Optical fiber switching method, control unit, and optical transmission system

Abstract

An optical fiber switching method, a control unit, and an optical transmission system, which belong to the technical field of communications. The optical transmission system comprises a control unit, a plurality of first optical switches, a plurality of second optical switches, a plurality of primary optical fibers and a plurality of backup optical fibers, wherein an ith first optical switch and an ith second optical switch are respectively connected to two ends of an ith primary optical fiber, and the ith first optical switch and the ith second optical switch are further respectively connected to two ends of each backup optical fiber; the ith first optical switch receives an ith optical signal, and transmits the ith optical signal to the ith second optical switch by means of the ith primary optical fiber for output; different optical signals bear different pieces of service data; and the control unit controls the ith first optical switch and the ith second optical switch to switch the ith primary optical fiber, the performance of which is lower than a first performance threshold, to an idle target backup optical fiber, the performance of which is higher than or equal to the first performance threshold. The present application can solve the problem of a halved system capacity, and is used for the transmission of optical signals.

Description

Fiber optic switching method, control unit, optical transmission system

[0001] This application claims priority to Chinese patent application filed on November 13, 2024, with application number 202411628980.X and entitled "Fiber Optic Switching Method, Control Unit, Optical Transmission System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to an optical fiber switching method, a control unit, and an optical transmission system. Background Technology

[0003] With the development of communication technology, data center interconnection (DCI) network systems have gradually evolved from exchanging data based on electrical signals to exchanging data based on optical signals.

[0004] The DCI network system employs an optical multiplex section protection (OMSP) architecture. For example, the DCI network system includes two planes, with optical signals in different planes carrying different service data; each plane has a primary fiber and a backup fiber, and the optical signal of each plane is transmitted on the primary fiber within that plane; and, in the event of a failure in the primary fiber, the optical signal is switched to transmission on the backup fiber within that plane.

[0005] However, when both the primary and backup optical fibers in the same plane fail, the transmission of optical signals in that plane will be interrupted, thereby reducing the capacity of the DCI network system by half. Summary of the Invention

[0006] This application provides a fiber optic switching method, a control unit, and an optical transmission system, which can solve the problem of halving the capacity of DCI network systems. The solution provided by this application is as follows:

[0007] In a first aspect, an optical transmission system is provided, comprising: multiple first optical switches, multiple second optical switches, a control unit, multiple main optical fibers, and multiple backup optical fibers. The number of first optical switches and the number of second optical switches can be the same or different. The i-th first optical switch and the i-th second optical switch are respectively connected to both ends of the i-th main optical fiber, and the i-th first optical switch and the i-th second optical switch are also respectively connected to both ends of each backup optical fiber; i ≥ 1. The i-th first optical switch is used to receive the i-th optical signal from the multiple optical signals and transmit the i-th optical signal to the i-th main optical fiber; the i-th second optical switch is used to output the i-th optical signal received from the i-th main optical fiber; the multiple optical signals carry different service data. Each of the multiple optical signals can be a single-wavelength optical signal or a multi-wavelength optical signal, and the wavelengths of different optical signals can be the same or different. The control unit is used to control the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber when the performance of the i-th main optical fiber is lower than a first performance threshold and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions; the switching conditions include: being idle and having performance higher than or equal to the first performance threshold.

[0008] In the optical transmission system provided in this application, multiple first optical switches can receive multiple optical signals carrying different service data and transmit these signals to multiple second optical switches via multiple main optical fibers. Furthermore, each first and second optical switch is connected not only to its corresponding main optical fiber but also to multiple backup optical fibers. When the performance of a main optical fiber falls below a first performance threshold, the control unit can control the first and second optical switches connected to that main optical fiber to switch it to a backup optical fiber, thereby restoring the transmission of optical signals on that main optical fiber. Since both the first and second optical switches are connected to multiple backup optical fibers, multiple backup optical fibers are available when switching from a main optical fiber to a backup optical fiber is required. Even if one backup optical fiber fails, other backup optical fibers can be used for switching. Therefore, interruptions to optical signals on the main optical fiber can be reduced, increasing the capacity of the optical transmission system.

[0009] Furthermore, as described above, the optical transmission system provided in this application switches the optical fiber that is activated by an optical switch to achieve the switching of the optical signal transmission path. These optical switches are, for example, the aforementioned first optical switch, second optical switch, etc. Because the switching speed of the optical switch is relatively fast, it can ensure that the switching speed of the optical fiber in the optical transmission system is relatively fast, and that the transmission of the optical signal on the optical fiber can be quickly restored (for example, within 50 milliseconds).

[0010] Furthermore, optical switches are less expensive, therefore, the optical transmission system provided in this application is also less expensive.

[0011] Furthermore, when the number of backup optical fibers is less than the number of main optical fibers, this application can protect a large number of main optical fibers with a small number of backup optical fibers, thereby reducing the optical fiber resources in the optical transmission system and making it suitable for scenarios where optical fiber resources are relatively scarce.

[0012] Optionally, the optical transmission system further includes a light source connected to the end of each of the i-th main optical fiber and multiple backup optical fibers away from the i-th second optical switch; the light source is used to transmit probe light to each of the i-th main optical fiber and multiple backup optical fibers. The wavelength of the probe light is different from the wavelength of the optical signal, therefore, the probe light and the optical signal can be transmitted simultaneously in the same optical fiber. A first power detector is disposed on the optical path from each of the i-th main optical fiber and multiple backup optical fibers to the i-th second optical switch. The control unit can be used to determine, based on the power of the probe light detected by the first power detector, that the performance of the i-th main optical fiber is lower than a first performance threshold, and to determine that the performance of the target backup optical fiber is higher than or equal to the first performance threshold.

[0013] The power detected by the power detector (such as the first power detector) in this application can be the absolute optical power or the relative change in optical power, and this application does not limit this. The power detector in this application can be a device capable of detecting power, such as a photodetector.

[0014] Furthermore, there are several ways to make the performance of the i-th main optical fiber fall below the first performance threshold.

[0015] For example, the performance of the i-th main optical fiber being lower than the first performance threshold includes: the i-th main optical fiber being open-circuited. In this case, the performance of the target backup optical fiber being higher than or equal to the first performance threshold includes: the target backup optical fiber not being open-circuited.

[0016] For example, the performance of the i-th main optical fiber being lower than the first performance threshold includes: the target performance parameter of the i-th main optical fiber being less than the minimum value among the target performance parameters of the plurality of backup optical fibers, and the difference between the minimum value and the target performance parameter of the i-th main optical fiber being greater than the parameter threshold; the larger the target performance parameter of the i-th main optical fiber, the higher the performance of the i-th main optical fiber.

[0017] Furthermore, the above description uses the switching condition of being idle and having performance higher than or equal to the first performance threshold as an example. Optionally, the switching condition may also include other conditions, such as: performance higher than or equal to a second performance threshold, where the second performance threshold is greater than the first performance threshold. Therefore, when a backup fiber is idle and its performance is higher than or equal to the first performance threshold, the control unit can also determine whether the performance of the backup fiber is higher than or equal to the second performance threshold. Only when the performance of the backup fiber is higher than or equal to the second performance threshold can it be determined that the backup fiber has higher performance and can effectively transmit optical signals. Therefore, the control unit can determine that the backup fiber meets the switching condition.

[0018] Optionally, when the i-th main optical fiber has a corresponding backup optical fiber, if the backup optical fiber corresponding to the i-th main optical fiber meets the switching conditions, then the target backup optical fiber is the backup optical fiber corresponding to the i-th main optical fiber; if the backup optical fiber corresponding to the i-th main optical fiber does not meet the switching conditions, then the target backup optical fiber is different from the backup optical fiber corresponding to the i-th main optical fiber. It is evident that the control unit will control the i-th main optical fiber to preferentially switch to its corresponding backup optical fiber. This avoids the occupation of backup optical fibers corresponding to other main optical fibers, allowing other main optical fibers to quickly switch to their corresponding main optical fibers when their performance is poor.

[0019] Optionally, when the backup optical fiber corresponding to the i-th main optical fiber does not meet the switching conditions, the control unit can sequentially determine whether the backup optical fiber meets the switching conditions in order of total optical fiber length from small to large and / or optical fiber performance from high to low, until a backup optical fiber that meets the switching conditions is found, and the backup optical fiber is used as the target backup optical fiber.

[0020] Optionally, the above-mentioned control unit can be implemented in various ways. For example, the control unit includes: a first controller and a second controller; the first controller is used to control the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber when the performance of the i-th main optical fiber is lower than a first performance threshold and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions; the second controller is used to control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber when the performance of the i-th main optical fiber is lower than the first performance threshold and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions.

[0021] Furthermore, whether the performance of the i-th primary optical fiber is lower than the first performance threshold, and whether the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, can be determined by either the first controller or the second controller. For example, if the second controller determines whether the performance of the i-th primary optical fiber is lower than the first performance threshold and whether the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the second controller is used to control the i-th second optical switch to switch the i-th primary optical fiber to the target backup optical fiber, and to send a switching instruction to the first controller. This switching instruction indicates that the i-th primary optical fiber should be switched to the target backup optical fiber. The first controller is used to control the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber according to the switching instruction.

[0022] The second controller can send the switching instruction in the following ways: (1) The second controller can control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber after sending the switching instruction. (2) The second controller can control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber at the same time as sending the switching instruction. (3) The second controller can first control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber, and then send the switching instruction. In both methods (1) and (2), the switching instruction can be sent without waiting for the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber. In this way, the first controller can control the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber as early as possible, thereby shortening the time for the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber as a whole, and reducing the recovery time of the optical signal transmission on the i-th main optical fiber.

[0023] Optionally, the optical transmission system provided in this application further includes a third optical switch and a fourth optical switch; the target backup optical fiber is connected to the aforementioned plurality of first optical switches through the third optical switch, and the target backup optical fiber is also connected to the aforementioned plurality of second optical switches through the fourth optical switch.

[0024] Assuming the target backup fiber corresponds to the j-th main fiber among multiple main fibers, where j≥1 and j≠i; then, the third optical switch can be used to connect the target backup fiber to the j-th first optical switch (the first optical switch connected to the j-th main fiber), and the fourth optical switch is used to connect the target backup fiber to the j-th second optical switch (the second optical switch connected to the j-th main fiber). It is evident that the third optical switch connected to each backup fiber defaults to connecting the first optical switch connected to that backup fiber and the corresponding main fiber, and the fourth optical switch connected to each backup fiber defaults to connecting the second optical switch connected to that backup fiber and the corresponding main fiber. The control unit is used to control the third and fourth optical switches to switch the j-th main fiber to the i-th main fiber when the performance of the i-th main fiber is lower than a first performance threshold, and the multiple backup fibers include a target backup fiber that meets the switching conditions.

[0025] In other words, when the control unit switches the i-th main optical fiber to the target backup optical fiber, it also controls the third optical switch to change the conduction of the first optical switch, and controls the fourth optical switch to change the conduction of the second optical switch. This ensures that the third optical switch connects the target backup optical fiber to the i-th first optical switch, and the fourth optical switch connects the target backup optical fiber to the i-th second optical switch. Thus, the i-th optical signal can be transmitted sequentially through the i-th first optical switch, the third optical switch, the target backup optical fiber, and the fourth optical switch to the i-th second optical switch.

[0026] This example illustrates the scenario where the j-th primary optical fiber corresponding to the target backup fiber is different from the i-th primary optical fiber. When the j-th primary optical fiber corresponding to the target backup fiber is the same as the i-th primary optical fiber, the third optical switch defaults to connecting the target backup fiber to the i-th first optical switch, and the fourth optical switch defaults to connecting the target backup fiber to the i-th second optical switch. Therefore, the control unit does not need to control the third and fourth optical switches to quickly switch the i-th primary fiber to the target backup fiber, allowing the i-th optical signal to be transmitted sequentially through the i-th first optical switch, the third optical switch, the target backup fiber, and the fourth optical switch to the i-th second optical switch.

