One-way fiber optic transmission system

Abstract

The application relates to the technical field of optical fiber transmission, and discloses a one-way 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 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 select the second optical splitter to receive the optical signal transmitted by the first optical fiber or to select the third optical splitter to receive the optical signal transmitted by the second optical fiber according to the detection results of the first detection module and / or the second detection module; the technical scheme can effectively reduce the misjudgment rate and improve the accuracy and response speed of link switching.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical transmission, in particular to a unidirectional optical fiber transmission system. BACKGROUND

[0002] With the rapid development of communication networks, optical fiber communication systems have become the mainstream information transmission means and are widely used in metropolitan area networks, data centers and long-distance backbone networks and other scenarios. In actual deployment, in order to ensure the stability of the optical line and the continuity of the service, an optical line protection mechanism is usually introduced to switch to the standby link in time when the main link fails, thereby improving the reliability and anti-interference ability of the system. In order to reduce the occupation of optical fiber resources, some schemes attempt to use a unidirectional optical fiber transmission structure to implement main-backup protection, that is, two optical fiber paths in a single direction are used to transmit the same signal, and the signal is detected and switched. However, such a system still has many challenges in link state judgment, switching delay control and mis-switching suppression. The existing unidirectional optical fiber transmission scheme often lacks an efficient monitoring and selection mechanism, and cannot identify optical fiber link failure or quality degradation in time, resulting in the inability to quickly switch to the standby path when the link degrades or is interrupted, thereby affecting the overall reliability and transmission quality of the system. SUMMARY

[0003] Embodiments of the present application provide a unidirectional optical fiber transmission system to solve the above technical problems.

[0004] Embodiments of the present application provide a unidirectional optical fiber transmission system, comprising 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, one end of the first optical fiber is connected to a first output end of the first optical splitter, one end of the second optical fiber is connected to a second output end of the first optical splitter, 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 an 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 an input end of the third optical splitter, a first output end of the third optical splitter is connected to an 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 an input end of the first detection module, an output end of the second filter is connected to an input end of the second detection module, and the control module is connected to an output end of the first detection module, an output end of the second detection module and a control end of the optical switching module, respectively.

[0005] The control module controls the optical switch module to select the second optical splitter to receive the optical signal transmitted by the first optical fiber or to select the third optical splitter to receive the optical signal transmitted by the second optical fiber according to the detection result of the first detection module and / or the second detection module when the first optical splitter receives the optical signal and outputs the optical signal to the first optical fiber and the second optical fiber respectively.

[0006] Optionally, when the first optical splitter receives the optical signal, the first optical signal and the second optical signal are generated in the same proportion, the first optical signal is output to the first optical fiber, and the second optical signal is output to the second optical fiber.

[0007] Optionally, the second optical splitter generates the third optical signal and the fourth optical signal in a preset proportion based on the first optical signal, outputs the third optical signal to the optical switch module, and outputs the fourth optical signal to the first filter.

[0008] Optionally, the first filter outputs the fifth optical signal to the first detection module after filtering the fourth optical signal, the first detection module detects the power of the fifth optical signal and outputs the detection result to the control module, and the control module controls the optical switch module to select the third optical splitter when the detection result of the fifth optical signal is abnormal.

[0009] Optionally, the first filter filters the fourth optical signal according to a waveband range, so that the fifth optical signal is within a preset waveband range.

[0010] Optionally, the third optical splitter generates the sixth optical signal and the seventh optical signal in a preset proportion based on the second optical signal, outputs the sixth optical signal to the optical switch module, and outputs the seventh optical signal to the second filter.

[0011] Optionally, the second filter outputs the eighth optical signal to the second detection module after filtering the seventh optical signal, the second detection module detects the power of the eighth optical signal and outputs the detection result to the control module, and the control module controls the optical switch module to select the second optical splitter when the detection result of the eighth optical signal is abnormal.

[0012] Optionally, the first filter filters the seventh optical signal according to a waveband range, so that the eighth optical signal is within a preset waveband range.

[0013] Optionally, the control module is further configured to periodically sample and slidingly average the power value output by the first detection module to construct a time trend graph of the link signal; when the power value continuously shows a downward trend, the control module sends a link degradation warning signal and enters a pre-switch preparation state.

