Double-core optical fiber link loss self-repairing and redundancy switching method

Abstract

The invention relates to the technical field of passive optical networks, and discloses a dual-core optical fiber link loss self-repairing and redundancy switching method, which comprises the following steps of: establishing a resonance transmission state sensitive to physical disturbance; when the state is damaged due to disturbance, forced reconstruction and secondary confirmation are executed firstly instead of being switched immediately so as to distinguish transient impact and a hard fault, and the state is physically switched to a standby link only after the hard fault is confirmed. A traditional indirect mode depending on external measurement and threshold judgment is changed, and judgment delay and response delay are avoided; a secondary confirmation mechanism effectively avoids unnecessary switching caused by transient disturbance, and the operation stability of the system in a complex environment is improved.

Description

Technical Field

[0001] The invention relates to a dual-core optical fiber link loss self-repair and redundancy switching method, belonging to the technical field of passive optical networks. Background Art

[0002] Currently, in passive optical networks, to ensure link reliability, a redundant protection method of primary and backup dual-core optical fibers is commonly used. In existing technologies, the working logic of this type of protection method usually relies on periodic measurement of link status. For example, by monitoring changes in optical power, when the measured value exceeds a certain switching threshold, an independent control unit initiates the switching action and switches the service from the primary fiber to the backup fiber.

[0003] However, this technical approach of managing continuously changing physical processes through discrete sampling has direct limitations when dealing with random instantaneous physical layer failures in optical fiber links: 1. The existence of response delay. Due to the temporal and logical separation of measurement, decision-making, and execution, there is a response time between the actual occurrence of the physical failure and the completion of the switching action. This response time is difficult to meet the requirements in some business scenarios with high time sensitivity; 2. The ambiguity of the judgment threshold. The changing process of optical fiber loss is diverse. A fixed switching threshold cannot simultaneously take into account high sensitivity and high accuracy. If the threshold is set improperly, it is easy to lead to untimely switching for real faults or frequent misjudgments due to short-term disturbances; 3. Increased system complexity.

[0004] To address these shortcomings, some solutions introduce more complex monitoring protocols and external management units, which increases system complexity and potential failure points. Therefore, the technical challenge addressed by this present invention is to develop a link protection method that can instantaneously respond to real physical layer failures while minimizing misjudgments and switching delays. Summary of the Invention

[0005] The present invention provides a dual-core optical fiber link loss self-repair and redundancy switching method, the main purpose of which is to solve the problem of how to construct a link protection method that can respond instantaneously to real physical layer faults while avoiding misjudgment and switching delay, which is more simple and efficient.

[0006] To achieve the above objectives, the present invention provides a dual-core optical fiber link loss self-repair and redundancy switching method, which includes:

[0007] Step a: establishing a resonant transmission state based on frustrated total internal reflection on a primary optical fiber link to transmit a service optical signal in the resonant transmission state;

[0008] Step b: when the primary optical fiber link is physically disturbed, causing the resonant transmission state to be destroyed and causing the optical power of the service optical signal at the receiving end to drop instantaneously below the fault determination threshold, it is determined that an initial fault has occurred on the primary link;

[0009] Step c, in response to the determination of the initial fault, performing a forced reconstruction operation for the resonant transmission state;

[0010] Step d: performing a secondary confirmation on whether the primary optical fiber link has recovered to the resonant transmission state within a confirmation time window sufficient to complete the forced reconstruction operation and transmit the restored service optical signal to the receiving end;

[0011] In step e, only when the primary optical fiber link fails to recover to the resonant transmission state within the confirmation time window, is it determined that a hard failure has occurred in the primary link, and the transmission path of the service optical signal is physically switched from the primary optical fiber link to the backup optical fiber link instantaneously.

[0012] Preferably, in step a, a resonant transmission state is established on the main optical fiber link by actively controlling and maintaining the optical transmission interface spacing in the transmitting coupler at a resonant distance using a piezoelectric ceramic actuator in the transmitting coupler provided at the transmitting end of the main optical fiber link.

[0013] Preferably, the method further comprises a step of performing closed-loop adaptive maintenance on the resonant transmission state, the step comprising: capturing the service optical signal reflected from the transmitting coupler at the transmitting end, and generating an entropy voltage signal V inversely proportional to the transmission efficiency of the resonant transmission state according to the intensity of the captured reflected light. entropy ; and use the entropy voltage signal to drive the reference voltage V of the piezoelectric ceramic actuator base Continuous reverse feedback fine-tuning is performed to dynamically lock the optical transmission interface spacing in the transmitting coupler at the optimal resonance point that minimizes the intensity of the reflected light, where the final driving voltage V drive Follow these rules: V drive =V base -α·V entropy , where α is a feedback coefficient value that ensures the stability of negative feedback.