[0027] Furthermore, the control unit can also be used to control the third and fourth optical switches to switch the j-th main optical fiber to the i-th main optical fiber based on the third optical switch meeting the operating conditions. Therefore, before controlling the third and fourth optical switches to switch the j-th main optical fiber to the i-th main optical fiber, the control unit can determine whether the third optical switch meets the operating conditions. Only when the operating conditions are met will the control unit control the third and fourth optical switches to switch the j-th main optical fiber to the i-th main optical fiber, thus ensuring effective transmission of the optical signal after the fiber switch. If the operating conditions are not met, the control unit will not control the third and fourth optical switches to switch the j-th main optical fiber to the i-th main optical fiber.

[0028] The above operating conditions can be achieved in various ways. For example, the operating conditions include the third optical switch not being faulty. Another example is that the operating conditions include the insertion loss of the third optical switch being less than the insertion loss threshold. Yet another example is that the operating conditions include the third optical switch not being faulty and the insertion loss of the third optical switch being less than the insertion loss threshold.

[0029] Under operating conditions including a fault-free third optical switch, the optical transmission system also includes a second power detector connected to the aforementioned third optical switch. This third optical switch is also used to connect the second power detector to the i-th first optical switch. After the control unit controls the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, it can determine that the third optical switch is not faulty based on the power of the i-th optical signal detected by the second power detector. It is understood that after the control unit controls the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, the i-th optical signal can be transmitted to the second power detector. At this time, the control unit can detect the power of the i-th optical signal through the second power detector and determine whether the third optical switch is faulty based on this power.

[0030] Under operating conditions, including an insertion loss of the third optical switch less than the insertion loss threshold, the optical transmission system includes a third power detector in addition to the aforementioned second power detector. This third power detector is connected between the third optical switch and the i-th first optical switch. The control unit, after controlling the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, determines the insertion loss of the third optical switch based on the power of the i-th optical signal detected by the second and third power detectors, respectively. It can be understood that after the control unit controls the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, the i-th optical signal can be transmitted from the i-th first optical switch sequentially through the third power detector and the third optical switch to the second power detector. At this time, the control unit can detect the power of the i-th optical signal through the second and third power detectors, respectively, and determine the insertion loss of the third optical switch based on these powers.

[0031] Optionally, the optical transmission system provided in this application may further include: a third power detector; the third power detector is located on the optical path from the i-th first optical switch to the target backup optical fiber. The control unit is used to determine whether the fiber switching is successful based on the optical signal power detected by the third power detector after controlling the i-th primary optical fiber to switch to the target backup optical fiber (e.g., after controlling the i-th first optical switch and the i-th second optical switch to switch the i-th primary optical fiber to the target backup optical fiber). It can be understood that the third power detector is located on the optical path from the i-th first optical switch to the target backup optical fiber. If the fiber switching is successful (the i-th primary optical fiber switches to the target backup optical fiber), the i-th optical signal will pass through the third power detector, and the optical signal power detected by the third power detector will be high. If the fiber switching is unsuccessful (the i-th primary optical fiber does not switch to the target backup optical fiber), the i-th optical signal will not pass through the third power detector, and the optical signal power detected by the third power detector will be low. Therefore, the control unit can determine whether the fiber switching is successful based on the optical signal power detected by the third power detector.

[0032] The above description uses the example of switching the i-th main optical fiber to the target backup optical fiber when the performance of the i-th main optical fiber is lower than the first performance threshold. Optionally, in some cases, when the performance of the i-th main optical fiber is lower than the first performance threshold, if none of the backup optical fibers meet the switching conditions, and the i-th first optical switch and the i-th second optical switch are both connected to at least one other main optical fiber, then it is possible to search among the other main optical fibers for a main optical fiber that meets the switching conditions, so as to switch the i-th main optical fiber to the main optical fiber that meets the switching conditions. In this way, it avoids the inability to recover the optical signal transmission on the i-th main optical fiber when none of the backup optical fibers meet the switching conditions, thus increasing the probability of recovering the optical signal transmission. For example, the i-th first optical switch and the i-th second optical switch are also respectively connected to both ends of each of the other main optical fibers in at least one other main optical fiber, which is different from the i-th main optical fiber. The control unit is further configured to control the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target main optical fiber when the performance of the i-th main optical fiber is lower than the first performance threshold, multiple backup optical fibers do not meet the switching conditions, and at least one other main optical fiber includes the target main optical fiber that meets the switching conditions.

[0033] Secondly, this application also provides an optical fiber switching method, which is executed by a control unit in an optical transmission system provided by any design in the first aspect. The optical fiber switching method includes: when the performance of the i-th main optical fiber is lower than a first performance threshold, and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the control unit controls the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber; the switching conditions include: being idle and having performance higher than or equal to the first performance threshold.

[0034] There are several ways to make the performance of the i-th main fiber optic cable fall below the first performance threshold.

[0035] For example, the performance of the i-th main optical fiber being lower than the first performance threshold includes: the i-th main optical fiber being open-circuited. In this case, the performance of the target backup optical fiber being higher than or equal to the first performance threshold includes: the target backup optical fiber not being open-circuited.

[0036] For example, the performance of the i-th main optical fiber is lower than the first performance threshold, including: the target performance parameter of the i-th main optical fiber is less than the minimum value among the target performance parameters of multiple backup optical fibers, and the difference between the minimum value and the target performance parameter of the i-th main optical fiber is greater than the parameter threshold; the larger the target performance parameter of the i-th main optical fiber, the higher the performance of the i-th main optical fiber.

[0037] Furthermore, the above content uses the switching condition including idle and performance higher than or equal to the first performance threshold as an example. Optionally, the switching condition may also include other conditions. For example, the switching condition may also include: performance higher than or equal to the second performance threshold, and the second performance threshold is greater than the first performance threshold.

[0038] Optionally, the optical transmission system further includes a light source connected to the end of each of the i-th main optical fiber and multiple backup optical fibers away from the i-th second optical switch; the light source is used to transmit probe light to each of the i-th main optical fiber and multiple backup optical fibers. The wavelength of the probe light is different from the wavelength of the optical signal, therefore, the probe light and the optical signal can be transmitted simultaneously in the same optical fiber. A first power detector is provided on the optical path from each of the i-th main optical fiber and multiple backup optical fibers to the i-th second optical switch. The control unit can determine, based on the power of the probe light detected by the first power detector, that the performance of the i-th main optical fiber is lower than a first performance threshold, and that the performance of the target backup optical fiber is higher than or equal to the first performance threshold.

[0039] Optionally, the i-th primary optical fiber has a corresponding backup optical fiber; when the backup optical fiber corresponding to the i-th primary optical fiber meets the switching conditions, the target backup optical fiber is the backup optical fiber corresponding to the i-th primary optical fiber; when the backup optical fiber corresponding to the i-th primary optical fiber does not meet the switching conditions, the target backup optical fiber is different from the backup optical fiber corresponding to the i-th primary optical fiber. It is evident that the control unit will control the i-th primary optical fiber to preferentially switch to its corresponding backup optical fiber. This avoids the occupation of backup optical fibers corresponding to other primary optical fibers, allowing other primary optical fibers to quickly switch to their corresponding primary optical fibers when their performance is poor.

[0040] Optionally, the control unit includes a first controller and a second controller; when the performance of the i-th main optical fiber is lower than a first performance threshold and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the first controller controls the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber; when the performance of the i-th main optical fiber is lower than the first performance threshold and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the second controller controls the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber.

[0041] Optionally, the control unit controls the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber, and further includes: when the performance of the i-th main optical fiber is lower than a first performance threshold and multiple backup optical fibers include the target backup optical fiber that meets the switching conditions, the second controller sends a switching instruction to the first controller, the switching instruction being used to indicate that the i-th main optical fiber is switched to the target backup optical fiber; the first controller can control the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber according to the switching instruction.

[0042] Furthermore, the second controller can send the switching instruction in the following ways: (1) The second controller can control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber after sending the switching instruction. (2) The second controller can control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber at the same time as sending the switching instruction. (3) The second controller can first control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber, and then send the switching instruction. In both methods (1) and (2), the switching instruction can be sent without waiting for the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber. In this way, the first controller can control the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber as early as possible, thereby shortening the time for the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber as a whole, and reducing the recovery time of the optical signal transmission on the i-th main optical fiber.

[0043] Optionally, the control unit can also determine that the fiber optic switching is successful based on the optical signal power detected by the third power detector, where the third power detector is located on the optical path from the i-th first optical switch to the target backup fiber optic cable.

[0044] Optionally, the optical transmission system further includes a third optical switch and a fourth optical switch connected to the target backup optical fiber; the target backup optical fiber is connected to multiple first optical switches via the third optical switch and to multiple second optical switches via the fourth optical switch; the target backup optical fiber corresponds to the j-th main optical fiber among multiple main optical fibers, j≥1, j≠i; the third optical switch is used to connect the target backup optical fiber to the j-th first optical switch, and the fourth optical switch is used to connect the target backup optical fiber to the j-th second optical switch; the optical fiber switching method provided in this application embodiment further includes: when the performance of the i-th main optical fiber is lower than a first performance threshold, and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the control unit controls the third optical switch and the fourth optical switch to switch the j-th main optical fiber to the i-th main optical fiber.

[0045] For example, when the control unit controls the third optical switch and the fourth optical switch to switch the j-th main optical fiber to the i-th main optical fiber, it can control the third optical switch and the fourth optical switch to switch the j-th main optical fiber to the i-th main optical fiber based on the fact that the third optical switch meets the operating conditions.

[0046] The above operating conditions can be achieved in various ways. For example, the operating conditions include the third optical switch not being faulty. Another example is that the operating conditions include the insertion loss of the third optical switch being less than the insertion loss threshold. Yet another example is that the operating conditions include the third optical switch not being faulty and the insertion loss of the third optical switch being less than the insertion loss threshold.

[0047] Under operating conditions including a fault-free third optical switch, the optical transmission system also includes a second power detector connected to the aforementioned third optical switch. This third optical switch is also used to connect the second power detector to the i-th first optical switch. After the control unit controls the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, it can determine that the third optical switch is not faulty based on the power of the i-th optical signal detected by the second power detector. It is understood that after the control unit controls the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, the i-th optical signal can be transmitted to the second power detector. At this time, the control unit can detect the power of the i-th optical signal through the second power detector and determine whether the third optical switch is faulty based on this power.

[0048] Under operating conditions, including an insertion loss of the third optical switch less than the insertion loss threshold, the optical transmission system includes a third power detector in addition to the aforementioned second power detector. This third power detector is connected between the third optical switch and the i-th first optical switch. The control unit, after controlling the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, determines the insertion loss of the third optical switch based on the power of the i-th optical signal detected by the second and third power detectors, respectively. It can be understood that after the control unit controls the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, the i-th optical signal can be transmitted from the i-th first optical switch sequentially through the third power detector and the third optical switch to the second power detector. At this time, the control unit can detect the power of the i-th optical signal through the second and third power detectors, respectively, and determine the insertion loss of the third optical switch based on these powers.

[0049] Optionally, the i-th first optical switch and the i-th second optical switch are also respectively connected to the two ends of each of the other main optical fibers in at least one other main optical fiber, and the other main optical fibers are different from the i-th main optical fiber; when the performance of the i-th main optical fiber is lower than the first performance threshold, multiple backup optical fibers do not meet the switching conditions, and at least one other main optical fiber includes the target main optical fiber that meets the switching conditions, the control unit can control the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target main optical fiber.

