Optical fiber testing apparatus, system, and method

Abstract

An optical fiber testing apparatus, wherein a test module (10) emits first test light of a wavelengths, and a wavelength combining and splitting module (20) distributes the first test light of a wavelengths to a plurality of optical fibers. The first test light of a wavelengths is reflected or backscattered in the plurality of optical fibers to form second test light of a wavelengths, and the second test light of a wavelengths is then transmitted to the test module (10) via the wavelength combining and splitting module (20). The test module (10) tests the second test light of a wavelengths, so as to acquire physical parameters of the plurality of optical fibers, which is equivalent to performing parallel testing on the plurality of optical fibers by means of one test module (10), facilitating the improvement of the testing efficiency of the optical fibers. Further disclosed are an optical fiber transmission system and an optical fiber testing method.

Description

An optical fiber detection device, system, and method

[0001] This application claims priority to Chinese Patent Application No. 202411632898.4, filed on November 14, 2024, entitled "An Fiber Optic Detection Device, System and Method", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical transmission, and more particularly to an optical fiber detection device, system, and method. Background Technology

[0003] In the field of OTDRs, including optical time domain reflectometry (OTDR), phase-sensitive optical time domain reflectometry (φOTDR), and distributed acoustic sensing (DAS), parameters such as vibration, temperature, and stress in the environment of optical fiber can be detected in a distributed manner by utilizing backscattering (such as Rayleigh scattering) or reflection in optical fiber. There is a wide range of application needs in scenarios such as optical cable digitization and oil and gas leaks.

[0004] In practical applications, OTDR devices typically need to test multiple different optical fibers, such as different single-mode fibers within different optical cables or different cores in multi-core optical fibers. Currently, the mainstream solution usually uses a single OTDR device to cover a single optical fiber, employing an optical switch to switch the fiber connected to the single OTDR device. This is essentially time-division multiplexing of the testing of multiple fibers separately, resulting in low testing efficiency for multiple fibers. Summary of the Invention

[0005] This application provides an optical fiber testing device, system, and method. Multiple optical fibers can be tested in parallel using a single testing module, which helps improve the testing efficiency of optical fibers.

[0006] In a first aspect, embodiments of this application provide an optical fiber detection device, comprising: a detection module and a multiplexing / splitting module. The multiplexing / splitting module includes a first port and multiple second ports. The first port is connected to the detection module, and each second port is used to connect to a corresponding optical fiber. The detection module emits a first detection light of wavelength *a*. The *a* wavelengths of the first detection light are input to the multiplexing / splitting module through the first port, where *a* is an integer greater than 1. The multiplexing / splitting module transmits the *a* wavelengths of the first detection light to the corresponding multiple optical fibers through the multiple second ports, effectively splitting the *a* wavelengths of the first detection light. The *a* wavelengths of the first detection light are reflected or backscattered in the multiple optical fibers to form *a* wavelengths of second detection light. The multiplexing / splitting module combines the *a* wavelengths of the second detection light and transmits the combined *a* wavelengths of the second detection light to the detection module through the first port. The detection module detects the *a* wavelengths of the second detection light to obtain the physical parameters of the multiple optical fibers.

[0007] In this embodiment, the detection module emits a first detection light of wavelength *a*. A multiplexing / demultiplexing module distributes this first detection light of wavelength *a* into multiple optical fibers. The first detection light of wavelength *a* is reflected or backscattered in the multiple optical fibers to form a second detection light of wavelength *a*. This second detection light of wavelength *a* is then transmitted back to the detection module via the multiplexing / demultiplexing module. The detection module detects the second detection light of wavelength *a* to obtain the physical parameters of the multiple optical fibers. This is equivalent to performing parallel detection on multiple optical fibers through a single detection module, which improves the detection efficiency of the optical fibers.

[0008] In some possible implementations, the number of second ports is equal to 'a', and 'a' wavelengths of first detection light are transmitted to 'a' optical fibers through 'a' second ports respectively. Given that the number of wavelengths of the first detection light emitted by the detection module at the same time is determined to be 'a', the detection module can obtain the physical parameters of 'a' optical fibers in one go through parallel detection, thereby maximizing the detection efficiency of the optical fibers.

[0009] In some possible implementations, the number of second ports is less than 'a', and at least two wavelengths of first detection light are transmitted to the same optical fiber through the same second port. That is, the at least two wavelengths of first detection light emitted by the detection module can also be transmitted to the same optical fiber via a multiplexing / demultiplexing module. This not only supports parallel detection of multiple optical fibers and the distribution of at least two wavelengths of first detection light to the same optical fiber, but also improves the detection capability of that optical fiber.

[0010] In some possible implementations, the number of second ports is greater than 'a'. Specifically, the multiplexing / splitting module is used to transmit the 'a' wavelengths of first detection light to 'a' optical fibers through 'a' second ports respectively during a first time period. The multiplexing / splitting module is also used to transmit at least one wavelength of the 'a' wavelengths of first detection light to at least one corresponding optical fiber through at least one second port other than the 'a' second ports during a second time period, wherein the at least one wavelength of first detection light is reflected or backscattered in the at least one optical fiber other than the 'a' optical fibers to form at least one wavelength of second detection light. The multiplexing / splitting module is also used to transmit the at least one wavelength of second detection light to the detection module through the first port. The detection module is also used to detect the at least one wavelength of second detection light to obtain the physical parameters of the at least one optical fiber other than the 'a' optical fibers. That is, if the number of optical fibers to be detected is greater than the number of wavelengths of the first detection light emitted by the optical fiber detection device in a single transmission, then the optical fiber detection device cannot detect all optical fibers by emitting 'a' wavelengths of first detection light in a single transmission. In this scenario, the detection module needs to emit a first detection light of wavelength 'a' multiple times to detect all optical fibers. Each time the optical fiber detection device emits a first detection light of wavelength 'a' covering different combinations of optical fibers, so as to enable the detection of all optical fibers in scenarios with a large number of optical fibers.

[0011] In some possible implementations, the detection module is an optical time domain reflectometry (OTDR) module, and the physical parameters of the optical fiber are its loss parameters. This implementation is applied to scenarios involving optical fiber loss detection, thereby improving the efficiency of optical fiber loss detection.

[0012] In some possible implementations, the detection module is a distributed acoustic sensing (DAS) or distributed vibration sensing (DVS) module, and the physical parameters of the optical fiber are at least one of the fiber's vibration parameters and stress parameters. The DAS module can also detect the temperature of the optical fiber. This implementation uses a DAS or DVS module to detect the physical parameters of the optical fiber, enriching the application scenarios of this solution.

