that the present invention can be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the disclosure thorough and complete and to fully convey the scope of the invention to those skilled in the art. In the drawings, the dimensions and relative dimensions of layers and regions may be exaggerated for clarity. Like reference numerals denote like elements throughout.

[0019] It should be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" another element or layer, it may be directly on, adjacent to, connected to, or coupled to the other element or layer, or there may be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Thus, a first element, component, region, layer, or part discussed below may be represented as a second element, component, region, layer, or part without departing from the teachings of the present invention.

[0020] The purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present invention. When used herein, the singular forms "a", "an", and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0021] In order to fully understand the present invention, detailed structures and steps will be provided in the following description to illustrate the technical solutions proposed by the present invention. Preferred embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may also have other implementations.

[0022] Example 1 This embodiment provides a unidirectional optical fiber transmission system. Figure 1As shown, it includes a first optical splitter 101, a second optical splitter 105, a third optical splitter 106, a first optical fiber 102, a second optical fiber 103, a first filter 104, a second filter 107, a first detection module 108, a second detection module 110, an optical switching module 109 and a control module 111. The first output end of the first optical splitter 101 is connected to one end of the first optical fiber 102, the second output end of the first optical splitter 101 is connected to one end of the second optical fiber 103, the other end of the first optical fiber 102 is connected to the input end of the second optical splitter 105, the first output end of the second optical splitter 105 is connected to the input end of the first filter 104, the second output end of the second optical splitter 105 is connected to the first switching end of the optical switching module 109, the other end of the second optical fiber 103 is connected to the input end of the third optical splitter 106, and the first output end of the third optical splitter 106 is connected to the second filter The first optical filter 104 is connected to the input end of the first detection module 108, the output end of the second filter 107 is connected to the input end of the second detection module 110, and the control module 111 is respectively connected to the output end of the first detection module 108, the output end of the second detection module 110 and the control end of the optical switching module 109; when the first optical splitter 101 receives the optical signal and outputs the optical signal to the first optical fiber 102 and the second optical fiber 103 respectively, the control module 111 controls the optical switching module 109 to select the second optical splitter 105 to receive the optical signal transmitted by the first optical fiber 102, or to select the third optical splitter 106 to receive the optical signal transmitted by the second optical fiber 103 according to the detection result of the first detection module 108 or the second detection module 110.

[0023] The first optical splitter 101 receives an input optical signal and distributes it to two output ports in a preset ratio, outputting it to a first optical fiber 102 and a second optical fiber 103, respectively. This achieves redundant signal distribution and provides a primary and backup path for subsequent links. The first optical fiber 102 and the second optical fiber 103 serve as the primary and backup optical links, respectively, transmitting the optical signal output by the first optical splitter 101 to subsequent processing modules. If the primary link (first optical fiber 102) fails, the backup link (second optical fiber 103) can be switched to. The second optical splitter 105, located after the first optical fiber 102, receives the optical signal transmitted by it and splits it into two. One path is sent to the first filter 104 for signal detection, and the other path is connected to the optical switching module 109 for service use. The third optical splitter 106, located after the second optical fiber 103, performs the same function as the second optical splitter 105. After receiving the optical signal from the second optical fiber 103, one path is sent to the second filter 107 for signal detection, and the other path is connected to the optical switching module 109 for standby use. The first filter 104 and the second filter 107 are used to filter the optical signals output from the second optical splitter 105 and the third optical splitter 106, respectively, to remove signals in non-target bands, thereby improving the accuracy of signal detection. The first detection module 108 and the second detection module 110 respectively receive the output signals of the first filter 104 and the second filter 107, and detect the power, quality, or integrity of the signals, generating detection results and outputting them to the control module 111 for determining the link status. The optical switching module 109 includes at least two input ports and one output port, and is used to selectively connect the outputs of the second optical splitter 105 and the third optical splitter 106; it switches the receiving path according to the control signal of the control module 111 to achieve link switching of the service signal. The control module 111 is the core control unit of the system. It receives the detection results from the first detection module 108 and the second detection module 110, and determines whether the current primary link (the first optical fiber 102) is abnormal based on the detection results. If an abnormality is detected, it controls the optical switching module 109 to switch from the second optical splitter 105 receiving the signal from the first optical fiber 102 to the third optical splitter 106 receiving the signal from the second optical fiber 103, thereby realizing dynamic switching and protection of the optical path.