[0050] Thirdly, a control unit is provided, which can be a control unit in an optical transmission system provided by any of the designs in the first aspect. The optical transmission system includes: a control unit, multiple first optical switches, multiple second optical switches, multiple main optical fibers, and multiple backup optical fibers; the i-th first optical switch and the i-th second optical switch are respectively connected to the two ends of the i-th main optical fiber, and the i-th first optical switch and the i-th second optical switch are also respectively connected to the two ends of each backup optical fiber; i ≥ 1; the i-th first optical switch is used to receive the i-th optical signal from the multiple optical signals and transmit the i-th optical signal to the i-th main optical fiber; the i-th second optical switch is used to output the i-th optical signal received from the i-th main optical fiber; the multiple optical signals carry different service data respectively; the control unit is used to: when the performance of the i-th main optical fiber is lower than a first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, control the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber; the switching conditions include: idle and performance higher than or equal to the first performance threshold.

[0051] Optionally, the performance of the i-th main optical fiber being lower than the first performance threshold includes: the i-th main optical fiber being disconnected.

[0052] Optionally, the performance of the i-th main optical fiber being lower than the first performance threshold includes: the target performance parameter of the i-th main optical fiber being less than the minimum value among the target performance parameters of multiple backup optical fibers, and the difference between the minimum value and the target performance parameter of the i-th main optical fiber being greater than the parameter threshold; the larger the target performance parameter of the i-th main optical fiber, the higher the performance of the i-th main optical fiber.

[0053] Optionally, the switching conditions may also include: performance being higher than or equal to a second performance threshold, and the second performance threshold being greater than a first performance threshold.

[0054] Optionally, the optical transmission system further includes a light source, which connects to the end of each of the i-th main optical fiber and multiple backup optical fibers away from the i-th second optical switch; the light source is used to transmit probe light to each of the i-th main optical fiber and multiple backup optical fibers, the wavelength of the probe light being different from the wavelength of the optical signal; a first power detector is provided on the optical path from each of the i-th main optical fiber and multiple backup optical fibers to the i-th second optical switch; the control unit is used to: determine, based on the power of the probe light detected by the first power detector, that the performance of the i-th main optical fiber is lower than a first performance threshold, and that the performance of the target backup optical fiber is higher than or equal to the first performance threshold.

[0055] Optionally, the i-th main optical fiber has a corresponding backup optical fiber; when the backup optical fiber corresponding to the i-th main optical fiber meets the switching conditions, the target backup optical fiber is the backup optical fiber corresponding to the i-th main optical fiber; when the backup optical fiber corresponding to the i-th main optical fiber does not meet the switching conditions, the target backup optical fiber is different from the backup optical fiber corresponding to the i-th main optical fiber.

[0056] Optionally, the control unit includes: a first controller and a second controller; the first controller is used to control the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber when the performance of the i-th main optical fiber is lower than a first performance threshold and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions; the second controller is used to control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber when the performance of the i-th main optical fiber is lower than the first performance threshold and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions.

[0057] Optionally, the second controller is further configured to send a switching instruction to the first controller when the performance of the i-th main optical fiber is lower than the first performance threshold and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions. The switching instruction is used to indicate that the i-th main optical fiber is switched to the target backup optical fiber. The first controller is configured to control the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber according to the switching instruction.

[0058] Optionally, the second controller is used to control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber after sending the switching instruction.

[0059] Optionally, the optical transmission system further includes a third optical switch and a fourth optical switch connected to the target backup optical fiber; the target backup optical fiber is connected to multiple first optical switches via the third optical switch and to multiple second optical switches via the fourth optical switch; the target backup optical fiber corresponds to the j-th main optical fiber among multiple main optical fibers, j≥1, j≠i; the third optical switch is used to connect the target backup optical fiber to the j-th first optical switch, and the fourth optical switch is used to connect the target backup optical fiber to the j-th second optical switch; the control unit is used to: when the performance of the i-th main optical fiber is lower than a first performance threshold, and multiple backup optical fibers include the target backup optical fiber that meets the switching conditions, control the third optical switch and the fourth optical switch to switch the j-th main optical fiber to the i-th main optical fiber.

[0060] Optionally, the control unit is used to: based on the fact that the third optical switch meets the operating conditions, control the third optical switch and the fourth optical switch to switch the j-th main optical fiber to the i-th main optical fiber.

[0061] Optionally, the optical transmission system further includes a second power detector; the third optical switch is also used to connect the second power detector to the i-th first optical switch; the control unit is used to: after controlling the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber, determine that the third optical switch is not faulty based on the power of the i-th optical signal detected by the second power detector; the operating conditions include: the third optical switch is not faulty.

[0062] Optionally, the optical transmission system further includes a second power detector and a third power detector; the third optical switch is also used to connect the second power detector to the i-th first optical switch, and the third power detector is located on the optical path from the i-th first optical switch to the third optical switch; the control unit is used to: after controlling the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber, determine the insertion loss of the third optical switch based on the power of the i-th optical signal detected by the second power detector and the third power detector respectively; the operating conditions include: the insertion loss of the third optical switch is less than the insertion loss threshold.

[0063] Optionally, the optical transmission system further includes: a third power detector; the third power detector is located on the optical path from the i-th first optical switch to the target backup optical fiber; the control unit is used to: after controlling the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber, determine that the optical fiber switching is successful based on the optical signal power detected by the third power detector.

[0064] Optionally, the i-th first optical switch and the i-th second optical switch are respectively connected to both ends of each of the other main optical fibers in at least one other main optical fiber, and the other main optical fibers are different from the i-th main optical fiber; the control unit is also used to: when the performance of the i-th main optical fiber is lower than a first performance threshold, multiple backup optical fibers do not meet the switching conditions, and at least one other main optical fiber includes a target main optical fiber that meets the switching conditions, control the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target main optical fiber.

[0065] Fourthly, this application also provides a chip including programmable logic circuitry and / or program instructions, which, when running, are used to implement the method executed by a control unit or any controller (such as a first controller or a second controller) in the method provided by the second aspect above in the embodiments of this application.

[0066] The effects of the second to fourth aspects mentioned above can be referred to the effects of the corresponding designs in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0067] Figure 1 is a schematic diagram of a DCI network system provided in an embodiment of this application;

[0068] Figure 2 is a schematic diagram of an optical transmission system provided in an embodiment of this application;

[0069] Figure 3 is a schematic diagram of optical signal transmission provided in an embodiment of this application;

[0070] Figure 4 is a schematic diagram of another optical signal transmission provided in an embodiment of this application;

[0071] Figure 5 is a schematic diagram of another optical transmission system provided in an embodiment of this application;

[0072] Figure 6 is a schematic diagram of another optical transmission system provided in an embodiment of this application;

[0073] Figure 7 is a schematic diagram of another optical transmission system provided in an embodiment of this application;

[0074] Figure 8 is a schematic diagram of another optical signal transmission provided in an embodiment of this application;

[0075] Figure 9 is a schematic diagram of another optical transmission system provided in an embodiment of this application;

[0076] Figure 10 is a schematic diagram of another optical transmission system provided in an embodiment of this application;

[0077] Figure 11 is a schematic diagram of another optical transmission system provided in an embodiment of this application;

[0078] Figure 12 is a schematic diagram of another optical transmission system provided in an embodiment of this application;

[0079] Figure 13 is a schematic diagram of another optical transmission system provided in an embodiment of this application;

[0080] Figure 14 is a schematic diagram of another optical transmission system provided in an embodiment of this application;

[0081] Figure 15 is a flowchart of an optical fiber switching method provided in an embodiment of this application;

[0082] Figure 16 is a schematic diagram of the interaction between the first controller and the second controller in a control unit provided in an embodiment of this application. Detailed Implementation

[0083] This application provides an optical transmission system, which can be a DCI network system or other systems that require communication via optical signals.

[0084] DCI network systems primarily use point-to-point (PTP) networking. As shown in Figure 1, a DCI network system has two planes: Plane 1 and Plane 2. Each plane includes a multiplexing unit, a demultiplexer, a main optical fiber, a backup optical fiber, an optical switch, and multiple optical amplifiers (APAs). Within each plane, multiple wavelengths of optical signals are combined into a single optical signal in the multiplexing unit. This single optical signal is then split by the optical splitter and transmitted to the main optical fiber and the backup optical fiber, respectively. The optical switch can selectively transmit the optical signal from the main optical fiber or the backup optical fiber to the demultiplexer, which then splits the single optical signal into individual wavelengths before outputting them. Furthermore, the optical signals in Plane 1 and Plane 2 carry different service data.

[0085] Within each optical plane, the optical switch typically selects to transmit the optical signal from the primary optical fiber to the wavelength division multiplexing (WDM) unit. When the primary optical fiber fails, the optical switch stops transmitting the optical signal from the primary optical fiber to the WDM unit and instead transmits the optical signal from the backup optical fiber to the WDM unit, thereby restoring service within that plane.

[0086] However, when both the primary and backup fiber optic cables in a given plane fail simultaneously, optical signals within that plane cannot be transmitted effectively, making it impossible to restore services within that plane. Consequently, due to the service interruption in one of the two planes, the total capacity of the entire DCI network system is halved.

[0087] This application provides an optical transmission system that can restore the transmission of optical signals in a plane when all optical fibers in one of the multiple planes fail, thereby avoiding a halving of the capacity of the optical transmission system.

[0088] For example, Figure 2 is a schematic diagram of the structure of an optical transmission system provided in an embodiment of this application. As shown in Figure 2, the optical transmission system includes: multiple first optical switches 01, multiple second optical switches 02, a control unit 03, multiple main optical fibers 041 and multiple backup optical fibers 042.

[0089] Figure 2 uses two first optical switches 01 and two second optical switches 02 as an example. It is understood that the number of first optical switches 01 and second optical switches 02 may not be 2, and the number of first optical switches 01 and second optical switches 02 may be the same or different. This application embodiment does not limit this.

[0090] The i-th first optical switch 01 among multiple first optical switches 01 and the i-th second optical switch 02 among multiple second optical switches 02 are respectively connected to the two ends of the i-th main optical fiber 041 among multiple main optical fibers 041. The i-th first optical switch 01 and the i-th second optical switch 02 are also respectively connected to the two ends of each backup optical fiber 042; i≥1. For example, in Figure 2, the first first optical switch 01 and the first second optical switch 02 counted from top to bottom are respectively connected to the two ends of the first main optical fiber 041 counted from top to bottom. The first first optical switch 01 and the first second optical switch 02 are also respectively connected to the two ends of each backup optical fiber 042. In Figure 2, the second first optical switch 01 and the second second optical switch 02 from top to bottom are respectively connected to the two ends of the second main optical fiber 041 from top to bottom. The second first optical switch 01 and the second second optical switch 02 are also respectively connected to the two ends of each backup optical fiber 042.

[0091] The i-th first optical switch 01 is used to receive the i-th optical signal from the multiple optical signals and transmit the i-th optical signal to the i-th main optical fiber; the i-th second optical switch is used to output the i-th optical signal received from the i-th main optical fiber; the multiple optical signals carry different service data respectively. It can be seen that after the multiple optical signals are transmitted to the optical transmission system provided in this application embodiment, they will be transmitted to multiple first optical switches 01 respectively, wherein each first optical switch 01 receives one optical signal, and different first optical switches 01 receive different optical signals. Each first optical switch 01 can transmit the received optical signal to the corresponding second optical switch 02 through the corresponding main optical fiber 041, and different optical switches 01 transmit the received optical signals to different second optical switches 02 through different main optical fibers 041. Each of the above multiple optical signals can be a single-wavelength optical signal or a multi-wavelength optical signal, and the wavelengths of different optical signals can be the same or different. The i-th optical signal can be the optical signal of the i-th plane, so the n optical signals can be the optical signals of n planes.

