Optical splitter and optical signal processing method for passive optical network

Abstract

An embodiment of the present disclosure provides an optical splitter and an optical signal processing method for a passive optical network, the optical splitter including a planar lightwave circuit optical splitter and a planar lightwave circuit filter array including a thin film filter module, the planar lightwave circuit optical splitter is used to split an input optical signal into multiple sub-signals and input the multiple sub-signals to corresponding thin film filters, and the thin film filter module is used to filter the multiple sub-signals and output multiple target sub-signals.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure is based on and claims priority to Chinese patent application CN2023100424135, filed on January 28, 2023, entitled "Optical splitter for passive optical network and optical signal processing method," and Chinese patent application CN2023109122840, filed on January 28, 2023, entitled "Optical splitter for passive optical network and optical signal processing method," the entire disclosures of which are incorporated herein by reference.

[0002] The present disclosure relates to the field of passive optical networks, and more particularly to optical splitters and optical signal processing methods for passive optical networks. [Background technology]

[0003] A passive optical network (PON) is a point-to-multipoint network system that mainly consists of an optical line terminal (OLT) at the central office, an optical network unit (ONU) or optical network termination (ONT) at the user's end, and an optical distribution network (ODN). The optical distribution network in a passive optical network is an optical distribution network for branching / combining or multiplexing / separating optical signals between the optical line terminal and the optical network terminal. It may include optical passive devices such as optical fibers, optical splitters, optical couplers, optical fiber connectors, and wavelength division multiplexers. The multi-branch structure based on optical passive devices such as optical splitters poses significant challenges to the fault detection technology and topology of optical distribution networks.

[0004] In related art, the following measures are mainly adopted to facilitate fault detection and identification of optical fibers in optical distribution networks: modifying a conventional planar lightwave circuit (PLC) optical splitter, mainly by etching a Bragg grating filter on the branch output waveguide of the PLC optical splitter chip of the conventional optical splitter, or by writing an optical fiber Bragg grating filter on the branch optical fiber of the optical splitter.

[0005] This method requires etching a Bragg grating filter into the branching output waveguide of a PLC optical splitter chip, which requires customization and increases chip costs. Alternatively, an optical fiber Bragg grating must be written into the branching optical fiber of the optical splitter, which also requires changes to the production process and significantly increases manufacturing costs. Furthermore, the gratings written using these two methods are highly sensitive to environmental temperature, and the center wavelength of the preset filter is prone to temperature-dependent shifts, affecting system stability. Furthermore, because the characteristics of the grating filter itself determine the reflective characteristics for a specific wavelength, the ONU / ONT can only identify the port connections of the optical splitter in the connected ODN in the form of wavelength encoding, which cannot resolve the optical fiber link identification function of an end-to-end optical time domain reflectometer (OTDR).

[0006] As mentioned above, the related art has not yet proposed a good solution to the problems that the production cost of optical splitters in passive optical networks is high, the center wavelength of preset filters is easily shifted by temperature, and it is disadvantageous to accurately identify optical fiber faults. Summary of the Invention [Problem to be solved by the invention]

[0007] The embodiments of the present disclosure provide an optical splitter for a passive optical network and an optical signal processing method to at least solve the problems in the related art that the manufacturing cost of optical splitters in passive optical networks is high, and the center wavelength of a preset filter is easily shifted by temperature, which is disadvantageous in accurately identifying faults in optical fibers. [Means for solving the problem]

[0008] According to one embodiment of the present disclosure, there is provided an optical splitter for a passive optical network, the optical splitter including: a planar lightwave circuit optical splitter; a thin-film filter module including a plurality of thin-film filters; and a planar lightwave circuit filter array consisting of a plurality of common ports, a plurality of reflection ports, and a plurality of transmission ports, wherein the planar lightwave circuit optical splitter is used to split an input optical signal into a plurality of sub-signals based on power and input the plurality of sub-signals to corresponding thin-film filters in the planar lightwave circuit filter array, each sub-signal being input to one thin-film filter; the thin-film filter module is used to filter the plurality of sub-signals and output a plurality of target sub-signals, the common port, the reflection ports, and the transmission ports in the planar lightwave circuit filter array are respectively connected to the thin-film filters via optical paths formed by optical waveguides, the thin-film filters are configured to transmit optical signals of a predetermined wavelength and reflect optical signals other than the predetermined wavelength, and the target sub-signals include the transmission sub-signals and / or the reflection sub-signals.

[0009] According to another embodiment of the present disclosure, there is provided an optical signal processing method for a passive optical network that is applied to an optical splitter of the passive optical network in the above-mentioned embodiment, the method including: splitting an input optical signal into multiple sub-signals by power using a planar lightwave circuit optical splitter; inputting the multiple sub-signals into thin film filter modules in a planar lightwave circuit filter array, wherein each sub-signal is input to one thin film filter in the thin film filter module; and filtering the multiple sub-signals through the thin film filter modules to obtain multiple target sub-signals.

[0010] According to yet another embodiment of the present disclosure, there is provided an optical signal processing system for a passive optical network, comprising an M-stage optical splitter including an ith-stage optical splitter and an i+1-stage optical splitter, wherein the ith-stage optical splitter and the i+1-stage optical splitter are the optical splitters of the passive optical network described above, and each branch port of the ith-stage optical splitter is respectively connected to a common port of one i+1-stage optical splitter, wherein M is an integer greater than 1 and i is any integer from 1 to M−1, and when each ith-stage optical splitter includes N branch ports, each branch port of the ith-stage optical splitter is connected to a common port of N i+1-stage optical splitters. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a block diagram of an optical splitter in a passive optical network according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic diagram of a three-port thin film filter according to an embodiment of the present disclosure. [Figure 3] FIG. 1 is a transmission and reflection spectrum diagram of a three-port thin film filter according to an embodiment of the present disclosure. [Figure 4] 1 is a schematic diagram of a planar lightwave circuit optical splitter according to an embodiment of the present disclosure. [Figure 5]1 is a schematic diagram of a planar lightwave circuit filter array according to an embodiment of the present disclosure. [Figure 6] 1 is a schematic diagram of a planar lightwave circuit optical splitter and a planar lightwave circuit filter array connected in series in an embodiment of the present disclosure. [Figure 7] FIG. 10 is a reflection spectrum diagram of a single passband filter of a planar lightwave circuit filter array in an embodiment of the present disclosure. [Figure 8] FIG. 10 is a transmission spectrum diagram of a dual passband filter of a planar lightwave circuit filter array in an embodiment of the present disclosure. [Figure 9] FIG. 1 is a schematic diagram of a planar lightwave circuit optical splitter and an arrayed waveguide grating connected in parallel in an embodiment of the present disclosure. [Figure 10] FIG. 2 is a schematic diagram of a planar lightwave circuit optical splitter and a multi-channel wavelength division multiplexer connected in parallel in accordance with an embodiment of the present disclosure. [Figure 11] 1 is a schematic diagram of a planar lightwave circuit optical splitter connected to an optical fiber array in accordance with an embodiment of the present disclosure. [Figure 12] 1 is a schematic diagram of a planar lightwave circuit filter array and an optical fiber array connected together in accordance with an embodiment of the present disclosure; [Figure 13] 1 is a schematic diagram of a planar lightwave circuit optical splitter and a planar lightwave circuit filter array connected via an optical fiber. [Figure 14] 1 is a flowchart of an optical signal processing method in a passive optical network according to an embodiment of the present disclosure. [Figure 15] FIG. 1 is a block diagram of an optical signal processing system for a passive optical network according to an embodiment of the present disclosure. [Figure 16] 1 is a schematic configuration diagram of an optical signal processing system in a passive optical network according to an embodiment of the present disclosure. [Figure 17] FIG. 2 is a schematic diagram illustrating a wavelength plan of a detected optical signal of a two-stage optical splitter according to an embodiment of the present disclosure. [Figure 18] FIG. 2 is a schematic diagram of an optical splitter of a passive optical network in an embodiment of the present disclosure. [Figure 19] FIG. 2 is a schematic diagram of an optical splitter of a passive optical network based on wavelength division multiplexing in an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, the embodiments of the present disclosure will be described in detail based on the embodiments with reference to the drawings. It should be noted that terms such as "first" and "second" in the specification and claims of this disclosure and the above drawings are intended to distinguish between similar objects and are not necessarily used to describe a specific order or priority.