[0013] In some possible implementations, the detection module includes a light source and a modulator. The modulator modulates *a* radio frequency (RF) signals onto the light emitted by the light source to form a first detection light with *a* wavelengths, wherein the *a* RF signals have different frequencies. In this implementation, the frequencies of the RF signals can be flexibly adjusted, thereby improving the flexibility of the detection light wavelength.

[0014] In some possible implementations, the detection module includes an optical receiving unit, an RF power divider, and a processing units. The optical receiving unit converts a second detection light of a wavelengths into electrical signals; the RF power divider divides the electrical signals into a RF signals, each with a different frequency; and the a processing units process each of the a RF signals to obtain the physical parameters of the multiple optical fibers. In this implementation, after the RF power divider distinguishes the a RF signals with different frequencies, a RF converter (ADC) can be used to perform analog-to-digital conversion on each of the a RF signals. Each ADC only needs to cover a small frequency range, resulting in low implementation cost.

[0015] In some possible implementations, the detection module includes an optical receiving unit and a digital signal processor (DSP). The optical receiving unit converts the second detection light of wavelengths *a* into digital signals; the DSP performs digital signal processing on the digital signals to obtain the physical parameters of multiple optical fibers. This implementation utilizes the processing of the DSP to distinguish the second detection light of wavelengths *a*, thereby determining the physical parameters of each of the *a* optical fibers, resulting in a simpler hardware structure.

[0016] In some possible implementations, the detection module includes *a* light sources, each emitting a wavelength of first detection light, with low implementation cost per light source. Alternatively, the detection module includes a single light source, emitting a wavelength of first detection light, eliminating the need for multiple light sources and reducing space requirements.

[0017] In some possible implementations, the detection module includes a beam splitting unit, *a* optical receiving units, and *a* processing units. The beam splitting unit transmits *a* wavelengths of second detection light to the *a* optical receiving units respectively; the *a* optical receiving units convert the *a* wavelengths of second detection light into *a* electrical signals respectively; and the *a* processing units process the *a* electrical signals respectively to obtain the physical parameters of the *a* optical fibers. This implementation distinguishes the *a* wavelengths of second detection light by the beam splitting unit before photoelectric conversion, and then the *a* processing units process the *a* electrical signals after photoelectric conversion to determine the physical parameters of multiple optical fibers. This beam splitting approach has a lower cost.

[0018] In some possible implementations, the first detection light of each wavelength is a light pulse, which makes it easier to better distinguish the reflection or backscattering of the first detection light at different locations in the optical fiber.

[0019] In some possible implementations, at least two of the a-wavelength first detection light beams are emitted at different times, meaning the detection module emits multiple wavelength light pulses in a time-division multiplexing manner. If the detection module is an OTDR module, it is beneficial to improve power detection accuracy and measurement speed; if the detection module is a DAS module or DVS module, it is beneficial to improve the sampling rate.

[0020] In some possible implementations, the multiplexing / splitting module is a filter or a wavelength selective switch (WSS).

[0021] Secondly, embodiments of this application provide an optical fiber transmission system. The optical fiber transmission system includes a first site, a second site, and an optical fiber detection device as described in any embodiment of the first aspect. The first site and the second site are connected by multiple optical fibers, and the optical fiber detection device is deployed at at least one of the first and second sites. The multiplexing / splitting module of the optical fiber detection device is connected to the multiple optical fibers through multiple second ports.

[0022] Thirdly, embodiments of this application provide an optical fiber transmission system. The optical fiber transmission system includes a first station, a second station, a third station, and an optical fiber detection device as described in any embodiment of the first aspect. The first station is connected to the second station and the third station respectively via two optical fibers. The optical fiber detection device is deployed at the first station, and the multiplexing / splitting module of the optical fiber detection device is connected to the two optical fibers respectively via two second ports.

[0023] Fourthly, embodiments of this application provide an optical fiber detection method, which is applied to an optical fiber detection device. The optical fiber detection device includes a detection module and a multiplexing / splitting module, wherein the multiplexing / splitting module includes a first port and multiple second ports, the first port is connected to the detection module, and each second port is used to connect to a corresponding optical fiber. The method includes: emitting a first detection light of wavelength a through the detection module, the first detection light of wavelength a being input into the multiplexing / splitting module through the first port, where a is an integer greater than 1; transmitting the first detection light of wavelength a through the multiple second ports to the corresponding multiple optical fibers through the multiple multiple second ports, wherein the first detection light of wavelength a is reflected or backscattered in the multiple optical fibers to form second detection light of wavelength a; multiplexing the second detection light of wavelength a through the multiplexing / splitting module, and transmitting the multiplexed second detection light of wavelength a through the first port to the detection module; and detecting the second detection light of wavelength a through the detection module to obtain the physical parameters of the multiple optical fibers.

[0024] In some possible implementations, the number of second ports is equal to a, and the first detection light of a wavelengths is transmitted to a optical fiber through a second port respectively.

[0025] In some possible implementations, the number of second ports is less than a, and at least two wavelengths of first detection light are transmitted to the same optical fiber through the same second port.

[0026] In some possible implementations, the number of second ports is greater than 'a'. Transmitting 'a' wavelengths of first detection light to corresponding optical fibers via multiple second ports using a multiplexing / splitting module includes: transmitting 'a' wavelengths of first detection light to 'a' optical fibers respectively via 'a' second ports during a first time period using the multiplexing / splitting module. The method further includes: transmitting at least one wavelength of the 'a' wavelengths of first detection light to at least one corresponding optical fiber via at least one second port other than 'a' second ports during a second time period using the multiplexing / splitting module, wherein the at least one wavelength of first detection light is reflected or backscattered in the at least one optical fiber other than 'a' to form at least one wavelength of second detection light; transmitting the at least one wavelength of second detection light to a detection module via a first port using the multiplexing / splitting module; and detecting the at least one wavelength of second detection light using the detection module to obtain the physical parameters of the at least one optical fiber other than 'a'.

[0027] In some possible implementations, the detection module is an OTDR module, and the physical parameters of the optical fiber are the loss parameters of the optical fiber.

[0028] In some possible implementations, the detection module is a DAS module or a DVS module, and the physical parameters of the optical fiber are at least one of the vibration parameters and stress parameters of the optical fiber.

[0029] In some possible implementations, the detection module includes a light source and a modulator. Emitting a first detection light of a wavelengths via the detection module includes modulating a radio frequency signals onto the light emitted by the light source using the modulator to form the first detection light of a wavelengths, wherein the frequencies of the a radio frequency signals are all different.

[0030] In some possible implementations, the detection module includes an optical receiving unit, an RF power divider, and a processing units. The detection module detects a second detection light of a wavelengths to obtain the physical parameters of a optical fibers by: converting the a wavelengths of the second detection light into electrical signals using the optical receiving unit; dividing the electrical signals into a different RF signals using the RF power divider; and processing the a RF signals separately using the a processing units to obtain the physical parameters of multiple optical fibers.