[0024] The technical effect of this embodiment is that: by respectively setting a splitter, a filter and a detection module on the primary and backup optical fiber paths, and the control module 111 intelligently controlling the optical switching module 109 according to the detection results to realize link switching, it can automatically switch to the backup optical fiber path when the primary optical fiber link fails or the signal quality decreases, thereby ensuring the continuous and stable transmission of the optical signal. The system has a simple structure, rapid response and low resource occupancy, which significantly improves the reliability of the transmission link and the fault tolerance of the system, and is particularly suitable for scenarios with tight optical fiber resources or high reliability requirements. Compared with the unidirectional optical fiber transmission solution in the prior art, which lacks effective detection and switching strategies and is prone to false switching or switching delays, this technical solution effectively reduces the misjudgment rate and improves the accuracy and response speed of link switching. In addition, the system structure maintains the low resource occupancy characteristics of the unidirectional optical fiber transmission architecture, and while realizing the primary and backup protection functions, it takes into account the system integration and economy, and is particularly suitable for application scenarios with tight optical fiber resources or high requirements for link stability.

[0025] As an embodiment, when receiving an optical signal, the first optical splitter 101 generates a first optical signal and a second optical signal in the same ratio, and outputs the first optical signal to the first optical fiber 102 and the second optical signal to the second optical fiber 103 .

[0026] The first optical splitter 101 is used to receive an external optical signal and split it in the same proportion to generate a first optical signal and a second optical signal. The first optical signal is output to the first optical fiber 102 through the first output port, and the second optical signal is output to the second optical fiber 103 through the second output port. This enables redundant transmission of the same optical signal, provides a primary and backup path for subsequent links, and improves the reliability and fault resistance of the entire system.

[0027] As an implementation, the second optical splitter 105 generates a third optical signal and a fourth optical signal according to a preset ratio based on the first optical signal, outputs the third optical signal to the optical switching module 109 , and outputs the fourth optical signal to the first filter 104 .

[0028] The second optical splitter 105 is configured to receive the first optical signal from the first optical fiber 102 and split the optical signal based on a preset ratio to generate a third optical signal and a fourth optical signal. The third optical signal, if it accounts for more than 90% (e.g., 98%), is transmitted via the second output port to the optical switching module 109 for subsequent service signal output. The fourth optical signal, if it accounts for no more than 10% (e.g., 2%), is transmitted via the first output port to the first filter 104 for link quality monitoring by the first detection module 108.

[0029] The technical effect of this embodiment is that by adopting a 98% and 2% splitting ratio design in the second splitter 105, most of the optical power can be used for normal business transmission to ensure sufficient signal strength, while only a small part of the optical power is extracted for link status detection, effectively taking into account both transmission efficiency and real-time monitoring requirements. This embodiment significantly improves the system's ability to perceive the status of the main link without interrupting business, and realizes an efficient and stable link protection switching mechanism.

[0030] As an embodiment, the first filter 104 filters the fourth optical signal and outputs a fifth optical signal to the first detection module 108. The first detection module 108 detects the power of the fifth optical signal and outputs the detection result to the control module 111. When the detection result of the fifth optical signal is abnormal, the control module 111 controls the optical switching module 109 to select the third splitter 106.