[0092] The control unit 03 controls multiple first optical switches 01 and multiple second optical switches 02 to switch a primary optical fiber 041 to restore services on that primary optical fiber 041 when its performance is poor. For example, the control unit 03 controls the i-th first optical switch 01 and the i-th second optical switch 02 to switch the i-th primary optical fiber 041 to the target backup optical fiber 042 when the performance of the i-th primary optical fiber 041 is lower than a first performance threshold and multiple backup optical fibers 042 include a target backup optical fiber 042 that meets the switching conditions. The switching conditions include: being idle and having performance higher than or equal to the first performance threshold.

[0093] An idle fiber refers to an optical fiber that is not transmitting optical signals carrying service data. When the performance of the i-th main fiber is lower than a first performance threshold, the performance of the i-th main fiber is poor. In this case, if the i-th optical signal continues to be transmitted on the i-th main fiber, it will result in the i-th optical signal being unable to be transmitted effectively. The target backup fiber is idle and its performance is higher than or equal to the first performance threshold. Therefore, the target backup fiber can support the effective transmission of the i-th optical signal. At this time, the control unit can control the i-th first optical switch 01 and the i-th second optical switch 02 to switch the i-th main fiber to the target backup fiber. The performance of an optical fiber can be represented by its performance parameters (such as the negative of the power attenuation of light on the fiber). Correspondingly, the aforementioned first performance threshold can also be represented by the threshold of these performance parameters.

[0094] When the control unit 03 controls the i-th first optical switch 01 and the i-th second optical switch 02 to switch the i-th main optical fiber 041 to the target backup optical fiber 042, it can control the i-th first optical switch 01 to stop transmitting the i-th optical signal to the i-th main optical fiber and control the i-th first optical switch 01 to transmit the i-th optical signal to the target backup optical fiber 042. The control unit 03 can also control the i-th second optical switch 02 to stop outputting the i-th optical signal received from the i-th main optical fiber 041 and output the i-th optical signal received from the target backup optical fiber 042. As can be seen, when the performance of the i-th main optical fiber 041 is lower than the first performance threshold, the control unit 03 can switch the i-th main optical fiber 041 to the target backup optical fiber 042 by controlling the first optical switch 01 and the second optical switch 02, thereby switching the i-th optical signal from the i-th main optical fiber 041 to the target backup optical fiber 042 and restoring the transmission of the i-th optical signal on the i-th main optical fiber 041.

[0095] For example, referring to Figure 3, suppose the first optical signal is transmitted to the first optical switch 01, which transmits the first optical signal to the first main optical fiber 041. The first second optical switch 02 can output the optical signal received from the first main optical fiber 041. Referring to Figure 4, if the performance of the first main optical fiber 041 is lower than a first performance threshold, and the first backup optical fiber 042 meets the switching conditions, then the control unit 03 can control the first optical switch 01 to transmit the received optical signal to the first backup optical fiber 042, and the first second optical switch 02 can output the optical signal received from the first backup optical fiber 042. In this way, the first optical signal is switched from the first main optical fiber 041 to the first backup optical fiber, restoring the transmission of the first optical signal.

[0096] In this embodiment, the control unit 03 controls the i-th first optical switch 01 and the i-th second optical switch 02 to switch the i-th main optical fiber to the target backup optical fiber when the performance of the i-th main optical fiber is lower than the first performance threshold, in order to restore the transmission of the i-th optical signal. It is understood that the control unit 03 can also control the first and second optical switches connected to other main optical fibers to switch those main optical fibers to backup optical fibers when the performance of other main optical fibers is lower than the first performance threshold, in order to restore the transmission of the optical signal transmitted on those main optical fibers. This embodiment will not elaborate on this further.

[0097] The aforementioned target backup fiber can be any one of multiple backup fibers that meets the switching conditions. Both the first optical switch and the second optical switch are connected to these multiple backup fibers. Therefore, both the first optical switch and the second optical switch support switching the main fiber to any backup fiber.

[0098] In summary, in the optical transmission system provided by this application embodiment, multiple first optical switches can receive multiple optical signals carrying different service data and transmit these signals to multiple second optical switches via multiple main optical fibers. Furthermore, each first and second optical switch is connected not only to its corresponding main optical fiber but also to multiple backup optical fibers. When the performance of a main optical fiber falls below a first performance threshold, the control unit can control the first and second optical switches connected to that main optical fiber to switch it to a backup optical fiber, thereby restoring the transmission of optical signals on that main optical fiber. Since both the first and second optical switches are connected to multiple backup optical fibers, multiple backup optical fibers are available when switching from a main optical fiber to a backup optical fiber is required. Even if one backup optical fiber fails, other backup optical fibers can be used for switching. Therefore, interruptions to optical signals on the main optical fiber can be reduced, improving the reliability of optical signal transmission and increasing the capacity of the optical transmission system.

[0099] For example, suppose the performance of the first primary fiber 041 in Figure 2 is below a first performance threshold. In one scenario, if the first backup fiber 042 meets the switching conditions, the control unit 02 can control the first optical switch 01 and the first optical switch 02 to switch the first primary fiber 041 to the first backup fiber 042, thereby restoring the transmission of the first optical signal. In another scenario, if the first backup fiber 042 does not meet the switching conditions, but the second backup fiber 042 does, the control unit 03 can control the first optical switch 01 and the first optical switch 02 to switch the first primary fiber 041 to the second backup fiber 042, thereby restoring the transmission of the first optical signal. It can be seen that when the first backup optical fiber 041 does not meet the switching conditions, the first main optical fiber 041 can be switched to the second backup optical fiber 042. Therefore, the probability of restoring the transmission of the first optical signal is increased, and the capacity of the optical transmission system is increased.

[0100] Furthermore, as described above, the optical transmission system provided in this application uses an optical switch (OSW) to switch the optical fiber that is conducting, thereby switching the transmission path of the optical signal. These optical switches are, for example, the first optical switch and the second optical switch mentioned above. Because the switching speed of the optical switch is relatively fast, it ensures a fast switching speed of the optical fiber in the optical transmission system and guarantees that the transmission of the optical signal on the optical fiber can be quickly restored (e.g., within 50 milliseconds). Moreover, the cost of the optical switch is low; therefore, the cost of the optical transmission system provided in this application is also low.

[0101] Furthermore, when the number of backup optical fibers is less than the number of main optical fibers, the embodiments of this application can protect a large number of main optical fibers with a small number of backup optical fibers, thereby reducing the optical fiber resources in the optical transmission system, which is suitable for scenarios where optical fiber resources are relatively scarce.

[0102] Figure 5 is a schematic diagram of another optical transmission system provided in an embodiment of this application. As shown in Figure 5, based on Figure 2, a first power detector 05 is provided on the optical path from the i-th main optical fiber 041 and the multiple backup optical fibers 042 to the i-th second optical switch 02. In this embodiment of the application, the i-th main optical fiber 041 is taken as the first main optical fiber 041, the i-th first optical switch 01 is taken as the first first optical switch 01, and the i-th second optical switch 02 is taken as the first second optical switch.

[0103] The optical transmission system also includes a light source (not shown in Figure 5), which connects to the end of each of the i-th main optical fiber 041 and the multiple backup optical fibers 042 furthest from the i-th second optical switch 02. The light source is used to transmit probe light to each of the i-th main optical fiber 041 and the multiple backup optical fibers 042. The wavelength of the probe light is different from the wavelength of the optical signal; therefore, the probe light and the optical signal can be transmitted simultaneously in the same optical fiber.

[0104] The control unit 03 can be used to determine, based on the power of the probe light detected by the first power detector 05, that the performance of the i-th main optical fiber 041 is lower than a first performance threshold, and to determine that the target backup optical fiber 042 meets the switching conditions. For the first power detector 05 on the optical path from any of the i-th main optical fiber 041 and multiple backup optical fibers 042 to the second optical switch 02, the control unit 03 can compare the power of the probe light detected by the first power detector 05 with the power of the probe light that the first power detector 05 should ideally detect, to determine whether the performance of any optical fiber is lower than the first performance threshold.

[0105] The power detected by the power detector (such as the first power detector 05) in this application embodiment can be the absolute optical power or the relative change in optical power, and this application embodiment does not limit this. The power detector in this application embodiment can be a device capable of detecting power, such as a photoelectric detector (PD).

[0106] In this embodiment, the control unit 03 determines whether the performance of the optical fiber is lower than a first performance threshold based on the detection result of the first power detector 05. In this case, the control unit 03 needs to be connected to the first power detector 05 (not shown in Figure 5) via wired or wireless means. It is understood that the control unit 03 can also determine these conditions in other ways, in which case the optical transmission system may not include the first power detector 05. For example, the control unit 03 receives the judgment results of these conditions input by the operator and makes judgments based on these results.

[0107] Furthermore, there are several ways to make the performance of the i-th main optical fiber fall below the first performance threshold.

[0108] For example, the performance of the i-th main optical fiber being lower than the first performance threshold includes: the i-th main optical fiber being open-circuited. In this case, the performance of the target backup optical fiber being higher than or equal to the first performance threshold includes: the target backup optical fiber not being open-circuited (also referred to as loss of signal (LOS)). For instance, if the optical signal power detected by the first power detector 05 between a certain optical fiber and the i-th second optical switch 02 is less than the power threshold, the control unit 03 can determine that the optical fiber is open-circuited. If the power of the detection light detected by the first power detector 05 between a certain optical fiber and the i-th second optical switch 02 is greater than or equal to the power threshold, the control unit 03 can determine that the optical fiber is not open-circuited. This power threshold can be zero or a value greater than zero.

[0109] For example, the performance of the i-th main optical fiber being lower than the first performance threshold includes: the target performance parameter of the i-th main optical fiber is less than the minimum value among the target performance parameters of the multiple backup optical fibers, and the difference between the minimum value and the target performance parameter of the i-th main optical fiber is greater than the parameter threshold; the larger the target performance parameter of the i-th main optical fiber, the higher the performance of the i-th main optical fiber. In this case, the performance of the target backup optical fiber being higher than or equal to the first performance threshold includes: the target performance parameter of the target backup optical fiber is greater than the target performance parameter of the i-th main optical fiber, and the difference between the target performance parameter of the target backup optical fiber and the target performance parameter of the i-th main optical fiber is greater than the parameter threshold. The above parameter threshold can be zero or any value greater than zero. The control unit can determine the target performance parameter of any optical fiber based on the power of the detection light detected by the first power detector 05 between any optical fiber and the i-th second optical switch. For example, the target performance parameter is the power detected by the first power detector 05, or the ratio of that power to a fixed value, etc.

[0110] Furthermore, the above description uses the switching condition of being idle and having performance higher than or equal to the first performance threshold as an example. Optionally, the switching condition may also include other conditions, such as: performance higher than or equal to a second performance threshold, where the second performance threshold is greater than the first performance threshold. Therefore, when a backup fiber is idle and its performance is higher than or equal to the first performance threshold, the control unit can also determine whether the performance of the backup fiber is higher than or equal to the second performance threshold. Only when the performance of the backup fiber is higher than or equal to the second performance threshold can it be determined that the backup fiber has higher performance and can effectively transmit optical signals. Therefore, the control unit can determine that the backup fiber meets the switching condition.

[0111] Optionally, at least one of the multiple main optical fibers 041 corresponds one-to-one with at least one of the multiple backup optical fibers 042; the at least one main optical fiber 041 may be some or all of the multiple main optical fibers 041, and the at least one backup optical fiber 042 may also be some or all of the multiple backup optical fibers 042, and this application embodiment does not limit this. For example, in Figure 2, the main optical fiber 041 and the backup optical fiber 042 correspond in each plane.

[0112] The one-to-one correspondence between the at least one main optical fiber 041 and the at least one backup optical fiber 042 can be stored in the control unit 03, or stored outside the control unit 03 in a location that can be read by the control unit 03.