[0014] Optionally, the control module collects the power output value of the first detection module once per second, calculates the power mean value by using a preset time period sliding window, outputs a warning signal if the power mean value continuously decreases and is lower than a first threshold value, and controls the optical switching module to perform a link switching operation if the power mean value decreases to be lower than a second threshold value.

[0015] The technical effect of the embodiment of the present application is that: by respectively arranging the optical splitters, filters and detection modules on the main and standby optical fiber paths, and intelligently controlling the optical switching module to realize link switching according to the detection results by the control module, the continuous and stable transmission of optical signals can be ensured by automatically switching to the standby optical fiber path when the main optical fiber link fails or the signal quality decreases. The optical fiber transmission system has simple structure, rapid response and low resource occupation, significantly improves the reliability of the transmission link and the fault tolerance of the system, and is particularly suitable for scenes with tight optical fiber resources or high reliability requirements. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 is a first structure schematic view of a one-way optical fiber transmission system provided by the embodiment one of the present application;

[0018] 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

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely by combining the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] It is to be understood that the application can assume various alternative forms of embodiment, and it is accordingly intended that the definition of the application be limited only to the extent of the appended claims. Throughout the drawings, the same reference numerals are used for the same elements in the various figures. Like numbers refer to like elements throughout.

[0021] It will be understood that when an element or layer is referred to as being "on" or "connected to" another element or layer, it can be directly on or connected to the other element or layer or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element or layer, there are no intervening elements or layers present. It will also be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms since such terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section.

[0022] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0023] For the purposes of promoting an understanding of the principles of the application, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the application is intended by the specification of these embodiments. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the application as described herein are contemplated with the scope of the application.

[0024] Example One

[0025] Example One provides a unidirectional fiber optic transmission system, such as Figure 1As shown, it comprises 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 switch 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 switch module 109, the other end of the second optical fiber 103 is connected to the input end of the third optical splitter 106, the first output end of the third optical splitter 106 is connected to the input end of the second filter 107, the second output end of the third optical splitter 106 is connected to the second switching end of the optical switch module 109, the output end of the first 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 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 switch module 109 respectively. 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 switch module 109 to select the second optical splitter 105 to receive the optical signal transmitted by the first optical fiber 102 or 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.

[0026] The first optical splitter 101 is configured to receive the input optical signal and distribute the optical signal to two output ends according to a preset ratio, and output the optical signal to the first optical fiber 102 and the second optical fiber 103 respectively, so as to realize the redundant distribution of the signal and provide a main and standby path for the subsequent link. The first optical fiber 102 and the second optical fiber 103 are used as a main optical link and a standby optical link respectively, and are configured to transmit the optical signal output by the first optical splitter 101 to a subsequent processing module. If the main link (the first optical fiber 102) fails, the standby link (the second optical fiber 103) can be switched to. The second optical splitter 105 is arranged after the first optical fiber 102, receives the optical signal transmitted by the first optical fiber 102, and divides the optical signal into two parts, one of which is sent to the first filter 104 for signal detection, and the other of which is connected to the optical switching module 109 for service use. The third optical splitter 106 is arranged after the second optical fiber 103 and corresponds to the function of the second optical splitter 105. After receiving the optical signal of the second optical fiber 103, the third optical splitter 106 transmits one part of the optical signal to the second filter 107 for signal detection, and the other part of the optical signal is connected to the optical switching module 109 as a backup. The first filter 104 and the second filter 107 are configured to filter the optical signals output by the second optical splitter 105 and the third optical splitter 106 respectively, so as to remove the signals of non-target wave bands, thereby improving the signal detection accuracy. The first detection module 108 and the second detection module 110 receive the output signals of the first filter 104 and the second filter 107 respectively, and detect the power, quality or integrity of the signals, and generate detection results output to the control module 111, so as to judge the link state. The optical switching module 109 includes at least two input ends and one output end, and is configured to selectively connect between the outputs of the second optical splitter 105 and the third optical splitter 106; the optical switching module 109 switches the receiving path according to the control signal of the control module 111, so as to realize the link switching of the service signal. The control module 111 is a core control unit of the system, receives the detection results from the first detection module 108 and the second detection module 110, and judges whether the current main link (the first optical fiber 102) is abnormal based on the detection results; if an abnormality is detected, the control module 111 controls the optical switching module 109 to switch from the second optical splitter 105 receiving the signal of the first optical fiber 102 to the third optical splitter 106 receiving the signal of the second optical fiber 103, so as to realize the dynamic switching and protection of the optical path.