[0031] The first filter 104 filters the fourth optical signal based on the wavelength range to keep the fifth optical signal within a preset wavelength range. The first filter 104 receives the fourth optical signal from the second optical splitter 105, performs spectral filtering on non-target wavelength components, noise, reflected stray light, and other components, retaining only valid signals within the intended wavelength range, and outputs the filtered fifth optical signal to the first detection module 108. This process helps improve the accuracy of optical power detection and the system's anti-interference capability. For example, assume the input fourth optical signal is a mixed light with a wavelength range of 1530nm to 1570nm, and the target communication signal is in the 1530nm to 1550nm band. The first filter 104 filters out optical signals outside the 1530nm to 1550nm band, retaining only valid optical signals in the 1530nm to 1550nm band, and outputs the fifth optical signal for detection, thus avoiding misjudgment of power fluctuations caused by ambient stray light. The first detection module 108 receives the fifth optical signal output by the first filter 104, detects its optical power, and determines whether it is within the normal range. If the optical power is detected to be below a set threshold (e.g., due to high link loss, fiber breakage, or loose connection), an abnormality result is sent to the control module 111. For example, during normal communication, the power of the fifth optical signal is -10 dBm; the system-set abnormality threshold is -25 dBm. If the first detection module 108 detects a power drop to -30 dBm, it indicates severe optical signal attenuation on the main link, possibly due to a physical fiber break or optical source abnormality. In this case, an abnormality signal is output to the control module 111. The control module 111 receives the detection result from the first detection module 108 and determines whether the main link is currently functioning properly. If the detection result is abnormal, it immediately generates a control instruction to control the optical switching module 109 to switch the receiving path from the second optical splitter 105 to the third optical splitter 106, thereby enabling the second optical fiber 103 (the backup link) to continue transmitting service signals and implement link protection. For example: When the control module 111 receives the power abnormality status reported by the first detection module 108, it will issue a switching instruction to disconnect the optical switching module 109 from the second optical splitter 105 and select the third optical splitter 106 to switch the optical signal receiving path to the second optical fiber 103 transmission path to ensure that the optical signal continues to be transmitted uninterruptedly, thereby avoiding service interruption or data loss.

[0032] The technical effect of this embodiment is that: through the coordinated cooperation of the first filter 104, the first detection module 108 and the control module 111, the optical signal status of the main link can be monitored in real time, and when an optical power abnormality is detected, the optical switching module 109 is automatically controlled to switch the receiving path to the backup link, thereby realizing rapid protection switching of the link; this embodiment not only improves the system's response speed and intelligence to link failures, but also ensures the continuity and stability of communications without interrupting business, significantly improving the reliability and fault resistance of the optical fiber transmission system.

[0033] As an implementation, the third optical splitter 106 generates a sixth optical signal and a seventh optical signal according to a preset ratio based on the second optical signal, outputs the sixth optical signal to the optical switching module 109 , and outputs the seventh optical signal to the second filter 107 .

[0034] The third optical splitter 106 is used to receive the second optical signal from the second optical fiber 103 and split it according to a preset ratio to generate a sixth optical signal and a seventh optical signal. The sixth optical signal is the main output signal, accounting for the majority of the optical power, exceeding 90% (e.g., 98%) of the total output signal. It is transmitted via the second output port of the optical splitter to the optical switching module 109 for backup path access for service signals. The seventh optical signal is a detection signal, accounting for a smaller portion of the optical power, less than 10% (e.g., 2%) of the total signal. It is output via the first output port to the second filter 107 and then to the second detection module 110 for link status monitoring. This structure enables parallel monitoring and availability determination of the backup link.

[0035] The technical benefits of this embodiment are as follows: by introducing an asymmetric splitting design (e.g., a 98% to 2% splitting ratio) in the third optical splitter 106, it ensures that the majority of optical power is used for normal service transmission on the backup link, guaranteeing signal strength and communication quality. Furthermore, by extracting a small portion of the optical signal for quality monitoring, the status of the backup optical link can be monitored in real time. In the event of a failure on the primary link, the system can safely and quickly switch to the verified backup link, significantly improving the reliability and seamlessness of the switchover process, thereby enhancing the robustness and service continuity of the overall optical transmission system.