[0031] In some possible implementations, the detection module includes an optical receiving unit and a DSP. Detecting a second detection light of a wavelengths to obtain the physical parameters of a optical fibers by the detection module includes: converting the second detection light of a wavelengths into digital signals by the optical receiving unit; and performing digital signal processing on the digital signals by the DSP to obtain the physical parameters of multiple optical fibers.

[0032] In some possible implementations, the detection module includes *a* light sources. Emitting first detection light of *a* wavelengths through the detection module includes: emitting first detection light of *a* wavelengths through each of the *a* light sources. Alternatively, the detection module includes light sources, and emitting first detection light of *a* wavelengths through the detection module includes: emitting first detection light of *a* wavelengths through the light sources.

[0033] In some possible implementations, the detection module includes a beam splitting unit, a optical receiving units, and a processing units. Detecting the second detection light of a wavelengths to obtain the physical parameters of a optical fibers by the detection module includes: transmitting the second detection light of a wavelengths to the a optical receiving units respectively via the beam splitting unit; converting the second detection light of a wavelengths into a electrical signals by the a optical receiving units respectively; and processing the a electrical signals by the a processing units respectively to obtain the physical parameters of multiple optical fibers.

[0034] In some possible implementations, the first detection light of each wavelength is a light pulse.

[0035] In some possible implementations, at least two of the first detection lights of a wavelengths have different emission times.

[0036] In some possible implementations, the multiplexing / splitting module is a filter or a WSS. Attached Figure Description

[0037] Figure 1 is a schematic diagram of the first scenario of optical fiber detection in an embodiment of this application;

[0038] Figure 2 is a schematic diagram of a second scenario for fiber optic detection in an embodiment of this application;

[0039] Figure 3 is a schematic diagram of the third scenario of fiber optic detection in the embodiments of this application;

[0040] Figure 4 is a schematic diagram of the fourth scenario of optical fiber detection in the embodiments of this application;

[0041] Figure 5 is a schematic diagram of a fiber optic detection device in an embodiment of this application;

[0042] Figure 6 is a schematic diagram of an application scenario of the optical fiber detection device in an embodiment of this application;

[0043] Figure 7 is a schematic diagram of another application scenario of the optical fiber detection device in the embodiments of this application;

[0044] Figure 8 is a schematic diagram of a light pulse used for detection light in an embodiment of this application;

[0045] Figure 9 is a schematic diagram of time-division multiplexing of detection light in an embodiment of this application;

[0046] Figure 10 is a schematic diagram of a detection module in an embodiment of this application;

[0047] Figure 11 is a schematic diagram of another structure of the detection module in an embodiment of this application;

[0048] Figure 12 is a schematic diagram of another structure of the detection module in an embodiment of this application;

[0049] Figure 13 is a schematic diagram of another structure of the detection module in an embodiment of this application;

[0050] Figure 14 is a schematic diagram of one embodiment of the same route detection implemented by the optical fiber detection device in this application;

[0051] Figure 15 is a schematic diagram of a comparison result of the same route detection in an embodiment of this application;

[0052] Figure 16 is a flowchart of an optical fiber detection method in an embodiment of this application. Detailed Implementation

[0053] This application provides an optical fiber testing device, system, and method. Multiple optical fibers can be tested in parallel using a single testing module, which helps improve the testing efficiency of optical fibers.

[0054] It should be noted that the terms "first," "second," etc., in this application specification, claims, and the accompanying drawings are used to distinguish similar objects, not to limit a specific order or sequence. It should be understood that the above terms can be used interchangeably where appropriate so that the embodiments described in this application can be implemented in a sequence other than that described in this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0055] The fiber optic testing device provided in this application embodiment can be deployed at a site connected to multiple optical fibers. This means that the multiple wavelengths of detection light emitted by the fiber optic testing device can be distributed to the multiple optical fibers connected to the site. The fiber optic testing device then performs parallel detection on the detection light reflected or backscattered from the multiple optical fibers, thereby acquiring the physical parameters of multiple optical fibers in parallel, which is beneficial to improving the detection efficiency of the optical fibers. The following section first introduces some application scenarios for the fiber optic testing device provided in this application embodiment.

[0056] Figure 1 is a schematic diagram of the first scenario for fiber optic detection in this application embodiment. As shown in Figure 1, in a data center interconnect (DCI) scenario, multiple optical fibers are deployed between site 1 and site 2. Taking site 1 as an example, site 1 is equipped with multiple optical communication devices, such as optical transport units (OTUs). A wavelength division multiplexer is used to combine optical signals of multiple wavelengths from multiple optical communication devices. After combining, the optical signals are then amplified and sent into the optical fiber for transmission to site B. As shown in Figure 1, site 1 uses a 4-fiber 3-route scheme to send optical signals to site 2, and similarly, site 2 also uses a 4-fiber 3-route scheme to send optical signals to site 1. That is, a total of 8 optical fibers are deployed between site 1 and site 2, and at least one optical fiber must be transmitting optical signals normally in each transmission direction at all times. Therefore, it is necessary to be able to efficiently detect these 8 optical fibers. Deploying the fiber optic detection device provided in this application embodiment at at least one of the above-mentioned sites can significantly reduce the equipment cost and detection time of the above-mentioned same-route detection.

[0057] Figure 2 is a schematic diagram of a second scenario for fiber optic detection in this application embodiment. As shown in Figure 2, in one fiber optic sensing scenario, since the fiber optic length between stations usually exceeds the detection capability of a single device, it is necessary to use two devices to cover the upstream and downstream areas simultaneously. Taking the fiber optic detection device provided in this application embodiment deployed at station 2 in Figure 2 as an example, this fiber optic detection device needs to cover two fibers, one upstream and one downstream. That is, the fiber optic detection device needs to emit detection light 1 to fiber 1 and detection light 2 to fiber 2 simultaneously. Therefore, the fiber optic detection device provided in this application embodiment can improve the detection efficiency of fiber optics without increasing the number of detection devices.

[0058] Figure 3 is a schematic diagram of a third scenario for fiber optic detection in this application embodiment. As shown in Figure 3, in another fiber optic sensing scenario, the site is deployed on a ring fiber. By deploying the fiber optic detection device provided in this application embodiment at the site, the fiber optic detection device needs to emit detection light 1 in a clockwise direction and detection light 2 in a counterclockwise direction into the fiber optic cable. Detection light 1 and detection light 2 are emitted simultaneously. In this way, even if the fiber is broken at a certain position, the fiber on both sides of the broken position can still be detected, and the efficiency of fiber optic detection is improved.