[0014] Preferably, after switching the transmission path of the service optical signal to the backup optical fiber link in step e, the method further includes a step of instantaneously verifying the integrity of the backup optical fiber link, which step includes: using the first service optical pulse sent to the backup optical fiber link after the switch as a detection pulse; and monitoring at the transmitting end whether there is a photon echo formed by the reflection of the detection pulse at the fault point of the backup optical fiber link within an echo gating time window determined by the optical path of the backup optical fiber link; if the presence of a photon echo is detected within the echo gating time window, it is determined that a silent fault exists in the backup optical fiber link.

[0015] Preferably, the method also includes a step of identifying the type of physical disturbance during the destruction of the resonant transmission state, which step includes: in step b, heterodyning the service optical signal whose transmission efficiency is changing in the main optical fiber link with a reference optical signal with a stable frequency transmitted through the backup optical fiber link to generate a beat signal; and using a group of parallel bandpass filters with different center frequencies to classify the beat signal, so as to identify the type of physical disturbance that causes the failure of the main optical fiber link based on the bandpass filter through which the beat signal passes.

[0016] Preferably, the method further includes a step of globally adaptively recalibrating the resonant transmission state, the step comprising: driving the operating voltage of the piezoelectric ceramic actuator to perform a full-area scan covering its entire safe operating range according to a time period or external instruction; during the full-area scan, continuously capturing the reflected service optical signal and determining a voltage value that can make the reflected light intensity reach a global minimum; and setting the determined voltage value as a new reference voltage V in the closed-loop adaptive maintenance step. base .

[0017] Preferably, determining whether an initial fault occurs on the primary link in step b is achieved by detecting an output signal of a photodetector provided at a receiving end of the primary optical fiber link, and the presence or absence of the output signal of the photodetector is used to determine whether an initial fault occurs.

[0018] Preferably, in step e, the transmission path of the service optical signal is physically switched from the main optical fiber link to the backup optical fiber link by cutting off the power supply to the piezoelectric ceramic actuator in the transmitting end coupler so that the elastic structure inside it is restored to the default physical state of switching the optical path to the backup optical fiber link.

[0019] Preferably, in step c, the forced reconstruction operation refers to the local controller at the receiving end sending a reset instruction to the piezoelectric ceramic actuator at the transmitting end through a signaling channel when an initial fault is detected, causing the actuator to re-execute an action of establishing a resonant transmission state.

[0020] Preferably, the method also includes a step of monitoring the long-term health of the resonant transmission state, which includes: continuously monitoring the differential temperature difference caused by the absorption of the reflected business optical signal by deploying a differential temperature sensor at the core reflected light absorption point in the transmitting coupler and the environmental reference area; and determining whether a predictive maintenance alarm needs to be generated based on whether the growth trend slope of the differential temperature difference over a long period exceeds a maintenance threshold.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. By constructing a resonant transmission state that relies on the stability of the physical form and directly binding the link's communication capability to the physical health state, the traditional indirect method of measuring first and then switching is changed. It no longer requires independent and delayed sampling measurement and threshold judgment of optical fiber loss. Instead, it uses the physical disturbance itself as an energy source to directly trigger the destruction of the resonant state, making the occurrence of the fault and the formation of the switching instruction the same event at the physical level, thereby avoiding the inherent response delay problem caused by the hesitation in judgment due to the vague threshold setting in the traditional method.

[0023] 2. After determining that an initial link failure has occurred, the method of the present invention does not immediately perform switching, but first performs a forced reconstruction operation and performs a secondary confirmation. This trial-and-confirmation mechanism enables the system to effectively distinguish between transient physical shocks and unrecoverable hard failures, avoiding unnecessary redundant switching and upper-layer business jitter caused by short-term disturbances. While maintaining the ability to respond almost instantaneously to real faults, the system also has the ability to tolerate non-continuous interference in complex environments, thereby improving operational stability in high-frequency vibration or impact scenarios.

