Optical communication link detection method and device

Abstract

The invention provides an optical communication link detection method and device, and the method comprises the steps: receiving an optical signal, carrying out the photoelectric conversion of the optical signal into an electric signal, and carrying out the detection of an optical communication link according to the parameters of the electric signal, the parameters of the electric signal comprise a comparison value of the highest level distribution and the lowest level distribution of the electric signal, and the frequency response curve characteristics of the electric signal. According to the method, the information of the optical communication link can be determined, namely the intensity and / or the chirp coefficient of multipath interference MPI noise can be determined, so that the MPI effect and the chirp effect in the optical communication link can be detected to know the damage condition of the optical communication link, additional hardware equipment is not needed, and the cost is low. Besides, the influence of the MPI effect and the chirp effect on the optical communication link (namely, the intensity and the chirp coefficient of the MPI noise) can be obtained through the method, so that operation such as optimizing the optical communication link can be executed subsequently according to the intensity and the chirp coefficient of the MPI noise.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of communication, and more particularly, to an optical communication link detection method and device. BACKGROUND

[0002] With the continuous development of communication technology, the interconnection distance of optical fiber is increased, so that there are a large number of optical fiber connectors on the optical communication link, which increases the probability of damage to the optical communication link, and the damage to the optical communication link will cause multi-path interference (MPI) effect or chirp effect. For example, the MPI effect in the optical communication link is mainly caused by the inevitable pollution of the optical fiber end face of the optical fiber connector by pollutants. MPI will have a negative impact on the optical signal transmitted in the optical communication link and will reduce the signal quality of the optical signal. For another example, the chirp effect is mainly caused by the change of the injected current in the direct current laser. The chirp effect will change the pulse shape of the optical signal transmitted in the optical communication link, resulting in a decrease in the quality of the optical signal.

[0003] At present, for the MPI effect, the OTDR technology is mainly used to measure the position of the optical fiber end face contaminated by dirt, but this technology needs manual cleaning to reduce the end face reflection, which is high in cost. For the chirp effect, special instruments and special detection circuits are mainly used for chirp detection, which is high in cost. In addition, the damage to the optical communication link can also be checked by detecting the optical power, but when the optical communication link has damage causing MPI effect but the optical power is normal, it is impossible to judge that the link has multi-path interference problem, and manual link investigation is still needed, which is high in cost.

[0004] Therefore, how to detect the damage in the optical communication link in a low-cost manner is a technical problem to be solved at present. SUMMARY

[0005] The present application provides an optical communication link detection method and device, which can detect the damage in the optical communication link in a low-cost manner.

[0006] In a first aspect, a method for detecting an optical communication link is provided. The method comprises: receiving a first optical signal, and performing photoelectric conversion on the first optical signal to obtain a first electrical signal; determining information of the optical communication link based on a parameter of the first electrical signal, the optical communication link being used to transmit the first optical signal, the parameter of the first electrical signal comprising at least one of: a comparison value of a highest level distribution and a lowest level distribution of the first electrical signal, a frequency response curve characteristic of the first electrical signal; and the information of the optical communication link comprising at least one of: an intensity of multipath interference (MPI) noise, a chirp coefficient; wherein the intensity of the MPI noise is used to measure the influence of the MPI effect on the optical communication link, and the chirp coefficient is used to measure the influence of the chirp effect on the optical communication link.

[0007] The frequency response curve characteristic of the first electrical signal comprises at least one of: a curve characteristic of a frequency response curve of the first electrical signal itself, and a curve characteristic of a frequency response curve of the equalizer compensating for the first electrical signal.

[0008] Based on the above scheme, by receiving an optical signal, the optical signal is converted into an electrical signal through photoelectric conversion, and based on a parameter of the electrical signal, the parameter of the electrical signal comprises a comparison value of a highest level distribution and a lowest level distribution of the electrical signal, and a frequency response curve characteristic of the electrical signal, information of an optical communication link can be determined, that is, the intensity of the multipath interference (MPI) noise and / or the chirp coefficient are determined, so that the MPI effect and the chirp effect in the optical communication link can be detected to understand the damage of the optical communication link, without the need for additional hardware devices, and the cost is low. In addition, through the method, the influence of the MPI effect and the chirp effect on the optical communication link (i.e., the intensity of the MPI noise and the chirp coefficient) can be obtained, so that subsequent operations such as optimizing the optical communication link can be performed according to the intensity of the MPI noise and the chirp coefficient.