[0036] As an embodiment, the second filter 107 filters the seventh optical signal and outputs the eighth optical signal to the second detection module 110. The second detection module 110 detects the power of the eighth optical signal and outputs the detection result to the control module 111. When the detection result of the eighth optical signal is abnormal, the control module 111 controls the optical switching module 109 to select the second splitter 105.

[0037] The first filter 104 filters the seventh optical signal based on a wavelength range to keep the eighth optical signal within a preset wavelength range. The second filter 107 receives the seventh optical signal output from the third optical splitter 106, effectively filters out stray light, non-target wavelength components, or noise, and outputs the purified eighth optical signal to the second detection module 110. This filter ensures that the detection signal has stable spectral characteristics and a high signal-to-noise ratio, thereby improving the accuracy and reliability of optical power detection. For example, assume that the system's intended communication wavelength is 1550 nm ± 5 nm (i.e., a wavelength range of 1545 nm to 1555 nm). However, due to reflections, scattering, or interference from other light sources in the optical fiber, the seventh optical signal may be contaminated with components from other wavelengths, such as non-target wavelengths of 1530 nm and 1570 nm. In this case, the first filter 104, based on the preset wavelength range, allows only optical signals between 1545 nm and 1555 nm to pass through, blocking all other wavelengths. This results in the output of the eighth optical signal containing only the wavelengths between 1545 nm and 1555 nm. This process significantly improves the accuracy of subsequent optical power assessments by the second detection module 110, preventing interference signals from being mistakenly identified as link failures and ensuring the reliability of system detection results. The second detection module 110 receives the eighth optical signal output by the second filter 107, performs real-time optical power testing, and transmits the test results (e.g., whether the optical intensity meets the standard) to the control module 111. This module is used to assess the current availability of the backup link (the second optical fiber 103) and obtain its health status in advance. For example, if the normal optical power is set to no less than -15 dBm, if the detection module detects that the eighth optical signal power is -30 dBm, this indicates that the backup optical link may have excessive fiber loss or a connection anomaly. In this case, an abnormal status signal will be output, indicating that the backup link is unavailable. The control module 111 continuously receives test results from the second detection module 110. If an abnormal power level in the eighth optical signal is detected, the control module 111 controls the optical switching module 109 to enable the second optical splitter 105, maintaining or restoring access to the primary link to prevent communication interruption caused by switching to the failed backup link. For example, when the primary link detects an anomaly and prepares for switching, the control module 111 first determines whether the backup link is abnormal. If the second detection module 110 reports that the backup link is also faulty, the control module 111 will terminate the switching action, keep the primary link path unchanged, or trigger a system alarm to avoid erroneous switching.

[0038] As an embodiment, the control module 111 is also used to periodically sample and perform sliding average calculation on the power value output by the first detection module 108 to construct a time trend graph of the link signal; when the power value continues to show a downward trend, the control module issues a link degradation warning signal and enters a pre-switching preparation state.

[0039] The control module 111 not only determines the link status based on the single detection results of the first detection module 108, but also periodically samples and calculates a sliding average of the power output by the first detection module 108 to construct a time trend graph of the link signal, enabling early detection and early warning of changes in link performance. Specifically, the control module 111 samples the power value of the fifth optical signal output by the first detection module 108 once per second and stores these continuously collected power values ​​in a circular buffer queue, forming a time window. The time window is 5 seconds long, meaning that the control module 111 calculates the power average based on the five most recent sampled values. The control module 111 compares the current power average with the previous power average. If the average value continues to decline over three consecutive sampling periods and the current average value is below a first preset threshold (e.g., -20 dBm), the control module 111 determines that the primary link is at risk of degradation and issues a link degradation warning signal. Furthermore, if the average power drops below a second threshold (e.g., -25dBm), control module 111 immediately controls optical switch module 109 to switch the link from enabling second optical splitter 105 to enabling third optical splitter 106, thereby enabling the backup link to continue transmitting service signals. This embodiment also includes state caching and delayed judgment logic to avoid misjudgments caused by occasional interference. For example: the power detected at the 1st second is -18.2dBm; the power detected at the 2nd second is -18.7dBm; the power detected at the 3rd second is -19.5dBm; the power detected at the 4th second is -20.3dBm; the power detected at the 5th second is -21.1dBm; the sliding average continuously decreases from -18.5dBm to -20.8dBm, and is lower than the first threshold of -20dBm, the control module 111 outputs a degradation warning; if it further decreases to -25.6dBm in the 6th second, which is lower than the second threshold of -25dBm, the link switching operation is immediately performed.