[0024] 3. The method of the present invention tightly couples the two processes of redundant switching and backup link verification. It uses the first service optical pulse after switching to the backup link as the detection signal. By instantly monitoring the presence of a characteristic echo generated by the backup link failure point at the sending end, it simultaneously realizes the instant verification of the backup link availability at the moment the switching action is completed. This design solves the hidden danger of silent failures of the backup link in traditional redundancy solutions, ensures that each redundant switching is an effective and reliable recovery operation, and avoids the risk of complete communication interruption caused by switching to a failed backup link.

[0025] 4. The method of the present invention also provides a mechanism for online, closed-loop adaptive maintenance of the resonant transmission state. It converts the reflected light signal, which is regarded as useless information during normal communication, into a core negative feedback signal that represents the health of the resonant state. Through continuous fine-tuning, the system can actively combat the slow performance degradation caused by factors such as device aging or environmental temperature drift, helping to keep the link running near a higher efficiency point. This approach is further combined with a mechanism for global adaptive recalibration based on a time period or external instructions, so that the system can not only cope with small drifts, but also adapt to large changes in environmental baselines, thereby maintaining performance margin and operational reliability throughout the entire life cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the timing interaction when the method of the present invention responds to transient physical disturbances;

[0027] Figure 2 It is a functional module diagram of the adaptive control mechanism of the transmitting coupler in the method of the present invention;

[0028] Figure 3 The figure is a flowchart of the overall execution logic of the method of the present invention. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] The present invention provides a dual-core optical fiber link loss self-repair and redundancy switching method, which is applied to the field of passive optical network technology. The core process of its technical solution includes the following stages: first, establishing and maintaining a resonant transmission state that is sensitive to physical disturbances on the main optical fiber link; second, when the resonant state is destroyed due to physical disturbances, performing a mandatory transient reconstruction and secondary confirmation to distinguish between transient impacts and hard faults; finally, only after confirming a hard fault, performing a physical switch to a backup optical fiber link, and verifying the integrity of the backup link after the switch is completed.

[0031] In a communication network with high requirements for service continuity, a technical challenge is how to quickly and accurately respond to sudden changes in the loss of the main optical fiber link. To this end, the method of the present invention is configured to establish a resonant transmission state based on frustrated total internal reflection on the main optical fiber link and transmit the service optical signal under this state. The establishment of this resonant transmission state is achieved at the transmitting end of the main optical fiber link through a transmitting coupler with a built-in piezoelectric ceramic actuator. The piezoelectric ceramic actuator is applied with a reference voltage V base When the optical transmission interface is connected to the fiber optic cable, the distance between the two internal optical transmission interfaces is actively controlled and maintained at a preset resonant distance. At this distance, the optical signal forms a highly efficient resonant tunneling in the form of a tunnel effect, thereby coupling the service optical signal into the main optical fiber. This configuration makes the physical stability of the link directly related to its communication capability.

[0032] To ensure that the resonant transmission state can be maintained at the operating point in the face of factors such as device aging or environmental temperature drift, the system is equipped with a closed-loop adaptive maintenance procedure. This procedure uses the reflected light signal during normal communication as a negative feedback signal. Specifically, the transmitting end captures the business light signal reflected back from the transmitting coupler and generates an entropy voltage signal V that is inversely proportional to the efficiency of the resonant transmission state based on its intensity. entropy This signal is used to drive the reference voltage V of the piezoelectric ceramic actuator. base Continuous reverse feedback fine-tuning is performed, where the final drive voltage V drive Follow V drive =V base -ɑ·V entropy The rule is that α is the feedback coefficient value, which is obtained by injecting a step disturbance signal into the feedback loop during the system debugging phase and observing V drive The response curve of the optical transmission system is obtained by selecting a coefficient value that can make the system reach the critical damping state. Through this negative feedback mechanism, the system can resist tiny performance drift and dynamically lock the optical transmission interface spacing at the point where the reflected light intensity is minimized.