[0027] The technical effect of the embodiment is that: by respectively arranging the optical splitter, the filter and the detection module on the main and standby optical fiber paths, and intelligently controlling the optical switching module 109 to realize link switching according to the detection result of the control module 111, the continuous and stable transmission of the optical signal can be ensured when the main optical fiber link fails or the signal quality decreases. The system structure is simple, fast in response and low in resource occupation, significantly improves the reliability of the transmission link and the fault tolerance of the system, and is especially suitable for scenes where optical fiber resources are scarce or high reliability is required. Compared with the problem that the one-way optical fiber transmission scheme in the prior art lacks effective detection and switching strategy and is prone to mis-switching or switching delay, the technical scheme effectively reduces the misjudgment rate and improves the accuracy and response speed of link switching. In addition, the system structure maintains the low resource occupation characteristic of the one-way optical fiber transmission architecture, while realizing the main and standby protection function, and takes into account the system integration and economy, and is especially suitable for application scenes where optical fiber resources are scarce or the requirement for link stability is high.

[0028] As an implementation manner, when the first optical splitter 101 receives the optical signal, the first optical signal and the second optical signal are generated in the same proportion, the first optical signal is output to the first optical fiber 102, and the second optical signal is output to the second optical fiber 103.

[0029] The first optical splitter 101 is configured to receive an externally input optical signal, and split the optical signal 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 a first output end, and the second optical signal is output to the second optical fiber 103 through a second output end, thereby realizing redundant transmission of the same optical signal and providing a main and standby path for subsequent link transmission, and improving the reliability and fault tolerance of the overall system.

[0030] As an implementation manner, the second optical splitter 105 generates a third optical signal and a fourth optical signal based on the first optical signal in a preset proportion, so as to output the third optical signal to the optical switching module 109 and output the fourth optical signal to the first filter 104.

[0031] 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 proportion to generate a third optical signal and a fourth optical signal. The third optical signal accounts for more than 90% (for example, 98%) and is transmitted to the optical switching module 109 through a second output end, and is used for subsequent business signal output; the fourth optical signal accounts for not more than 10% (for example, 2%) and is transmitted to the first filter 104 through a first output end, and then the first detection module 108 performs link quality monitoring.

[0032] The technical effect of the embodiment is that: by adopting the 98% and 2% splitting ratio design in the second optical splitter 105, most of the optical power can be used for normal service transmission, ensuring sufficient signal strength, while only a small part of the optical power is extracted for link state detection, effectively balancing the transmission efficiency and real-time monitoring needs. The embodiment significantly improves the system's perception ability of the main link state without interrupting the service, and realizes an efficient and stable link protection switching mechanism.

[0033] As an implementation, 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 switch module 109 to select the third optical splitter 106.