[0040] The technical benefit of this implementation is that, by introducing a time-trend monitoring mechanism, link performance degradation can be identified in advance, rather than relying solely on single-point anomaly detection. This significantly improves the system's sensitivity and ability to predict hidden link failures. This implementation can issue an early warning before a link fails completely and prepare for a switchover operation in advance, enabling fast, smooth, and reliable service handover and improving the robustness and anti-interference capabilities of the fiber optic transmission system.

[0041] As an embodiment, after the optical switching module 109 completes switching from the primary link (i.e., the second optical splitter 105) to the backup link (i.e., the third optical splitter 106), to ensure reliable communication quality on the backup link, the control module 111 further performs a post-switching link stability detection process. Specifically, the process includes the following steps: the control module collects the power output value of the first detection module once per second and calculates the power average using a sliding window over a preset time period; if the power average continuously decreases and falls below a first threshold, a warning signal is output; if the power average falls below a second threshold, the control module is controlled to perform a link switching operation. After completing the control instruction of the optical switching module 109, the control module 111 starts the post-switching observation timer, and the observation window time is set to 5 seconds. During this observation window, the control module 111 collects the power value of the eighth optical signal output by the second detection module 110 once per second and caches it in the stability detection queue. The control module 111 evaluates the continuously sampled power values ​​to determine whether they are all within a preset normal operating range (for example, -10 dBm to -18 dBm). If the consecutive sampled values ​​are all within this range, the control module 111 confirms that the switch is successful and maintains the current backup link connection. If any sampled value during the observation window is lower than -18 dBm or higher than -10 dBm (i.e., the power fluctuates or decreases abnormally), the control module 111 immediately determines that the backup link is unstable. The control module 111 rolls back the switching operation and re-selects the second optical splitter 105 to restore the primary link. At the same time, the control module 111 outputs a system alarm signal to indicate that the backup link is abnormal, facilitating further inspection by system maintenance personnel. This process can be combined with strategies such as sliding mean determination and short-term jitter tolerance settings to further enhance the accuracy of stability assessments. For example: Sampling at 1 second: -13.2 dBm; Sampling at 2 seconds: -14.1 dBm; Sampling at 3 seconds: -12.8 dBm; Sampling at 4 seconds: -19.4 dBm (below the stable range). Control module 111 determines that the backup link is unstable and issues a fallback command. Optical switching module 109 switches back to the primary link and issues a system alarm.

[0042] This implementation effectively avoids secondary communication interruptions caused by potential issues with the backup link itself by introducing a post-switching link quality verification mechanism, ensuring that the switchover operation is both complete and reliable. This solution enhances the system's closed-loop control over switching operations, improving fault tolerance, security, and business continuity. It is particularly suitable for fiber-optic transmission applications requiring extremely high communication stability.

