Method of identifying ont and storage medium

Abstract

The application provides a method for identifying an ONT and a storage medium, and belongs to the technical field of optical communication. The method is applied to an identification system, and the method comprises the following steps: a first detection light with a scanning wavelength and a polarization state is sent to a household cable by the identification device, the wavelength of the first detection light comprises a plurality of transmission wavelengths of an FP ONT, the identification device receives first reflected light reflected by the household cable each time, and the power of the first reflected light is determined. Since the FP resonant cavity of the FP ONT has not only a wavelength periodic selection effect but also a polarization selectivity, that is to say, only a specific wavelength of an optical signal satisfying a specific polarization state can be reflected back and forth in the FP resonant cavity and is enhanced, and the optical signal cannot be attenuated, so if the power of the first reflected light presents a periodic change with the wavelength, it is determined that the household cable is connected with the FP ONT. In this way, whether the household cable is connected with the FP ONT can be identified.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a method and storage medium for identifying an ONT. Background Technology

[0002] In optical access networks, passive optical networks (PONs) are point-to-multipoint systems, including optical line terminals (OLTs), optical distribution networks (ODNs), and optical network terminals (ONTs).

[0003] Over time, Ethernet Passive Optical Network (EPON) has expanded to 10G EPON and then to 50G PON in optical access networks. Since EPON and 10G EPON are still widely used in existing networks, deploying 50G PON requires consideration of the coexistence of EPON, 10G EPON, and 50G PON ONTs under the same PON port. However, EPON sometimes uses Fabry-Perot (FP) ONTs. FP ONTs generate optical signals using FP lasers, and their uplink wavelength range overlaps with that of 50G PON. This means that EPON uplink optical signals will enter the 50G PON receiving channel, and vice versa. Furthermore, 50G PON downlink optical signals, after reflection in the optical path, will also enter the EPON receiving channel, causing mutual interference. Therefore, it is necessary to identify the EPON FP ONTs in order to replace them. Summary of the Invention

[0004] This application provides a method and storage medium for identifying an ONT, capable of identifying the FP ONT of an EPON. The technical solution adopted is as follows:

[0005] In a first aspect, this application provides a method for identifying an Online Terminal (ONT). This method is applied to an identification system, which includes an identification device for connecting to a drop cable. The method includes: the identification device sending a first detection light with a scanning wavelength and polarization state to the drop cable, wherein the wavelength of the first detection light includes multiple transmission wavelengths of the FP ONT; the identification device receiving a first reflected light returned by the drop cable and determining the power of the first reflected light; if the power of the first reflected light exhibits a periodic change with the wavelength of the first detection light, then the identification device determines that the drop cable is connected to the FP ONT.

[0006] In the scheme shown in this application, the identification device sends detection light to the drop cable, and scans the wavelength and polarization state while sending the detection light. This is equivalent to sending detection light of multiple wavelengths and different polarization states one by one. After sending detection light of a certain wavelength each time, the identification device receives the first reflected light reflected by the drop cable and determines the power of the first reflected light. Since the FP resonant cavity of the FP ONT not only has wavelength periodicity selection but also polarization selectivity, that is, only light signals of a specific wavelength that meet a specific polarization state can be reflected back and forth in the FP resonant cavity and be enhanced without being attenuated, if the power of the first reflected light changes periodically with the wavelength, it is determined that the drop cable is connected to the FP ONT. In this way, it is possible to identify whether the drop cable is connected to the FP ONT.

[0007] In one alternative approach, when the ONT is a FP ONT, the period of power variation of the first reflected light with wavelength should be a target value, which is related to the cavity length of the FP ONT. This way, when determining whether the drop cable is connected to the FP ONT, considering the periodic variation as a target value can improve identification accuracy.

[0008] In one alternative approach, the multiple transmission wavelengths include the transmission wavelengths of the EPON's distributed feedback (DFB) ONT. Considering that the DFB ONT also has a resonant cavity, to accurately identify whether it is an FP ONT, in the transmission wavelengths of the DFB ONT, it is determined that there is no target wavelength with a first power change amplitude greater than a first threshold, indicating that the power has not changed abruptly, thus excluding the DFB ONT. Here, the first power change amplitude is the change amplitude of the power of the first reflected light corresponding to the target wavelength relative to a first power, where the first power is greater than the power of the first reflected light corresponding to the target wavelength. Alternatively, in the transmission wavelengths of the DFB ONT, it is determined that there is no target wavelength with a second power change amplitude less than a second threshold, indicating that the power has not changed abruptly, thus excluding the DFB ONT. Here, the second power change amplitude is the change amplitude of the power of the first reflected light corresponding to the target wavelength relative to a second power, where the second power is less than the power of the first reflected light corresponding to the target wavelength. This improves the identification accuracy.

[0009] In one alternative approach, if the drop cable is connected to a DFB ONT, the detection light of the scanning wavelength is simultaneously altered. After the detection light enters the DFB laser within the DFB ONT, due to the single-wavelength selectivity of the DFB laser, when the wavelength of the detection light is adjusted to match the center wavelength of the resonant cavity's filter spectrum, the detection light dissipates inside the DFB laser. Therefore, the power of the reflected light drops sharply at this point, exhibiting a large, downward-pointing peak. Thus, if the target wavelength is determined to exist within the transmission wavelength range of the DFB ONT, the identification device determines that the drop cable is connected to the EPON's DFB ONT, enabling the identification of the EPON's DFB ONT.

[0010] In one alternative approach, the first detection light is a pulsed light or a direct current light. When detecting a particular drop cable, the identification device is used to connect to that drop cable without affecting the ONTs connected to other drop cables, thereby reducing the impact of detection on services.

[0011] In one alternative approach, the identification device can be deployed in the central office equipment room. The first detection light is pulsed light. The identification system also includes a first optical combiner / splitter and a second optical combiner / splitter. The identification device is connected to the splitting port of the first optical combiner / splitter. The optical combiner / splitter's optical combiner port is used to connect to the optical combiner port of the first-level optical combiner / splitter in the ODN. The optical combiner / splitter's optical combiner port is used to connect to the first optical combiner in the ODN. The first optical combiner / splitter's optical combiner port is used to connect to the optical combiner port of the second optical combiner / splitter. The second optical combiner / splitter's optical combiner port is used to connect to the drop cable. The first optical combiner / splitter is the upstream optical combiner connected to the second optical combiner / splitter. The second optical combiner / splitter is the optical combiner in the ODN that is connected to the drop cable. The identification device broadcasts a first detection light through a first beam combiner / splitter. This first detection light then passes through a second beam combiner / splitter to reach the drop cable. The first beam combiner / splitter receives a second reflected light transmitted from the second beam combiner / splitter and sends this second reflected light back to the identification device. This second reflected light includes the first reflected light. Based on the first reflection peak information of the second reflected light, the identification device determines the power of the first reflected light. This first reflection peak information includes the peak power of the reflection peaks at each wavelength and the reception time. Thus, since the drop cable is directly plugged into the second beam combiner / splitter, the detected drop cable can be clearly identified, allowing for a more accurate correlation between the drop cable and the detection result.