[0009] In combination with the first aspect, in some implementations of the first aspect, the information of the optical communication link is determined based on the parameter of the first electrical signal, comprising: determining the intensity of the MPI noise based on the comparison value of the highest level distribution and the lowest level distribution of the first electrical signal; and / or, determining the chirp coefficient based on the frequency response curve characteristic of the first electrical signal.

[0010] Based on the above scheme, the method can specifically determine the intensity of the MPI noise based on the comparison value of the highest level distribution and the lowest level distribution of the first electrical signal, and / or determine the chirp coefficient based on the frequency response curve characteristic of the first electrical signal, further specifying the determination manner of the intensity of the MPI noise and the chirp coefficient, so that subsequent operations such as judging whether the link is damaged and whether the link needs to be repaired can be performed according to the intensity of the MPI noise and the chirp coefficient, without the need for additional hardware devices, and the cost is low.

[0011] In some implementations of the first aspect, according to the comparison value of the highest level distribution and the lowest level distribution of the first electrical signal, the intensity of the MPI noise is determined, including: obtaining a first correspondence relationship, the first correspondence relationship including a plurality of correspondence relationships between comparison values of a plurality of highest level distributions and lowest level distributions and intensities of a plurality of MPI noises; and determining, according to the first correspondence relationship, the intensity of the multipath interference (MPI) noise corresponding to the comparison value of the highest level distribution and the lowest level distribution of the first electrical signal, the plurality of comparison values of the highest level distribution and the lowest level distribution including the comparison value of the highest level distribution and the lowest level distribution of the first electrical signal.

[0012] Based on the above scheme, by obtaining the correspondence relationship between the plurality of comparison values of the highest level distribution and the lowest level distribution and the intensities of the plurality of MPI noises, the intensity of the MPI noise corresponding to the comparison value of the highest level distribution and the lowest level distribution of the first electrical signal can be quickly and accurately determined, and no additional equipment is needed, which is low in cost.

[0013] In some implementations of the first aspect, the comparison value of the highest level distribution and the lowest level distribution includes at least one of a standard deviation difference value of the highest level distribution and the lowest level distribution, a standard deviation ratio value of the highest level distribution and the lowest level distribution, a variance difference value of the highest level distribution and the lowest level distribution, or a variance ratio value of the highest level distribution and the lowest level distribution.

[0014] Based on the above scheme, the intensity of the MPI noise can be determined according to any one or more of the standard deviation difference value of the highest level distribution and the lowest level distribution, the standard deviation ratio value of the highest level distribution and the lowest level distribution, the variance difference value of the highest level distribution and the lowest level distribution, or the variance ratio value of the highest level distribution and the lowest level distribution, so that the determination of the intensity of the MPI noise is more flexible. In addition, since the multi-level has monotonicity, the comparison value of the highest level distribution and the lowest level distribution can better reflect the amplitude of the level, so as to obtain a more accurate intensity of the MPI noise.

[0015] In some implementations of the first aspect, the first correspondence relationship is obtained by simulation of an optical communication link simulation system, and the optical communication link simulation system is used to simulate the MPI effect in the optical communication link.

[0016] Based on the above scheme, the MPI effect in the optical communication link is simulated by simulation, so as to obtain the first correspondence relationship, that is, the correspondence relationship between the plurality of comparison values of the highest level distribution and the lowest level distribution and the intensities of the plurality of MPI noises, so that the intensity of the MPI noise corresponding to the comparison value of the highest level distribution and the lowest level distribution of the first electrical signal determined by using the first correspondence relationship is more accurate.

[0017] In some implementations of the first aspect, according to the frequency response curve feature of the first electrical signal, the chirp coefficient is determined by: obtaining a second correspondence relationship, the second correspondence relationship including a plurality of frequency response curve features and a plurality of chirp coefficients; and determining the chirp coefficient corresponding to the frequency response curve feature of the first electrical signal according to the second correspondence relationship, the plurality of frequency response curve features including the frequency response curve feature of the first electrical signal.