[0043] As one embodiment, first filter 104 and second filter 107 are configured as multi-band selective filters, such as tunable optical filters or parallel filter banks, to support signal selection and extraction across multiple communication bands, meeting the monitoring requirements for services at different wavelengths. Accordingly, first detection module 108 and second detection module 110 are each equipped with multiple optical power detection channels, each corresponding to a preset key communication wavelength. These channels are used to perform power detection on received signals across multiple bands and output the detected values ​​to control module 111. The specific implementation includes: the first detection module 108 includes three independent optical power detection channels, corresponding to wavelengths of 1550nm, 1530nm, and 1570nm, respectively, for extracting corresponding band signals from the fifth optical signal output by the first filter 104 and performing independent power measurement. Similarly, the second detection module 110 can be equipped with a multi-band detection channel corresponding to the first detection module 108 for multi-band quality monitoring of the backup link. The control module 111 receives the power detection results of multiple bands and comprehensively determines the current status of the optical link through logical judgment (such as all bands meet the requirements, at least one band is abnormal, etc.). If the power of any key band is detected to be lower than a preset threshold value (such as -25dBm), the control module 111 determines that there is a risk of link degradation and can issue an early warning or trigger link switching. The multi-band configuration can also be used to adapt to scenarios where multiple wavelength services are transmitted simultaneously (such as CWDM and DWDM systems), realizing unified monitoring and intelligent judgment of multiple service wavelengths on a single link. For example: During the detection process: Channel 1 (1550nm): -12dBm; Channel 2 (1530nm): -27dBm (abnormal); Channel 3 (1570nm): -14dBm; the control module 111 determines: Due to the abnormal power in the 1530nm band, the link may only be blocked for some wavelengths or there may be problems such as filter aging and light source fluctuations, and immediately outputs a link degradation warning.

[0044] This implementation significantly enhances the system's comprehensive link status awareness in multi-wavelength communication environments by introducing a multi-band filtering and detection mechanism, avoiding the blind spots inherent in traditional single-band monitoring. The system provides real-time visibility into the transmission status of different service wavelengths, enhancing the compatibility and intelligent judgment capabilities of optical fiber transmission systems in CWDM / DWDM scenarios and ensuring transmission stability and service quality when multiple services are running concurrently.

[0045] As an extended embodiment, the first filter 104 and the second filter 107 are configured as an optical filter system with coordinated wavelength selection capabilities. Specifically, under normal operating conditions, the control module 111 controls the first filter 104 and the second filter 107 to be synchronously set to the same target wavelength band (e.g., 1530 nm to 1550 nm), thereby filtering out the fifth and eighth optical signals corresponding to the target wavelength band from the fourth optical signal output by the second optical splitter 105 and the seventh optical signal output by the third optical splitter 106, respectively. The first detection module 108 and the second detection module 110 respectively perform power detection on the fifth and eighth optical signals and output the detection results to the control module 111. The control module 111 compares and analyzes the two detection results to determine the signal status of the current primary link (first optical fiber 102) and the backup link (second optical fiber 103) under the same wavelength conditions. Specifically, the control module 111 includes but is not limited to: determining whether the power of the primary link in the target band is on a downward trend or is lower than a first threshold; determining whether the signal of the backup link in the same band is stable and the power is higher than a second threshold; if the primary link signal is degraded and the backup link signal is normal, issuing a link degradation warning signal in advance and preparing for switching; if both the primary and backup links are abnormal in the band, maintaining the current link connection status and outputting a system alarm to avoid erroneous switching.

[0046] Furthermore, the control module 111 can also instruct the first filter 104 and the second filter 107 to synchronously switch to alternative bands (such as 1530nm±1nm, 1570nm±1nm) based on the abnormal trend of the main link signal in the current target band to perform multi-band cross-validation and enhance the system's ability to identify complex interference or band-specific attenuation.

[0047] Through the above implementation, the system can make intelligent judgments based on the synchronization detection results of the primary and backup links under the same wavelength conditions, thereby achieving more accurate link status evaluation and protection switching control.