[0012] In one optional approach, the identification device sends a second detection light with a scanning wavelength and polarization state to the first beam combiner / splitter. The second detection light overlaps with the wavelength and polarization state of the first detection light. The first beam combiner / splitter sends the second detection light to a second beam combiner / splitter, which in turn sends the second detection light to the drop cable. The first beam combiner / splitter receives a third reflected light sent by the second beam combiner / splitter and sends the third reflected light to the identification device. The identification device determines the second reflection peak information of the third reflected light, wherein the second reflection peak information includes the peak power and reception time of the reflection peaks at each wavelength. Based on the first and second reflection peak information, the identification device determines the power of the first reflected light. Thus, when the identification device is deployed in the central office equipment room, before the second beam splitter is connected to the drop cable, the identification device obtains the reflection peak information of each drop cable connected to the second beam splitter in advance. This provides a reference when determining the reflection peak information corresponding to a particular drop cable, thereby enabling a more accurate determination of the first reflected light corresponding to that drop cable.

[0013] In one alternative approach, the identification device performs the identification ONT process after receiving the test command. That is, the identification device receives the test command before sending the first test light to the drop cable. The test command is used to indicate the start of sending the first test light.

[0014] In one alternative approach, the second beam combiner / splitter is a coupler.

[0015] In one alternative approach, when the end of the drop cable is not connected to an ONT, the end face of the drop cable does not exhibit significant wavelength selectivity in reflecting the detection light. Therefore, if the power of the first reflected light does not show a periodic change with wavelength, or if the period of such a periodic change is not a target value, the identification device determines that the drop cable is not connected to an ONT, wherein the target value is related to the cavity length of the FP ONT. This also allows for the identification of whether the drop cable is connected to an ONT.

[0016] In one alternative approach, the identification device outputs indication information indicating that the drop cable is connected to the FP ONT. This allows maintenance personnel to be notified promptly that the FP ONT has been identified.

[0017] Secondly, this application provides a computer-readable storage medium including program instructions that, when executed by the identification device, enable the identification device to perform the identification process in the first aspect or any optional mode of the first aspect.

[0018] Thirdly, this application provides a computer program product including program instructions stored in a computer-readable storage medium. The processor of the identification device reads the program instructions from the computer-readable storage medium and executes the program instructions, causing the identification device to perform the identification process provided by the first aspect or any optional method of the first aspect. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the PON architecture provided in an exemplary embodiment of this application;

[0020] Figure 2 This is a schematic diagram illustrating the coexistence of EPON and 50G PON according to an exemplary embodiment of this application;

[0021] Figure 3 This is a schematic diagram of the structure of an identification device provided in an exemplary embodiment of this application;

[0022] Figure 4 This is a schematic diagram illustrating one usage of the identification device provided in an exemplary embodiment of this application;

[0023] Figure 5 This is a schematic diagram illustrating another usage of the identification device provided in an exemplary embodiment of this application;

[0024] Figure 6 This is a schematic diagram illustrating another usage of the identification device provided in an exemplary embodiment of this application;

[0025] Figure 7 This is a schematic diagram illustrating the principle of identifying an ONT provided in an exemplary embodiment of this application;

[0026] Figure 8 This is a schematic diagram illustrating the relationship between reflectivity and wavelength provided in an exemplary embodiment of this application;

[0027] Figure 9 This is a schematic diagram of a method for identifying an ONT provided in an exemplary embodiment of this application;

[0028] Figure 10 This is a schematic diagram of a scenario for identifying an ONT provided by an exemplary embodiment of this application;

[0029] Figure 11 This is a schematic diagram illustrating another scenario for identifying an ONT, provided by an exemplary embodiment of this application;

[0030] Figure 12 This is a schematic diagram illustrating another scenario for identifying an ONT provided by an exemplary embodiment of this application;

[0031] Figure 13 This is a schematic diagram illustrating another principle for identifying an ONT, provided by an exemplary embodiment of this application;

[0032] Figure 14 This is another structural schematic diagram of the identification device provided in an exemplary embodiment of this application. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0034] In optical access networks (ODNs) within PONs, compared to traditional broadband access networks (such as digital subscriber lines, DSL), the ODN achieves transmission from the OLT to multiple user terminals through a point-to-multipoint connection method. It features wide geographical coverage, a large number of branch optical paths, and complex scenarios. Furthermore, it lacks power supply, leading to challenges for operators in the actual construction, activation, operation, and maintenance of ODNs, including resource visibility and difficulties in fault location and troubleshooting. In particular, if a user no longer leases the operator's network, they only need to return their home optical modem (ONT). The drop cable connected to the ONT remains connected to a port on the ODN splitter, occupying available ODN resources. Over time, this results in a large number of ports being virtually occupied, making it impossible for operators to distinguish which ports are available when activating services for new users. Therefore, it is necessary to identify which ports are virtually occupied, meaning the drop cable connected to that port is not connected to the ONT at the end. Figure 1 As shown, the OLT is connected to the ONT via the ODN. The ODN includes a primary optical splitter, a secondary optical splitter 1, and a secondary optical splitter 2. The primary optical splitter is connected to the OLT and to the secondary optical splitters 1 and 2. The secondary optical splitters 1 and 2 are connected to the ONT via drop cables. The drop cable connected to port 1 of the secondary optical splitter 1 is connected to the ONT, while the drop cable connected to port 2 is suspended and not connected to the ONT. The drop cable connected to port 1 of the secondary optical splitter 2 is connected to the ONT.

[0035] Furthermore, with the evolution of PON, PON has evolved from EPON and 10G EPON to 50G PON. However, before evolving to 50G PON, the ONT used by users also included EPON's FP ONT. FP ONT refers to an ONT that generates optical signals through an FP laser. At this time, the OLT optical module includes the transceiver section of 50G PON and the transceiver section of EPON. The transceiver section of 50G PON includes the electrical signal processing module, the transmitting module, and the receiving module of 50G PON. The transceiver section of EPON includes the electrical signal processing module, the transmitting module, and the receiving module. The transmitting module is used to convert electrical signals into optical signals, and the receiving module is used to convert optical signals into electrical signals. The FP ONT of EPON has a transmit wavelength range of 1260nm–1360nm and a receive wavelength range of 1480nm–1500nm, while the ONT of 50G PON has a transmit wavelength range of 1284nm–1288nm and a receive wavelength range of 1340nm–1344nm. It is evident that the transmit wavelength ranges of the FP ONT and the ONT overlap, causing uplink optical signals from the FP ONT to enter the receive channel of the 50G PON, and vice versa. Furthermore, the receive wavelength range of the ONT overlaps with the transmit wavelength range of the FP ONT, causing reflected light from the downlink optical signals of the 50G PON to also enter the receive channel of the EPON. (See [link to relevant documentation]). Figure 2 .