[0018] Based on the above scheme, by obtaining the correspondence relationship between the plurality of frequency response curve features and the plurality of chirp coefficients, the chirp coefficient matching the frequency response curve feature of the first electrical signal can be quickly and accurately determined, and no additional equipment is needed, which is low in cost.

[0019] In some implementations of the first aspect, the method further includes: receiving a second optical signal and performing photoelectric conversion on the second optical signal to obtain a second electrical signal, the first optical signal corresponding to a first time, the second optical signal corresponding to a second time, the second time being after the first time; and determining whether the optical communication link has chirp degradation according to a frequency response curve feature of the second electrical signal and a frequency response curve feature of the first electrical signal, the optical communication link also being used to transmit the second optical signal.

[0020] The first optical signal and the second optical signal are the same optical signal sent by the sending device at different times. The frequency response curve feature of the second electrical signal includes at least one of the following: a curve feature of a frequency response curve of the second electrical signal itself, and a curve feature of a frequency response curve of the equalizer compensating for the second electrical signal.

[0021] Based on the above scheme, the second optical signal is received after the first optical signal, and is photoelectrically converted into the second electrical signal. According to the frequency response curve features of the first electrical signal and the second electrical signal, it can be determined whether the optical communication link transmitting the first optical signal and the second optical signal has chirp degradation. It can be understood that at different times, the same optical signal sent by the sending end is received. When the optical communication link is damaged during this period of time, the same optical signal will be affected by the damage of the optical communication link, so that the frequency response curve features of the electrical signals corresponding to the optical signals received at different times are different. According to the different frequency response curve features, it can be determined whether the optical communication link has chirp degradation. No additional equipment is needed, which is low in cost.

[0022] With reference to the first aspect, in some implementations of the first aspect, the method further includes: determining, according to the second correspondence, a chirp coefficient corresponding to a frequency response curve feature of the second electrical signal, the plurality of frequency response curve features including the frequency response curve feature of the second electrical signal; and determining, according to the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal and the chirp coefficient corresponding to the frequency response curve feature of the first electrical signal, whether the optical communication link has chirp degradation.

[0023] Based on the above scheme, the method can further determine the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal through the second correspondence, and determine whether the optical communication link has chirp degradation according to the chirp coefficients of the two electrical signals obtained at the two time points, without the need for additional equipment, thereby reducing costs.

[0024] With reference to the first aspect, in some implementations of the first aspect, when the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal is greater than the chirp coefficient corresponding to the frequency response curve feature of the first electrical signal, the optical communication link has chirp degradation.

[0025] Based on the above scheme, by comparing the chirp coefficients of the two electrical signals obtained at the two time points, when the chirp coefficient of the electrical signal at the latter time point (i.e., the second electrical signal) is greater than the chirp coefficient of the electrical signal at the former time point (i.e., the first electrical signal), it can be determined that the optical communication link transmitting the first optical signal and the second optical signal has chirp degradation, without the need for additional equipment, thereby reducing costs.

[0026] With reference to the first aspect, in some implementations of the first aspect, the method further includes: determining, according to the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal and the chirp coefficient corresponding to the frequency response curve feature of the first signal, a chirp degradation value, the chirp degradation value being used to measure a degree of the chirp degradation.

[0027] Based on the above scheme, the method can further measure the degree of the chirp degradation through a chirp degradation value, which not only can measure the chirp degradation without the need for additional equipment, thereby reducing costs, but also can quantify the chirp degradation, thereby facilitating subsequent operations such as optimizing the optical communication link according to the chirp degradation value.

[0028] With reference to the first aspect, in some implementations of the first aspect, the frequency response curve feature includes at least one of the following: information of a stationary point of a frequency response curve, information of a slope between stationary points of a frequency response curve, a degree of curvature of a frequency response curve, and position information of a concave-convex part of a frequency response curve.

[0029] Based on the above scheme, the method can specifically determine the chirp coefficient according to one or more of the stationary point information of the frequency response curve, the slope information between the stationary points of the frequency response curve, the bending degree of the frequency response curve, and the position information of the concave-convex part of the frequency response curve, so that the determination manner of the chirp coefficient is more flexible.

[0030] In combination with the first aspect, in some implementations of the first aspect, the second correspondence is obtained by simulation of an optical communication link simulation system configured to simulate the chirp effect in the optical communication link.