[0048] Based on the collaborative extraction of key wavelength signals by the first filter 104 and the second filter 107, this embodiment further introduces a band stability evaluation mechanism and weighted decision logic to improve the decision accuracy and robustness of multi-band signals in link switching judgment. Specifically, it includes: The control module 111 continuously samples the power detection results output by the first detection module 108 and the second detection module 110 in multiple target bands (e.g., 1530nm, 1550nm, and 1570nm), and constructs a power change trend chart for each band under the primary and backup links. The following parameters are set for each band: Stability threshold ΔP: the maximum power fluctuation allowed per unit time (e.g. 0.5dBm); Jitter counter: If the fluctuation exceeds ΔP for n consecutive times (e.g., 3 times), the band is considered unstable; Packet loss threshold: If the power value is lower than the minimum receivable threshold (such as -30dBm), it will be immediately marked as "band failure".

[0049] Based on the detection results of multiple bands, the control module 111 calculates a "comprehensive health score" for each link. Specifically, each band is recorded as an indicator, and sub-scores are calculated based on its power average, fluctuation frequency, jitter number and other parameters. Different bands can be assigned priority weights (for example, the main service band has a higher weight). All sub-scores are weighted and summed to form the total link health score. Example: The main link score S = 0.5 × S1 (1550 nm) + 0.3 × S2 (1530 nm) + 0.2 × S3 (1570 nm).

[0050] If the health score of the primary link is lower than the set switching threshold and the score of the backup link is higher than the access threshold, the control module 111 issues a switching instruction; after the switching, the backup link is continuously scored. If its health score continues to decrease within a certain time window or the band fails, it immediately falls back to the primary link; the score cache is retained before and after the switching for maintenance and analysis.

[0051] This implementation, by introducing a band stability assessment and dynamic weighted scoring mechanism, enables simultaneous monitoring and comprehensive assessment of primary and backup links across multiple key bands. This effectively identifies hidden link failures caused by attenuation, jitter, or instability at specific wavelengths, enabling more precise handover or fallback operations. Compared to traditional solutions based solely on single-wavelength power assessment, this approach significantly improves the accuracy and robustness of link status assessment, reduces the risk of mishandover, and enhances the system's intelligent adaptability and service continuity in multi-wavelength communication environments.

[0052] As a further extended embodiment, the first filter 104 and the second filter 107 are configured as tunable filters capable of dynamically switching between multiple preset target wavelength bands based on control commands from the control module 111. This allows them to filter out optical signals within specific wavelength ranges to improve detection accuracy. Specifically, the first detection module 108 and the second detection module 110 each have multiple optical power detection channels, each corresponding to a specific wavelength band (e.g., 1530 nm, 1550 nm, and 1570 nm). These channels are used to detect the power values ​​of different wavelength components in the output signals of the first filter 104 and the second filter 107, respectively. The control module 111 is configured to periodically collect output power data from each detection channel and construct a link scoring model based on the detection results from multiple wavelength bands. The link scoring model includes, but is not limited to, the following dimensions: the instantaneous value, sliding mean, fluctuation range, jitter frequency, and number of packet losses for each wavelength band. Based on the detection quality and service priority of each wavelength band, the control module 111 calculates a "link health score" for each primary link and backup link, respectively, and uses this score to determine whether to perform link switching or fallback.

[0053] Furthermore, the control module 111 can adjust the weight of each band in the link score according to a preset strategy to achieve dynamic optimization and adaptive adjustment of band selection. For example, when the service is mainly carried on a preset band, such as the 1550nm band, this band is given the highest weight in the scoring model; if the band score drops below the set threshold and the backup link score is better than the main link, a link switch is executed. After the switch, the control module 111 continuously monitors the band detection results of the backup link. If a downward trend in the score or band failure is detected, the fallback mechanism is executed, the receiving path is switched back to the original main link, and a system alarm signal is output to prompt maintenance personnel to investigate the link anomaly.

[0054] This implementation enhances the system's link status recognition accuracy in complex transmission environments through multi-band collaborative detection and scoring decisions, improves the intelligence and stability of link switching, and is suitable for link protection applications in multi-wavelength optical communication systems such as DWDM / CWDM.