[0013] FIG. 1 is a block diagram of an optical splitter of a passive optical network according to an embodiment of the present disclosure. As shown in FIG. 1, the optical splitter of the passive optical network includes a planar lightwave circuit optical splitter 12 and a planar lightwave circuit filter array 14.

[0014] In this embodiment, the planar lightwave circuit filter array 14 is comprised of a thin film filter module, a plurality of common ports, a plurality of reflective ports, and a plurality of transmissive ports, and the thin film filter module includes a plurality of thin film filters.

[0015] Furthermore, one common port, one reflection port, one transmission port in the planar lightwave circuit filter array and one thin film filter in the thin film filter module can constitute one three-port thin film filter.

[0016] In this embodiment, the planar lightwave circuit optical splitter 12 is used to split the input optical signal into multiple sub-signals according to power, and input the multiple sub-signals to corresponding thin film filters (TFFs) in the planar lightwave circuit filter array, with each sub-signal being input to one thin film filter.

[0017] In this embodiment, a thin film filter module is used to filter the plurality of sub-signals and output a plurality of target sub-signals. The thin film filter module can be designed and processed as a whole, which is advantageous for large-scale and low-cost production, and improves production efficiency and yield.

[0018] In some embodiments, thin film filter modules can be assembled from multiple pre-fabricated thin film filters and can even be produced as a whole at the filter production stage.

[0019] According to an embodiment of the present disclosure, a passive optical network optical splitter is configured using a planar lightwave circuit optical splitter and a planar lightwave circuit filter array, and the planar lightwave circuit filter array filters the detected optical signal, so that a single detected optical wavelength corresponds to a single optical link, thereby achieving accurate identification of optical fiber faults, while reducing the difficulty of manufacturing the optical splitter and significantly improving the temperature-dependent shift characteristics of the center wavelength of the preset filter, thereby improving the reliability of the passive optical network. This solves the problems of the related art, such as the high production costs of passive optical network optical splitters and the tendency of the center wavelength of the preset filter to shift with temperature, which are disadvantageous in accurately identifying optical fiber faults.

[0020] The thin film filters in the embodiments of the present disclosure are all three-port thin film filters. Fig. 2 is a schematic diagram of a three-port thin film filter in the embodiments of the present disclosure. As shown in Fig. 2, the three-port thin film filter has the following features: It has a common port 21, a reflection port 22, a transmission port 23 and a thin film filter 24.

[0021] In this embodiment, the common port 21, the reflection port 22 and the transmission port 23 of the thin film filter are respectively connected to the thin film filter 24 via optical paths formed by optical waveguides, the thin film filter 24 is configured to transmit optical signals of a predetermined wavelength and reflect optical signals other than the predetermined wavelength, and the target sub-signal includes the transmission sub-signal and / or the reflection sub-signal.

[0022] In this embodiment, a thin film filter 24 is used to filter the sub-signals input from the common port 21 of the thin film filter and output a transmitted sub-signal from the transmitted port 23 and / or a reflected sub-signal from the reflected port 22.

[0023] In this embodiment, the thin film filter can be selected according to the filtering requirements, and the filter types include, but are not limited to, single bandpass filtering, dual bandpass filtering, and bandstop filtering.

[0024] 3 is a transmission and reflection spectrum diagram of a three-port thin film filter according to an embodiment of the present disclosure. As shown in FIG. 3, the solid lines represent transmittance data of optical signals of different wavelengths, and the dashed lines represent reflectance data of optical signals of different wavelengths.

[0025] In this embodiment, when the thin film filter 24 is bandpass filtering, the transmittance of the optical signal of the specified wavelength is close to 100% and the reflectance is close to 0, and the reflectance of the optical signal other than the specified wavelength is close to 100% and the transmittance is close to 0.

[0026] Specifically, the transmittance and reflectance of the optical signal may be adjusted to a specific value X%, where X is a value between 0 and 100, as needed.

[0027] 4 is a schematic diagram of a planar lightwave circuit optical splitter according to an embodiment of the present disclosure. As shown in FIG. 4, the planar lightwave circuit optical splitter 12 includes one common port and N branch ports.

[0028] 5 is a schematic diagram of a planar lightwave circuit filter array according to an embodiment of the present disclosure. As shown in FIG. 5, the planar lightwave circuit filter array 14 includes N common ports, N reflective ports, N transmission ports, and N thin film filters, each corresponding to one common port, one reflective port, and one transmission port, and the N thin film filters have different preset transmission wavelengths.

[0029] In this embodiment, the incident angle of the filter can be adjusted by designing the waveguide in the planar lightwave circuit filter array. When the incident angle is 0 degrees, a planar lightwave circuit filter array module based on a two-port filter can be realized. When the incident angle is greater than 0 degrees, a planar lightwave circuit filter array based on a three-port filter can be realized. At the same time, adjusting the magnitude of the incident angle allows for adjustment of the optical path direction and fine tuning of the center wavelength of the corresponding transmission port.

[0030] Furthermore, the planar lightwave circuits of the planar lightwave circuit filter array can be designed so that the incident angle of the optical path is greater than 0, thereby forming a three-port planar lightwave circuit filter array including a common port, a reflection port, and a transmission port.