[0036] Based on this, embodiments of this application provide a method for identifying an ONT. In this method, a detection light is sent to the drop cable, and a first reflected light returned by the drop cable is received. If the power of the first reflected light changes periodically with the wavelength of the detection light, it is determined that the drop cable is connected to the FP ONT. In this way, it is possible to identify whether the drop cable is connected to the FP ONT.

[0037] Additionally, see Figure 2 The ONT may also include a DFB ONT for EPON, which generates optical signals via a DFB laser. The DFB ONT has a transmission wavelength range of 1290nm to 1330nm and a reception wavelength range of 1480nm to 1500nm, which does not conflict with 50G PON, but can still be identified using the scheme of the embodiments of this application.

[0038] ONT may also include a 10G EPON ONT, which has a transmission wavelength range of 1260nm to 1280nm and a reception wavelength range of 1575nm to 1580nm, and does not conflict with 50G PON.

[0039] The method for identifying ONTs is applied to an identification system, which includes an identification device that can connect to the drop cable to be detected. This identification device can identify the status of the drop cable, i.e., whether it is connected to an EPON FP ONT, an EPON DFB ONT, or has no ONT connected. The ONT can be of any type, as shown in Table 1.

[0040] Table 1

[0041] State 1 No ONT connected State 2 It is connected to the EPON FP ONT State 3 It is connected to the EPON DFB ONT State 4 Other ONTs are connected

[0042] The identification device has the ability to scan wavelengths and can also adjust the polarization state of the transmitted detection light. The structure of the identification device is described in [reference needed]. Figure 3 The identification device includes a signal module and an identification module. The signal module includes a signal generation module, an optical polarization controller, a beam combiner / splitter (or circulator), and a detector. The signal generation module is connected to the optical polarization controller via optical fiber, the optical polarization controller is connected to the beam combiner / splitter via optical fiber, the beam combiner / splitter is connected to the detector via optical fiber, the detector is connected to the identification module, and the beam combiner / splitter is connected to the optical port of the identification device, which is used to connect to an external optical fiber. The signal generation module outputs tunable wavelength detection light to the optical polarization controller, which adjusts the polarization state of the detection light and outputs the adjusted detection light to the beam combiner / splitter. The beam combiner / splitter also receives reflected light from the drop cable and outputs the reflected light to the detector. The detector converts the reflected light into an electrical signal and outputs the electrical signal to the identification module. Based on the power of the electrical signal, the identification module determines whether the drop cable is connected to an ONT (On-Demand Terminal). If an ONT is connected, it determines the type of ONT.

[0043] Optionally, the signal module and the identification module can be integrated into a single device. Alternatively, the signal module and the identification module can be installed as separate devices, with the signal module serving as a test instrument and the identification module serving as an identification program, both mounted on a hardware device such as a terminal, or the identification module as a hardware module. The following explanation will use the integration of the signal module and the identification module into a single device as an example.

[0044] Alternatively, the identification device can also be understood as an optical time domain reflectometer (OTDR) with variable wavelength and polarization state.

[0045] Optionally, the identification device can be used in three ways. One method involves using the identification device as a testing instrument, directly inserting the drop cable into the identification device at the location of the beam splitter, thus connecting the drop cable to the beam splitter within the identification device. The identification device then sends detection light to the drop cable; this detection light can be pulsed or DC light. See [link to relevant documentation]. Figure 4 .

[0046] Another approach involves deploying the identification device as a detection equipment within the central office equipment room. The identification system includes the identification device and a first optical combiner / splitter. The first optical combiner / splitter includes a combining port and two splitting ports. The combining port connects to the combining port of the first-level splitter in the ODN, one splitting port connects to the OLT, and the other splitting port connects to the identification device. Through the first optical combiner / splitter, the detection light and the service light are combined and transmitted in the optical fiber until they reach the ONT at the end. This detection light is pulsed light. (See [link to relevant documentation]). Figure 5 In adopting Figure 5 When using this method, the distances between the ends of multiple drop cables and the OLT are determined and are not the same.

[0047] Another approach involves deploying the identification device as a detection equipment within the central office equipment room. The identification system includes an identification device, a first optical combiner / splitter, and a second optical combiner / splitter. The first optical combiner / splitter includes a combining port and two splitting ports. The combining port connects to the combining port of the first-level splitter in the ODN, one splitting port connects to the OLT, and the other splitting port connects to the identification device. The combining port of the second optical combiner / splitter connects to the target splitting port of the first optical combiner / splitter. One splitting port of the second optical combiner / splitter connects to the second optical combiner / splitter, and the other splitting port connects to the drop cable. The first optical combiner / splitter is the upstream splitter of the second optical combiner / splitter. The target splitting port connects to the second optical combiner / splitter before connecting to it. The second optical combiner / splitter is the one that connects to the drop cable to be detected before identifying the ONT. See [link to relevant documentation]. Figure 6 The first beam splitter is a primary beam splitter, and the second beam splitter is a secondary beam splitter 2.

[0048] Figures 4 to 6 The dashed lines in the diagram indicate the fiber optic connection method before identifying the ONT. Figure 6 When using this method, the distance between the end of the drop cable and the OLT can be uncertain.

[0049] Regardless of the usage method, the principle for identifying FP ONTs is the same, as follows:

[0050] Figure 7A schematic diagram of the ONT (Optical Transmitter-Receiver) is provided. The ONT is an integrated optical transmitter-receiver assembly. Detection light enters the ONT through the drop cable, passes through the ONT's connector, and then enters the bi-directional optical sub-assembly (BOSA). In the BOSA, the detection light passes through a filter (such as a 45-degree filter), which directs different wavelengths of light signals in different directions. For example, Figure 7 In this process, optical signals with wavelengths greater than A pass through a 45-degree filter and enter the receiving component, which includes a detector. Optical signals with wavelengths less than or equal to A pass through a 45-degree filter and enter the transmitting component, which includes an FP laser or a DFB laser.

[0051] The FP laser includes a gain medium and an FP resonant cavity. The gain medium can generate optical signals within a certain wavelength range. The optical signals are reflected back and forth between the enhancing lens and the high-reflection mirror of the FP resonant cavity. At the same time, the FP resonant cavity has a wavelength periodicity selection function and also has polarization selectivity. That is to say, only optical signals of a specific wavelength that meet a specific polarization state can be reflected back and forth in the FP resonant cavity and be enhanced. The optical signal will not be attenuated. The specific wavelength is the wavelength of the laser generated by the FP laser of ONT.