[0113] When there is a one-to-one correspondence between at least one main optical fiber 041 and at least one backup optical fiber 042, if the backup optical fiber 042 corresponding to the i-th main optical fiber 041 meets the switching conditions, then the target backup optical fiber 042 is the backup optical fiber 042 corresponding to the i-th main optical fiber 041; if the backup optical fiber 042 corresponding to the i-th main optical fiber 041 does not meet the switching conditions, then the target backup optical fiber 042 is different from the backup optical fiber 042 corresponding to the i-th main optical fiber 041.

[0114] When the performance of the i-th main optical fiber 041 is lower than a first performance threshold, the control unit 03 can determine whether the i-th main optical fiber 041 has a corresponding backup optical fiber 042. If the i-th main optical fiber 041 has a corresponding backup optical fiber 042, and the backup optical fiber 042 meets the switching conditions, then the control unit 03 can control the i-th main optical fiber 041 to switch to the corresponding backup optical fiber 042. If the i-th main optical fiber 041 has a corresponding backup optical fiber 042, and the backup optical fiber 042 does not meet the switching conditions, then the control unit 03 can control the i-th main optical fiber 041 to switch to one of the backup optical fibers 042 among the multiple backup optical fibers 042, excluding the backup optical fiber 042 corresponding to the i-th main optical fiber 041. As can be seen, the control unit 03 will control the i-th main optical fiber 041 to switch to the corresponding backup optical fiber 042 first. In this way, the backup optical fiber 042 corresponding to other main optical fibers 041 can be avoided, so that other main optical fibers 041 can quickly switch to the corresponding main optical fiber 041 when the performance is poor.

[0115] When the backup optical fiber 042 corresponding to the i-th main optical fiber 041 does not meet the switching conditions, the control unit 03 can sequentially determine whether the backup optical fiber 042 meets the switching conditions in order of total optical fiber length from small to large or optical fiber performance from high to low, until a backup optical fiber 042 that meets the switching conditions is found, and the backup optical fiber 042 is taken as the target backup optical fiber 042.

[0116] If the i-th main fiber 041 does not have a corresponding backup fiber 042, and if among the multiple backup fibers 042 there is a backup fiber 042 that does not correspond to the main fiber 041 (i.e., the multiple backup fibers 042 include backup fibers 042 other than the aforementioned at least one backup fiber 042), then the control unit 03 can control the i-th main fiber 041 to switch to a backup fiber 042 among these backup fibers 042 that does not correspond to the main fiber 041 and meets the switching conditions. If the i-th main fiber 041 does not have a corresponding backup fiber 042, and among the multiple backup fibers 042 there is also no backup fiber 042 that does not correspond to the main fiber 041 (i.e., the multiple backup fibers 042 do not include backup fibers 042 other than the aforementioned at least one backup fiber 042), then the control unit 03 can control the i-th main fiber 041 to switch to any one of the multiple backup fibers 042 that meets the switching conditions.

[0117] Of course, there is no such correspondence between the multiple main optical fibers 041 and the multiple backup optical fibers 042. The control unit 03 can control the i-th main optical fiber 041 to randomly switch to a backup optical fiber 042. Each of the above-mentioned at least one main optical fiber 041 can also correspond to multiple backup optical fibers 042, instead of corresponding to one backup optical fiber 042. Furthermore, different main optical fibers 041 correspond to different backup optical fibers 042. This application embodiment does not limit this.

[0118] Optionally, the control unit 03 can be implemented in various ways. For example, the control unit 03 can be a controller connected to each first optical switch 01 and each second optical switch 02, used to control the switching of optical fibers by each first optical switch 01 and each second optical switch 02. As shown in Figure 5, the control unit 03 includes: a first controller 031 and a second controller 032; the first controller 031 is connected to the i-th first optical switch 01 and used to control the switching of optical fibers by the i-th first optical switch 01; the second controller 032 is connected to the i-th second optical switch 02 and used to control the switching of optical fibers by the i-th second optical switch 02.

[0119] For example, the first controller 031 is configured to control the i-th first optical switch 01 to switch the i-th main optical fiber 041 to the target backup optical fiber 042 when the performance of the i-th main optical fiber 041 is lower than a first performance threshold and multiple backup optical fibers 042 include a target backup optical fiber 042 that meets the switching conditions. The second controller 032 is configured to control the i-th second optical switch 02 to switch the i-th main optical fiber 041 to the target backup optical fiber 042 when the performance of the i-th main optical fiber 041 is lower than the first performance threshold and multiple backup optical fibers 042 include a target backup optical fiber 042 that meets the switching conditions.

[0120] Furthermore, whether the performance of the i-th primary optical fiber is lower than the first performance threshold, and whether the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, can be determined by either the first controller or the second controller. For example, if the second controller determines whether the performance of the i-th primary optical fiber is lower than the first performance threshold and whether the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the second controller is used to control the i-th second optical switch to switch the i-th primary optical fiber to the target backup optical fiber, and to send a switching instruction to the first controller. This switching instruction indicates that the i-th primary optical fiber should be switched to the target backup optical fiber. The first controller is used to control the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber according to the switching instruction.

[0121] The second controller 032 can send the switching instruction in the following ways: (1) After sending the switching instruction, the second controller 032 can control the i-th second optical switch 02 to switch the i-th main optical fiber 041 to the target backup optical fiber 042. (2) The second controller can control the i-th second optical switch 02 to switch the i-th main optical fiber 041 to the target backup optical fiber 042 at the same time as sending the switching instruction. (3) The second controller can first control the i-th second optical switch 02 to switch the i-th main optical fiber 041 to the target backup optical fiber 042, and then send the switching instruction. In both methods (1) and (2), there is no need to wait for the i-th second optical switch 02 to switch the i-th main optical fiber 041 to the target backup optical fiber 042 before sending the switching instruction. In this way, the first controller 031 can control the i-th first optical switch 01 to switch the i-th main optical fiber 041 to the target backup optical fiber 042 as early as possible, thereby shortening the time for the i-th first optical switch 01 and the i-th second optical switch 02 to switch the i-th main optical fiber 041 to the target backup optical fiber 042 as a whole, and reducing the recovery time of the optical signal transmission on the i-th main optical fiber 041.

[0122] The control unit 03 may include multiple first controllers 031 and multiple second controllers 032. Each first controller 031 corresponds one-to-one with a multiple first optical switches 01. Each first controller 031 controls the corresponding first optical switch 01 to perform fiber optic switching, and each second controller 032 controls the corresponding second optical switch 02 to perform fiber optic switching. In this case, the second controller 032 corresponding to the second optical switch 02 connected to each main optical fiber 041 has a signaling transmission channel (which can also be an optical fiber) with the first controller 031 corresponding to the first optical switch 01 connected to that main optical fiber 041. The aforementioned switching instruction can be transmitted from the second controller 032 to the first controller 031 through this signaling transmission channel. Each first optical switch 01 and its corresponding first controller 031 can be located on the same board, while different first optical switches 01 can be located on different boards; similarly, each second optical switch 02 and its corresponding second controller 032 can be located on the same board, while different second optical switches 02 can be located on different boards.

[0123] It is understood that multiple first optical switches 01 can also share a first controller 031, which controls the fiber switching of each first optical switch 01; multiple second optical switches 02 can also share a second controller 032, which controls the fiber switching of each second optical switch 02. In this case, there is a signaling transmission channel (which can also be an optical fiber) between the second controller 032 and the first controller 031, and the aforementioned switching instruction can be transmitted from the second controller 032 to the first controller 031 through the signaling transmission channel.

[0124] Optionally, please continue to refer to Figure 5. The optical transmission system provided in this application embodiment also includes a third optical switch 06 and a fourth optical switch 07. The target backup optical fiber 042 is connected to the above-mentioned multiple first optical switches 01 through the third optical switch 06, and the target backup optical fiber 041 is also connected to the above-mentioned multiple second optical switches 02 through the fourth optical switch 07.

[0125] Assuming the target backup fiber 042 corresponds to the j-th main fiber 041 among multiple main fibers 041, where j ≥ 1 and j ≠ i; then, the third optical switch 06 is used to connect the target backup fiber 042 to the j-th first optical switch 01 (the first optical switch 01 connected to the j-th main fiber 041), and the fourth optical switch 07 is used to connect the target backup fiber 042 to the j-th second optical switch 02 (the second optical switch connected to the j-th main fiber 041). It can be seen that the third optical switch 06 connected to each backup fiber 042 defaults to connecting the backup fiber 042 to the first optical switch 01 connected to the corresponding main fiber 041, and the fourth optical switch 07 connected to each backup fiber 042 defaults to connecting the backup fiber 042 to the second optical switch 02 connected to the corresponding main fiber 041. The control unit 03 is used to control the third optical switch 06 and the fourth optical switch 07 to switch the j-th main optical fiber 041 to the i-th main optical fiber 041 when the performance of the i-th main optical fiber 01 is lower than the first performance threshold and multiple backup optical fibers 042 include a target backup optical fiber 042 that meets the switching conditions.

[0126] In other words, when the control unit 03 controls the switching of the i-th main optical fiber 01 to the target backup optical fiber 042, it also controls the third optical switch 06 to change the conduction of the first optical switch 01, and controls the fourth optical switch 07 to change the conduction of the second optical switch 02. This causes the third optical switch 06 to connect the target backup optical fiber 042 to the i-th first optical switch 01, and the fourth optical switch 07 to connect the target backup optical fiber 042 to the i-th second optical switch 02. Thus, the i-th optical signal can be transmitted sequentially through the i-th first optical switch 01, the third optical switch 06, the target backup optical fiber 042, and the fourth optical switch 07 to the i-th second optical switch 02.

[0127] Here, we take the example where the j-th main fiber 041 corresponding to the target backup fiber 042 is different from the i-th main fiber 041. When the j-th main fiber 041 corresponding to the target backup fiber 042 is the same as the i-th main fiber 041, the third optical switch 06 defaults to connecting the target backup fiber 042 with the i-th first optical switch 01, and the fourth optical switch 07 defaults to connecting the target backup fiber 042 with the i-th second optical switch 02. Therefore, the control unit 03 does not need to control the third optical switch 06 and the fourth optical switch 07 to quickly switch the i-th main fiber to the target backup fiber, so that the i-th optical signal can be transmitted sequentially through the i-th first optical switch 01, the third optical switch 06, the target backup fiber 042, and the fourth optical switch 07 to the i-th second optical switch 02.

[0128] Furthermore, the control unit 03 can also be used to control the third optical switch 06 and the fourth optical switch 07 to switch the j-th main optical fiber 041 to the i-th main optical fiber 041 based on the third optical switch 06 meeting the operating conditions. It can be seen that before controlling the third optical switch 06 and the fourth optical switch 07 to switch the j-th main optical fiber 041 to the i-th main optical fiber 041, the control unit 03 can also determine whether the third optical switch 06 meets the operating conditions. Only when it is determined that the third optical switch 06 meets the operating conditions will the control unit 03 control the third optical switch 06 and the fourth optical switch 07 to switch the j-th main optical fiber 041 to the i-th main optical fiber 041. If it is determined that the third optical switch 06 does not meet the operating conditions, the control unit 03 will not control the third optical switch 06 and the fourth optical switch 07 to switch the j-th main optical fiber 041 to the i-th main optical fiber 041.

[0129] The above operating conditions can be achieved in various ways. For example, the operating conditions include the third optical switch 06 not being faulty. Another example is that the operating conditions include the insertion loss of the third optical switch 06 being less than the insertion loss threshold. Yet another example is that the operating conditions include the third optical switch 06 not being faulty, and the insertion loss of the third optical switch 06 being less than the insertion loss threshold.