[0059] Figure 4 illustrates a fourth scenario for fiber optic detection in this application embodiment. As shown in Figure 4, in an automatically switched optical network (ASON) scenario, the main fiber and the backup fiber need to be on two different physical routes. For example, as shown in Figure 4, path 1 is the main fiber, and path 2 is the backup fiber. Due to inaccuracies in the operator's asset management system, the logical route of the optical link does not match its actual physical route, resulting in partial co-routing of the primary and backup fibers. As shown in Figure 4, paths 1 and 2 are partially co-routing in the interval between site 5 and site 6. Co-routing typically refers to two fibers being in the same optical cable (same cable) or the same trench (same trench), with a relatively close physical distance. When the optical cable suffers external damage, there is a possibility that both the primary and backup fibers may break simultaneously, requiring the activation of path 3. The fiber optic detection device provided in this application embodiment can be deployed at at least one of the aforementioned sites 1 to 6. The fiber optic detection device simultaneously emits detection light to the primary and backup fibers between sites, thereby detecting the co-routing situation of the primary and backup fibers and improving the detection efficiency of fiber co-routing.

[0060] It should be noted that the fiber optic testing device provided in this application embodiment can be applied to scenarios not limited to those described above. For example, it can also be applied to other scenarios such as fiber optic quality monitoring between sites (transmit and receive dual fibers) and multi-directional fiber multiplexing at site outgoing points. In other words, the fiber optic testing device provided in this application embodiment can be deployed in any scenario involving multi-fiber transmission, and will not be described in detail here. The fiber optic testing device provided in this application embodiment will be described in detail below.

[0061] Figure 5 is a schematic diagram of a fiber optic detection device according to an embodiment of this application. As shown in Figure 5, the fiber optic detection device includes a detection module 10 and a multiplexing / splitting module 20. The multiplexing / splitting module includes a first port 201 and a second ports 202. The first port 201 is connected to the detection module 10, and the a second ports 202 are each connected to a fiber optic cable, where a is an integer greater than 1. It should be noted that the number of fibers connected to the multiplexing / splitting module 20 depends on the actual scenario requirements and is not limited here. Figure 5 illustrates an example where the four second ports 202 of the multiplexing / splitting module 20 are each connected to four fibers.

[0062] Specifically, the detection module 10 emits a first detection light of a wavelengths. This a-wavelength first detection light is input to the multiplexing / demultiplexing module 20 through its first port 201. It should be understood that the detection light differs from the service light. Although both are transmitted through optical fibers, the difference lies in the source: the service light originates from optical communication devices such as OTUs and is used for service transmission, while the detection light originates from the detection module 10 and is used to detect fiber quality. The detection light may or may not carry service information; this is not specifically defined here. The multiplexing / demultiplexing module 20 transmits the a-wavelength first detection light to a optical fibers through a second port 202, effectively demultiplexing the a-wavelength first detection light. Wavelength demultiplexing can also be referred to as wavelength demultiplexing. For example, in Figure 5, the four wavelengths of the first detection light are denoted as detection light 1, detection light 2, detection light 3, and detection light 4. Detection light 1 is transmitted to optical fiber 1, detection light 2 to optical fiber 2, detection light 3 to optical fiber 3, and detection light 4 to optical fiber 4.

[0063] It should be understood that the first detection light undergoes reflection or backscattering during transmission in the optical fiber. In this embodiment, the first detection light that undergoes reflection or backscattering is referred to as the second detection light. The second detection light of *a* wavelengths is transmitted to the multiplexing / demultiplexing module 20 through *a* second ports 202. The multiplexing / demultiplexing module 20 then combines the *a* wavelengths of the second detection light and transmits the combined *a* wavelengths of the second detection light to the detection module 10 through the first port 201. This combination can also be referred to as wavelength multiplexing. Furthermore, the detection module 10 is used to detect the *a* wavelengths of the second detection light to obtain the physical parameters of *a* optical fibers. This is equivalent to allowing parallel detection of multiple optical fibers through a single detection module, which is beneficial for improving the detection efficiency of optical fibers.

[0064] In some possible scenarios, the number of wavelengths of the first detection light emitted by the detection module 10 is greater than the number of optical fibers to be detected. That is, multiple wavelengths of detection light emitted by the detection module 10 can also be transmitted to the same optical fiber via the multiplexing / demultiplexing module 20. Taking Figure 5 as an example, assuming the detection module 10 also emits detection light 5, both detection light 5 and detection light 1 are transmitted to optical fiber 1 via the multiplexing / demultiplexing module 20. In this way, not only can multiple optical fibers be detected in parallel, distributing multiple wavelengths of detection light to the same optical fiber 1, but the detection capability of optical fiber 1 can also be improved.

[0065] It should be noted that the embodiments of this application do not limit the specific physical parameters of the optical fiber obtained by the detection module 10 through detecting the second detection light. Generally speaking, the type of physical parameters that the detection module 10 can detect depends on the type of the detection module 10. As an example, the detection module 10 is an optical time domain reflectometry (OTDR) module, and the physical parameters that the detection module 10 can detect include, but are not limited to, the loss parameters of the optical fiber. As another example, the detection module 10 is a distributed acoustic sensing (DAS) module, and the physical parameters that the detection module 10 can detect include, but are not limited to, at least one of the vibration parameters, stress parameters, and temperature of the optical fiber. As yet another example, the detection module 10 is a distributed vibration sensing (DVS) module, and the physical parameters that the detection module 10 can detect include, but are not limited to, at least one of the vibration parameters and stress parameters of the optical fiber.

[0066] It should be noted that the embodiments of this application do not limit the specific type of the multiplexing / splitting module 20. Any module that can distribute the input light to the corresponding port based on the wavelength can be regarded as the multiplexing / splitting module 20. For example, the multiplexing / splitting module 20 can be a filter or a wavelength selective switch (WSS), etc.

[0067] In practical application scenarios, the optical fiber detection device provided in this application embodiment can be deployed in a communication system with multiple service optical transmissions. Therefore, it is necessary to couple the first detection light into the optical fiber that transmits the service light. Several possible implementation methods are provided below.