[0031] Based on the above scheme, the chirp effect in the optical communication link is simulated in a simulated manner, so that the second correspondence is obtained, that is, the correspondence between the multiple frequency response curve characteristics and the multiple chirp coefficients can be accurately obtained, so that the chirp coefficient corresponding to the frequency response curve characteristic of the first electrical signal or the chirp coefficient corresponding to the frequency response curve characteristic of the second electrical signal determined by using the second correspondence is more accurate.

[0032] The second aspect provides a device. The device is configured to execute the first aspect and any one of the implementations thereof. Specifically, the device includes a processor and a memory configured to store a computer program; the processor is configured to call and run the computer program from the memory, so that the device executes the first aspect and any one of the implementations thereof.

[0033] In an implementation, the device is a receiving device. When the device is a receiving device, the transceiving unit can be a transceiver, or an input / output interface. The processing unit can be at least one processor. Optionally, the transceiver can be a transceiving circuit. Optionally, the input / output interface can be an input / output circuit.

[0034] In another implementation, the device can be a chip, a chip system, or a circuit in a receiving device. At this time, the transceiving unit can be an input / output interface, an interface circuit, an output circuit, an input circuit, a pin, or a related circuit on the chip, the chip system, or the circuit; the processing unit can be at least one processor, a processing circuit, or a logic circuit, etc.

[0035] The third aspect provides a computer readable storage medium. The computer readable storage medium stores a computer program. When the computer program is run, the method of any one of the implementations of the first aspect is executed.

[0036] The fourth aspect provides a computer program product containing instructions. When the computer program product is run, the method provided by any one of the implementations of the first aspect is executed.

[0037] In a fifth aspect, a chip is provided, and the chip includes a processor and an interface, the processor reads instructions through the interface, and executes the method provided in any one of the implementation manners of the first aspect.

[0038] Optionally, as an implementation manner, the chip further includes a memory, and the memory stores a computer program or instructions, and the processor is configured to execute the computer program or instructions stored on the memory, and when the computer program or instructions are executed, the processor is configured to execute the method provided in any one of the implementation manners of the first aspect.

[0039] In a sixth aspect, a computer program is provided, and when the computer program is executed, the method provided in any one of the implementation manners of the first aspect is executed.

[0040] In a seventh aspect, a system is provided, and the system includes the device of the second aspect.

[0041] The possible designs and beneficial effects of the second aspect to the seventh aspect can refer to the description of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 A networking schematic diagram of an optical power detection scheme.

[0043] Figure 2 An optical communication scene schematic diagram suitable for embodiments of the present application.

[0044] Figure 3 A schematic flowchart of an optical communication link detection method 300 provided by the present application.

[0045] Figure 4 An optical communication link simulation system structure schematic diagram.

[0046] Figure 5 An optical communication link and MPI effect in the optical communication link schematic diagram.

[0047] Figure 6 A schematic diagram of the difference value / ratio of the standard deviation of the highest level distribution and the lowest level distribution under different MPI noise intensities.

[0048] Figure 7 A frequency response curve under different line width enhancement factors alpha (alpha).

[0049] Figure 8 A frequency response curve of an LMS equalizer under different chirp coefficients.

[0050] Figure 9 A schematic block diagram of an optical communication link detection device 1000 provided by embodiments of the present application.

[0051] Figure 10is a schematic block diagram of the optical communication link detection apparatus 2000 provided by an embodiment of the present application.

[0052] Figure 11 is a schematic block diagram of the chip system 3000 provided by an embodiment of the present application. DETAILED DESCRIPTION

[0053] In order to facilitate understanding of the embodiments of the present application, the following points are first explained.

[0054] First, in the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0055] Second, in each embodiment of the present application, the terms and / or descriptions of different embodiments are consistent and can be mutually referenced if there is no special description and no logical conflict, and the technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0056] Third, in the embodiments of the present application, "first", "second", and various numerical numbers (for example, "#1", "#2", etc.) are only for the convenience of description and do not limit the scope of the embodiments of the present application. The size of the serial number of each process below does not mean the execution order, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application. It should be understood that the objects thus described can be interchanged under appropriate circumstances, so as to be able to describe schemes other than the embodiments of the present application. In addition, in the embodiments of the present application, the words such as "S310" are only for the convenience of description and are not limited to the order of execution steps.