[0130] As shown in Figure 6, assuming the third optical switch 06 is functioning correctly, the optical transmission system also includes a second power detector 08 connected to the third optical switch 06. The third optical switch 06 is also used to connect the second power detector 08 to the i-th first optical switch 01. After controlling the i-th first optical switch 01 to switch the i-th main optical fiber 041 to the target backup optical fiber 042, the control unit 03 can determine that the third optical switch 06 is functioning correctly based on the power of the i-th optical signal detected by the second power detector 08. It is understood that after the control unit 03 controls the i-th first optical switch 01 to switch the i-th main optical fiber to the target backup optical fiber 042, the i-th optical signal can be transmitted to the second power detector 08. At this time, the control unit 03 can detect the power of the i-th optical signal through the second power detector 08 and determine whether the third optical switch 06 is faulty based on this power.

[0131] Under operating conditions, including an insertion loss of the third optical switch 06 less than the insertion loss threshold, as shown in Figure 6, the optical transmission system includes a third power detector 09 in addition to the aforementioned second power detector 08. This third power detector 09 is connected between the third optical switch 06 and the i-th first optical switch 01. The control unit 03, after controlling the i-th first optical switch 01 to switch the i-th main optical fiber 041 to the target backup optical fiber 042, determines the insertion loss of the third optical switch based on the power of the i-th optical signal detected by the second power detector 08 and the third power detector 09, respectively. It can be understood that after the control unit 03 controls the i-th first optical switch 01 to switch the i-th main optical fiber to the target backup optical fiber 042, the i-th optical signal can be transmitted from the i-th first optical switch 01 sequentially through the third power detector 09 and the third optical switch 06 to the second power detector 08. At this time, the control unit 03 can detect the power of the i-th optical signal through the second power detector 08 and the third power detector 09 respectively, and determine the insertion loss of the third optical switch 06 based on these powers.

[0132] It is understood that the optical transmission system provided in this application embodiment may also exclude the aforementioned third optical switch 06 and fourth optical switch 07. In this case, the aforementioned third optical switch 06 can be replaced with a beam combiner, and the aforementioned fourth optical switch 07 can be replaced with a beam splitter.

[0133] Furthermore, the optical transmission system provided in this application embodiment may further include: a third power detector; the third power detector is located on the optical path from the i-th first optical switch 01 to the target backup optical fiber 042. The control unit 03 is used to determine that the fiber switching is successful based on the optical signal power detected by the third power detector after controlling the i-th main optical fiber to switch to the target backup optical fiber (e.g., after controlling the i-th first optical switch 01 and the i-th second optical switch 02 to switch the i-th main optical fiber to the target backup optical fiber). It can be understood that the third power detector is located on the optical path from the i-th first optical switch 01 to the target backup optical fiber 042. If the fiber switching is successful (the i-th main optical fiber is switched to the target backup optical fiber), the i-th optical signal will pass through the third power detector, and the optical signal power detected by the third power detector will be high. If the fiber switching is unsuccessful (the i-th main optical fiber is not switched to the target backup optical fiber), the i-th optical signal will not pass through the third power detector, and the optical signal power detected by the third power detector will be low. Therefore, the control unit 03 can determine whether the optical fiber switching was successful based on the optical signal power detected by the third power detector.

[0134] In the above embodiments, the example is taken where, when the performance of the i-th main optical fiber is lower than a first performance threshold, there is a target backup optical fiber among the multiple backup optical fibers that meets the switching conditions, and the i-th main optical fiber is switched to this target backup optical fiber. Optionally, in some cases, when the performance of the i-th main optical fiber is lower than the first performance threshold, if none of the multiple backup optical fibers meet the switching conditions, and the i-th first optical switch and the i-th second optical switch are both connected to at least one other main optical fiber, then it is also possible to search among the other main optical fibers for a main optical fiber that meets the switching conditions, so as to switch the i-th main optical fiber to a main optical fiber that meets the switching conditions. In this way, it avoids the situation where the transmission of the optical signal on the i-th main optical fiber cannot be recovered when none of the multiple backup optical fibers meet the switching conditions, thus increasing the probability of recovering the transmission of the optical signal.

[0135] For example, the i-th first optical switch and the i-th second optical switch are respectively connected to both ends of each of at least one other main optical fiber, which is different from the i-th main optical fiber. The control unit is further configured to control the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target main optical fiber when the performance of the i-th main optical fiber is lower than a first performance threshold, multiple backup optical fibers do not meet the switching conditions, and at least one other main optical fiber includes a target main optical fiber that meets the switching conditions. The at least one other main optical fiber can be all or part of the main optical fibers other than the i-th main optical fiber among the multiple main optical fibers.

[0136] As shown in Figure 7, based on Figure 2, taking i = 1 as an example, the first optical switch and the first optical switch are also connected to the two ends of the second main optical fiber, respectively. As shown in Figure 8, the control unit is also used to control the first optical switch and the first optical switch to switch the first main optical fiber to the target main optical fiber (the second main optical fiber) when the performance of the first main optical fiber is lower than the first performance threshold, multiple backup optical fibers do not meet the switching conditions, and the second main optical fiber meets the switching conditions.

[0137] Furthermore, after switching the i-th primary fiber to another fiber (such as the aforementioned target backup fiber or the aforementioned target primary fiber), the control unit can also detect whether the i-th primary fiber has recovered its performance (possibly due to maintenance performed on the i-th primary fiber). For example, it can detect whether the performance of the i-th primary fiber is higher than or equal to a first performance threshold. Moreover, after determining that the i-th primary fiber has recovered its performance, the control unit can switch the other fiber back to the i-th primary fiber, so that the other fiber can transmit other optical signals.

[0138] In addition, similar to the third optical switch, fourth optical switch, first power detector, second power detector and third power detector in the aforementioned embodiments, as shown in Figure 8, the target main optical fiber 041 can also be connected to the first optical switch 01 that needs to be connected through the third optical switch 06, and the target main optical fiber 041 can also be connected to the second optical switch 02 that needs to be connected through the fourth optical switch 07. A first power detector 05 can also be provided on the optical path between the target main optical fiber 041 and the second optical switch 02. A light source (not shown in Figure 9) can also be connected to the target main optical fiber 041, and the third optical switch 06 connected to the target main optical fiber 041 can also be connected to the second power detector 08 and the third power detector 09.

[0139] The function of the third optical switch connected to the target primary fiber is similar to that of the third optical switch connected to the target backup fiber, with the difference being: the third optical switch connected to the target backup fiber is used to connect the target backup fiber to the j-th first optical switch connected to its corresponding j-th primary fiber; the fourth optical switch connected to the target backup fiber is used to connect the target backup fiber to the j-th second optical switch connected to its corresponding j-th primary fiber. Assuming the target primary fiber is the h-th primary fiber (h≥1), then the third optical switch connected to the target primary fiber is used to connect the target primary fiber to the h-th first optical switch, and the fourth optical switch connected to the target primary fiber is used to connect the target primary fiber to the h-th second optical switch.

[0140] The first power detector installed on the optical path between the target main optical fiber and the second optical switch can refer to the first power detector installed on the optical path between the target backup optical fiber and the second optical switch; the second power detector and the third power detector connected to the third optical switch connected to the target main optical fiber can refer to the second power detector and the third power detector connected to the third optical switch connected to the target backup optical fiber; the functions of the control unit related to these new components can also refer to the corresponding functions of the control unit in the foregoing embodiments.

[0141] In the aforementioned embodiment, i is taken as 1. It can be understood that i can be any value. Therefore, each main optical fiber could be the i-th main optical fiber, each backup optical fiber could be the target backup optical fiber, and each main optical fiber could also be the target main optical fiber. To support the assumption that i can be any value, please refer to Figure 10. Each second optical switch 02 connects to each optical fiber, and a first power detector 05 is provided on the optical path from each second optical switch 02 to each optical fiber. The end of each optical fiber furthest from the second optical switch is connected to a light source. The function of the first power detector 05 on the optical path from each second optical switch 02 to each optical fiber can be referred to as the function of the first power detector on each connected optical fiber from the i-th second optical switch.

[0142] Optionally, referring to Figure 10, each optical fiber can be connected to a third optical switch 06 and a fourth optical switch 07 at both ends. Each optical fiber is connected to each first optical switch 01 via the third optical switch 06 and to each second optical switch 07 via the fourth optical switch 07. The third optical switch connected to each backup optical fiber can refer to the third optical switch connected to the aforementioned target backup optical fiber, and the third optical switch connected to each main optical fiber can refer to the third optical switch connected to the aforementioned target main optical fiber; the fourth optical switch connected to each backup optical fiber can refer to the fourth optical switch connected to the aforementioned target backup optical fiber, and the fourth optical switch connected to each main optical fiber can refer to the fourth optical switch connected to the aforementioned target main optical fiber.

[0143] Optionally, referring to Figure 10, a third power detector 09 is provided on the optical path from each first optical switch 01 to each optical fiber. The function of each third power detector 09 can be referred to the function of the third power detector on the optical path from the i-th first optical switch to the target backup optical fiber.

[0144] When the performance of any main optical fiber in Figure 10 is lower than the first performance threshold, the control unit can control the main optical fiber to switch to the backup optical fiber in the same plane, or switch to the backup optical fiber in another plane, or switch to the main optical fiber in another plane.

[0145] For example, to support any value for i, please refer to Figure 11. Based on Figure 10, each third optical switch 06 is also connected to a second power detector 08. The function of the second power detector 08 connected to each third optical switch 06 can be referred to the function of the second power detector connected to the third optical switch in the aforementioned target backup fiber connection.

[0146] For example, Figure 10 shows a backup fiber in each plane corresponding to a primary fiber in the same plane. Optionally, in some embodiments, the primary and backup fibers may not have a corresponding relationship, and the primary fiber may not be considered for switching to other primary fibers. In this case, the optical transmission system can be as shown in Figure 12. The number of primary fibers and the number of backup fibers in Figure 12 may be the same or different. When the performance of any primary fiber in Figure 12 is lower than a first performance threshold, the control unit can control the primary fiber to switch to any of the multiple backup fibers.

[0147] As another example, based on Figure 10, as shown in Figure 13, the optical transmission system can further include more primary optical fibers (such as primary fiber 041 in planes 3 and 4 of Figure 13). These newly added primary optical fibers in Figure 13 share the backup optical fibers in Figure 10 with the existing primary optical fibers in Figure 10. Furthermore, the primary optical fibers in Figure 10 support switching to other primary optical fibers in Figure 10, while the primary optical fibers in Figure 13 do not support switching to other primary optical fibers. When the performance of any of the newly added primary optical fibers in Figure 13 falls below a first performance threshold, the control unit can control that primary optical fiber to switch to any backup optical fiber.

[0148] Optionally, when the control unit includes multiple first controllers and multiple second controllers, the multiple first controllers correspond one-to-one with multiple planes, and the multiple second controllers also correspond one-to-one with the multiple planes. Each first controller is used to control the first optical switch and the third optical switch in the corresponding plane to switch optical fibers, and each second controller is used to control the second optical switch and the fourth optical switch in the corresponding plane to switch optical fibers. The first optical switch in the i-th plane is the i-th first optical switch, the second optical switch in the i-th plane is the i-th second optical switch, the third optical switch in the i-th plane includes a third optical switch connected to the i-th main optical fiber and a third optical switch connected to the corresponding backup optical fiber; the fourth optical switch in the i-th plane includes a fourth optical switch connected to the i-th main optical fiber and a fourth optical switch connected to the corresponding backup optical fiber.

[0149] Each first controller and its corresponding first optical switch in the same plane can be housed on the same board, while different first optical switches 01 can be housed on different boards; each second controller and its corresponding second optical switch in the same plane can be housed on the same board, while different second optical switches can be housed on different boards. Optionally, each first controller and its corresponding third optical switch, second power detector, and / or third power detector in the same plane can be housed on the same board; each second controller and its corresponding fourth optical switch and / or first power detector in the same plane can be housed on the same board. The first power detector in the i-th plane is connected to the second optical switch in the i-th plane; the second power detector in the i-th plane is connected to the third optical switch in the i-th plane; and the third power detector in the i-th plane is connected to the first optical switch in the i-th plane.