[0068] Figure 6 is a schematic diagram of an application scenario of the fiber optic detection device in this application embodiment. In this application scenario, the service light from the optical communication equipment and the detection light from the fiber optic detection device are coupled to the optical fiber through a fiber interface unit (FIU). As shown in Figure 6, taking a transmission scenario with 4 optical fibers as an example, there are 4 wavelengths of detection light from the fiber optic detection device. Detection light 1 and service light 1 are coupled to optical fiber 1 through FIU 301, detection light 2 and service light 2 are coupled to optical fiber 2 through FIU 302, detection light 3 and service light 3 are coupled to optical fiber 3 through FIU 303, and detection light 4 and service light 4 are coupled to optical fiber 4 through FIU 304. It should be noted that this application embodiment does not limit whether the transmission directions of the detection light and service light in the same optical fiber are the same. Taking fiber 1 in Figure 6 as an example, both detection light 1 and service light 1 are coupled to fiber 1 through FIU 301 at one end of fiber 1, that is, the transmission directions of detection light 1 and service light 1 in fiber 1 are the same; or, detection light 1 is coupled to fiber 1 through FIU 301 at one end of fiber 1, and service light 1 is coupled to fiber 1 through FIU 301 at the other end of fiber 1, that is, the transmission directions of detection light 1 and service light 1 in fiber 1 are opposite.

[0069] Figure 7 is a schematic diagram of another application scenario of the optical fiber detection device in this application embodiment. In this application scenario, the service light from the optical communication equipment and the detection light from the detection module 10 in the optical fiber detection device are both input to the multiplexing / splitting module 20 in the optical fiber detection device. The multiplexing / splitting module 20 then distributes the detection light and service light of each wavelength to the corresponding optical fiber. As shown in Figure 6, the multiplexing / splitting module 20 can specifically be a WSS. Taking a transmission scenario with 4 optical fibers as an example, the multiplexing / splitting module 20 includes 5 first ports 201 and 4 second ports 202. The detection light of 4 wavelengths from the detection module 10 is input to the multiplexing / splitting module 20 from one of the first ports 201, and the 4 service lights are input to the multiplexing / splitting module 20 from the other 4 first ports 201 respectively. The multiplexing / demultiplexing module 20 distributes each input service light and each detection light to the corresponding second port 202. Service light 1 and detection light 1 are transmitted to fiber 1 through one of the second ports 202, service light 2 and detection light 2 are transmitted to fiber 2 through one of the second ports 202, service light 3 and detection light 3 are transmitted to fiber 3 through one of the second ports 202, and service light 4 and detection light 4 are transmitted to fiber 4 through one of the second ports 202.

[0070] Figure 8 is a schematic diagram of an embodiment of this application using optical pulses for detection light. In some possible scenarios, the first detection light emitted by the detection module 10 at wavelengths of a are all optical pulses, which facilitates better differentiation of reflection or backscattering of the first detection light at different positions in the optical fiber. As shown in Figure 8, taking four first detection lights of different wavelengths as detection light 1, detection light 2, detection light 3, and detection light 4 as an example, detection light 1, detection light 2, detection light 3, and detection light 4 correspond to different wavelengths in the frequency domain, and detection light 1, detection light 2, detection light 3, and detection light 4 are all periodically repeating optical pulses in the time domain.

[0071] Figure 9 is a schematic diagram of time-division multiplexing of detection light in an embodiment of this application. Based on the scenario shown in Figure 8, in one possible implementation, the detection module 10 emits multiple wavelength light pulses in a time-division manner. If the detection module 10 is an OTDR module, it is beneficial to improve the power detection accuracy and measurement speed; if the detection module 10 is a DAS module, it is beneficial to improve the sampling rate. Furthermore, in the scenario where the detection module 10 uses a light source and a modulator, the modulator does not need to modulate multiple frequency radio frequency signals at the same time, and the implementation cost of the modulator is lower. As shown in Figure 9, detection light 1, detection light 2, detection light 3, and detection light 4 are four light pulses of different wavelengths, and the detection module 10 emits detection light 1, detection light 2, detection light 3, and detection light 4 in chronological order.

[0072] It should be noted that the detection module 10 provided in this application embodiment can have multiple implementation forms, which will be described below.

[0073] Figure 10 is a schematic diagram of a detection module in an embodiment of this application. As shown in Figure 10, the detection module 10 includes a light source 101, a modulator 102, an RF driving unit 103, and a circulator 104. In the light emission direction of the detection module 10, the RF driving unit 104 provides the modulator 102 with a RF signals of different frequencies, which can also be referred to as a subcarriers. The modulator 102 modulates the a RF signals onto the light emitted by the light source 101 to form a first detection light of a wavelengths. The first detection light of a wavelengths is transmitted to the multiplexing / demultiplexing module 20 through the circulator 104. In the scenario shown in Figure 8, the modulator 102 is also used to modulate the first detection light in the form of light pulses. It should be understood that by adopting the above-described implementation of the light source 101, modulator 102, and RF driving unit 103, the frequency of the RF signal can be flexibly adjusted, thereby making the wavelength of the detection light more flexible.

[0074] The detection module 10 also includes an optical receiving unit 105, an RF power divider 106, and a processing units 107. In the optical receiving direction of the detection module 10, a second detection light of a wavelengths reflected or backscattered from the optical fiber is transmitted to the detection module 10 via a multiplexing / splitting module 20, and then to the optical receiving unit 105 via a circulator 104. Specifically, the optical receiving unit 105 can be a coherent receiver. The light source 101 also provides local oscillator light to the optical receiving unit 105. The optical receiving unit 105 coherently receives the a wavelengths of the second detection light based on the local oscillator light to convert it into an electrical signal. The RF power divider 106 divides the electrical signal into a RF signals of different frequencies, and the a RF signals are transmitted to the a processing units 107 respectively. Furthermore, the a processing units 107 process the a RF signals respectively to obtain the physical parameters of the a optical fibers. Figure 10 illustrates an example of four processing units 107 processing four RF signals respectively.

[0075] Figure 11 is a schematic diagram of another structure of the detection module in this embodiment. Unlike the implementation shown in Figure 10, as shown in Figure 11, the detection module 10 does not use an RF power divider 106, but instead uses a digital signal processor (DSP) 108. In the light emission direction of the detection module 10, the implementation in Figure 11 is similar to that in Figure 10, and will not be described again here. In the light receiving direction of the detection module 10, the light receiving unit 105 can convert the second detection light of a wavelengths into digital signals, which are then processed by the DSP 108 to obtain the physical parameters of the a optical fibers.

[0076] By comparing the implementation methods shown in Figures 10 and 11, it can be seen that the implementation method shown in Figure 10 uses an RF power divider 106 to distinguish *a* RF signals of different frequencies, thus distinguishing the second detection light of *a* wavelengths and determining the physical parameters of *a* optical fibers. The implementation method shown in Figure 11 uses DSP processing to distinguish the second detection light of *a* wavelengths and determine the physical parameters of *a* optical fibers. Although the implementation method shown in Figure 10 is more complex in hardware structure than that shown in Figure 11, after using the RF power divider 106 to distinguish the *a* RF signals of different frequencies, it can use *a* analog-to-digital converters (ADCs) to perform analog-to-digital conversion on the *a* RF signals respectively. Each ADC only needs to cover a small frequency range, resulting in lower implementation costs. In contrast, the implementation method shown in Figure 11 distinguishes the second detection light of *a* wavelengths through digital signal processing, requiring an ADC that can cover a larger frequency range, resulting in higher implementation costs.