[0034] The first filter 104 filters the fourth optical signal according to a wavelength range, so that the fifth optical signal is within a preset wavelength range. The first filter 104 receives the fourth optical signal from the second optical splitter 105, filters the non-target wavelength components, noise light, reflected stray light and the like in the fourth optical signal, and only retains the effective signal within the expected wavelength range, and outputs the filtered fifth optical signal to the first detection module 108. This processing helps to improve the accuracy of optical power detection and the anti-interference ability of the system. For example, assuming that the input fourth optical signal is mixed light with a wavelength range of 1530 nm~1570 nm, and the target communication signal is located in the 1530 nm~1550 nm wavelength band. The first filter 104 filters out the optical signal outside the 1530 nm~1550 nm wavelength band, and only retains the effective optical signal within the 1530 nm~1550 nm wavelength band, so as to output the fifth optical signal for detection, avoiding misjudgment of power fluctuation caused by environmental stray light. The first detection module 108 receives the fifth optical signal output by the first filter 104, detects the optical power value thereof, and judges whether the value is within a normal range. If the detected optical power is lower than a set threshold value (such as large link loss, optical fiber breakage, loose connection, etc.), the abnormal result is sent to the control module 111. For example, during normal communication, the power of the fifth optical signal is -10 dBm; the abnormal threshold value set by the system is -25 dBm. When the first detection module 108 detects that the power decreases to -30 dBm, it indicates that the main link optical signal is severely attenuated, and there may be physical fiber breakage or abnormal light source. At this time, an abnormal signal is output to the control module 111. The control module 111 receives the detection result from the first detection module 108, judges whether the current main link is in a normal state. When the detection result is abnormal, a control instruction is generated immediately to control the optical switching module 109 to switch the receiving path from the second optical splitter 105 to the third optical splitter 106, so as to enable the second optical fiber 103 (standby link) to continue transmitting the service signal, thereby realizing link protection. For example, when the control module 111 receives the power abnormal state reported by the first detection module 108, it issues a switching instruction to make the optical switching module 109 disconnect the connection with 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, so as to ensure that the optical signal continues to be transmitted without interruption, thereby avoiding service interruption or data loss.

[0035] The technical effect of the embodiment is that through the cooperation of the first filter 104, the first detection module 108 and the control module 111, the optical signal state of the main link can be monitored in real time, and when the optical power is detected to be abnormal, the optical switching module 109 is automatically controlled to switch the receiving path to the standby link, so that the rapid protection switching of the link is realized. The embodiment not only improves the response speed and intelligent degree of the system to the link fault, but also ensures the continuity and stability of communication without interrupting the service, and significantly improves the reliability and fault resistance of the optical fiber transmission system.

[0036] As an embodiment, the third optical splitter 106 generates a sixth optical signal and a seventh optical signal based on the second optical signal according to a preset ratio, outputs the sixth optical signal to the optical switching module 109, and outputs the seventh optical signal to the second filter 107.

[0037] The third optical splitter 106 is configured to receive the second optical signal from the second optical fiber 103 and split the second optical signal according to a preset ratio to generate a sixth optical signal and a seventh optical signal. The sixth optical signal is a main output signal and occupies most of the optical power, which is more than 90% (for example, 98%) of the entire output signal, and is transmitted to the optical switching module 109 through the second output end of the optical splitter for standby path access of the service signal. The seventh optical signal is a detection signal and occupies a small part of the optical power, which is less than 10% (for example, 2%) of the entire signal, and is output to the second filter 107 through the first output end and then sent to the second detection module 110 for link state monitoring. This structure realizes parallel monitoring and availability judgment of the standby link.

[0038] The technical effect of the embodiment is that by introducing an asymmetric splitting design (such as a 98% and 2% splitting ratio) in the third optical splitter 106, on the one hand, most of the optical power can be ensured for normal service transmission of the standby link, and the signal strength and communication quality are guaranteed; on the other hand, a small proportion of optical signals are extracted for quality monitoring, and the state of the standby optical link can be mastered in real time. When the main link fails, the system can safely and quickly switch to the verified normal standby link, significantly improving the reliability and seamlessness of the switching process, thereby enhancing the robustness and continuous service capability of the overall optical transmission system.

[0039] As an embodiment, the second filter 107 outputs an eighth optical signal to the second detection module 110 after filtering the seventh optical signal, the second detection module 110 detects the power of the eighth optical signal and outputs the detection result to the control module 111, and the control module 111 controls the optical switching module 109 to select the second optical splitter 105 when the detection result of the eighth optical signal is abnormal.