[0052] Thus, if the drop cable is connected to an FP ONT, after the detection light enters the FP laser inside the ONT, the FP resonant cavity exhibits selective periodicity for different wavelengths of light signals. (See [link to relevant documentation]). Figure 7 The filter spectrum of the FP resonant cavity is used to scan the wavelength of the detection light while simultaneously changing its polarization state. The power of the reflected light from the drop cable will change with the wavelength, as shown in the curve. Figure 8 The power exhibits a periodic variation with wavelength. The period of this variation is related to the cavity length of the FP resonator; for example, the period is equal to the cavity length of the FP resonator, such as 1 mm. Furthermore, Figure 7 The paper also provides a set of wavelength-amplitude relationships for the filter spectrum of the corresponding FP resonant cavity. The dashed line represents the continuous optical signal output by the FP laser, which is filtered by the filter spectrum to obtain discrete optical signals of multiple wavelengths.

[0053] In addition to the gain medium and resonant cavity, a grating is etched between the high-reflection film and the anti-reflection film in a DFB laser. This grating possesses both wavelength-selective and polarization-selective characteristics, enabling it to select a narrower frequency optical signal from a wide range of wavelengths for output. The wavelength of this narrower frequency optical signal is related to the refractive index of the grating, and this wavelength is the wavelength of the laser light generated by the DFB laser.

[0054] Thus, if the drop cable is connected to a DFB ONT, the detection light of the scanning wavelength is simultaneously changed. After the detection light enters the DFB laser inside the DFB ONT, due to the single-wavelength selectivity of the DFB laser, see [reference needed]. Figure 7 As shown in the filter spectrum, when the wavelength of the detection light is tuned to match the center wavelength of the filter spectrum of the resonant cavity, the detection light is dissipated inside the DFB laser. Therefore, the power of the reflected light drops sharply at this point, exhibiting a downward-pointing peak, resulting in the lowest power of the reflected light. (See [reference]). Figure 8 The reflection spectrum of the DFB resonant cavity is shown.

[0055] When the ONT is not connected to the end of the drop cable, if the detection light of the scanning wavelength encounters an ultra-physical contact (UPC) connector, an angled physical contact (APC) connector, or a fiber break at the end of the drop cable, the reflection of the detection light from the end face of the drop cable will not show significant wavelength selectivity. Therefore, the curve of the reflected light changing with wavelength will be essentially a straight line. See [reference needed]. Figure 8 The UPC reflectance spectrum is shown.

[0056] The following outlines the process for identifying ONTs; see [link to ONT identification method]. Figure 9 Steps S101 to S103.

[0057] In step S101, the identification device sends a first detection light with a scanning wavelength and polarization state to the target access cable, wherein the wavelength of the first detection light includes multiple transmission wavelengths of the FP ONT.

[0058] In this embodiment, the target drop cable is the optical fiber connected to the port to be tested in the second optical splitter of the ODN. When the identification device determines whether the ONT connected to the target drop cable is an FP ONT, the identification device sends a first detection light to the target drop cable. During the transmission of the first detection light, the identification device scans the wavelength and polarization state of the first detection light. The wavelength of the first detection light includes multiple transmission wavelengths of the FP ONT. For example, the wavelength range of the first detection light covers the transmission wavelength range of the FP ONT; or, for example, the wavelength range of the first detection light is smaller than the transmission wavelength range of the FP ONT. In this way, it is equivalent to sending detection light of multiple wavelengths one by one, and switching multiple polarization states for each wavelength.

[0059] Here, when scanning the wavelength and polarization state of the first detection light, the wavelength can be fixed, and then all polarization states can be scanned. Then, the wavelength can be switched to the next wavelength, and then all polarization states can be scanned until the wavelength and polarization state of the first detection light are completely scanned.

[0060] Alternatively, when scanning the wavelength and polarization state of the first detection light, the polarization state can be fixed, then all wavelengths can be scanned, then the next polarization state can be switched, and then all wavelengths can be scanned again, until the wavelength and polarization state of the first detection light are completely scanned. Here, "all polarization states" includes the specific polarization state described above. It should be noted that because the polarization state of the optical signal changes during transmission, we may not be able to obtain that specific polarization state in advance; therefore, we will send detection light with multiple polarization states.

[0061] Optionally, for ease of recording, the wavelengths of the scanned detection light can be scanned in ascending order or descending order. This application does not limit the scanning order in its embodiments.

[0062] In step S102, the identification device receives the first reflected light returned by the target cable and determines the power of the first reflected light.

[0063] In this embodiment, after each change in wavelength or polarization state, the identification device receives the first reflected light returned by the target cable and determines the power of the first reflected light at each wavelength according to the transmission order of the optical signal, thereby determining the power variation curve with wavelength.

[0064] In this variation curve, power can be expressed using reflectivity or a power value. Reflectivity is equal to the ratio of received power to transmitted power. When the variation curve includes reflectivity, it can be called a return loss curve. If a specific power value is used, the transmitted power of the detection light at each wavelength is the same; or, if the transmitted power of the detection light at each wavelength is equivalent to the same value, the power value of the reflected light at each wavelength is obtained.

[0065] It should be noted that the change in power of the first reflected light with the wavelength of the first detected light can be represented by the change in reflectivity with wavelength or by the change in power with wavelength; the two are equivalent.

[0066] Step S103: Using the change curve, determine whether the power of the first reflected light changes periodically with wavelength. If it does change periodically, the identification device determines that the target drop cable is connected to the FP ONT.

[0067] If the change is non-periodic, or even if it is periodic but the period is not the target value, then the target drop cable is not connected to the ONT.

[0068] If, among the transmission wavelengths of the DFB ONT, a target wavelength with a corresponding first power variation amplitude greater than a first threshold is identified, then the target drop cable is determined to be connected to the EPON's DFB ONT. Here, the first power variation amplitude is the variation amplitude of the power of the first reflected light corresponding to the target wavelength relative to a first power; the first power is greater than the power of the first reflected light corresponding to the target wavelength; the first power is a power selected from all powers of the first reflected light, such as the maximum power, or a custom power; and the first threshold is obtained based on empirical values ​​or through simulation of the DFB ONT's reflection characteristics. Alternatively, if, among the transmission wavelengths of the DFB ONT, a target wavelength with a corresponding second power variation amplitude less than a second threshold is identified, then the target drop cable is determined to be connected to the EPON's DFB ONT. Here, the second power variation amplitude is the variation amplitude of the power of the first reflected light corresponding to the target wavelength relative to a second power; the second power is less than or equal to the power of the first reflected light corresponding to the target wavelength; the second power is a power selected from all powers of the first reflected light, such as the minimum power, or a custom power; and the second threshold is obtained based on empirical values ​​or through simulation of the DFB ONT's reflection characteristics.

[0069] It should be noted that whether the power of the first reflected light changes periodically with wavelength can be understood as: it may be a periodic trend, but not necessarily strictly periodic. This is because the reflectivity of the FP ONT for detection light of different wavelengths is somewhat different.