[0077] Figure 12 is a schematic diagram of another structure of the detection module in this embodiment. Unlike the embodiments shown in Figures 10 and 11, as shown in Figure 12, in the light emission direction of the detection module 10, the detection module 10 does not have a radio frequency driving unit 103. Instead, the modulator 102 modulates the light output from each of the a light sources 101 into light pulses, generating a first detection light of a wavelengths. The first detection light of a wavelengths is transmitted to the multiplexing / demultiplexing module 20 via the circulator 104. Of course, in some possible scenarios, the first detection light of a wavelengths generated by a single light source 101 can also be directly emitted to the circulator 104 and transmitted to the multiplexing / demultiplexing module 20 via the circulator 104. That is, the first detection light of a wavelengths does not take the form of light pulses, and in this case, the modulator 102 may not be provided in the detection module 10.

[0078] The detection module 10 also includes a beam splitting unit 109, a light receiving units 110, and a processing units 107. In the light receiving direction of the detection module 10, a second detection light of a wavelengths, reflected or backscattered from the optical fiber, is transmitted to the detection module 10 via a multiplexing / splitting module 20 and then to the beam splitting unit 109 via a circulator 104. The beam splitting unit 109 transmits the a second detection light of a wavelengths to the a light receiving units 110 respectively. The a light receiving units 110 convert the a second detection light of a wavelengths into a electrical signals, and the a processing units 107 process the a electrical signals to obtain the physical parameters of the a optical fibers.

[0079] Figure 13 is a schematic diagram of another structure of the detection module in this application embodiment. Unlike the implementation shown in Figure 12, as shown in Figure 13, in the light emission direction of the detection module 10, the detection module 10 does not use multiple light sources 101. Instead, the modulator 102 modulates the light of a wavelengths output by a single light source 101 into light pulses, which are then used as the first detection light. In the light receiving direction of the detection module 10, the implementation in Figure 13 is similar to that in Figure 12, and will not be described again here. Of course, in some possible scenarios, the first detection light of a wavelengths generated by a single light source 101 can also be directly emitted to the circulator 104 and transmitted through the circulator 104 to the multiplexing / demultiplexing module 20. That is, the first detection light of a wavelengths does not take the form of light pulses, and in this case, the modulator 102 may not be provided in the detection module 10.

[0080] It should be noted that, unlike the embodiments shown in Figures 10 and 11, the embodiments shown in Figures 12 and 13 distinguish the second detection light of a wavelengths by the beam splitting unit 109 before photoelectric conversion. Then, the a processing units 107 process the a electrical signals after photoelectric conversion to determine the physical parameters of the a optical fibers respectively. By comparing the embodiments shown in Figures 12 and 13, it can be seen that the embodiment shown in Figure 12 emits the first detection light of a wavelengths by a light source, and the implementation cost of each light source is relatively low. The embodiment shown in Figure 13 emits the first detection light of a wavelengths by a single light source, which does not require a large number of light sources and occupies less space.

[0081] In some possible scenarios, if the number of optical fibers to be detected exceeds the number of wavelengths of the first detection light emitted by the optical fiber detection device in a single transmission, then the optical fiber detection device cannot detect all optical fibers by emitting 'a' wavelengths of first detection light in a single transmission. In this case, the detection module 10 needs to emit 'a' wavelengths of first detection light multiple times to detect all optical fibers, with each 'a' wavelength of first detection light emitted by the optical fiber detection device covering a different combination of optical fibers. That is, the 'a' optical fibers fed into the first transmission of 'a' wavelengths of first detection light by the optical fiber detection device are not exactly the same as the 'a' optical fibers fed into the second transmission of 'a' wavelengths of first detection light by the optical fiber detection device.

[0082] Especially in the co-route detection scenario shown in Figure 4 above, a DAS module is needed to detect the vibration parameters of the optical fiber. This requires not only acquiring the vibration parameters of all optical fibers but also performing pairwise correlation comparisons of these parameters to achieve co-route identification of multiple optical fibers. Using the optical fiber detection device provided in this embodiment, even in scenarios with multiple optical fiber transmission paths, the detection efficiency can still be significantly improved compared to existing technologies. A specific embodiment is provided below.

[0083] Figure 14 is a schematic diagram of one implementation method of co-route detection using an optical fiber detection device in this application. As shown in Figure 14, this scenario involves the deployment of 6 optical fibers. The optical fiber detection device emits detection light of 4 different wavelengths at a time, and the device needs to emit in 3 batches. The specific implementation methods for these 3 batches are shown in (1), (2), and (3) of Figure 14, respectively. After each batch is emitted, the optical fiber detection device performs pairwise correlation comparisons on the vibration parameters of the detected optical fibers, specifically calculating the correlation of the vibration parameters in different spatial and temporal dimensions.

[0084] As shown in Figure 14(1), the four wavelengths of detection light emitted by the detection module 10 in the first batch are transmitted to optical fibers 1, 2, 3 and 4 respectively after passing through the wavelength division multiplexing module 20. The detection module 10 can detect the vibration parameters of optical fibers 1, 2, 3 and 4, and perform pairwise correlation comparisons on the detected vibration parameters of these four optical fibers.

[0085] As shown in Figure 14(2), the detection light of the four wavelengths emitted by the detection module 10 in the second batch is transmitted to optical fibers 1, 2, 5 and 6 respectively after passing through the wavelength division multiplexing module 20. The detection module 10 can detect the vibration parameters of optical fibers 1, 2, 5 and 6, and perform pairwise correlation comparisons on the detected vibration parameters of these four optical fibers.

[0086] As shown in Figure 14(3), the four wavelengths of detection light emitted by the detection module 10 in the third batch are transmitted to optical fibers 3, 4, 5 and 6 respectively after passing through the wavelength division multiplexing module 20. The detection module 10 can detect the vibration parameters of optical fibers 3, 4, 5 and 6, and perform pairwise correlation comparisons on the detected vibration parameters of these four optical fibers.

[0087] Figure 15 is a schematic diagram of a comparison result of co-route detection in an embodiment of this application. The detection module 10 integrates all the results of pairwise correlation comparison of the vibration parameters of the six optical fibers and can find regions with high local correlation. For example, as shown in Figure 15, the z11~z12 region on optical fiber 1 and the z21~z22 region on optical fiber 2 are in the same trench. The physical distance between these regions is relatively close, and there is a possibility that the main and backup optical fibers will break simultaneously when the optical cable is damaged externally.