[0033] When the main optical fiber link is physically disturbed, causing the resonant transmission state to be destroyed and causing the optical power of the business optical signal at the receiving end to drop instantaneously below the fault judgment threshold, the system determines that an initial fault has occurred in the main link. The judgment of this initial fault is achieved by detecting the presence or absence of the output signal of the photoelectric detector set at the receiving end of the main optical fiber link. In response to the judgment of the initial fault, the system does not switch immediately, but performs a forced reconstruction operation. The operation is performed by the local controller at the receiving end to send a reset instruction to the piezoelectric ceramic actuator at the transmitting end through the signaling channel, causing it to re-execute the action of establishing the resonant transmission state. Subsequently, within a preset confirmation time window, the system performs a second confirmation on whether the main optical fiber link has recovered to the resonant transmission state. This confirmation time The value of the time window is set to the sum of the transmission delay of the optical signal in a round trip in the optical fiber link and the response time of the piezoelectric ceramic actuator. This trial-and-confirmation mechanism is used to distinguish between transient physical shocks and irrecoverable hard faults. Only when the primary optical fiber link fails to recover to the resonant transmission state within the confirmation time window is it determined that a hard fault has occurred in the primary link. At this time, the system physically switches the transmission path of the service optical signal from the primary optical fiber link to the backup optical fiber link. This switching is achieved by cutting off the power supply to the piezoelectric ceramic actuator in the transmitting end coupler, so that its internal elastic structure returns to the default physical state of switching the optical path to the backup optical fiber link. This switching process does not rely on software decisions, and its response speed is only limited by the physical characteristics of the circuit and mechanical structure.

[0034] To avoid the risk of switching to a failed backup link, the method of the present invention further includes a step of instantaneously verifying the integrity of the backup optical fiber link after the switching is performed. This step uses the first service optical pulse sent to the backup optical fiber link after the switching as a detection pulse, and monitors at the transmitting end whether there is a photon echo formed by the reflection of the detection pulse at the fault point of the backup optical fiber link within an echo gating time window determined by the optical path of the backup optical fiber link. If a photon echo is detected, it is determined that a silent fault exists in the backup optical fiber link. This design is intended to verify the effectiveness of each redundant switching. To adapt to baseline changes in the external environment, the closed-loop adaptive maintenance mechanism can also be combined with a global environment adaptive recalibration step. This step drives the working voltage of the piezoelectric ceramic actuator to perform a full-area scan covering its entire safe operating range based on a time period or external instruction. During the scanning process, the reflected service optical signal is continuously captured, and a voltage value that can make the reflected light intensity reach the global minimum is determined. The determined voltage value is then set as a new reference voltage V in the closed-loop adaptive maintenance step. base , which helps maintain its performance margin during the system's operating cycle.

[0035] In addition, to provide fault diagnosis information, the method of the present invention may also include a step of identifying the type of physical disturbance during the destruction of the resonant transmission state. This step involves heterodyning a service optical signal experiencing a change in transmission efficiency in the primary optical fiber link with a frequency-stable reference optical signal transmitted through a backup optical fiber link to generate a beat signal. The beat signal is then classified using a set of parallel bandpass filters with different center frequencies. The type of physical disturbance of the fault is identified based on the bandpass filters through which the beat signal passes. To monitor the long-term health of the resonant transmission state, the system may also be configured with a monitoring step. This step continuously monitors the differential temperature difference generated by the absorption of the reflected service optical signal using differential temperature sensors deployed between the core reflected light absorption point within the transmitting coupler and the environmental reference zone. Whether a predictive maintenance alarm needs to be generated is determined based on whether the slope of the differential temperature difference's growth trend over a long period exceeds a maintenance threshold. The maintenance threshold is a pre-calibrated value set based on correlation data established through accelerated aging testing that characterizes the relationship between a specific temperature difference growth slope and the degree of system performance degradation. This method is used to provide predictive maintenance information.

[0036] Example 1: In a passive optical network environment supporting a high-frequency trading system, when a primary optical fiber link carrying a data stream that is highly sensitive to network jitter and delay is subjected to continuous and non-destructive mechanical vibration due to maintenance work on adjacent equipment, the resonant transmission state established on the link is instantaneously destroyed by the physical disturbance. In view of this operating condition, the photoelectric detector at the receiving end of the system determines that an initial fault has occurred due to the decrease in the optical power of the service optical signal, but the system does not immediately switch to the backup optical fiber link. Instead, it immediately initiates a forced reconstruction and secondary confirmation procedure. The local controller at the receiving end communicates with the system to determine that the fault has occurred. A reset command is sent to the piezoelectric ceramic actuator at the transmitter through the signaling channel. Since the mechanical vibration is a transient physical shock, the physical integrity of the optical fiber link is not permanently damaged, and the resonant transmission state is successfully reconstructed within the preset confirmation time window. The receiver detects the recovery of the service optical signal in the secondary confirmation and cancels the switching command. The high sensitivity of the resonant transmission state to physical disturbances provides the time prerequisite for the execution of the secondary confirmation mechanism, which transforms the former sensitivity from a vulnerability that may lead to misjudgment into a deterministic criterion for identifying the persistence of the fault.