[0055] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A unidirectional optical fiber transmission system, characterized in that: include: a first optical splitter, a second optical splitter, a third optical splitter, a first optical fiber, a second optical fiber, a first filter, a second filter, a first detection module, a second detection module, an optical switching module, and a control module, wherein the first output end of the first optical splitter is connected to one end of the first optical fiber, the second output end of the first optical splitter is connected to one end of the second optical fiber, the other end of the first optical fiber is connected to the input end of the second optical splitter, the first output end of the second optical splitter is connected to the input end of the first filter, the second output end of the second optical splitter is connected to the first switching end of the optical switching module, the other end of the second optical fiber is connected to the input end of the third optical splitter, the first output end of the third optical splitter is connected to the input end of the second filter, the second output end of the third optical splitter is connected to the second switching end of the optical switching module, the output end of the first filter is connected to the input end of the first detection module, the output end of the second filter is connected to the input end of the second detection module, and the control module is connected to the output end of the first detection module, the output end of the second detection module, and the control end of the optical switching module, respectively; When the first optical splitter receives an optical signal and outputs the optical signal to the first optical fiber and the second optical fiber respectively, the control module controls the optical switching module to enable the second optical splitter to receive the optical signal transmitted by the first optical fiber, or to enable the third optical splitter to receive the optical signal transmitted by the second optical fiber, based on the detection results of the first detection module and / or the second detection module.

2. The unidirectional optical fiber transmission system according to claim 1, wherein: When receiving an optical signal, the first optical splitter generates a first optical signal and a second optical signal in the same ratio, and outputs the first optical signal to the first optical fiber and outputs the second optical signal to the second optical fiber.

3. The unidirectional optical fiber transmission system according to claim 2, wherein: The second optical splitter generates a third optical signal and a fourth optical signal according to a preset ratio based on the first optical signal, so as to output the third optical signal to the optical switching module and output the fourth optical signal to the first filter.

4. The unidirectional optical fiber transmission system according to claim 3, wherein: The first filter filters the fourth optical signal and outputs a fifth optical signal to the first detection module. The first detection module detects the power of the fifth optical signal and outputs the detection result to the control module. When the detection result of the fifth optical signal is abnormal, the control module controls the optical switching module to select the third optical splitter.

5. The unidirectional optical fiber transmission system according to claim 4, wherein: The first filter filters the fourth optical signal according to a wavelength range, so that the fifth optical signal is within a preset wavelength range.

6. The unidirectional optical fiber transmission system according to claim 2, wherein: The third optical splitter generates a sixth optical signal and a seventh optical signal according to a preset ratio based on the second optical signal, so as to output the sixth optical signal to the optical switching module and output the seventh optical signal to the second filter.

7. The unidirectional optical fiber transmission system according to claim 6, wherein: The second filter filters the seventh optical signal and outputs an eighth optical signal to the second detection module. The second detection module detects the power of the eighth optical signal and outputs the detection result to the control module. When the detection result of the eighth optical signal is abnormal, the control module controls the optical switching module to select the second optical splitter.

8. The unidirectional optical fiber transmission system according to claim 7, wherein: The first filter filters the seventh optical signal according to a wavelength range, so that the eighth optical signal is within a preset wavelength range.

9. The unidirectional optical fiber transmission system according to claim 4, wherein: The control module is also used to periodically sample and perform sliding average calculation on the power value output by the first detection module to construct a time trend graph of the link signal; when the power value continues to show a downward trend, the control module issues a link degradation warning signal and enters a pre-switching preparation state.

10. The unidirectional optical fiber transmission system according to claim 9, wherein: The control module collects the power output value of the first detection module once per second, and calculates the power average using a sliding window in a preset time period; if the power average continuously decreases and is lower than a first threshold, an early warning signal is output; if the power average drops below a second threshold, the optical switching module is controlled to perform a link switching operation.

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