[0057] At the same time, any embodiment or design scheme described as "exemplary" or "for example" in the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. On the contrary, the words "exemplary" or "for example" are intended to present the relevant concept in a specific manner, so as to facilitate understanding.

[0058] Fourth, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those clearly listed steps or units, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0059] V. The term "storage" or "preservation" in this application can refer to storage in one or more memory devices. These memory devices can be separately configured or integrated into an encoder, decoder, processor, or device. Alternatively, some memory devices can be separately configured, while others can be integrated into a decoder, processor, or device. The type of memory can be any form of storage medium, and this is not limited.

[0060] VI. In the embodiments of this application, “under the circumstances of…”, “when…”, and “if…” can sometimes be used interchangeably. It should be noted that when the distinction is not emphasized, their intended meanings are consistent.

[0061] VII. In this application, unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship. For example, A / B can mean A or B. In this application, "and / or" is merely a description of the relationship between the related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural.

[0062] For ease of understanding, the terminology used in the embodiments of this application is briefly described below.

[0063] I. Pulse Amplitude Modulation (PAM) - 4

[0064] PAM-4 is a modulation technique that uses four levels to transmit signals. Each symbol period of a PAM-4 signal can represent 2 bits of logic information (such as 00, 01, 10, 11).

[0065] Compared to non-return-to-zero (NRZ) modulation, PAM-4 signals have twice the transmission capacity of NRZ signals, significantly improving signal transmission efficiency.

[0066] II. MPI in optical communication links

[0067] With the continuous development of communication technology, fiber optic interconnection distances are increasing, especially in centralized radio access network (CRAN) scenarios. The fiber optic interconnection distance between baseband units and remote radio units (RRUs) / active antenna units (AAUs) can reach up to 10 km. Optical communication links contain devices such as multiplexers / demultiplexers, optical distribution boxes, and optical distribution frames (ODFs), requiring a large number of fiber optic connectors to connect these devices via fiber optic cables for long-distance optical signal transmission. The increased number of fiber optic connectors leads to more nodes requiring maintenance in the fiber optic system, which in turn means more nodes prone to failure and a higher probability of damage to the optical communication link. Damage to the optical communication link can cause the MPI (Mean Differential Interference) effect.

[0068] Over time, the fiber optic end faces of fiber optic connectors inevitably become contaminated. At least one new transmission path will form between any two contaminated fiber end faces. As the number of contaminated fiber end faces accumulates, numerous new transmission paths will form within the fiber optic system. Optical signals transmitted along these new transmission paths constitute noise compared to optical signals transmitted along the main path (direct transmission without reflection), affecting signal quality; this phenomenon is known as the MPI effect.

[0069] Currently, OTDR technology is mainly used to measure the location of contaminated fiber optic end faces. By inputting a pulse signal (hereinafter referred to as the "transmit signal") into the fiber optic link, this pulse signal, when transmitted through the fiber, will reflect a portion of its energy when it passes through a fiber optic connector with strong reflection capabilities. This reflected signal (hereinafter referred to as the "reflected signal") can then be detected at the transmitting end. Since the connectors appear in different positions within the fiber optic link, OTDR technology can determine the distance of the abnormal reflection point relative to the transmitting end by measuring the time delay between the reflected signal and the transmitted signal at the transmitting end, thereby measuring the location of the abnormal (e.g., contaminated) fiber optic connector. However, this technology requires manual cleaning to reduce end face reflections and mitigate the MPI effect, resulting in high labor costs. Furthermore, the detection of anomalies requires interrupting ongoing optical communication services, making real-time MPI detection impossible.

[0070] III. Chirp Effect in Optical Communication Links

[0071] Chirp refers to the instantaneous frequency change of an optical pulse in the time domain. This change may be caused by the interaction between the optical pulse and the fiber medium during propagation (such as dispersion and nonlinear effects). Chirp can be linear (i.e., the frequency changes linearly with time) or nonlinear (i.e., the frequency changes nonlinearly with time). A wave whose instantaneous frequency changes with time is called a chirped wave. If, as the frequency increases with time, a low-frequency wave appears first and then a high-frequency wave appears, that is, the rising edge of the optical pulse is low-frequency and the falling edge is high-frequency, it is called positive chirp or upper chirp; conversely, if the rising edge of the optical pulse is high-frequency and the falling edge is low-frequency, it is called negative chirp or lower chirp.