[0040] The first filter 104 filters the seventh optical signal according to the wavelength range, so that the eighth optical signal is within the preset wavelength range. The second filter 107 receives the seventh optical signal output from the third optical splitter 106, effectively filters out the stray light, non-target wavelength components or noise, and outputs the purified eighth optical signal to the second detection module 110. The filter can ensure that the detection signal has stable spectral characteristics and high signal-to-noise ratio, thereby improving the accuracy and reliability of optical power detection. For example, assuming that the system expects to transmit a communication wavelength of 1550nm±5nm (i.e., the wavelength range is 1545nm to 1555nm), but due to reflection, scattering or other light source interference in the optical fiber, the seventh optical signal may contain other wavelength components, such as 1530nm, 1570nm, etc. Non-target wavelength signals. At this time, the first filter 104 allows only the optical signal of 1545nm~1555nm to pass according to the set wavelength range, and blocks the optical signal of the remaining wavelength, thereby outputting the eighth optical signal containing only 1545nm~1555nm. This process significantly improves the accuracy of the second detection module 110 in judging the optical power, avoids mistaking the interference signal as a basis for link failure, and ensures the reliability of the system detection result. The second detection module 110 receives the eighth optical signal output by the second filter 107, detects the optical power in real time, and sends the detection result (such as whether the light intensity meets the standard) to the control module 111. The module is used to evaluate whether the standby link (second optical fiber 103) is currently available, and to know its health status in advance. For example, set the normal optical power to be not less than -15dBm, if the detection module detects that the power of the eighth optical signal is -30dBm, it means that the standby optical link may have high fiber loss or connection abnormality, at this time the abnormal state signal will be output, prompting that the link is not available. The control module 111 continuously receives the detection result from the second detection module 110. When the power of the eighth optical signal is detected to be abnormal, the control module 111 controls the optical switching module 109 to select the second optical splitter 105, maintains or restores the main link access, and prevents communication interruption caused by switching to the faulty standby link. For example, when the main link detects an abnormality and is ready to switch, the control module 111 first judges whether the standby link is abnormal. If the second detection module 110 reports that the standby link also has a fault, the control module 111 will terminate the switching action, keep the main link path unchanged or trigger a system alarm to avoid false switching.

[0041] As an implementation, the control module 111 is also used for periodic sampling and sliding average calculation of the power value output by the first detection module 108 to construct a time trend graph of the link signal; when the power value continuously shows a downward trend, the control module issues a link degradation warning signal and enters a pre-switching preparation state.

[0042] The control module 111 not only determines the link state according to the single detection result of the first detection module 108, but also periodically samples and performs sliding average calculation on the power value output by the first detection module 108 to construct a time trend graph of the link signal, so as to realize early perception and early warning of the link performance change. Specifically, the control module 111 collects the power value of the fifth optical signal output by the first detection module 108 once per second, and stores the continuously collected power values in a ring buffer queue to form a time window. The length of the time window is 5 seconds, that is, the control module 111 calculates the power average value based on the last 5 sampling values. The control module 111 compares the change trend between the current power average value and the last power average value, if the average value continuously decreases in the last three sampling periods, and the current average value is lower than the first preset threshold (for example, -20 dBm), the control module 111 determines that the main link has a degradation risk, and outputs a link degradation warning signal. Further, if the power average value decreases to below the second threshold (for example, -25 dBm), the control module 111 immediately controls the optical switching module 109 to perform link switching, from selecting the second optical splitter 105 to selecting the third optical splitter 106, to enable the standby link to continue transmitting the service signal. This embodiment can also set state buffer and delay judgment logic to avoid false judgment caused by occasional interference. For example, the first second detection power is -18.2 dBm, the second second detection power is -18.7 dBm, the third second detection power is -19.5 dBm, the fourth second detection power is -20.3 dBm, the fifth second detection power is -21.1 dBm, the sliding average value continuously decreases from -18.5 dBm to -20.8 dBm, and is lower than the first threshold -20 dBm, the control module 111 outputs a degradation warning; if the sixth second further decreases to -25.6 dBm, which is lower than the second threshold -25 dBm, the link switching operation is immediately performed.

[0043] The technical effect of the embodiment is that the link performance degradation process can be recognized in advance by introducing a time trend monitoring mechanism, instead of relying on single-point abnormal judgment, which significantly improves the response sensitivity and prediction ability of the system to the link hidden fault. The embodiment can issue a warning before the link completely fails and prepare for switching operation in advance, so as to realize fast, smooth and reliable service connection switching, and improve the robustness and anti-interference ability of the optical fiber transmission system.