[0037] Subsequently, in this application scenario, when an erroneous operation caused an irreversible permanent microbend in the main optical fiber link, the resonant transmission state was destroyed again, and the system also performed forced reconstruction and secondary confirmation. In this event, since the physical damage to the optical fiber was persistent, the resonant transmission state could not be reconstructed within the confirmation time window, and the receiving end failed to detect the recovery of the service optical signal. The system then determined that this event was a hard fault. The judgment result triggered a physical switch to the backup optical fiber link. This switch was achieved by cutting off the power supply to the piezoelectric ceramic actuator in the transmitting end coupler. After the switch was completed, the first service optical pulse was used as a detection pulse to execute the backup. The link integrity check confirmed that the backup link was intact because no photon echo was detected within the echo gating time window. High-frequency trading services resumed transmission on the backup link after a sub-millisecond switch. The operating logic of this method changes the judgment method of setting discrete thresholds in the continuously changing loss process, and instead constructs a judgment system that associates the physical health status of the link with two definable logical states: reconfigurable or non-reconfigurable. The original dilemma about setting the switching threshold is transformed into a decidable physical problem under this system: whether the physical system can recover its initial steady state within a preset time after being disturbed.

[0038] Example 2: In order to objectively verify the response time and the ability to distinguish different fault types of the method of the present invention, a test platform for performance comparison was built. The platform included a sample group of the present invention and a control group. Both groups were equipped with a main and a backup optical fiber link with a length of 1 km, and a programmable piezoelectric ceramic fiber squeezer as a unified disturbance source; wherein, the sample group of the present invention was configured according to the specific implementation method, and the control group adopted a conventional protection method based on optical power threshold monitoring. When the optical power dropped by more than 3dB, the controller drove the photoelectric switch to perform switching; in the experiment, a key parameter of the sample group of the present invention, the confirmation time window, was set to balance the timeliness of fault confirmation and the physical possibility of reconstruction operation, and its value was T window Follow the T window ≥2·L·n / c+T piezo The rule is as follows: L is the length of the optical fiber link, n is the core refractive index, c is the speed of light in vacuum, and T piezo is the actuator response time. For a 1 km link, the confirmation time window is set to 10 μs.

[0039] The experimental results show that the speed of the sample group of the present invention in responding to hard faults and the stability in dealing with transient shocks show significant orders of magnitude differences from those of the control group. When a hard fault condition that causes optical power attenuation greater than 20dB is applied, the total interruption time of the control group from the occurrence of the fault to the completion of the switching is 1.52ms, which includes the time for optical power detection, software decision-making and photoelectric switch execution. In contrast, the total interruption time of the sample group of the present invention is 10.2μs, which is consistent with the aforementioned 10μs confirmation time window and physical switching time. Its response time is determined by the physical mechanism and preset parameters.

[0040] When applying a transient physical shock to simulate non-continuous interference, the difference in operational logic between the two approaches becomes even more pronounced. This shock causes a transient drop in optical power of approximately 5dB, lasting for 1μs. Under this condition, the control group initiated a complete redundant switching that caused a 1.e-05s service interruption due to optical loss exceeding its 3dB switching threshold. However, the inventive group experienced no switching, with only a single service optical signal recovery process lasting 1.8μs recorded. Its forced reconstruction and secondary confirmation mechanism verified the link's recoverability within this confirmation time window, thereby suppressing the switching action. This result confirms that the inventive method achieves an effective balance between instantaneous response to physical layer failures and avoiding switching caused by short-term disturbances.

[0041] Example 3: This example combines Figures 1 to 3 , a dual-core optical fiber link loss self-repair and redundancy switching method is described. Figure 1 As shown in the figure, when the system operating normally on the main optical fiber link is subjected to a transient physical disturbance, causing the optical power at the receiving end to drop and the initial fault to be detected by it, the local controller sends a reset command to the sending end through the signaling channel, instructing the piezoelectric ceramic at the sending end to perform a forced reconstruction operation to rebuild the resonant transmission state. After the optical signal is restored, the local controller initiates a secondary confirmation within a preset confirmation time window, and after successful confirmation, finally cancels the switching command, allowing the system to resume normal operation.