[0150] For example, as shown in Figure 14, assume the optical transmission system has three planes. Each plane includes a first board, a second board, a main optical fiber, and a backup optical fiber. The first board includes the aforementioned first controller, first optical switch, and third optical switch, as well as the aforementioned second and third power detectors (the internal structure of the first board is not shown in Figure 14). The second board includes a second controller, a second optical switch, and a fourth optical switch, as well as the aforementioned first power detector (the internal structure of the second board is not shown in Figure 14). The first boards in different planes are interconnected, and the second boards in different planes are also interconnected.

[0151] The aforementioned board can be referred to as an optical switch board. Optionally, it can be considered that the components other than the first controller in the board containing the first controller are integrated into the first controller, and the components other than the second controller in the board containing the second controller are integrated into the second controller. In this case, the board containing the first controller is also the first controller, and the board containing the second controller is also the second controller.

[0152] In the above embodiments, the transmission of an optical signal from the first optical switch to the second optical switch is taken as an example. Optionally, the optical signal can also be transmitted from the second optical switch to the first optical switch. In this case, the first optical switch has the function of the second optical switch in the aforementioned embodiments, the second optical switch has the function of the first optical switch in the aforementioned embodiments, the third optical switch has the function of the fourth optical switch in the aforementioned embodiments, and the fourth optical switch has the function of the third optical switch in the aforementioned embodiments.

[0153] This application embodiment also provides an optical fiber switching method, which is executed by a control unit in any of the optical transmission systems provided in this application embodiment, as shown in Figure 15. The optical fiber switching method includes:

[0154] S101. When the performance of the i-th main optical fiber is lower than the first performance threshold, and multiple backup optical fibers include the target backup optical fiber that meets the switching conditions, the control unit controls the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber; the switching conditions include: idle and performance higher than or equal to the first performance threshold.

[0155] There are several ways to make the performance of the i-th main fiber optic cable fall below the first performance threshold.

[0156] For example, the performance of the i-th main optical fiber being lower than the first performance threshold includes: the i-th main optical fiber being open-circuited. In this case, the performance of the target backup optical fiber being higher than or equal to the first performance threshold includes: the target backup optical fiber not being open-circuited.

[0157] For example, the performance of the i-th main optical fiber is lower than the first performance threshold, including: the target performance parameter of the i-th main optical fiber is less than the minimum value among the target performance parameters of multiple backup optical fibers, and the difference between the minimum value and the target performance parameter of the i-th main optical fiber is greater than the parameter threshold; the larger the target performance parameter of the i-th main optical fiber, the higher the performance of the i-th main optical fiber.

[0158] Furthermore, the above content uses the switching condition including idle and performance higher than or equal to the first performance threshold as an example. Optionally, the switching condition may also include other conditions. For example, the switching condition may also include: performance higher than or equal to the second performance threshold, and the second performance threshold is greater than the first performance threshold.

[0159] Optionally, the optical transmission system further includes a light source connected to the end of each of the i-th main optical fiber and multiple backup optical fibers away from the i-th second optical switch; the light source is used to transmit probe light to each of the i-th main optical fiber and multiple backup optical fibers. The wavelength of the probe light is different from the wavelength of the optical signal, therefore, the probe light and the optical signal can be transmitted simultaneously in the same optical fiber. A first power detector is provided on the optical path from each of the i-th main optical fiber and multiple backup optical fibers to the i-th second optical switch. The control unit can determine, based on the power of the probe light detected by the first power detector, that the performance of the i-th main optical fiber is lower than a first performance threshold, and that the performance of the target backup optical fiber is higher than or equal to the first performance threshold.

[0160] Optionally, the i-th primary optical fiber has a corresponding backup optical fiber; when the backup optical fiber corresponding to the i-th primary optical fiber meets the switching conditions, the target backup optical fiber is the backup optical fiber corresponding to the i-th primary optical fiber; when the backup optical fiber corresponding to the i-th primary optical fiber does not meet the switching conditions, the target backup optical fiber is different from the backup optical fiber corresponding to the i-th primary optical fiber. It is evident that the control unit will control the i-th primary optical fiber to preferentially switch to its corresponding backup optical fiber. This avoids the occupation of backup optical fibers corresponding to other primary optical fibers, allowing other primary optical fibers to quickly switch to their corresponding primary optical fibers when their performance is poor.

[0161] Optionally, the control unit includes a first controller and a second controller; in S101, when the performance of the i-th main optical fiber is lower than a first performance threshold and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the first controller controls the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber; when the performance of the i-th main optical fiber is lower than the first performance threshold and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the second controller controls the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber.

[0162] Optionally, the control unit controls the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber, and further includes: when the performance of the i-th main optical fiber is lower than a first performance threshold and multiple backup optical fibers include the target backup optical fiber that meets the switching conditions, the second controller sends a switching instruction to the first controller, the switching instruction being used to indicate that the i-th main optical fiber is switched to the target backup optical fiber; the first controller can control the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber according to the switching instruction.

[0163] For example, as shown in Figure 16, S101 includes:

[0164] S1011. When the performance of the i-th main optical fiber is lower than the first performance threshold and multiple backup optical fibers include the target backup optical fiber that meets the switching conditions, the second controller controls the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber.

[0165] S1012. When the performance of the i-th main optical fiber is lower than the first performance threshold and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the second controller sends a switching instruction to the first controller. The switching instruction is used to indicate that the i-th main optical fiber is switched to the target backup optical fiber.

[0166] S1013. The first controller controls the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber according to the switching instruction.

[0167] Furthermore, the second controller can send the switching instruction in the following ways: (1) The second controller can control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber after sending the switching instruction. (2) The second controller can control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber at the same time as sending the switching instruction. (3) The second controller can first control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber, and then send the switching instruction. In both methods (1) and (2), the switching instruction can be sent without waiting for the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber. In this way, the first controller can control the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber as early as possible, thereby shortening the time for the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber as a whole, and reducing the recovery time of the optical signal transmission on the i-th main optical fiber.

[0168] S102. The control unit determines that the fiber optic switching is successful based on the optical signal power detected by the third power detector. The third power detector is located on the optical path from the i-th first optical switch to the target backup fiber optic cable.

[0169] Optionally, the optical transmission system further includes a third optical switch and a fourth optical switch connected to the target backup optical fiber; the target backup optical fiber is connected to multiple first optical switches via the third optical switch and to multiple second optical switches via the fourth optical switch; the target backup optical fiber corresponds to the j-th main optical fiber among multiple main optical fibers, j≥1, j≠i; the third optical switch is used to connect the target backup optical fiber to the j-th first optical switch, and the fourth optical switch is used to connect the target backup optical fiber to the j-th second optical switch; the optical fiber switching method provided in this application embodiment further includes: when the performance of the i-th main optical fiber is lower than a first performance threshold, and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the control unit controls the third optical switch and the fourth optical switch to switch the j-th main optical fiber to the i-th main optical fiber.

[0170] For example, when the control unit controls the third optical switch and the fourth optical switch to switch the j-th main optical fiber to the i-th main optical fiber, it can control the third optical switch and the fourth optical switch to switch the j-th main optical fiber to the i-th main optical fiber based on the fact that the third optical switch meets the operating conditions.

[0171] The above operating conditions can be achieved in various ways. For example, the operating conditions include the third optical switch not being faulty. Another example is that the operating conditions include the insertion loss of the third optical switch being less than the insertion loss threshold. Yet another example is that the operating conditions include the third optical switch not being faulty and the insertion loss of the third optical switch being less than the insertion loss threshold.

[0172] Under operating conditions including a fault-free third optical switch, the optical transmission system also includes a second power detector connected to the aforementioned third optical switch. This third optical switch is also used to connect the second power detector to the i-th first optical switch. After the control unit controls the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, it can determine that the third optical switch is not faulty based on the power of the i-th optical signal detected by the second power detector. It is understood that after the control unit controls the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, the i-th optical signal can be transmitted to the second power detector. At this time, the control unit can detect the power of the i-th optical signal through the second power detector and determine whether the third optical switch is faulty based on this power.

[0173] Under operating conditions, including an insertion loss of the third optical switch less than the insertion loss threshold, the optical transmission system includes a third power detector in addition to the aforementioned second power detector. This third power detector is connected between the third optical switch and the i-th first optical switch. The control unit, after controlling the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, determines the insertion loss of the third optical switch based on the power of the i-th optical signal detected by the second and third power detectors, respectively. It can be understood that after the control unit controls the i-th first optical switch to switch the i-th primary optical fiber to the target backup optical fiber, the i-th optical signal can be transmitted from the i-th first optical switch sequentially through the third power detector and the third optical switch to the second power detector. At this time, the control unit can detect the power of the i-th optical signal through the second and third power detectors, respectively, and determine the insertion loss of the third optical switch based on these powers.

[0174] Optionally, the i-th first optical switch and the i-th second optical switch are also respectively connected to the two ends of each of the other main optical fibers in at least one other main optical fiber, and the other main optical fibers are different from the i-th main optical fiber; when the performance of the i-th main optical fiber is lower than the first performance threshold, multiple backup optical fibers do not meet the switching conditions, and at least one other main optical fiber includes the target main optical fiber that meets the switching conditions, the control unit can control the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target main optical fiber.

[0175] This application embodiment also provides a control unit, which can be the control unit in the optical transmission system provided in the foregoing embodiments. The description of the control unit in the optical transmission system provided in the foregoing embodiments can be referenced, and will not be repeated here. For example, the control unit is used to: when the performance of the i-th main optical fiber is lower than a first performance threshold, and multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, control the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber; the switching conditions include: being idle and having performance higher than or equal to the first performance threshold.

[0176] This application also provides a chip that includes programmable logic circuitry and / or program instructions, which, when running, are used to implement the methods executed by the control unit or any controller in this application.

[0177] In this application, the terms "first" and "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "at least one" refers to one or more, and "multiple" refers to two or more, unless otherwise expressly defined. The term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0178] The method embodiments and system embodiments provided in this application can be referenced interchangeably, and this application does not limit them. The order of operations in the method embodiments provided in this application can be appropriately adjusted, and operations can be added or removed as appropriate. Any variations that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application, and therefore will not be elaborated further.

[0179] It should be noted that all data and optical signals involved in this application have been authorized by the user or by all parties in full, and the collection, use, and processing of such data must comply with the relevant laws, regulations, and standards of the relevant countries and regions. For example, the data and optical signals involved in this application were obtained under full authorization.

[0180] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An optical transmission system, characterized in that, include: Control unit, multiple first optical switches, multiple second optical switches, multiple main optical fibers, and multiple backup optical fibers; The i-th first optical switch and the i-th second optical switch are respectively connected to the two ends of the i-th main optical fiber in the plurality of main optical fibers, and the i-th first optical switch and the i-th second optical switch are also respectively connected to the two ends of each of the backup optical fibers; i≥1; The i-th first optical switch is used to receive the i-th optical signal from the multiple optical signals and transmit the i-th optical signal to the i-th main optical fiber; the i-th second optical switch is used to output the i-th optical signal received from the i-th main optical fiber; the multiple optical signals carry different service data respectively; The control unit is configured to: when the performance of the i-th main optical fiber is lower than a first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, control the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber. The switching conditions include: being idle and having performance higher than or equal to the first performance threshold.

2. The optical transmission system according to claim 1, characterized in that, The performance of the i-th main optical fiber being lower than the first performance threshold includes: the i-th main optical fiber being disconnected.