[0031] In this embodiment, an optical signal input from a common port is split into two by the separation of the three-port thin film filter, and can be output from a reflection port and a transmission port, respectively. Conversely, an optical signal of a transmission wavelength input from the transmission port and an optical signal of a wavelength band other than the optical signal of the transmission wavelength input from the reflection port are wavelength-multiplexed by the three-port filter and then output from the common port.

[0032] In this embodiment, the planar lightwave circuit may be designed to form optical signal transmission lines for a common port, a transmission port, and a reflection port, and corresponding slots for embedding thin film filters. The optical signal transmission lines formed by the planar lightwave circuit may be non-linear or may be designed to have a curved shape according to device processing requirements. The optical signal transmission lines formed by multiple planar lightwave circuits may be designed to cross each other without affecting the normal transmission of optical signals. The paths along which the optical signals of the three ports are transmitted may be designed to control the transmission direction.

[0033] 6 is a schematic diagram of a planar lightwave circuit optical splitter and a planar lightwave circuit filter array connected in series in an embodiment of the present disclosure. As shown in FIG. 6, N branch ports of the planar lightwave circuit optical splitter are connected one-to-one to N common ports of the planar lightwave circuit filter array.

[0034] In this embodiment, the planar lightwave circuit optical splitter is used to split one optical signal input from a common port of the planar lightwave circuit optical splitter into N sub-signals according to power, and output the N sub-signals from N branch ports of the planar lightwave circuit optical splitter, respectively.

[0035] In this embodiment, the planar lightwave circuit filter array is used to filter the N sub-signals input from the N common ports of the planar lightwave circuit filter array using the N thin film filters, respectively, and output corresponding N transmitted sub-signals from the N transmitted ports and / or output corresponding N reflected sub-signals from the N reflected ports.

[0036] In this embodiment, the planar lightwave circuit optical splitter is used to split one optical signal input from a common port of the planar lightwave circuit optical splitter into N sub-signals according to power, and output the N sub-signals respectively from N branch ports of the planar lightwave circuit optical splitter, where the optical signal includes a traffic optical signal and a detection optical signal, and the sub-signals include a traffic sub-signal and a detection sub-signal.

[0037] Specifically, the traffic optical signal and the detection optical signal are in different wavelength bands. In this embodiment, the planar lightwave circuit filter array may have only a common port and a transmission port, or may have only a common port and a reflection port.

[0038] In this embodiment, the transmission wavelengths corresponding to the transmission ports of any of the single-passband thin-film filters in the planar lightwave circuit filter array are different, so the transmission wavelengths blocked by the reflection ports of any of the thin-film filters are different. Such a planar lightwave circuit filter array transmits optical signals of wavelength bands other than the transmission wavelength signal at the reflection port, but at the common port, there is no need for a strong reflection signal, such as a Bragg grating, onto which the transmission wavelength signal is incident (except when the incident angle is zero degrees). In this embodiment, a transmission filter is used, and the Bragg grating is a reflection grating.

[0039] In this embodiment, the N thin film filters of the planar lightwave circuit filter array may be an integrated thin film filter module, that is, one thin film filter module includes N thin film filters with different filter wavelengths.

[0040] In the embodiments of the present disclosure, the planar lightwave circuit filter array is easy to design, flexible to use, and independent of the optical splitter components, which is advantageous for large-scale and low-cost production. At the same time, the center wavelength of the thin film filter is not temperature sensitive, which greatly improves the device stability and system reliability.

[0041] 7 is a reflection spectrum diagram of a single passband filter of a planar lightwave circuit filter array according to an embodiment of the present disclosure. As shown in FIG. 7, the single passband thin film filter is configured to transmit only the detection sub-signal of a predetermined wavelength and to reflect all traffic sub-signals and other detection sub-signals other than the predetermined wavelength.

[0042] In this embodiment, when the N thin film filters are N single-passband thin film filters, the planar lightwave circuit filter array is used to filter the N sub-signals respectively through the N single-passband thin film filters, output corresponding N detection sub-signals of predetermined wavelengths from the N transmission ports, and output corresponding N traffic sub-signals and N detection sub-signals of wavelengths other than the predetermined wavelengths from the N reflection ports.

[0043] 8 is a transmission spectrum diagram of a dual passband filter of a planar lightwave circuit filter array according to an embodiment of the present disclosure. As shown in FIG. 8, the dual passband thin film filter is configured to transmit a detection sub-signal and a traffic optical signal (two wavelength bands) of preset wavelengths.

[0044] In this embodiment, when the N thin film filters are N dual passband thin film filters, the planar lightwave circuit filter array is used to filter the N sub-signals respectively through the N dual passband thin film filters, output corresponding N detection sub-signals and N traffic sub-signals of predetermined wavelengths from the N transmission ports, and output corresponding N detection sub-signals of wavelengths other than the predetermined wavelengths from the N reflection ports.

[0045] In this embodiment, in the downstream direction, traffic optical signals and detected optical signals are input through a common port of the optical splitter and output through N branch ports. The output signals of the N branch ports are input to N common ports of the pre-defined planar lightwave circuit filter array. Of the signals input to the common port of the optical waveguide of a specific thin film filter, downstream traffic optical signals are output through a transmission port. For optical detection signals with M>N wavelengths, only one of these pre-defined optical detection signal channel wavelengths is output through a transmission port.

[0046] In this embodiment, in the upstream direction, traffic optical signals are input through the transmission port of the filter and output through the common port. For optical detection signals with M>N wavelengths, only the backscattered signal of one of these preset detection optical signal channel wavelengths is input through the transmission port and output through the common port.

[0047] In this embodiment, if there is an optical splitter at the same stage, a strong reflected signal of the photodetection signal of the same wavelength from the other branch will return to the original path and interfere with the backscattered signal of the photodetection signal of the main branch. The main purpose of setting the angle of incidence of the filter greater than zero degrees is to reduce or eliminate interference with the backscattered signal of the photodetection signal of the main branch caused by the photodetection signal of the same wavelength from the other branch in the optical splitter at the same stage reflected back from the original path. This is because the photodetection signal of the same wavelength from the other branch is output from the reflection port rather than returning to the original path. A small angle of incidence is optimal; an angle of incidence less than 8° achieves both wavelength control and reduction of interference with the backscattered signal of the photodetection signal of the main branch caused by the reflected signal of the photodetection signal of the same wavelength from the other branch in the optical splitter at the same stage returning to the original path.

[0048] In another embodiment, the thin-film filter 24 further filters and combines a sub-signal of a predetermined reflection wavelength input from the reflection port 22 and a sub-signal of a predetermined transmission wavelength input from the transmission port 23, and outputs the combined reflection sub-signal and transmission sub-signal from the common port 21 of the thin-film filter.

[0049] In this embodiment, N branching ports of the planar lightwave circuit optical splitter are connected one-to-one to N reflection ports or N transmission ports of the planar lightwave circuit filter array.

[0050] In this embodiment, the planar lightwave circuit optical splitter can split one optical signal input from a common port of the planar lightwave circuit optical splitter into N sub-signals according to power, and output them respectively from N branch ports of the planar lightwave circuit optical splitter.