[0072] The aforementioned optical communication link impairments can also cause chirp. Chirp refers to the phenomenon where the frequency of an optical signal changes over time. Chirp can occur in various situations. For example, in a directly modulated laser, changes in the injected current lead to changes in carrier concentration, which in turn affects the refractive index of the laser's active layer, causing the phase of the optical field to change over time, ultimately resulting in a change in the frequency of the optical signal. Chirp can be positive, for example, in the case of ultrashort pulses, where material dispersion can be used to control pulse compression and broadening. However, chirp can also be negative, especially in long-distance, high-speed optical fiber communication. When optical signals propagate through the fiber, the different group velocities of different frequencies cause changes in the shape of the information-carrying pulse, limiting the effective transmission distance of the pulse—a manifestation of chirp degradation.

[0073] Currently, chirp detection is mainly performed using instruments. For example, a network analyzer measures the frequency response curve of the optical signal before and after passing through a dispersive medium, as well as the position information of its resonant peak, to detect the chirp coefficient of the optical signal. The chirp coefficient is a parameter used to describe the chirp of a light source; it reflects the frequency change caused by modulation during the leading and trailing edges of the light pulse emitted by the optical transmitter. It includes the linewidth enhancement factor, adiabatic chirp parameters, etc. Alternatively, the chirp coefficient of an optical signal can be measured using dedicated and complex detection circuits. These methods require specialized instruments and circuits, which are not only costly but also cannot perform real-time chirp detection.

[0074] Furthermore, regarding the loss caused by damage to the optical communication link, methods based on optical power can be used to detect the optical power in the link. When the optical attenuation in the link is excessive, it can be roughly determined that the link is damaged, for example, there is a possibility that dirt on the connectors is causing excessive optical attenuation. The basis for this judgment is as follows:

[0075] 1. Optical power loss is commonly used to represent optical attenuation in an optical communication link. When the optical power loss is too large and exceeds the theoretical loss value, that is, when the actual optical power loss value under the condition of optical communication link damage / abnormality is greater than the expected theoretical line optical attenuation value, it can be roughly judged that there is damage to the optical communication link.

[0076] Figure 1 This is a network diagram of an optical power detection scheme. Figure 1 As shown, the optical power transmitted by the transmitting end (Tx) is represented by Tx. When the optical signal is transmitted in the link shown in the diagram, the normal connector loss is 0.25dBm. Therefore, the optical signal reaches the receiving end (Rx) after passing through two optical cross-connect boxes. The theoretical optical power received by the receiving end is expressed as Rx = Tx - 0.25 × 2, which means the expected theoretical line optical attenuation is 0.5dBm. If there is an anomaly in the link, or in other words, if the link is damaged, abnormal losses will occur, such as... Figure 1 The abnormal connector loss shown is 1.5dBm. Therefore, the optical power received by the receiving end is Rx = Tx - (1.5 + 0.25), which means the actual optical power loss is 1.75dBm, which is greater than the expected theoretical line optical attenuation value of 0.5dBm. Therefore, it can be roughly determined that there is damage to the optical communication link.

[0077] 2. The presence of damage to the optical communication link can also be determined by comparing the uplink and downlink optical power loss values. A significant difference between the uplink and downlink loss values ​​suggests that the optical communication link is likely damaged.

[0078] However, the calculation of theoretical line optical attenuation values ​​is prone to significant errors because optical communication links are affected by numerous factors, including environmental factors, during actual operation. This leads to deviations in the theoretical line optical attenuation values, resulting in inaccurate detection of link damage. Furthermore, when damage to the optical communication link causes the MPI effect but the optical power is normal, it is impossible to determine if multipath interference is present, still requiring manual link inspection, which is costly.

[0079] Therefore, how to detect damage in optical communication links in a low-cost manner is a technical problem that urgently needs to be solved.

[0080] In view of this, this application provides a method and apparatus for detecting optical communication links, which can detect damage in optical communication links in a low-cost manner.