3. The optical transmission system according to claim 1, characterized in that, The performance of the i-th main optical fiber being lower than the first performance threshold includes: the target performance parameter of the i-th main optical fiber being less than the minimum value among the target performance parameters of the plurality of backup optical fibers, and the difference between the minimum value and the target performance parameter of the i-th main optical fiber being greater than the parameter threshold; the larger the target performance parameter of the i-th main optical fiber, the higher the performance of the i-th main optical fiber.

4. The optical transmission system according to any one of claims 1 to 3, characterized in that, The switching conditions also include: the performance is higher than or equal to a second performance threshold, and the second performance threshold is greater than the first performance threshold.

5. The optical transmission system according to any one of claims 1 to 4, characterized in that, The optical transmission system further includes a light source, which connects to one end of each of the i-th main optical fiber and the plurality of backup optical fibers that is away from the i-th second optical switch; the light source is used to transmit probe light to each of the i-th main optical fiber and the plurality of backup optical fibers, the wavelength of the probe light being different from the wavelength of the optical signal. A first power detector is provided on the optical path from the i-th main optical fiber and each of the multiple backup optical fibers to the i-th second optical switch; the control unit is configured to: determine, based on the power of the probe light detected by the first power detector, that the performance of the i-th main optical fiber is lower than a first performance threshold, and that the performance of the target backup optical fiber is higher than or equal to the first performance threshold.

6. The optical transmission system according to any one of claims 1 to 5, characterized in that, The i-th main optical fiber has a corresponding backup optical fiber; When the backup optical fiber corresponding to the i-th main optical fiber meets the switching condition, the target backup optical fiber is the backup optical fiber corresponding to the i-th main optical fiber. When the backup optical fiber corresponding to the i-th main optical fiber does not meet the switching conditions, the target backup optical fiber is different from the backup optical fiber corresponding to the i-th main optical fiber.

7. The optical transmission system according to any one of claims 1 to 6, characterized in that, The control unit includes: a first controller and a second controller; The first controller is used to control the first optical switch to switch the i-th main optical fiber to the target backup optical fiber when the performance of the i-th main optical fiber is lower than a first performance threshold and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions. The second controller is used to control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber when the performance of the i-th main optical fiber is lower than the first performance threshold and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions.

8. The optical transmission system according to claim 7, characterized in that, The second controller is further configured to send a switching instruction to the first controller when the performance of the i-th main optical fiber is lower than a first performance threshold and the plurality of backup optical fibers include a target backup optical fiber that meets the switching conditions. The switching instruction is used to indicate that the i-th main optical fiber is switched to the target backup optical fiber. The first controller is used to control the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber according to the switching instruction.

9. The optical transmission system according to claim 8, characterized in that, The second controller is used to control the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber after sending the switching instruction.

10. The optical transmission system according to any one of claims 1 to 9, characterized in that, The optical transmission system further includes a third optical switch and a fourth optical switch connected to the target backup optical fiber; the target backup optical fiber is connected to the plurality of first optical switches through the third optical switch, and to the plurality of second optical switches through the fourth optical switch; The target backup optical fiber corresponds to the j-th main optical fiber among the multiple main optical fibers, where j≥1 and j≠i; the third optical switch is used to connect the target backup optical fiber to the j-th first optical switch, and the fourth optical switch is used to connect the target backup optical fiber to the j-th second optical switch. The control unit is configured to: when the performance of the i-th main optical fiber is lower than a first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, control the third optical switch and the fourth optical switch to switch the j-th main optical fiber to the i-th main optical fiber.

11. The optical transmission system according to claim 10, characterized in that, The control unit is used to: based on the fact that the third optical switch meets the operating conditions, control the third optical switch and the fourth optical switch to switch the j-th main optical fiber to the i-th main optical fiber.

12. The optical transmission system according to claim 11, characterized in that, The optical transmission system further includes a second power detector; the third optical switch is also used to connect the second power detector to the i-th first optical switch. The control unit is used to: after controlling the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber, determine that the third optical switch is not faulty based on the power of the i-th optical signal detected by the second power detector; The operating conditions include: the third optical switch is not faulty.

13. The optical transmission system according to claim 11 or 12, characterized in that, The optical transmission system also includes a second power detector and a third power detector; The third optical switch is also used to connect the second power detector and the i-th first optical switch, wherein the third power detector is located on the optical path from the i-th first optical switch to the third optical switch; The control unit is used to: after controlling the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber, determine the insertion loss of the third optical switch based on the power of the i-th optical signal detected by the second power detector and the third power detector respectively; The operating conditions include: the insertion loss of the third optical switch is less than the insertion loss threshold.

14. The optical transmission system according to any one of claims 1 to 13, characterized in that, The optical transmission system further includes: a third power detector; the third power detector is located on the optical path from the i-th first optical switch to the target backup optical fiber; The control unit is used to: after controlling the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber, determine that the optical fiber switching is successful based on the optical signal power detected by the third power detector.

15. The optical transmission system according to any one of claims 1 to 14, characterized in that, The i-th first optical switch and the i-th second optical switch are also respectively connected to both ends of each of at least one other main optical fiber, and the other main optical fiber is different from the i-th main optical fiber; The control unit is further configured to: when the performance of the i-th main optical fiber is lower than a first performance threshold, the multiple backup optical fibers do not meet the switching conditions, and the at least one other main optical fiber includes a target main optical fiber that meets the switching conditions, control the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target main optical fiber.

16. A fiber optic switching method, characterized in that, The method is executed by a control unit in the optical transmission system according to any one of claims 1 to 15, the optical transmission system further comprising: a plurality of first optical switches, a plurality of second optical switches, a plurality of main optical fibers, and a plurality of backup optical fibers; the i-th first optical switch and the i-th second optical switch are respectively connected to the two ends of the i-th main optical fiber, and the i-th first optical switch and the i-th second optical switch are also respectively connected to the two ends of each backup optical fiber; i ≥ 1; the i-th first optical switch is used to receive the i-th optical signal from the multiple optical signals and transmit the i-th optical signal to the i-th main optical fiber; the i-th second optical switch is used to output the i-th optical signal received from the i-th main optical fiber; the multiple optical signals respectively carry different service data; The method includes: When the performance of the i-th main optical fiber is lower than the first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the i-th first optical switch and the i-th second optical switch are controlled to switch the i-th main optical fiber to the target backup optical fiber; the switching conditions include: being idle and having performance higher than or equal to the first performance threshold.

17. The method according to claim 16, characterized in that, The optical transmission system further includes a light source, which connects to one end of each of the i-th main optical fiber and the plurality of backup optical fibers that is away from the i-th second optical switch; the light source is used to transmit probe light to each of the i-th main optical fiber and the plurality of backup optical fibers, the wavelength of the probe light being different from the wavelength of the optical signal; a first power detector is provided on the optical path from each of the i-th main optical fiber and the plurality of backup optical fibers to the i-th second optical switch; The method further includes: Based on the power of the probe light detected by the first power detector, it is determined that the performance of the i-th main optical fiber is lower than a first performance threshold, and the performance of the target backup optical fiber is higher than or equal to the first performance threshold.

18. The method according to claim 16 or 17, characterized in that, The control unit includes a first controller and a second controller; when the performance of the i-th main optical fiber is lower than a first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, controlling the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber includes: When the performance of the i-th main optical fiber is lower than a first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the first controller controls the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber. When the performance of the i-th main optical fiber is lower than the first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the second controller controls the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber.

19. The method according to claim 18, characterized in that, When the performance of the i-th primary optical fiber is lower than a first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, controlling the i-th first optical switch and the i-th second optical switch to switch the i-th primary optical fiber to the target backup optical fiber further includes: When the performance of the i-th main optical fiber is lower than the first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the second controller sends a switching instruction to the first controller. The switching instruction is used to indicate that the i-th main optical fiber is switched to the target backup optical fiber. When the performance of the i-th main optical fiber is lower than a first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the first controller controls the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber, including: The first controller controls the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber according to the switching instruction.

20. The method according to claim 19, characterized in that, When the performance of the i-th main optical fiber is lower than a first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the second controller controls the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber, including: After sending the switching instruction, the second controller controls the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber.

21. The method according to any one of claims 16 to 20, characterized in that, The optical transmission system further includes a third optical switch and a fourth optical switch connected to the target backup optical fiber; the target backup optical fiber is connected to the plurality of first optical switches through the third optical switch, and to the plurality of second optical switches through the fourth optical switch; the target backup optical fiber corresponds to the j-th main optical fiber among the plurality of main optical fibers, j≥1, j≠i; the third optical switch is used to connect the target backup optical fiber to the j-th first optical switch, and the fourth optical switch is used to connect the target backup optical fiber to the j-th second optical switch; The method further includes: When the performance of the i-th main optical fiber is lower than the first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, the third optical switch and the fourth optical switch are controlled to switch the j-th main optical fiber to the i-th main optical fiber.

22. The method according to claim 21, characterized in that, The control of the third optical switch and the fourth optical switch to switch the j-th main optical fiber to the i-th main optical fiber includes: Based on the fact that the third optical switch meets the operating conditions, the third optical switch and the fourth optical switch are controlled to switch the j-th main optical fiber to the i-th main optical fiber.

23. The method according to claim 22, characterized in that, The optical transmission system further includes a second power detector; the third optical switch is also used to connect the second power detector to the i-th first optical switch. The method further includes: After controlling the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber, the third optical switch is determined to be fault-free based on the power of the i-th optical signal detected by the second power detector; the operating condition includes: the third optical switch is fault-free.

24. The method according to claim 22 or 23, characterized in that, The optical transmission system further includes a second power detector and a third power detector; the third optical switch is also used to connect the second power detector to the i-th first optical switch, and the third power detector is located on the optical path from the i-th first optical switch to the third optical switch; The method further includes: After controlling the i-th first optical switch to switch the i-th main optical fiber to the target backup optical fiber, the insertion loss of the third optical switch is determined based on the power of the i-th optical signal detected by the second power detector and the third power detector respectively; the operating conditions include: the insertion loss of the third optical switch is less than the insertion loss threshold.

25. The method according to any one of claims 16 to 24, characterized in that, The optical transmission system further includes: a third power detector; the third power detector is located on the optical path from the i-th first optical switch to the target backup optical fiber; After controlling the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber, the method further includes: The successful fiber optic switching is determined based on the optical signal power detected by the third power detector.

26. The method according to any one of claims 16 to 25, characterized in that, The i-th first optical switch and the i-th second optical switch are also respectively connected to both ends of each of at least one other main optical fiber, and the other main optical fiber is different from the i-th main optical fiber; The method further includes: When the performance of the i-th main optical fiber is lower than the first performance threshold, all of the multiple backup optical fibers do not meet the switching conditions, and at least one other main optical fiber includes a target main optical fiber that meets the switching conditions, the i-th first optical switch and the i-th second optical switch are controlled to switch the i-th main optical fiber to the target main optical fiber.

27. A control unit, characterized in that, The control unit belongs to the optical transmission system according to any one of claims 1 to 15. The optical transmission system further includes: a plurality of first optical switches, a plurality of second optical switches, a plurality of main optical fibers, and a plurality of backup optical fibers; the i-th first optical switch and the i-th second optical switch are respectively connected to the two ends of the i-th main optical fiber, and the i-th first optical switch and the i-th second optical switch are also respectively connected to the two ends of each backup optical fiber; i ≥ 1; the i-th first optical switch is used to receive the i-th optical signal from the multiple optical signals and transmit the i-th optical signal to the i-th main optical fiber; the i-th second optical switch is used to output the i-th optical signal received from the i-th main optical fiber; the multiple optical signals carry different service data respectively; The control unit is configured to: when the performance of the i-th main optical fiber is lower than a first performance threshold, and the multiple backup optical fibers include a target backup optical fiber that meets the switching conditions, control the i-th first optical switch and the i-th second optical switch to switch the i-th main optical fiber to the target backup optical fiber; the switching conditions include: being idle and having performance higher than or equal to the first performance threshold.

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