[0051] In this embodiment, the planar lightwave circuit filter array is used to filter the N sub-signals input from the N transmission ports of the planar lightwave circuit filter array by the N thin film filters respectively, and output corresponding N transmission sub-signals from the N common ports of the planar lightwave circuit filter array, and the target sub-signals are the transmission sub-signals.

[0052] In this embodiment, the planar lightwave circuit filter array can further be used to filter the N sub-signals input from the N reflection ports of the planar lightwave circuit filter array by the N thin film filters respectively, and output corresponding N reflection sub-signals from the N common ports of the planar lightwave circuit filter array, and the target sub-signals are the reflection sub-signals.

[0053] 9 is a schematic diagram of a planar lightwave circuit optical splitter and an arrayed waveguide grating connected in parallel in an embodiment of the present disclosure. As shown in FIG. 9, the optical splitter further includes a three-port wavelength division multiplexer and an arrayed waveguide grating (planar lightwave circuit array grating).

[0054] In this embodiment, the arrayed waveguide grating includes one common port and N branch ports, and the three-port wavelength division multiplexer includes one common port and two output ports.

[0055] Furthermore, the three-port wavelength division multiplexer is used to split an optical signal input from a common port of the three-port wavelength division multiplexer into a traffic optical signal and a detection optical signal, output them from two output ports of the three-port wavelength division multiplexer respectively, input the traffic optical signal to the common port of the planar lightwave circuit optical splitter, and input the detection optical signal to the common port of the arrayed waveguide grating or the multi-channel wavelength division multiplexer.

[0056] 10 is a schematic diagram of a planar lightwave circuit optical splitter and a multi-channel wavelength division multiplexer connected in parallel in an embodiment of the present disclosure. As shown in FIG. 10, the optical splitter further includes a three-port wavelength division multiplexer and a multi-channel wavelength division multiplexer.

[0057] In this embodiment, each of the multi-channel wavelength division multiplexers includes one common port and N branch ports.

[0058] In this embodiment, the three-port wavelength division multiplexer includes one common port and two output ports, and is used to split an optical signal input from the common port of the three-port wavelength division multiplexer into a traffic optical signal and a detection optical signal, output them from the two output ports of the three-port wavelength division multiplexer, input the traffic optical signal to the common port of the planar lightwave circuit optical splitter, and input the detection optical signal to the common port of the arrayed waveguide grating or the multi-channel wavelength division multiplexer.

[0059] In this embodiment, a planar lightwave circuit optical splitter is used to split the optical traffic signal into N traffic sub-signals by power.

[0060] In this embodiment, an arrayed waveguide grating or the multi-channel wavelength division multiplexer is used to split the detected optical signal into N detected sub-signals by wavelength.

[0061] In this embodiment, a planar lightwave circuit filter array is used to receive the N traffic sub-signals from the N transmission ports and the N detection sub-signals from the N reflection ports, or to receive the N traffic sub-signals from the N reflection ports and the N detection sub-signals from the N transmission ports.

[0062] In this embodiment, the planar lightwave circuit filter array is further used to combine the N traffic sub-signals and the N detected sub-signals into N target sub-signals through the N thin film filters, and output the N target sub-signals from N common ports of the planar lightwave circuit filter array, where the target sub-signals include the detected sub-signals and the traffic sub-signals.

[0063] In this embodiment, the N drop ports of the arrayed waveguide grating or the multi-channel wavelength division multiplexer may be respectively connected to the N transmission ports of a planar lightwave circuit filter array. The N drop ports of the planar lightwave circuit optical splitter are respectively connected to the N reflection ports of the planar lightwave circuit filter array. The planar lightwave circuit filter array is used to receive the N detection sub-signals from the N drop ports of the arrayed waveguide grating or the multi-channel wavelength division multiplexer from the N transmission ports and to receive the N traffic sub-signals from the N drop ports of the planar lightwave circuit optical splitter from the N reflection ports.

[0064] In this embodiment, the N branch ports of the arrayed waveguide grating or the multi-channel wavelength division multiplexer may be further connected to N reflection ports of the planar lightwave circuit filter array, respectively. The N branch ports of the planar lightwave circuit optical splitter are connected to N transmission ports of the planar lightwave circuit filter array, respectively. The planar lightwave circuit filter array is used to receive the N detection sub-signals from the N branch ports of the arrayed waveguide grating or the multi-channel wavelength division multiplexer from the N reflection ports and to receive the N traffic sub-signals from the N branch ports of the planar lightwave circuit optical splitter from the N transmission ports.

[0065] In another embodiment, the optical splitter further comprises one or more optical fiber arrays. In this embodiment, an optical fiber array is used to connect the planar lightwave circuit optical splitter and / or the planar lightwave circuit filter array, and the optical fiber array includes N branch ports and N branch optical fibers, and each branch port of the optical fiber array is connected to a corresponding branch optical fiber through an optical path formed by an optical waveguide.

[0066] 11 is a schematic diagram of a planar lightwave circuit optical splitter and an optical fiber array connected together in an embodiment of the present disclosure. As shown in FIG. 11, N branching ports of the planar lightwave circuit optical splitter are connected one-to-one to N branching ports of the optical fiber array.

[0067] In this embodiment, the N branching ports of the planar lightwave circuit optical splitter and the N branching ports of the optical fiber array are all optical waveguide ports, and the optical waveguide ports may be directly connected to each other.

[0068] 12 is a schematic diagram showing a connection between a planar lightwave circuit filter array and an optical fiber array in an embodiment of the present disclosure. As shown in FIG. 12, the optical waveguide ports (common ports, transmission ports, or reflection ports) of the planar lightwave circuit filter array and the optical waveguide ports (branch ports) of the optical fiber array are connected in a one-to-one relationship.

[0069] Fig. 13 is a schematic diagram of a planar lightwave circuit optical splitter and a planar lightwave circuit filter array connected via optical fibers. As shown in Fig. 13, the ports of the planar lightwave circuit optical splitter and the planar lightwave circuit filter array are both optical fibers.

[0070] In this embodiment, the optical fibers may be connected to each other by optical fiber connectors or hot melt (soldering).

[0071] In this embodiment, both the planar lightwave circuit optical splitter and the planar lightwave circuit filter array can convert the branch port into a branch optical fiber by connecting them to an optical fiber array.

[0072] In this embodiment, the optical fiber array can convert a planar lightwave circuit port into an optical fiber connection port, further expanding the application range of the planar lightwave circuit optical splitter and the planar lightwave circuit filter array, and in particular, upgrading passive optical network devices that only have conventional optical fiber ports.

[0073] Another embodiment of the present disclosure further provides an optical signal processing method for a passive optical network, which is applied to an optical splitter of the passive optical network of any of the above-described embodiments.