[0070] In one alternative approach, to accurately identify whether the target drop cable is connected to the FP ONT, after determining that the power of the first reflected light exhibits periodicity with wavelength, it is further determined whether the period is a target value. If the period is the target value, then the target drop cable is confirmed to be connected to the FP ONT. The target value is related to the cavity length of the FP ONT. The target value and cavity length satisfy the oscillation condition of the FP resonant cavity. For example, the target value is equal to the cavity length.

[0071] In one alternative approach, considering that a DFB ONT also has a resonant cavity, the power of the first reflected light may exhibit periodic variations with power changes outside the DFB ONT's transmission wavelength range. Therefore, if the first detection light includes the transmission wavelength of the DFB ONT, the power variation of the first reflected light within that transmission wavelength can be obtained. If the target wavelength is not found within the DFB ONT's transmission wavelength, it indicates that there is no power drop, and the ONT connected to the drop cable is not a DFB ONT. If the power of the first reflected light exhibits periodic variations with wavelength, then the target drop cable is determined to be connected to the ONT.

[0072] In one alternative approach, when the identification device determines that the target drop cable is connected to the FP ONT, it outputs an indication message to a terminal device used by maintenance personnel. This indication message indicates that the target drop cable is connected to the FP ONT. Upon receiving the indication message, the terminal device displays it, allowing maintenance personnel to replace the FP ONT with an ONT that does not conflict with the 50GPON.

[0073] Additionally, if the identification device determines that the target drop cable is not connected to the ONT, it outputs an indication message to the terminal device used by the maintenance personnel. This indication message indicates that the target drop cable is not connected to the ONT. After receiving the indication message, the terminal device displays it, and the maintenance personnel can record the target drop cable as a drop cable not connected to the ONT, and subsequently make the drop cable available to other users.

[0074] The following is about Figures 4 to 6 The usage methods are described separately.

[0075] 1. Adopt Figure 4 As shown in the instructions, the identification device is plugged into the inlet cable.

[0076] At the location where the drop cable connects to the second optical splitter, disconnect the drop cable from the second optical splitter and plug it into the identification device. The technician then controls the identification device to perform its functions. Figure 9 The process is shown below. Figure 10 This diagram illustrates one scenario for identifying an ONT (On-Top Telephone Unit). Each drop cable is disconnected from the secondary splitter and plugged into the identification device. The detection light is either pulsed or DC. This example uses the drop cables connected to the secondary splitter; however, the drop cables can be connected to any primary splitter. Figure 10 Between the central OLT and the primary optical splitter, there are also optical distribution frames (ODFs) and optical cable junction boxes, etc. The number of ODFs and optical cable junction boxes is set according to actual needs. Figure 10 Not shown in the image.

[0077] 2. Adopt Figure 5 As shown in the diagram, the identification device is connected to the incoming cable via a beam splitter.

[0078] When identifying the ONT, the identification device performs... Figure 9The illustrated process uses pulsed light as the first detection light. The process is as follows: By scanning the wavelength and polarization state of the first detection light, pulsed detection light of different wavelengths with different polarization states is generated. After being output from the identification device, the first detection light is coupled with the service optical signal through a first optical combiner / splitter and transmitted to an optical fiber for downlink transmission. After passing through an optical splitter in the ODN, the first detection light passes through the drop cable and enters the ONT at the end. The FP laser inside the ONT reflects the first detection light, obtaining reflected light. The reflected light is transmitted back to the first optical combiner / splitter and then enters the identification device. The detector in the identification device converts the reflected light into an electrical signal. The power of the electrical signal reflects the power of the reflected light. See [link to relevant documentation]. Figure 11 , Figure 11 The display shows the relationship between the power of the reflected light and the distance, with different pulses corresponding to different wavelengths. Because the distance between the end of the drop cable and the identification device varies, the time it takes for the reflected light to enter the detector also varies; therefore, it is possible to measure ONTs at different distances.

[0079] Since the first detection light is pulsed light, the power of the first reflected light detected by the detector also has a reflection peak. The identification device can obtain the peak power of the reflection peak generated at different drop cable ends, i.e., the power of the reflected light, through different reception times. Then, for each drop cable, the correspondence between the peak power and wavelength is determined. For a given drop cable, this correspondence is used to determine whether the peak power changes periodically with wavelength. If it is periodic, the drop cable is determined to be connected to the EPON's FP ONT. If it is non-periodic, or even if it is periodic but the period is not the target value, the drop cable is determined not to be connected to the ONT. If the target wavelength is found in the transmission wavelength of the DFB ONT, the drop cable is determined to be connected to the EPON's DFB ONT. It is assumed here that the power of the detection light at multiple wavelengths output by the identification device is the same.

[0080] It should be noted that when adopting Figure 4 In the illustrated usage, the identification device broadcasts the first detection light. Therefore, each drop cable connected to the OLT can receive the first detection light. The reflected light returning to the identification device then comes from the reflected light of multiple drop cables. Figure 11 The proposed solution can only identify whether a FP ONT is connected to the end of the drop cable that is at a different distance from the identification device. Based on the reception time, the identification device determines the distance between each drop cable end and the identification device, thus establishing a correspondence between distance, peak power, and wavelength. Since we know the distance between the drop cable and the identification device in advance, we can determine the peak power versus wavelength curve corresponding to the target drop cable.

[0081] 3. Adopt Figure 6As shown in the diagram, the identification device is connected to the incoming cable via a beam splitter.

[0082] Considering that the distance between the ends of multiple drop cables and the identification device may be close, and also considering that the identification device is deployed in the central office equipment room, the first detection light reaches the end of the drop cable only after passing through the splitter. Due to the insertion loss of the splitter, the dynamic range of the identification device is limited and it may not be able to detect the port of the splitter. Therefore, the identification system includes an identification device, a first beam splitter and a second beam splitter.

[0083] During ONT identification, maintenance personnel in the central office connect the combining port of the first optical combiner / splitter to the primary optical combiner in the ODN, connect one splitting port to the OLT, and connect the other splitting port to the identification device. At the location where the target drop cable connects to the second optical combiner / splitter (i.e., secondary optical combiner 2), the maintenance personnel unplug the fiber from the combining port of the second optical combiner / splitter and insert it into the combining port of the second optical combiner / splitter. They then connect the first splitting port of the second optical combiner / splitter to its combining port. Thus, the optical signal destined for the second optical combiner / splitter passes through it.