[0042] like Figure 2 As shown, the input business optical signal is sent to the coupler through a final drive voltage V drive The piezoelectric ceramic actuator controlled by the optical transmission interface adjusts the spacing to form a resonant tunneling effect, thereby coupling the signal to the main optical fiber. Part of the reflected light is captured by a negative feedback control unit to generate an entropy voltage signal V whose intensity is inversely proportional to the resonance efficiency. entropy , the signal is to a reference voltage V baseContinuous reverse feedback fine-tuning is performed to dynamically lock the system at the optimal resonance point. In addition, a global environment adaptive recalibration mechanism can also determine a new reference voltage V by scanning the entire domain based on cycles or external commands. base , to adapt to large environmental baseline changes.

[0043] like Figure 3 As shown in the figure, the system starts with the normal operation of the primary link in the resonant state. After the physical disturbance causes the received optical power to drop and is determined to be an initial fault, the system performs a forced reconstruction operation and enters the secondary confirmation link. If the primary link recovers resonance within the confirmation time window, the process returns to the normal operation state. If it fails to recover, it is determined that a hard fault has occurred and the system is physically switched to the backup link instantaneously. After the switch is completed, the integrity of the backup link is immediately checked using the first service pulse to prevent switching to the silent fault link, and finally the service is restored on the backup link.

[0044] Example 4: In an engineering practice of applying the method of the present invention to an unmanned optical transmission node, in order to ensure the long-term stable operation of the system, some core control parameters need to be calibrated offline before deployment to deal with the uncertainty that may be introduced by individual differences in hardware. The technical problem of this work is how to set values ​​and procedures with clear physical basis and non-empirical nature for the feedback coefficient α in the closed-loop adaptive maintenance procedure and the trigger logic of the global environment adaptive recalibration; in order to determine the value of the feedback coefficient α, the dynamic response characteristics of the system are calibrated on an optical test platform. This process applies a step voltage signal to the piezoelectric ceramic actuator to cause it to generate a step displacement, and at the same time uses a high-speed acquisition device to monitor and record the entropy voltage signal V generated by the disturbance. entropy The response curve is analyzed quantitatively to extract the peak overshoot percentage P. overshoot The time to reach steady state is T settling Two indicators, with a cost function J = w1·T settling +w2·P overshoot As the optimization target, w1 and w2 are weight coefficients set according to the different emphasis of business scenarios on response speed and stability. The value of the feedback coefficient ɑ is iteratively adjusted and the above step response test is repeated until a value α that minimizes the cost function J is found. This process aims to obtain a feedback coefficient value that enables the system to reach a critical damping or slightly underdamped response state under the hardware conditions.

[0045] The trigger logic for global environmental adaptive recalibration does not use a fixed time period, but is linked to a long-term health monitoring mechanism. During operation, the system continuously monitors the differential temperature difference signal output by the differential temperature sensor and reflects the degree of resonant state degradation, and calculates its growth trend slope over a long period. When this slope exceeds a certain proportion of the preset predictive maintenance alarm threshold, it indicates that the drift of the working reference point has accumulated to the extent that a global recalibration is required. At this time, the system automatically triggers the recalibration operation, and the execution of the recalibration is thus linked to the actual changes in the system's own health status.

[0046] The classification logic for identifying physical disturbance types is also established through offline calibration. On the test platform, low-frequency vibration and high-frequency impact signals with known spectral characteristics are applied to the main optical fiber link. The normalized power values ​​of the heterodyne interference beat signals corresponding to each disturbance are recorded after passing through a parallel bandpass filter group at each center frequency point. These power values ​​constitute feature vectors and are stored in a classification lookup table. During actual system operation, the Euclidean distance between the real-time monitored beat signal power vector and each feature vector in the lookup table is calculated, and the disturbance type is classified into the category corresponding to the feature vector with the smallest distance. Through this series of calibration procedures, the system's various adaptive and diagnostic functions thus obtain a traceable quantitative basis.