[0074] FIG. 14 is a flowchart of an optical signal processing method for a passive optical network according to an embodiment of the present disclosure. As shown in FIG. 14, the optical signal processing method includes the following steps S1402 to S1406.

[0075] In step S1402, the input optical signal is split into a plurality of sub-signals by power level using a planar lightwave circuit optical splitter.

[0076] In step S1404, the plurality of sub-signals are input to a plurality of thin film filters in a planar lightwave circuit filter array, with each sub-signal being input to one thin film filter.

[0077] In step S1406, the plurality of sub-signals are respectively filtered by the plurality of thin film filters to obtain a plurality of target sub-signals.

[0078] In this embodiment, step S1402 may specifically include the steps of receiving the optical signal through a common port of the planar lightwave circuit optical splitter; splitting the optical signal into N sub-signals according to power by the planar lightwave circuit optical splitter; and outputting the N sub-signals respectively from N branch ports of the planar lightwave circuit optical splitter, where each branch port of the planar lightwave circuit optical splitter outputs one sub-signal.

[0079] In this embodiment, step S1406 may specifically include the steps of receiving the N sub-signals through N common ports of the planar lightwave circuit filter array, where the planar lightwave circuit filter array includes N thin film filters, each thin film filter including one thin film filter, one common port, one reflection port and one transmission port; filtering the N sub-signals respectively through the N thin film filters of the planar lightwave circuit filter array to obtain N transmission sub-signals and N reflection sub-signals; and outputting corresponding transmission sub-signals respectively through the N transmission ports of the planar lightwave circuit filter array and / or outputting corresponding reflection sub-signals respectively through the N reflection ports of the planar lightwave circuit filter array, where the target sub-signal includes the reflection sub-signal and / or the transmission sub-signal.

[0080] In this embodiment, the optical signals include traffic optical signals and detection optical signals, and the sub-signals include traffic sub-signals and detection sub-signals.

[0081] Furthermore, the step of filtering the N sub-signals by the N thin film filters of the planar lightwave circuit filter array, respectively, to obtain N transmitted sub-signals and N reflected sub-signals specifically includes: if the thin film filters are single passband thin film filters, filtering the N sub-signals through the N single passband thin film filters, respectively, to obtain N transmitted sub-signals and N reflected sub-signals, wherein the transmitted sub-signals include detected sub-signals of predetermined wavelengths, and the reflected sub-signals include the traffic sub-signals and detected sub-signals of wavelengths other than the predetermined wavelength; If the thin film filters are dual passband thin film filters, the method may further include filtering the N sub-signals through the N dual passband thin film filters, respectively, to obtain N transmitted sub-signals and N reflected sub-signals, wherein the transmitted sub-signals include the traffic sub-signals and detected sub-signals of predetermined wavelengths, and the reflected sub-signals include detected sub-signals of wavelengths other than the predetermined wavelength.

[0082] In this embodiment, step S1406 may specifically include the steps of receiving N sub-signals through N transmission ports and / or N reflection ports of the planar lightwave circuit filter array, where the planar lightwave circuit filter array includes N thin film filters, each thin film filter including one thin film filter, one common port, one reflection port and one transmission port; filtering the N sub-signals by the N thin film filters of the planar lightwave circuit filter array, respectively, to obtain N transmission sub-signals and / or N reflection sub-signals; and outputting corresponding transmission sub-signals and / or reflection sub-signals through the N common ports of the planar lightwave circuit filter array, respectively, where the target sub-signals include the reflection sub-signals or the transmission sub-signals.

[0083] In this embodiment, before step S1402, the optical signal processing method for a passive optical network may further include the steps of: splitting the optical signal into a traffic optical signal and a detection optical signal by a three-port wavelength division multiplexer; inputting the traffic optical signal to a common port of the planar lightwave circuit optical splitter, where the planar lightwave circuit optical splitter is used to split the traffic optical signal into N traffic sub-signals by power; and inputting the detection optical signal to a common port of an arrayed waveguide grating or a multi-channel wavelength division multiplexer, where the arrayed waveguide grating and the multi-channel wavelength division multiplexer are used to split the detection optical signal into N detection sub-signals by wavelength.

[0084] In this embodiment, step S1404 may specifically include the steps of: inputting N traffic sub-signals output from the N branching ports of the planar lightwave circuit optical splitter into the planar lightwave circuit filter array, where each traffic sub-signal is input to one thin-film filter; and inputting N detection sub-signals output from the N branching ports of the arrayed waveguide grating or the multi-channel wavelength division multiplexer into the planar lightwave circuit filter array, where each detection sub-signal is input to one thin-film filter.

[0085] In this embodiment, step S1406 may specifically include the steps of receiving the N traffic sub-signals through N transmission ports of the planar lightwave circuit filter array and receiving the N detected sub-signals through N reflection ports of the planar lightwave circuit filter array, or receiving the N traffic sub-signals through N reflection ports of the planar lightwave circuit filter array and receiving the N detected sub-signals through N transmission ports of the planar lightwave circuit filter array; combining the N traffic sub-signals and the N detected sub-signals into N target sub-signals through N thin film filters of the planar lightwave circuit filter array, where each target sub-signal includes one detection sub-signal and one traffic sub-signal; and outputting the N target sub-signals through N common ports of the planar lightwave circuit filter array.

[0086] In another embodiment of the present disclosure, there is further provided a passive optical network optical signal processing system, which is configured from a plurality of passive optical network optical splitters according to the above-described embodiment.

[0087] FIG. 15 is a block diagram of an optical signal processing system for a passive optical network according to an embodiment of the present disclosure. As shown in FIG. 15, the system includes an i-th stage optical splitter 1502 and an i+1-th stage optical splitter 1504.

[0088] In this embodiment, the system includes an M-stage optical splitter, and the M-stage optical splitter includes at least an i-th stage optical splitter and an (i+1)-th stage optical splitter, where the i-th stage optical splitter and the (i+1)-th stage optical splitter are optical splitters of the passive optical network described in the above-mentioned embodiment, and each branch port of the i-th stage optical splitter is respectively connected to a common port of one (i+1)-th stage optical splitter, where M is an integer greater than 1, and i is an integer from 1 to M-1.

[0089] Specifically, M is the total number of stages of optical splitters, for example, a two-stage optical splitter includes a first stage optical splitter and a second stage optical splitter, a three-stage optical splitter includes a first stage optical splitter, a second stage optical splitter and a third stage optical splitter, etc.

[0090] Furthermore, when each of the i-stage optical splitters includes N branch ports, each branch port of the i-stage optical splitter is connected to a common port of N (i+1)-th stage optical splitters.

[0091] In this embodiment, the i-stage optical splitter is used to split an optical signal into N target signals of different wavelength ranges, and the preset transmission wavelength ranges of the N thin film filters in the i-stage optical splitter are different, or the i-stage optical splitter includes a multi-channel wavelength division multiplexer.