[0088] It should be noted that, in the existing technology, if two independent DAS modules are used to measure six optical fibers, a total of C(6,2) = 15 measurements are required to achieve pairwise correlation comparison of the vibration parameters of the six optical fibers. However, using the optical fiber detection device provided in this application embodiment, as shown in Figure 14, only 3 measurements are needed to achieve pairwise correlation comparison of the vibration parameters of the six optical fibers, improving the detection efficiency by 5 times. Extending this to a scenario where the optical fiber detection device emits detection light of N wavelengths at a time to measure M optical fibers, the total number of measurements is C(2*N / M,2), which, compared to the scheme using two independent DAS modules, improves the detection efficiency by C(N,2) / C(2*N / M,2).

[0089] Figure 16 is a schematic flowchart of an optical fiber detection method according to an embodiment of this application. This optical fiber detection method is implemented based on the optical fiber detection device described in the above embodiments. The structure of the optical fiber detection device can be referred to in the detailed description of any of the above embodiments, and will not be repeated here. The optical fiber detection method includes the following steps.

[0090] 1. The detection module emits a first detection light of wavelength a.

[0091] Specifically, a first detection light of wavelength *a* is input to the multiplexing / demultiplexing module through its first port. As an example, the detection module includes a light source, a modulator, and an RF drive unit. The RF drive unit provides the modulator with *a* RF signals of different frequencies, and the modulator modulates these *a* RF signals onto the light emitted by the light source, forming the first detection light of wavelength *a*. As another example, the detection module includes *a* light sources, each emitting a first detection light of wavelength *a*. As yet another example, the detection module includes a single light source, emitting a first detection light of wavelength *a* from this single light source.

[0092] In some possible scenarios, the first detection light of a wavelengths emitted by the detection module is a light pulse, and multiple light pulses of different wavelengths can be emitted by the detection module in a time-division manner.

[0093] 2. The first detection light of wavelengths a is transmitted to optical fibers a respectively through the multiplexing and splitting module.

[0094] Specifically, the first detection light of wavelength 'a' is transmitted to 'a' optical fibers through 'a' second ports of the multiplexing / demultiplexing module. The first detection light undergoes reflection or backscattering during transmission within the optical fibers, resulting in 'a' wavelengths of second detection light that are then transmitted back to the multiplexing / demultiplexing module.

[0095] 3. The second detection light of a wavelengths from a fiber is transmitted to the detection module through the multiplexing and splitting module.

[0096] Specifically, the second detection light of wavelength a is transmitted to the detection module through the first port of the multiplexing / splitting module.

[0097] 4. The detection module detects the second detection light of wavelength a to obtain the physical parameters of optical fiber a.

[0098] As an example, the detection module is an OTDR module, which can detect the fiber's loss parameters. As another example, the detection module is a DAS module, which can detect at least one of the fiber's vibration parameters, stress parameters, and temperature. As yet another example, the detection module is a DVS module, which can detect at least one of the fiber's vibration parameters and stress parameters.

[0099] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An optical fiber testing device, characterized by, include: The system includes a detection module and a multiplexing / splitting module, wherein the multiplexing / splitting module includes a first port and multiple second ports, the first port is connected to the detection module, and each second port is used to connect to a corresponding optical fiber; The detection module is used to emit a first detection light of a wavelengths, and the first detection light of a wavelengths is input to the multiplexing and splitting module through the first port, where a is an integer greater than 1; The multiplexing / splitting module is used to transmit the first detection light of the a wavelengths to the corresponding multiple optical fibers through the multiple second ports, wherein the first detection light of the a wavelengths is reflected or backscattered in the multiple optical fibers to form the second detection light of the a wavelengths. The multiplexing and splitting module is used to multiplex the second detection light of the a wavelengths, and transmit the multiplexed second detection light of the a wavelengths to the detection module through the first port; The detection module is used to detect the second detection light of the a wavelengths to obtain the physical parameters of the multiple optical fibers.

2. The optical fiber testing apparatus of claim 1, wherein, The number of the second ports is equal to a, and the a wavelengths of the first detection light are transmitted to a optical fiber through a second ports respectively.

3. The optical fiber testing apparatus of claim 1, wherein, The number of second ports is less than a, and at least two wavelengths of first detection light are transmitted to the same optical fiber through the same second port.

4. The optical fiber testing apparatus of claim 1, wherein, The number of the second port is greater than a; The wavelength division and multiplexing module is specifically used to transmit the first detection light of the a wavelengths to the a optical fiber through the a second ports respectively in the first time period. The multiplexing / splitting module is also used to transmit at least one wavelength of the first detection light of the a wavelengths to the corresponding at least one optical fiber through at least one second port other than the a second ports in the second time period, wherein the first detection light of the at least one wavelength is reflected or backscattered in the at least one optical fiber other than the a optical fiber to form a second detection light of at least one wavelength. The multiplexing / splitting module is also used to transmit the second detection light of at least one wavelength to the detection module through the first port; The detection module is also used to detect the second detection light of at least one wavelength to obtain the physical parameters of the at least one optical fiber other than the a optical fiber.

5. The optical fiber testing apparatus of any of claims 1-4, wherein, The detection module is an optical time domain reflectometer (OTDR) module, and the physical parameters of the optical fiber are the loss parameters of the optical fiber.

6. The optical fiber testing apparatus of any of claims 1-4, wherein, The detection module is a distributed acoustic wave sensor (DAS) module or a distributed vibration sensor (DVS) module, and the physical parameters of the optical fiber are at least one of the vibration parameters and stress parameters of the optical fiber.

7. The optical fiber testing apparatus of any of claims 1-6, wherein, The detection module includes a light source and a modulator. The modulator is used to modulate a radio frequency signals onto the light emitted by the light source to form a first detection light of a wavelengths, wherein the frequencies of the a radio frequency signals are different.

8. The optical fiber testing apparatus of claim 7, wherein, The detection module includes an optical receiving unit, an RF power divider, and a processing unit. The optical receiving unit is used to convert the second detection light of the a wavelengths into electrical signals; The radio frequency power divider is used to divide the electrical signal into a radio frequency signals, and the a radio frequency signals have different frequencies. The a processing units are used to process the a radio frequency signals respectively to obtain the physical parameters of the multiple optical fibers.

9. The optical fiber testing apparatus of claim 7, wherein, The detection module includes an optical receiving unit and a digital signal processor (DSP); The optical receiving unit is used to convert the second detection light of the a wavelengths into digital signals; The DSP is used to perform digital signal processing on the digital signal to obtain the physical parameters of the multiple optical fibers.