[0047] Example 5: In a system deployed in a power dispatching backbone network, in order to perform proactive verification of the long-term availability of its redundant links, the system initiates a backup link status verification procedure during a low-traffic period based on periodic instructions from a network management center or a locally preset inspection strategy. This procedure involves a transmitter injecting a probe optical pulse carrying a specific code and having a power lower than a service optical signal recognition threshold into a silent backup optical fiber link. The transmitter monitors, within an echo gating time window corresponding to the optical path of the backup optical fiber link, whether there is an echo of the probe optical pulse generated by a physical breakpoint in the link. Simultaneously, the receiver also monitors the probe optical pulse with the specific code. If the transmitter detects an echo or the receiver fails to report confirmation of receipt of the probe optical pulse within a preset time, the system determines that a silent fault exists in the backup optical fiber link and generates a maintenance alarm.

[0048] In order to implement the predictive maintenance alarm function in the long-term health monitoring mechanism of the device, a maintenance threshold for the differential temperature difference growth trend slope based on statistical data was set. Before the product was finalized, an accelerated aging test was performed on a batch of transmitting coupler modules. The tested modules were placed in a temperature and humidity cycle test chamber and operated continuously under simulated extreme operating conditions. The automated test system synchronously recorded the output value of the differential temperature sensor inside the module and the signal quality parameters measured by an external bit error rate tester and representing the actual optoelectronic performance of the module at fixed time intervals. After the test, a time correlation model between the differential temperature difference growth slope and the degradation of the signal quality parameters to a preset limit was established by performing regression analysis on the data of all tested modules. Finally, a temperature difference growth slope corresponding to the system failure probability reaching a preset upper limit within a specific maintenance cycle in the future was selected as the maintenance threshold for this batch of products and solidified into the monitoring logic of the equipment.

[0049] Example 6: To provide an accurate initial benchmark reference for subsequent online monitoring and adaptive control, an offline calibration procedure for constructing a device-specific response model for the transmitting coupler module of the present invention is performed during the final production inspection phase. This procedure places the transmitting coupler module to be calibrated on a test platform that integrates a laser interferometer and an optical power meter. A high-precision voltage source drives the piezoelectric ceramic actuator within the module, causing its operating voltage to be continuously scanned within its safe operating range. During this process, the laser interferometer measures and records the physical spacing of the optical transmission interface in real time, while the optical power meter synchronously records the optical power of the service optical signal coupled to the main optical fiber. This generates a specific data set that characterizes the relationship between voltage, spacing, and transmission efficiency. This data set is used to determine an optimal operating point that maximizes the transmission efficiency. The voltage value corresponding to this operating point is defined as the initial reference voltage V for the module. base , and stored in its non-volatile storage unit as a benchmark reference for all subsequent online operations.

[0050] During the initialization phase of device power-up, the first task is to verify whether the current physical state matches the stored reference model. To this end, the system performs a link establishment self-test procedure. The controller first reads the initial reference voltage V calibrated by the aforementioned procedure from the non-volatile storage unit. base and applies it to the piezoelectric ceramic actuator at the transmitting end. Subsequently, the system enters a preset link locking time window and continuously monitors the reflected light intensity at the transmitting coupler. If the reflected light intensity drops below a locking threshold that indicates that the resonant transmission state has been stably established within the time window, the self-test passes and the system immediately activates the closed-loop adaptive maintenance function. If the reflected light intensity fails to reach the locking threshold within the locking time window, the system determines that the main link has failed to be established and triggers an alarm or an attempt to switch to the backup link.

[0051] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A dual-core optical fiber link loss self-repair and redundancy switching method, characterized in that: The method includes: Step a: establishing a resonant transmission state based on frustrated total internal reflection on a primary optical fiber link to transmit a service optical signal in the resonant transmission state; Step b: when the primary optical fiber link is physically disturbed, causing the resonant transmission state to be destroyed and causing the optical power of the service optical signal at the receiving end to drop instantaneously below the fault determination threshold, it is determined that an initial fault has occurred on the primary link; Step c, in response to the determination of the initial fault, performing a forced reconstruction operation for the resonant transmission state; Step d: performing a secondary confirmation on whether the primary optical fiber link has recovered to the resonant transmission state within a confirmation time window sufficient to complete the forced reconstruction operation and transmit the restored service optical signal to the receiving end; In step e, only when the primary optical fiber link fails to recover to the resonant transmission state within the confirmation time window, is it determined that a hard failure has occurred in the primary link, and the transmission path of the service optical signal is physically switched from the primary optical fiber link to the backup optical fiber link instantaneously.

2. A dual-core optical fiber link loss self-repair and redundancy switching method according to claim 1, characterized in that: In step a, a resonant transmission state is established on the main optical fiber link by actively controlling and maintaining the optical transmission interface spacing within the transmitting coupler at a resonant distance using a piezoelectric ceramic actuator in the transmitting coupler provided at the transmitting end of the main optical fiber link.