[0044] As an implementation, 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 the reliable communication quality of the backup link, the control module 111 further performs a post-switching link stability detection process. Specifically, the control module collects the power output value of the first detection module once per second, and calculates the power mean value using a preset time period sliding window. If the power mean value continuously decreases and is lower than a first threshold value, a warning signal is output. If the power mean value decreases to be lower than a second threshold value, the control module controls the optical switching module to perform a link switching operation. After completing the control instruction of the optical switching module 109, the control module 111 starts a post-switching observation timer, and the observation window time is set to 5 seconds. Within the observation window, the control module 111 collects the eighth optical signal power value 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, and determines whether all of them are within a preset normal working range (for example, -10 dBm to -18 dBm). If all the continuously sampled values are within the range, the control module 111 confirms that the switching is successful, and maintains the current backup link connection. If any of the sampled values is lower than -18 dBm or higher than -10 dBm (i.e., the power appears abnormal fluctuation or decrease) during the observation window, the control module 111 immediately determines that the backup link is unstable. The control module 111 then reverts the switching operation, and reselects the second optical splitter 105 to restore to the primary link. At the same time, the control module 111 outputs a system warning signal to prompt the abnormal backup link, so as to facilitate further inspection by system maintenance personnel. This process can further enhance the stability evaluation accuracy in combination with strategies such as sliding mean value judgment and short-term jitter tolerance setting. For example, the first second sampling value is -13.2 dBm, the second second sampling value is -14.1 dBm, the third second sampling value is -12.8 dBm, and the fourth second sampling value is -19.4 dBm (lower than the stable range). The control module 111 determines that the backup link is unstable, issues a rollback instruction, the optical switching module 109 switches back to the primary link, and issues a system warning.

[0045] The embodiment effectively avoids the secondary communication interruption problem caused by hidden dangers in the backup link itself by introducing a post-switching link quality verification mechanism, and ensures that the switching operation is not only completed but also reliable. The scheme enhances the closed-loop control ability of the system for switching actions, improves the fault tolerance, safety, and service continuity of the system, and is particularly suitable for optical fiber transmission application scenarios with extremely high communication stability requirements.

[0046] As an implementation, the first filter 104 and the second filter 107 are configured as multi-band selective filters, for example, in the form of tunable optical filters or parallel filter banks, to support the selection and extraction of signals of multiple communication bands and meet the monitoring requirements of different wavelength services. Correspondingly, the first detection module 108 and the second detection module 110 are respectively provided with multiple optical power detection channels, each channel corresponding to a preset key communication wavelength, for respectively performing power detection on the received multiple-band signals and outputting detection values to the control module 111. The specific implementation includes that the first detection module 108 includes three independent optical power detection channels corresponding to wavelengths 1550 nm, 1530 nm and 1570 nm, 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 provided with multiple-band detection channels 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 judges the state of the current optical link through a logical judgment method (such as all bands meeting, at least one band being abnormal, etc.); if it is detected that the power of any key band is lower than a preset threshold value (such as -25 dBm), the control module 111 judges that there is a risk of link degradation and can issue a warning or trigger link switching; the multi-band configuration can also be used to adapt to the simultaneous transmission of multiple wavelength services (such as CWDM and DWDM systems) to realize unified monitoring and intelligent judgment of one link and multiple service wavelengths. For example, during the detection process: channel 1 (1550 nm): -12 dBm; channel 2 (1530 nm): -27 dBm (abnormal); channel 3 (1570 nm): -14 dBm; the control module 111 judges that since the power of the 1530 nm band is abnormal, the link may be only partially disconnected or there may be problems such as filter aging and light source fluctuation, and immediately outputs a link degradation warning.

[0047] The present embodiment significantly enhances the overall perception ability of the system for the link state in a multi-wavelength communication environment by introducing a multi-band filtering and detection mechanism, avoiding the detection blind area problem existing in traditional single-band monitoring. The system can master the transmission status of different service wavelengths in real time, improve the compatibility and intelligent judgment ability of the optical fiber transmission system in the CWDM / DWDM scene, and ensure the transmission stability and service quality during concurrent multi-service transmission.