[0092] In this embodiment, the N (i+1)th stage optical splitters are used to split the target signal into multiple target sub-signals with different wavelengths, and the preset transmission wavelengths of the multiple thin film filters in each (i+1)th stage optical splitter are different, or each (i+1)th stage optical splitter includes an arrayed waveguide grating (planar lightwave circuit array grating).

[0093] FIG. 16 is a schematic diagram of an optical signal processing system in a passive optical network according to an embodiment of the present disclosure. As shown in FIG. 16, the system includes a first-stage optical splitter and a second-stage optical splitter.

[0094] In this embodiment, the optical fiber between the wavelength division multiplexer (3-port wavelength division multiplexer) and the first-stage optical splitter is a trunk optical fiber. The optical fiber between the first-stage optical splitter and the second-stage optical splitter is a distribution optical fiber. The optical fiber between the second-stage optical splitter and the optical network terminal is a branch optical fiber.

[0095] In this embodiment, a multi-wavelength optical time-domain reflectometer (OTDR) detector is located on the optical line terminal (OLT) side, emits a detection light of a tunable specific wavelength, and transfers the detection light to a wavelength division multiplexer (CEx). The received wavelength is a detection light echo signal, and performs OTDR signal analysis. The wavelength division multiplexer (CEx) is located on the OLT side, and multiplexes the detection light signal wavelength with the downstream operating wavelength and sends it into the trunk optical fiber of the optical distribution network (ODN).

[0096] 17 is a wavelength plan schematic diagram of the detected optical signal of the two-stage optical splitter in the embodiment of the present disclosure. As shown in FIG. 17, the optical signal processing system of the passive optical network is configured with a two-stage optical splitter, including one first-stage optical splitter and eight second-stage optical splitters.

[0097] In this embodiment, each branch output wavelength band of the first-stage optical splitter is bound to a specific branch port. The first-stage optical splitter has a total of eight branch ports, numbered 1 to 8, and the wavelength bands are respectively corresponding to λ1band (wavelength band) to λ8band.

[0098] In this embodiment, the wavelengths of the second-stage optical splitter are periodically subdivided from each branch output wavelength band of the first-stage optical splitter. The wavelengths of the second-stage optical splitter are bound to specific branch ports. The first branch port of the first-stage optical splitter is connected to the first second-stage optical splitter, and the eighth branch port of the first-stage optical splitter is connected to the eighth second-stage optical splitter.

[0099] Specifically, the first second-stage optical splitter has eight branch ports with corresponding wavelengths λ11 to λ18, the eighth second-stage optical splitter has eight branch ports with corresponding wavelengths λ81 to λ88, and the wavelength divisions of the other numbers are estimated in this manner.

[0100] Furthermore, the wavelengths λ11 to λ18 are obtained by periodically subdividing the wavelength band λ1band, and the wavelengths λ81 to λ88 are obtained by periodically subdividing the wavelength band λ8band.The correspondence between the numbers of the optical detection wavelengths and the numbers of the optical splitter ports can be determined using the wavelength planning schematic diagram of the detected optical signals of the two-stage optical splitter in Figure 17.

[0101] According to the embodiments of the present disclosure, a single wavelength corresponds to a single optical fiber link, thereby realizing end-to-end detection of optical detection signals, i.e., optical link detection function using end-to-end backscattered signals, realizing optical splitter port identification function connected to ONU / ONT, and further realizing accurate identification of optical fiber faults. The wavelength planning in the embodiments of the present disclosure can also be adjusted according to application scenarios and filter types.

[0102] FIG. 18 is a schematic diagram of an optical splitter of a passive optical network in an embodiment of the present disclosure. As shown in FIG. 18, this optical splitter has a configuration in which a planar lightwave circuit optical splitter and a planar lightwave circuit filter array are connected in series.

[0103] In this embodiment, this configuration corresponds to adding one filter to each branch of a normal optical splitter. The transmission wavelengths of the filters in each branch of the optical splitter are different. This configuration can be used for the first stage optical splitter.

[0104] FIG. 19 is a schematic diagram of an optical splitter for a passive optical network based on wavelength division multiplexing in an embodiment of the present disclosure. As shown in FIG. 19, the optical splitter is configured by connecting a planar lightwave circuit optical splitter and a wavelength division multiplexer in parallel.

[0105] In this embodiment, the optical signal can be split into a traffic optical signal and a detection optical signal by wavelength division multiplexing (WDM), the traffic optical signal can be split into traffic sub-signals by a planar lightwave circuit optical splitter, the detection optical signal can be split into detection sub-signals by a multichannel wavelength division multiplexer, and the traffic sub-signals and detection sub-signals can be combined into a target sub-signal by a wavelength division multiplexer or a three-port filter. This configuration can be used in the second-stage optical splitter.

[0106] Furthermore, although the multi-channel wavelength division multiplexer may be replaced with a planar lightwave circuit array grating, in an optical signal processing system of a passive optical network consisting of multiple optical splitters, the first stage optical splitter is usually composed of a multi-channel wavelength division multiplexer and the second stage optical splitter is usually composed of a planar lightwave circuit array grating.

[0107] As specific examples of this embodiment, the examples described in the above-mentioned embodiments and exemplary embodiments can be referred to, and therefore, the description thereof will be omitted in this embodiment.

[0108] As will be apparent to those skilled in the art, each module or step of the present disclosure described above can be implemented by a general-purpose computing device, or can be integrated into a single computing device or distributed across a network of multiple computing devices, or can be implemented by program code executable on a computing device, which can be stored in a storage device and executed by a computing device. In some cases, it will be obvious to those skilled in the art that the illustrated or described steps can be executed in a different order from that shown here, or that each module or step can be implemented as an integrated circuit module, or that multiple modules or steps can be implemented as a single integrated circuit module. Thus, the present disclosure is not limited to any specific combination of hardware and software.

[0109] The above is merely a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Those skilled in the art can make various modifications and variations to the present disclosure. Any modifications, equivalent replacements, improvements, etc. within the principle of the present disclosure should be included within the protection scope of the present disclosure.

Claims

1. 1. An optical splitter for a passive optical network, comprising: a planar lightwave circuit optical splitter; a thin film filter module including a plurality of thin film filters; and a planar lightwave circuit filter array consisting of a plurality of common ports, a plurality of reflection ports, and a plurality of transmission ports; The planar lightwave circuit optical splitter is used to split an input optical signal into a plurality of sub-signals according to power, and input the plurality of sub-signals to corresponding thin film filters in the planar lightwave circuit filter array, each sub-signal being input to one thin film filter; the thin film filter module is used to filter the plurality of sub-signals and output a plurality of target sub-signals; An optical splitter for a passive optical network, wherein the common port, the reflection port, and the transmission port in the planar lightwave circuit filter array are each connected to the thin film filter via an optical path formed by an optical waveguide, the thin film filter is configured to transmit optical signals of a predetermined wavelength and reflect optical signals other than the predetermined wavelength, and the target sub-signal includes a transmission sub-signal and / or a reflection sub-signal.