3. A dual-core optical fiber link loss self-repair and redundancy switching method according to claim 1, characterized in that: The method also includes a step of performing closed-loop adaptive maintenance on the resonant transmission state, which includes: capturing the service optical signal reflected from the transmitting coupler at the transmitting end, and generating an entropy voltage signal V inversely proportional to the transmission efficiency of the resonant transmission state according to the intensity of the captured reflected light. entropy ; and use the entropy voltage signal to drive the reference voltage V of the piezoelectric ceramic actuator base Continuous reverse feedback fine-tuning is performed to dynamically lock the optical transmission interface spacing in the transmitting coupler at the optimal resonance point that minimizes the intensity of the reflected light, where the final driving voltage V drive Follow these rules: V drive =V base -α·V entropy , where α is a feedback coefficient value that ensures the stability of negative feedback.

4. A dual-core optical fiber link loss self-repair and redundancy switching method according to claim 1, characterized in that: After switching the transmission path of the service optical signal to the backup optical fiber link in step e, the method further includes a step of instantaneously verifying the integrity of the backup optical fiber link. This step includes: using the first service optical pulse sent to the backup optical fiber link after the switch as a probe pulse; and monitoring at the transmitting end within an echo gating time window determined by the optical path of the backup optical fiber link for the presence of a photon echo generated by reflection of the probe pulse at the fault point of the backup optical fiber link; if the presence of a photon echo is detected within the echo gating time window, it is determined that a silent fault exists in the backup optical fiber link.

5. The method for self-repair and redundancy switching of dual-core optical fiber link loss according to claim 1, characterized in that: The method also includes a step of identifying the type of physical disturbance during the destruction of the resonant transmission state, which step includes: in step b, performing heterodyne interference on a service optical signal in the main optical fiber link whose transmission efficiency is changing and a reference optical signal with a stable frequency transmitted through a backup optical fiber link to generate a beat signal; and using a group of parallel bandpass filters with different center frequencies to classify the beat signal, so as to identify the type of physical disturbance that caused the failure of the main optical fiber link based on the bandpass filter through which the beat signal passed.

6. A dual-core optical fiber link loss self-repair and redundancy switching method according to claim 3, characterized in that: The method also includes a step of globally adaptively recalibrating the resonant transmission state, which includes: driving the operating voltage of the piezoelectric ceramic actuator to perform a full-area scan covering its entire safe operating range based on a time period or external instruction; during the full-area scan, continuously capturing the reflected service light signal and determining a voltage value that can make the reflected light intensity reach a global minimum; and setting the determined voltage value as a new reference voltage V in the closed-loop adaptive maintenance step. base .

7. The method for self-repair and redundancy switching of a dual-core optical fiber link loss according to claim 1, characterized in that: In step b, determining whether an initial fault has occurred on the primary link is achieved by detecting the output signal of a photoelectric detector provided at the receiving end of the primary optical fiber link. The presence or absence of the output signal of the photoelectric detector is used to determine whether an initial fault has occurred.

8. The dual-core optical fiber link loss self-repair and redundancy switching method according to claim 1, characterized in that: In step e, the transmission path of the service optical signal is physically switched from the main optical fiber link to the backup optical fiber link by cutting off the power supply to the piezoelectric ceramic actuator in the transmitting end coupler so that its internal elastic structure returns to the default physical state of switching the optical path to the backup optical fiber link.

9. The method for self-repair and redundancy switching of a dual-core optical fiber link loss according to claim 1, characterized in that: In step c, the forced reconstruction operation refers to the local controller at the receiving end sending a reset instruction to the piezoelectric ceramic actuator at the transmitting end through the signaling channel when an initial fault is detected, so as to cause the actuator to re-execute the action of establishing the resonant transmission state.

10. A dual-core optical fiber link loss self-repair and redundancy switching method according to claim 3, characterized in that: The method also includes a step of monitoring the long-term health of the resonant transmission state, which includes: continuously monitoring the differential temperature difference caused by the absorption of the reflected business optical signal through a differential temperature sensor deployed at the core reflected light absorption point in the transmitting coupler and the environmental reference area; and determining whether a predictive maintenance alarm needs to be generated based on whether the growth trend slope of the differential temperature difference over a long period exceeds a maintenance threshold.

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