[0084] The identification device then sends a second detection light to the first beam combiner / splitter. During transmission, it scans the wavelength and polarization state of the second detection light. The second detection light shares the same wavelength and polarization state as the first detection light, meaning their wavelengths and polarization states overlap—this overlap can be partial or complete. The second detection light is transmitted from the first beam combiner / splitter to the second beam combiner / splitter. The second beam combiner / splitter outputs the second detection light through the first splitting port. The second beam combiner / splitter then outputs the second detection light to each connected drop cable, ensuring it reaches the end of the drop cable. When an ONT is connected to the end of the drop cable, the ONT sends reflected light to the connected drop cable. When no ONT is connected to the end of the drop cable, the end face of the drop cable sends reflected light to the second beam combiner / splitter. Upon receiving the reflected light, the second beam combiner / splitter sends the second reflected light to the second beam combiner / splitter. The identification device then determines the reception time and peak power of the reflection peaks at each wavelength in the second reflected light. Since the distance between the ends of different drop cables and the identification device is different, for the same drop cable, for different wavelengths of detection light, the identification device receives the reflection peaks returned by the drop cable at the same time each time (or can be understood as very different). The identification device finds the reflection peaks with the same reception time, and maps the wavelength of these reflection peaks to the peak power to obtain the correspondence between the peak power and the wavelength at each reception time, that is, the correspondence between the power of the reflected light and the wavelength.

[0085] Then, the maintenance personnel unplugged the target drop cable from the second splitter and inserted it into the second splitter port of the second optical combiner, connecting the second splitter port to the target drop cable. The second splitter port is different from the first splitter port. (See [link / reference]). Figure 12 The identification device sends a first detection light to the first beam combiner / splitter, and scans the wavelength and polarization state of the first detection light during transmission. The first detection light is transmitted through the first beam combiner / splitter to the second beam combiner / splitter. The second beam combiner / splitter outputs the first detection light through both its first and second splitting ports. The first detection light enters the second beam combiner, which outputs it to each connected drop cable, including the target drop cable. When an ONT is connected to the end of the drop cable, the ONT sends reflected light to the connected drop cable. When no ONT is connected to the end of the drop cable, the end face of the drop cable sends reflected light to the second beam combiner / splitter. After receiving the reflected light, the second beam combiner / splitter sends a second reflected light to the second beam combiner / splitter. The identification device determines the reception time and peak power of the reflection peaks of each wavelength in the second reflected light. Because the distance between the ends of different drop cables and the identification device varies, for the same drop cable, the identification device receives the reflection peaks returned by the drop cable at the same (or very similar) time for different wavelengths of detection light. The identification device finds multiple reflection peaks with the same reception time, maps the wavelength of these reflection peaks to their peak power, and obtains the correspondence between peak power and wavelength at each reception time. Since the target drop cable was originally connected to the second beam splitter, it is now connected to the second beam combiner, indicating that the distance between the end of the target drop cable and the identification device has changed. Therefore, the reception time of the reflection peaks reflected by the target drop cable will also change, but the peak power of the reflection peaks will remain basically unchanged. The identification device finds the correspondence between peak power and wavelength with overall shift in reception time from the obtained correspondence (which includes the correspondence obtained by sending the first and second detection lights), and determines this correspondence as the peak power and wavelength correspondence corresponding to the target drop cable, that is, obtains the correspondence between the power and wavelength of the first reflected light.

[0086] The identification device then uses the correspondence between peak power and wavelength. Using this correspondence, the device determines whether the peak power changes periodically with wavelength. If it does, the target drop cable is confirmed to be connected to the EPON's FP ONT. If it is non-periodic, or if it is periodic but the period is not the target value, the target drop cable is confirmed not to be connected to the ONT. If the target wavelength is found to exist in the DFB ONT's transmission wavelength range, the drop cable is confirmed to be connected to the EPON's DFB ONT.

[0087] It should be noted that the above explanation is based on sending the second detection light first. In another example, if the reception time corresponding to the target drop cable is obtained in advance, there is no need to send the second detection light; the target drop cable can be located using the reception time.

[0088] Alternatively, the peak power in the relationship curve can also be represented by reflectivity, which is equal to the ratio of peak power to the power of the transmitted detection light.

[0089] Optionally, when obtaining the correspondence between peak power and wavelength, an OTDR curve can be obtained first. The horizontal axis of the OTDR curve represents distance, which is the distance between the reflection point and the identification device, and the vertical axis represents the power of the reflected light. Then, the OTDR curves of multiple wavelengths are integrated together to obtain the correspondence between peak power and wavelength.

[0090] Optionally, before sending the first detection light, the identification device receives a detection command, which instructs the start of sending the first detection light. In one embodiment, maintenance personnel use an application on a terminal device (such as a mobile phone, tablet, or computer) to send a detection command to the identification device. After the identification device completes the identification, it returns a detection completion message to the terminal device to notify the maintenance personnel that the identification is complete. In another embodiment, the identification device has a detection button. When the maintenance personnel click the detection button, the identification device receives a detection command, and after the identification device completes the identification, it displays a detection completion message on the interface.

[0091] Optionally, the identification device receives a detection command before sending the second detection light, which instructs the start of sending the second detection light.

[0092] Optionally, the second combiner / splitter is a coupler that includes one multiplexing port and two splitting ports, which typically increases insertion loss by 3dB.

[0093] Optionally, when the identification device is deployed in the central office equipment room, before the test begins, the OLT does not schedule uplink transmission resources for the ONT, or the OLT broadcasts a notification to suspend uplink transmission. This can reduce the impact on the identification process.

[0094] The above explanation uses the target drop cable as an example. The testing method for each drop cable is the same and will not be repeated here. After testing all drop cables under the second splitter, replace the drop cable for testing the next splitter. After testing, remove the combiner / splitter in the optical path and restore the optical path.

[0095] Thus, the solution of this application embodiment can identify whether there is an EPON FP ONT in the network without the need for the user to go to the site to check, thereby improving the efficiency of ONT identification.

[0096] It should be noted that although the above explanation uses EPON's FP ONT as an example, since the FP resonant cavity principle of FP ONT is the same, the above method can also be used to identify FP ONTs in other passive optical networks.

[0097] This application embodiment also provides another scheme for identifying whether the drop cable is connected to an ONT, where the ONT can be any ONT. The identification principle is as follows: When the ONT is connected to the drop cable, it is connected through an optical fiber connector. Assuming that the end of the drop cable is connected to an ONT, when the pulse detection light is transmitted to the optical inlet of the ONT, the optical fiber connector at the optical inlet will generate the first reflection. Then, the remaining pulse detection light is transmitted through the optical fiber and reaches the BOSA, where a second reflection will occur at the 0-degree waveplate, lens, or other position in front of the detector in the receiving component. The distance between these two reflection points is usually between 10cm and 50cm. When the pulse width of the pulse detection light is relatively small, the identification device can distinguish the width broadening of the ONT's own reflection peak caused by two consecutive reflection surfaces. These two reflection surfaces include the reflection surface at the optical fiber connector at the optical inlet and the reflection surface generated by the BOSA. This width broadening refers to a wider reflection peak width compared to that generated by a single reflection surface. Figure 13 As shown, the solid black line reflection peak is caused by a UPC connector where the drop cable is not connected to the ONT or by a broken fiber (i.e., caused by a single reflective surface), while the dashed black line reflection peak is caused by a drop cable connected to the ONT (i.e., caused by two reflective surfaces). It is clearly visible that the width of the dashed black line reflection peak at the first position is greater than the width of the solid black line reflection peak at the first position, indicating that the dashed black line reflection peak represents a drop cable connected to the ONT. The first position is defined as the position X dB downwards from the top of the reflection peak. The value of X should be set according to actual needs, but should not be set too large, as an excessively large value will easily be drowned out by noise.