2. 2. The optical splitter of claim 1, wherein the thin film filter is used to filter the sub-signals input from the common port of the planar lightwave circuit filter array, output a transmitted sub-signal from the transmitted port, and / or output a reflected sub-signal from the reflected port.

3. the planar lightwave circuit optical splitter includes one common port and N branch ports; the planar lightwave circuit filter array includes N common ports, N reflection ports, and N transmission ports; the thin film filter module includes N thin film filters, each thin film filter corresponding to one common port, one reflection port, and one transmission port; and the N thin film filters have different preset transmission wavelengths; the N branch ports of the planar lightwave circuit optical splitter are connected one-to-one to the N common ports of the planar lightwave circuit filter array; the planar lightwave circuit optical splitter is used to split one optical signal input from a common port of the planar lightwave circuit optical splitter into N sub-signals according to power, and output the N sub-signals from N branch ports of the planar lightwave circuit optical splitter, respectively; 3. The optical splitter of claim 2, wherein the planar lightwave circuit filter array is used to filter the N sub-signals input from the N common ports of the planar lightwave circuit filter array using the N thin film filters, respectively, and output corresponding N transmitted sub-signals from the N transmitted ports and / or output corresponding N reflected sub-signals from the N reflected ports.

4. The planar lightwave circuit optical splitter is used to split one optical signal input from a common port of the planar lightwave circuit optical splitter into N sub-signals according to power, and output the N sub-signals from N branch ports of the planar lightwave circuit optical splitter, respectively, the optical signal includes a traffic optical signal and a detection optical signal, and the sub-signals include a traffic sub-signal and a detection sub-signal; If the N thin film filters are N single passband thin film filters, the planar lightwave circuit filter array is used to filter the N sub-signals by the N single passband thin film filters, respectively, and output corresponding N detected sub-signals of predetermined wavelengths from the N transmission ports, and output corresponding N traffic sub-signals and N detected sub-signals of wavelengths other than the predetermined wavelengths from the N reflection ports; 4. The optical splitter of claim 3, wherein when the N thin film filters are N dual passband thin film filters, the planar lightwave circuit filter array is used to filter the N sub-signals through the N dual passband thin film filters, respectively, and output N corresponding detection sub-signals and N traffic sub-signals of predetermined wavelengths from the N transmission ports, and output N corresponding detection sub-signals of wavelengths other than the predetermined wavelengths from the N reflection ports.

5. 2. The optical splitter of claim 1, wherein the thin film filter is used to filter and then combine a sub-signal of a predetermined reflection wavelength input from the reflection port and a sub-signal of a predetermined transmission wavelength input from the transmission port, and output the combined reflected sub-signal and transmitted sub-signal from a common port of the planar lightwave circuit filter array.

6. the planar lightwave circuit optical splitter includes one common port and N branch ports; the planar lightwave circuit filter array includes N common ports, N reflection ports, and N transmission ports; the thin film filter module includes N thin film filters, each thin film filter corresponding to one common port, one reflection port, and one transmission port; and the N thin film filters have different preset transmission wavelengths; the N branching ports of the planar lightwave circuit optical splitter are connected one-to-one to the N reflection ports or the N transmission ports of the planar lightwave circuit filter array; The planar lightwave circuit optical splitter is used to split one optical signal input from a common port of the planar lightwave circuit optical splitter into N sub-signals according to power, and output the sub-signals from the N branch ports of the planar lightwave circuit optical splitter, respectively; the planar lightwave circuit filter array is used to filter the N sub-signals input from the N transmission ports of the planar lightwave circuit filter array by the N thin film filters, respectively, and output corresponding N transmission sub-signals from the N common ports of the planar lightwave circuit filter array, wherein the target sub-signals are the transmission sub-signals; Alternatively, the optical splitter of claim 5, wherein the planar lightwave circuit filter array is used to filter the N sub-signals input from the N reflection ports of the planar lightwave circuit filter array using the N thin film filters, respectively, and output corresponding N reflection sub-signals from the N common ports of the planar lightwave circuit filter array, and the target sub-signals are the reflection sub-signals.

7. the optical splitter further includes a three-port wavelength division multiplexer and an arrayed waveguide grating or a multi-channel wavelength division multiplexer, each of which includes a common port and N branch ports; the three-port wavelength division multiplexer includes one common port and two output ports; the three-port wavelength division multiplexer is used to split an optical signal input from a common port of the three-port wavelength division multiplexer into a traffic optical signal and a detection optical signal, output the signals from two output ports of the three-port wavelength division multiplexer, input the traffic optical signal to the common port of the planar lightwave circuit optical splitter, and input the detection optical signal to the common port of the arrayed waveguide grating or the multi-channel wavelength division multiplexer; the planar lightwave circuit optical splitter is used to split the traffic optical signal into N traffic sub-signals by power; the arrayed waveguide grating or the multi-channel wavelength division multiplexer is used to split the detected optical signal into N detected sub-signals by wavelength; the planar lightwave circuit filter array is adapted to receive the N traffic sub-signals from the N transmission ports and the N detection sub-signals from the N reflection ports, or to receive the N traffic sub-signals from the N reflection ports and the N detection sub-signals from the N transmission ports; 7. The optical splitter of claim 6, wherein the planar lightwave circuit filter array is further used to combine the N traffic sub-signals and the N detected sub-signals into N target sub-signals by the N thin film filters and output the N target sub-signals from N common ports of the planar lightwave circuit filter array, the target sub-signals including the detected sub-signals and the traffic sub-signals.

8. the N branch ports of the arrayed waveguide grating or the multi-channel wavelength division multiplexer are respectively connected to the N transmission ports of the planar lightwave circuit filter array; the N branch ports of the planar lightwave circuit optical splitter are respectively connected to the N reflection ports of the planar lightwave circuit filter array; 8. The optical splitter of claim 7, wherein the planar lightwave circuit filter array is used to receive the N detection sub-signals from the N branch ports of the arrayed waveguide grating or the multi-channel wavelength division multiplexer from the N transmission ports and to receive the N traffic sub-signals from the N branch ports of the planar lightwave circuit optical splitter from the N reflection ports.

9. N branch ports of the arrayed waveguide grating or the multi-channel wavelength division multiplexer are respectively connected to N reflection ports of the planar lightwave circuit filter array; the N branch ports of the planar lightwave circuit optical splitter are respectively connected to the N transmission ports of the planar lightwave circuit filter array; 8. The optical splitter of claim 7, wherein the planar lightwave circuit filter array is used to receive the N detection sub-signals from the N branch ports of the arrayed waveguide grating or the multi-channel wavelength division multiplexer from the N reflection ports and to receive the N traffic sub-signals from the N branch ports of the planar lightwave circuit optical splitter from the N transmission ports.