10. The optical fiber testing apparatus of any of claims 1-6, wherein, The detection module includes a light sources, which are used to emit first detection light of a wavelengths respectively; or, The detection module includes a light source, which is used to emit first detection light of the a wavelengths.

11. The optical fiber testing apparatus of claim 10, wherein, The detection module includes a beam splitting unit, a light receiving units, and a processing unit; The beam splitting unit is used to transmit the second detection light of the a wavelengths to the a light receiving units respectively; The a optical receiving units are used to convert the a wavelengths of the second detection light into a electrical signals respectively; The a processing units are used to process the a electrical signals respectively to obtain the physical parameters of the multiple optical fibers.

12. The optical fiber testing apparatus of any of claims 1-11, wherein, The first detection light of each wavelength is a light pulse.

13. The optical fiber testing apparatus of claim 12, wherein, The emission times of at least two of the first detection lights of the a wavelengths are different.

14. The optical fiber testing apparatus of any of claims 1-13, wherein, The multiplexing / splitting module is a filter or a wavelength selective switch (WSS).

15. An optical fiber transmission system, characterized by, The optical fiber transmission system includes a first site, a second site, and an optical fiber detection device as described in any one of claims 1 to 14. The first site and the second site are connected by multiple optical fibers. The optical fiber detection device is deployed at at least one of the first site and the second site. The multiplexing and demultiplexing module of the optical fiber detection device is connected to the multiple optical fibers through multiple second ports.

16. An optical fiber transmission system, characterized by, The optical fiber transmission system includes a first site, a second site, a third site, and an optical fiber detection device as described in any one of claims 1 to 14. The first site is connected to the second site and the third site respectively via two optical fibers. The optical fiber detection device is deployed at the first site. The multiplexing / splitting module of the optical fiber detection device is connected to the two optical fibers respectively via two second ports.

17. An optical fiber testing method, characterized by, The fiber optic detection method is applied to a fiber optic detection device, which includes a detection module and a multiplexing / splitting module. The multiplexing / splitting module includes a first port and multiple second ports. The first port is connected to the detection module, and each second port is used to connect to a corresponding fiber optic cable. The method includes: The detection module emits a first detection light of wavelength a, which is input to the multiplexing / splitting module through the first port, where a is an integer greater than 1. The first detection light of a wavelengths is transmitted to the corresponding multiple optical fibers through the multiple second ports via the multiple multiple wavelengths of the multiple optical fibers, wherein the first detection light of a wavelengths is reflected or backscattered in the multiple optical fibers to form a second detection light of a wavelengths. The second detection light of wavelength a is combined by the multiplexing and splitting module, and the combined second detection light of wavelength a is transmitted to the detection module through the first port; The detection module detects the second detection light of wavelength a to obtain the physical parameters of the multiple optical fibers.

18. The method of claim 17, wherein, The number of the second ports is equal to a, and the a wavelengths of the first detection light are transmitted to a optical fiber through a second ports respectively.

19. The method of claim 17, wherein, The number of second ports is less than a, and at least two wavelengths of first detection light are transmitted to the same optical fiber through the same second port.

20. The method of claim 17, wherein, The number of the second port is greater than a; The transmission of the first detection light of wavelength a through the multiple second ports to the corresponding multiple optical fibers via the multiple multiple multiple detection modules includes: The multiplexing and splitting module transmits the first detection light of a wavelengths to a optical fiber through a second port respectively in the first time period; The method further includes: The multiplexing and splitting module transmits at least one wavelength of the first detection light of the a wavelengths to at least one corresponding optical fiber through at least one second port other than the a second ports in the second time period, wherein the first detection light of the at least one wavelength is reflected or backscattered in the at least one optical fiber other than the a optical fiber to form a second detection light of at least one wavelength. The at least one wavelength of the second detection light is transmitted to the detection module through the first port via the multiplexing / splitting module; The detection module detects the second detection light of at least one wavelength to obtain the physical parameters of the at least one optical fiber other than the a optical fiber.

21. The method according to any one of claims 17 to 20, characterized in that, The detection module is an optical time domain reflectometer (OTDR) module, and the physical parameters of the optical fiber are the loss parameters of the optical fiber.

22. The method of any one of claims 17-20, wherein, The detection module is a distributed acoustic wave sensor (DAS) module or a distributed vibration sensor (DVS) module, and the physical parameters of the optical fiber are at least one of the vibration parameters and stress parameters of the optical fiber.

23. The method of any one of claims 17-22, wherein, The detection module includes a light source and a modulator. The emission of first detection light of wavelength *a* through the detection module includes: The modulator modulates a radio frequency signals onto the light emitted by the light source to form a first detection light of a wavelengths, wherein the frequencies of the a radio frequency signals are different.

24. The method of claim 23, wherein, The detection module includes an optical receiving unit, an RF power divider, and a processing units. The detection module detects the second detection light of the a wavelengths to obtain the physical parameters of the a optical fibers, including: The optical receiving unit converts the second detection light of wavelength a into electrical signals. The electrical signal is divided into a radio frequency signals by the radio frequency power divider, and the a radio frequency signals have different frequencies. The a radio frequency signals are processed by the a processing units respectively to obtain the physical parameters of the multiple optical fibers.

25. The method of claim 23, wherein, The detection module includes an optical receiving unit and a digital signal processor (DSP). The detection module detects the second detection light at a wavelengths to obtain the physical parameters of the a optical fibers, including: The optical receiving unit converts the second detection light of the a wavelengths into digital signals. The DSP performs digital signal processing on the digital signal to obtain the physical parameters of the multiple optical fibers.

26. The method of any one of claims 17-22, wherein, The detection module includes *a* light sources, and the emission of first detection light of *a* wavelengths through the detection module includes: The a light sources emit the first detection light of the a wavelengths respectively; or, The detection module includes a light source, and emitting a first detection light of wavelength a through the detection module includes: The light source emits a first detection light of the specified wavelengths.

27. The method of claim 26, wherein, The detection module includes a beam splitting unit, a light receiving units, and a processing units. The detection module detects the second detection light at a wavelengths to obtain the physical parameters of the a optical fibers, including: The second detection light of a wavelengths is transmitted to the a light receiving units respectively through the beam splitting unit; The a optical receiving units respectively convert the a wavelengths of the second detection light into a electrical signals; The a electrical signals are processed by the a processing units respectively to obtain the physical parameters of the multiple optical fibers.

28. The method of any one of claims 17-27, wherein, The first detection light of each wavelength is a light pulse.

29. The method of claim 24, wherein, The emission times of at least two of the first detection lights of the a wavelengths are different.

30. The method of any one of claims 17-29, wherein, The multiplexing / splitting module is a filter or a wavelength selective switch (WSS).

Images