[0098] The recognition process is as follows:

[0099] like Figure 14 As shown, the identification system includes an identification device, a first optical combiner / splitter, and a second optical combiner / splitter. The identification device includes a signal generation module, an optical combiner / splitter (or circulator), a detector, and an identification module. The signal generation module is connected to the optical combiner / splitter, the optical combiner / splitter is connected to the detector, the detector is connected to the identification module, and the optical combiner / splitter is connected to the optical port of the identification device, which is used to connect to an external optical fiber. The first optical combiner / splitter includes a combining port and two splitting ports, and the second optical combiner / splitter also includes a combining port and two splitting ports. The first optical combiner / splitter is a coupler or a wavelength division multiplexer.

[0100] In the central office equipment room, maintenance personnel connect the combining port of the first optical combiner / splitter to the combining port of the first-level optical combiner / splitter in the ODN, connect one splitting port to the OLT, and connect the other splitting port to the identification device. At the location where the target drop cable connects to the second optical combiner / splitter, the maintenance personnel unplug the fiber from the combining port of the second optical combiner / splitter, insert it into the combining port of the second optical combiner / splitter, connect the first splitting port of the second optical combiner / splitter to its combining port, and connect the second splitting port to the target drop cable. A connection diagram can be found [link to diagram]. Figure 12 .

[0101] The wavelength of the first pulse light used by the identification device is typically selected from a band where the BOSA in the ONT has a high reflectivity for the detection light, i.e., the reflectivity is higher than a reflectivity threshold. This reflectivity threshold is determined with the goal of revealing the second reflecting surface. This band can be the reflected light band of a 45-degree filter, excluding the wavelength of the BOSA detector, so as not to affect the BOSA's optical signal reception. In this case, the second reflection is located at the 0-degree filter of the receiving component. The 0-degree filter transmits the light that the ONT needs to receive to the detector, while filtering out light that the ONT does not need to receive. Alternatively, this band can be the transmitted light of a 45-degree filter, where the wavelength of the first pulse light is not within the ONT's transmission wavelength range. In this case, the second reflection is located in the transmitting component. This first pulse light is a narrow pulse signal with high OTDR event resolution, meaning it can easily distinguish closely adjacent reflection events in the fiber optic link. The pulse width is less than or equal to the target value, which can be 3 ns.

[0102] The identification device outputs a first pulse light to the first beam combiner / splitter. The first beam combiner / splitter outputs the first pulse light to the first-stage beam splitter. The first pulse light is transmitted through the first-stage beam splitter to the second beam combiner / splitter. The second beam combiner / splitter outputs the first pulse light to its connected second beam splitter. The second beam splitter outputs the first pulse light to the target drop cable. When an ONT is connected to the end of the target drop cable, the ONT connector and BOSA reflect the received first pulse light, causing the reflected light to propagate in the drop cable. The target drop cable transmits the reflected light to the second beam splitter. When no ONT is connected to the end of the target drop cable, the connector at the end of the target drop cable reflects the input first pulse light, resulting in reflected light. The target drop cable transmits this reflected light to the second beam splitter. The second beam splitter outputs the reflected light to the second beam combiner / splitter, then to the first-stage beam splitter, and finally to the identification device. The detector in the identification device converts the reflected light into an electrical signal. The identification device determines the power and reception time of the reflected light using the electrical signal, generating an OTDR curve. The horizontal axis of the OTDR curve represents distance, and the vertical axis represents the power of the scattered or reflected light. The identification device then extracts the reflection peak information (the first reflection peak information) from the OTDR curve and uses this information to determine whether an ONT is connected to the end of the target drop cable.

[0103] In an alternative approach, as described above, even if the distance between the end of the target drop cable and the identification device is unknown, a second detection light, which is the first pulse light, can be sent in the manner described above. By comparing whether the reception time changes, the OTDR curve corresponding to the target drop cable can be determined.

[0104] In one alternative approach, the identification device acquires the width of the first position in the first reflection peak information, and determines the size of the width of the first position relative to a third threshold. If the width of the first position is greater than the third threshold, it is determined that the target drop cable end is connected to an ONT. If the width of the first position is not greater than the third threshold, it is determined that the target drop cable end is not connected to an ONT.

[0105] In another alternative approach, because the pulse shape of the first pulse light emitted by some identification devices may be distorted or broadened, the reflection peak generated when encountering a single reflecting surface will also be distorted or broadened, potentially resulting in a non-symmetrical Gaussian pulse shape with some broadening on the right. Therefore, comparing solely based on the width of the reflection peak can easily lead to misjudgment. Thus, standard reflection peak information can be obtained in advance as a reference, processed as follows:

[0106] The identification device acquires stored reference reflection peak information, which is either the pulse information of the first pulse light or the reflection peak information generated by the first pulse light on a single reflective surface. The reference reflection peak information includes the shape of the reflection peak and the width at a first position. Based on the first reflection peak information and the reference reflection peak information, the state of the port to be detected is determined.

[0107] Optionally, the process for determining whether an ONT is connected based on the first reflection peak information and the reference reflection peak information is as follows:

[0108] The identification device determines whether the shape of the reflection peak in the first reflection peak information is consistent with the shape of the reflection peak in the reference reflection peak information. If the two reflection peak shapes are inconsistent, the width of the reflection peak at the first position in the first reflection peak information is obtained, referred to as the first width, and the width of the reflection peak at the first position in the reference reflection peak information is obtained, referred to as the second width. The difference between the first width and the second width is calculated. The relationship between this difference and a fourth threshold is determined. If the difference is greater than the fourth threshold, it is determined that the target drop cable is connected to the ONT, i.e., the port to be detected is connected to the ONT. If the difference is not greater than the fourth threshold, it is determined that the target drop cable is not connected to the ONT, i.e., the port to be detected is not connected to the ONT. If the two reflection peak shapes are consistent, it means that there is only one reflecting surface, and the end of the target drop cable is not connected to the ONT, i.e., the port to be detected is not connected to the ONT. Here, the fourth threshold can be obtained from simulation.

[0109] The process for determining whether the shape of the reflection peak in the first reflection peak information is consistent with the shape of the reflection peak in the reference reflection peak information is as follows:

[0110] After aligning the height of the reflection peak in the first reflection peak information with the height of the reflection peak in the reference reflection peak information, it is determined whether the width difference at each position from the top to the second position is less than the fifth threshold. If it is less than the fifth threshold, the shape is determined to be consistent; otherwise, the shape is determined to be inconsistent. The fifth threshold can be set according to actual needs.