10. The optical splitter comprises: further comprising one or more optical fiber arrays; The optical splitter according to any one of claims 1 to 9, wherein the optical fiber array is used to connect the planar lightwave circuit optical splitter and / or the planar lightwave circuit filter array, the optical fiber array includes N branch ports and N branch optical fibers, and each branch port of the optical fiber array is connected to a corresponding branch optical fiber via an optical path formed by an optical waveguide.

11. An optical signal processing method for a passive optical network applied to an optical splitter of a passive optical network according to any one of claims 1 to 10, comprising: splitting an input optical signal into a plurality of sub-signals by power using a planar lightwave circuit optical splitter; inputting the plurality of sub-signals to thin film filter modules in a planar lightwave circuit filter array, each sub-signal being input to one thin film filter in the thin film filter module; filtering the plurality of sub-signals with the thin film filter module to obtain a plurality of target sub-signals; A method for processing optical signals in a passive optical network, comprising:

12. The step of splitting the input optical signal into a plurality of sub-signals by power using a planar lightwave circuit optical splitter includes: receiving the optical signal via a common port of the planar lightwave circuit optical splitter; splitting the optical signal into N sub-signals by power using the planar lightwave circuit optical splitter; and outputting the N sub-signals from N branch ports of the planar lightwave circuit optical splitter, respectively, wherein each branch port of the planar lightwave circuit optical splitter outputs one sub-signal.

13. filtering the plurality of sub-signals with the thin film filter module to obtain a plurality of target sub-signals, receiving the N sub-signals via N common ports of the planar lightwave circuit filter array, wherein a thin film filter module of the planar lightwave circuit filter array includes N thin film filters, each thin film filter corresponding to one common port, one reflection port, and one transmission port; filtering the N sub-signals with the N thin film filters, respectively, to obtain N transmitted sub-signals and N reflected sub-signals; 13. The method of claim 12, comprising: outputting corresponding transmitted sub-signals via N transmitted ports of the planar lightwave circuit filter array, respectively; and / or outputting corresponding reflected sub-signals via N reflected ports of the planar lightwave circuit filter array, respectively; wherein the target sub-signals include the reflected sub-signals and / or the transmitted sub-signals.

14. filtering the N sub-signals with the N thin film filters to obtain N transmitted sub-signals and N reflected sub-signals, respectively, the optical signal includes a traffic optical signal and a detection optical signal, and the sub-signals include a traffic sub-signal and a detection sub-signal; if the thin film filters are single passband thin film filters, filtering the N sub-signals through the N single passband thin film filters, respectively, to obtain N transmitted sub-signals and N reflected sub-signals, wherein the transmitted sub-signals include detected sub-signals of predetermined wavelengths, and the reflected sub-signals include the traffic sub-signals and detected sub-signals of wavelengths other than the predetermined wavelength; 14. The method of claim 13, further comprising: if the thin film filters are dual passband thin film filters, filtering the N sub-signals through the N dual passband thin film filters, respectively, to obtain N transmitted sub-signals and N reflected sub-signals, wherein the transmitted sub-signals include the traffic sub-signals and detected sub-signals of predetermined wavelengths, and the reflected sub-signals include detected sub-signals of wavelengths other than the predetermined wavelength.

15. filtering the plurality of sub-signals with the thin film filter module to obtain a plurality of target sub-signals, receiving N sub-signals via N transmission ports and / or N reflection ports of the planar lightwave circuit filter array, wherein the thin film filter modules of the planar lightwave circuit filter array include N thin film filters, each thin film filter corresponding to one common port, one reflection port and one transmission port; filtering the N sub-signals by N thin film filters of the thin film filter module, respectively, to obtain N transmitted sub-signals and / or N reflected sub-signals; and outputting corresponding transmitted and / or reflected sub-signals via N common ports of the planar lightwave circuit filter array, respectively, wherein the target sub-signals include the reflected sub-signals or the transmitted sub-signals.

16. splitting the optical signal into a traffic optical signal and a detection optical signal by a three-port wavelength division multiplexer; inputting the traffic optical signal into a common port of the planar lightwave circuit optical splitter, the planar lightwave circuit optical splitter being used to split the traffic optical signal into N traffic sub-signals by power; 16. The method of claim 15, comprising: inputting the detected optical signal into a common port of an arrayed waveguide grating or a multi-channel wavelength division multiplexer, the arrayed waveguide grating and the multi-channel wavelength division multiplexer being used to split the detected optical signal into N detected sub-signals by wavelength.

17. inputting the plurality of sub-signals into thin film filter modules in a planar lightwave circuit filter array, inputting N traffic sub-signals output from the N branch ports of the planar lightwave circuit optical splitter into the planar lightwave circuit filter array, each traffic sub-signal being input to one thin film filter; and inputting N detected sub-signals output from N branch ports of the arrayed waveguide grating or the multi-channel wavelength division multiplexer into the planar lightwave circuit filter array, wherein each detected sub-signal is input to one thin film filter.

18. filtering the plurality of sub-signals with the thin film filter module to obtain a plurality of target sub-signals, receiving the N traffic sub-signals via N transmission ports of the planar lightwave circuit filter array and receiving the N detection sub-signals via N reflection ports of the planar lightwave circuit filter array; or receiving the N traffic sub-signals via N reflected ports of the planar lightwave circuit filter array and receiving the N detected sub-signals via N transmitted ports of the planar lightwave circuit filter array; combining the N traffic sub-signals and the N detected sub-signals into N target sub-signals by N thin film filters of the thin film filter module, each target sub-signal including one detected sub-signal and one traffic sub-signal; and outputting the N target sub-signals through N common ports of the planar lightwave circuit filter array.

19. 1. An optical signal processing system for a passive optical network, comprising: An M-stage optical splitter including an i-th stage optical splitter and an i+1-th stage optical splitter, wherein the i-th stage optical splitter and the i+1-th stage optical splitter are optical splitters of a passive optical network according to any one of claims 1 to 10, and each branch port of the i-th stage optical splitter is respectively connected to a common port of one i+1-th stage optical splitter, M is an integer greater than 1, and i is any integer from 1 to M-1; An optical signal processing system for a passive optical network, wherein when each of the i-th stage optical splitters includes N branch ports, each branch port of the i-th stage optical splitter is connected to a common port of N i+1-th stage optical splitters.

20. The i-th stage optical splitter is used to split an optical signal into N target signals of different wavelength ranges, and the N thin film filters in the i-th stage optical splitter have different preset transmission wavelength ranges, or the i-th stage optical splitter includes a multi-channel wavelength division multiplexer; 20. The system of claim 19, wherein the N i+1-th stage optical splitters are used to split the target signal into multiple target sub-signals of different wavelengths, and the preset transmission wavelengths of multiple thin film filters in the i+1-stage optical splitters are different, or the i+1-st stage optical splitter includes an arrayed waveguide grating.

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