[0048] As an extended embodiment, the first filter 104 and the second filter 107 are configured as an optical filter system with cooperative wavelength band selection capability, specifically including: in a normal working state, the control module 111 controls the first filter 104 and the second filter 107 to be synchronously set to the same target wavelength band (for example, 1530nm to 1550nm) to filter out the fifth optical signal and the eighth optical signal 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 perform power detection on the fifth optical signal and the eighth optical signal, respectively, and output the detection results to the control module 111, respectively. The control module 111 compares and analyzes the two detection results to judge the signal state of the current main link (the first optical fiber 102) and the standby link (the second optical fiber 103) under the same wavelength condition, specifically including but not limited to: judging whether the power of the main link on the target wavelength band is in a downward trend or lower than a first threshold value; judging whether the signal of the standby link on the same wavelength band is stable and the power is higher than a second threshold value; if the main link signal is degraded and the standby link signal is normal, a link degradation early warning signal is sent in advance and switching is prepared; if both the main link and the standby link are abnormal on the wavelength band, the current link connection state is maintained and a system alarm is output to avoid false switching.

[0049] Further, the control module 111 can also instruct the first filter 104 and the second filter 107 to synchronously switch to an alternative wavelength band (such as 1530nm±1nm, 1570nm±1nm) according to the abnormal trend of the main link signal on the current target wavelength band, to perform multi-wavelength cross verification and improve the recognition ability of the system to complex interference or wavelength attenuation.

[0050] Through the above embodiments, the system can intelligently judge based on the synchronous detection results of the main link and the standby link under the same wavelength condition, to realize more accurate link state evaluation and protection switching control.

[0051] On the basis of the above-mentioned cooperation of the first filter 104 and the second filter 107 in extracting key wavelength signals, the present embodiment further introduces a wavelength stability evaluation mechanism and a weighted decision logic to improve the decision accuracy and robustness of multi-wavelength signals in link switching judgment. Specifically including:

[0052] The control module 111 continuously samples the power detection results output by the first detection module 108 and the second detection module 110 on multiple target wavelength bands (for example, 1530nm, 1550nm, 1570nm), and constructs a power change trend graph of each wavelength band under the main link and the standby link. Each wavelength band is set with the following parameters:

[0053] Stable threshold ΔP: maximum power fluctuation allowed in a unit time (such as 0.5dBm);

[0054] Jitter counter: if the fluctuation exceeds ΔP for n times (e.g. 3 times), it is determined that the band is unstable.

[0055] Packet loss threshold: if the power value is lower than the minimum acceptable threshold (e.g. -30dBm), it is immediately marked as "band failure".

[0056] The control module 111 calculates the "comprehensive health score" for each link based on the detection results of multiple bands, which specifically includes: each band is recorded as an index, and the sub-score is calculated according to the power average, fluctuation frequency, jitter times and other parameters; different bands can be set with priority weight (such as higher weight for business main band); the total score of the link health is obtained by weighted sum of all sub-scores; for example:

[0057] Main link score S = 0.5 x S1 (1550nm) + 0.3 x S2 (1530nm) + 0.2 x S3 (1570nm).

[0058] If the main link health score is lower than the set switching threshold, and the standby link score is higher than the access threshold, the control module 111 issues a switching instruction; after switching, the standby link continues to be scored, and if its health score continues to decline or the band fails within a certain time window, it immediately falls back to the main link; both before and after switching, the score cache is retained for maintenance analysis.

[0059] The present embodiment realizes the synchronous monitoring and comprehensive judgment of the main and standby links in multiple key bands by introducing the band stability evaluation and dynamic weighting scoring mechanism, can effectively identify the implicit faults caused by specific wavelength attenuation, jitter or instability in the link, and accordingly perform more accurate switching or fallback operation. Compared with the traditional scheme based on only single wavelength power judgment, the present scheme significantly improves the accuracy and robustness of link state judgment, reduces the risk of mis-switching, and enhances the intelligent adaptation ability and business continuity guarantee level of the system in the multi-wavelength communication environment.