[0111] It should be noted that the first position can be a single location point or multiple location points. For example, the first position includes every location point from the top to the first position.

[0112] It should also be noted that when generating the OTDR curve, the first pulse light can be sent multiple times to obtain multiple sets of data. The OTDR curve is then generated by averaging these multiple sets of data. Furthermore, the above explanation uses the generation of an OTDR curve as an example. Alternatively, the reflection peak information at the end of the target drop cable can be read directly from the data without generating an OTDR curve.

[0113] All of the above-mentioned optional technical solutions can be combined in any way to form the optional embodiments of this application, and will not be described in detail here.

[0114] This application also provides a computer program product including program instructions stored in a computer-readable storage medium. The processor of the identification device reads the program instructions from the computer-readable storage medium and executes the program instructions, causing the identification device to perform the process executed by the identification module described above.

[0115] In this application, the terms "first" and "second," etc., are used to distinguish identical or similar items that have substantially the same function and purpose. It should be understood that there is no logical or temporal dependency between "first" and "second," nor does it limit the quantity or order of execution. It should also be understood that although the following description uses the terms "first" and "second," etc., to describe various elements, these elements should not be limited by the terms. These terms are merely used to distinguish one element from another. For example, without departing from the scope of various examples, a first detection light can be referred to as a second detection light, and similarly, a second detection light can be referred to as a first detection light. Both the first and second detection lights can be detection lights, and in some cases, they can be separate and distinct detection lights.

[0116] The phrase "at least one" in the preceding text can be understood as one or more.

[0117] The above description is merely an exemplary 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 such 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. A method of identifying an optical network terminal (ONT), characterized by, The method is applied to an identification system, the identification system including an identification device for connecting to a home access cable; the method includes: The identification device sends a first detection light with a scanning wavelength and polarization state to the in-home cable, wherein the wavelength of the first detection light includes multiple transmission wavelengths of Fabry-Perot FP ONT; The identification device receives the first reflected light returned by the inlet cable and determines the power of the first reflected light; If the power of the first reflected light changes periodically with the wavelength of the first detected light, the identification device determines that the drop cable is connected to the FP ONT.

2. The method of claim 1, wherein, Before the identification device determines that the drop cable is connected to the FPONT, the method further includes: The period of the periodic change is determined as a target value, wherein the target value is related to the cavity length of the FP ONT.

3. The method according to claim 1 or 2, characterized in that, The plurality of transmission wavelengths include the transmission wavelengths of the distributed feedback DFB ONT of the Ethernet passive optical network; Before the identification device determines that the drop cable is connected to the FP ONT, the method further includes: Among the transmission wavelengths of the DFB ONT, it is determined that there is no target wavelength with a corresponding first power change amplitude greater than a first threshold, wherein the first power change amplitude is the change amplitude of the power of the first reflected light corresponding to the target wavelength relative to a first power, and the first power is greater than the power of the first reflected light corresponding to the target wavelength; or... Among the transmission wavelengths of the DFB ONT, it is determined that there is no target wavelength with a corresponding second power change amplitude less than a second threshold, wherein the second power change amplitude is the change amplitude of the power of the first reflected light corresponding to the target wavelength relative to the second power, and the second power is less than or equal to the power of the first reflected light corresponding to the target wavelength.

4. The method of claim 3, wherein, The method further includes: If the target wavelength is present in the transmission wavelength of the DFB ONT, the identification device determines that the drop cable is connected to the DFB ONT.

5. The method according to any one of claims 1 to 4, characterized in that, The first detection light is a pulsed light or a direct current light, and the identification device is used to connect to the inbound cable.

6. The method according to any one of claims 1 to 4, characterized in that, The first detection light is pulsed light. The identification system further includes a first beam combiner and a second beam combiner. The identification device is connected to the beam splitter port of the first beam combiner. The beam combining port of the first beam combiner is used to connect to the beam combining port of a first-level beam splitter in the optical distribution network. The beam combining port of the second beam combiner is used to connect to the first beam splitter in the optical distribution network. The first beam splitter port of the second beam combiner is used to connect to the beam combining port of the second beam splitter in the optical distribution network. The second beam splitter port of the second beam combiner is used to connect to the drop cable. The first beam splitter is the upstream beam splitter connected to the second beam splitter. The second beam splitter is the beam splitter in the optical distribution network that is connected to the drop cable. The identification device sends a first detection light with a scanning wavelength and polarization state to the in-home cable, including: The identification device sends the first detection light to the first beam combiner / splitter, the first beam combiner / splitter sends the first detection light to the second beam combiner / splitter, and the second beam combiner / splitter sends the first detection light to the drop cable. The identification device receives the first reflected light returned by the in-home cable and determines the power of the first reflected light, including: The first beam combiner receives the second reflected light sent by the second beam combiner and sends the second reflected light to the identification device, wherein the second reflected light includes the first reflected light; The identification device determines the power of the first reflected light based on the first reflection peak information of the second reflected light, wherein the first reflection peak information includes the peak power and reception time of the reflection peaks of each wavelength in the first detection light.

7. The method of claim 6, wherein, Before the second optical splitter port is connected to the drop cable, the method further includes: The identification device sends a second detection light with a scanning wavelength and polarization state to the first beam combiner / splitter, the first beam combiner / splitter sends the second detection light to the second beam combiner / splitter, the second beam combiner / splitter sends the second detection light to the drop cable, and the wavelength and polarization state of the second detection light overlap with those of the first detection light; The first beam combiner / splitter receives the third reflected light sent by the second beam combiner / splitter and sends the third reflected light to the identification device; The identification device determines the second reflection peak information of the third reflected light, wherein the second reflection peak information includes the peak power and reception time of the reflection peaks of each wavelength in the second detection light; The identification device determines the power of the first reflected light based on the first reflection peak information of the second reflected light, including: The identification device determines the power of the first reflected light based on the first reflection peak information and the second reflection peak information.

8. The method according to claim 6 or 7, characterized in that, The second beam combiner / splitter is a coupler.

9. The method according to any one of claims 1 to 8, characterized in that, Before the identification device sends a first detection light with a scanning wavelength and polarization state to the in-home cable, the method further includes: Receive a detection command, wherein the detection command is used to instruct the start of sending the first detection light.

10. The method according to any one of claims 1 to 9, characterized in that, The method further includes: If the power of the first reflected light does not exhibit a periodic change with the wavelength of the first detected light, or if the period of the periodic change is not a target value, then the identification device determines that the access cable is not connected to an ONT, wherein the target value is related to the cavity length of the FP ONT.

11. The method according to any one of claims 1 to 10, characterized in that, The method further includes: The identification device outputs indication information, wherein the indication information is used to indicate that the inbound cable is connected to the FP ONT.

12. A computer-readable storage medium, characterized in that, Includes program instructions, which, when executed by the identification device, cause the identification device to perform the identification process as described in any one of claims 1 to 11.

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