[0060] 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 according to control instructions of the control module 111, for filtering out optical signals in a specific wavelength range to improve detection accuracy. Specifically, the first detection module 108 and the second detection module 110 are respectively provided with multiple optical power detection channels, each channel corresponding to a specific wavelength band (such as 1530nm, 1550nm, 1570nm), for detecting 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 the output power data of each detection channel, and construct a link score model based on the detection results of multiple wavelength bands. The link score model includes but is not limited to the following dimensions: instantaneous value, sliding average, fluctuation range, jitter frequency, packet loss frequency, etc. of each wavelength band power. The control module 111 calculates the "link health score" of the primary link and the standby link respectively according to the detection quality of each wavelength band and the service priority, and judges whether to perform link switching or fallback operation accordingly.

[0061] Further, the control module 111 can adjust the weight values of each wavelength band in the link score according to a preset strategy, to realize dynamic optimization and adaptive adjustment of wavelength band selection. For example, when the service is mainly carried on a preset wavelength band, such as the 1550nm wavelength band, the highest weight is given to this wavelength band in the score model; if the score of this wavelength band drops below a set threshold, and the score of the standby link is better than that of the primary link, link switching is performed. After switching, the control module 111 continues to monitor the score of the standby link based on the detection results of the wavelength band, and if a downward trend of the score or a wavelength band failure is detected, a fallback mechanism is executed to switch the receiving path back to the original primary link, and a system alarm signal is output to prompt maintenance personnel to troubleshoot link abnormalities.

[0062] This embodiment enhances the link state recognition accuracy of the system in complex transmission environment through multi-wavelength band collaborative detection and score decision, 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.

[0063] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A unidirectional optical fiber transmission system, characterized in that, include: The system comprises a first beam splitter, a second beam splitter, a third beam 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. The first output terminal of the first beam splitter is connected to one end of the first optical fiber, and the second output terminal of the first beam splitter is connected to one end of the second optical fiber. The other end of the first optical fiber is connected to the input terminal of the second beam splitter. The first output terminal of the second beam splitter is connected to the input terminal of the first filter. The second output terminal of the second beam splitter is connected to the first switching terminal of the optical switching module. The other end of the second optical fiber is connected to the input terminal of the third beam splitter. The first output terminal of the third beam splitter is connected to the input terminal of the second filter. The second output terminal of the third beam splitter is connected to the second switching terminal of the optical switching module. The output terminal of the first filter is connected to the input terminal of the first detection module, and the output terminal of the second filter is connected to the input terminal of the second detection module. The control module is connected to the output terminals of the first and second detection modules and the control terminal of the optical switching module, respectively. When the first optical splitter receives an optical signal and outputs optical signals to the first optical fiber and the second optical fiber respectively, the control module controls the optical switching module to select the second optical splitter to receive the optical signal transmitted through the first optical fiber, or select the third optical splitter to receive the optical signal transmitted through 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 as described in claim 1, characterized in that, When the first optical splitter receives an optical signal, it generates a first optical signal and a second optical signal in the same proportion, and outputs the first optical signal to the first optical fiber and the second optical signal to the second optical fiber.

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

4. The unidirectional optical fiber transmission system as described in claim 3, characterized in that, After filtering the fourth optical signal, the first filter 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 beam splitter.

5. The unidirectional optical fiber transmission system as described in claim 4, characterized in that, The first filter filters the fourth optical signal according to the band range so that the fifth optical signal is within the preset band range.

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

7. The unidirectional optical fiber transmission system as described in claim 6, characterized in that, After filtering the seventh optical signal, the second filter 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 beam splitter.

8. The unidirectional optical fiber transmission system as described in claim 7, characterized in that, The first filter filters the seventh optical signal according to the band range so that the eighth optical signal is within the preset band range.

9. The unidirectional optical fiber transmission system as described in claim 4, characterized in that, The control module is also used to periodically sample and calculate the moving average of 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 decline, the control module issues a link degradation warning signal and enters a pre-switching preparation state.

10. The unidirectional optical fiber transmission system as described in claim 9, characterized in that, The control module collects the power output value of the first detection module once per second and calculates the average power using a preset time period sliding window. If the average power continuously decreases and falls below a first threshold, an early warning signal is output. If the average power drops below a second threshold, the optical switching module is controlled to perform a link switching operation.

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