[0081] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0082] Figure 2This is a schematic diagram of an optical communication scenario applicable to embodiments of this application. With the development of communication technology, base station architecture has evolved from distributed radio access network (DRAN) to centralized radio access network (CRAN). Figure 2 This illustrates a fronthaul link scenario in CRAN networking mode. The fronthaul link primarily refers to the connection between the AAU and BBU, such as... Figure 2 As shown, the AAU may include an optical module, which is an outdoor radio frequency module that transmits communication signals; the BBU may also include an optical module, located in a central office (CO), which is located inside a building. The optical module consists of optoelectronic devices, functional circuits, etc., and is used for photoelectric conversion in the fiber optic communication system. The optoelectronic devices of the optical module include transmitting and receiving parts. The transmitting end (Tx) converts the electrical signal to be transmitted into a suitable optical signal and sends it to the fiber optic link. The receiving end (Rx) then converts the received optical signal back into an electrical signal and outputs it to the receiving equipment, thereby achieving the purpose of data information transmission. Multiple base stations with radio frequency modules can be connected to the central office via lead-in cables through optical distribution boxes and trunk optical cables. To achieve efficient data transmission between the AAU and BBU, the AAU and BBU are connected by optical fibers. Any path of this connection is an optical communication link (or "fiber optic link"). The optical distribution boxes and other devices (not shown in the figure) included in the optical communication link can be connected by fiber optic connectors / fiber optic splices (not shown in the figure). In this application, AAU can... Figure 2 The optical communication link sends optical signals to the BBU, and the BBU can also transmit signals via optical communication links. Figure 2 The optical communication link sends optical signals to the AAU, and both the AAU and BBU can act as receiving devices to receive the optical signals.

[0083] It should be noted that the above optical communication scenarios are merely examples. It is understood that this application is applicable not only to the above-mentioned fronthaul link optical communication scenarios, but also to other optical communication scenarios, and this application does not limit them.

[0084] Figure 3 A schematic flowchart of the optical communication link detection method 300 provided in this application. Figure 3 The method shown can be performed by the transmitting and receiving devices, or by modules and / or devices (e.g., chips or integrated circuits) with corresponding functions installed in the transmitting and receiving devices, without limitation. The following description uses the transmitting and receiving devices as examples. Figure 3 As shown, the method includes:

[0085] S310, the transmitting device sends a first optical signal to the receiving device, and correspondingly, the receiving device receives the first optical signal from the transmitting device.

[0086] In one implementation, the transmitting device modulates information onto a first optical signal, which is then transmitted to a receiving device via an optical communication link. Correspondingly, the receiving device receives the first optical signal from the transmitting device via the optical communication link. In other words, the optical communication link is used to transmit the first optical signal.

[0087] For example, the transmitting device converts information into an electrical signal, then performs electro-optical conversion to obtain a first optical signal, and finally transmits the first optical signal through a first communication link.

[0088] S320, The receiving device performs photoelectric conversion on the first optical signal to obtain the first electrical signal.

[0089] The first electrical signal corresponds to a first level distribution, which includes a highest level distribution and a lowest level distribution.

[0090] Specifically, after receiving the first optical signal, the receiving device can convert it into a first electrical signal through photoelectric conversion. The first electrical signal carries the information modulated into the first optical signal by the transmitting device. By sampling and measuring the first electrical signal in real time, the level of each sampling point or time point is recorded. The distribution formed by these recorded levels is the first level distribution, which includes multiple levels.

[0091] In one approach, the receiving device can perform multiple measurements on the first electrical signal to obtain multiple first level distributions corresponding to the first electrical signal, thereby obtaining multiple highest level distributions and multiple lowest level distributions.

[0092] It is understandable that, due to limitations in the accuracy of the measuring tool and minor changes in the environment during the measurement of the first electrical signal, the result of a single measurement cannot completely and accurately reflect the level distribution of the first electrical signal. Therefore, in order to obtain a more accurate level distribution of the first electrical signal, the first electrical signal can be measured multiple times to reduce random errors and improve the confidence of the measurement results.

[0093] In multilevel modulation, the electrical signal is divided into multiple different amplitude levels, called levels. Each level represents a specific amplitude value that the signal can take. Among these levels, the highest level has the largest amplitude, while the lowest level has the smallest amplitude. The highest level distribution and the lowest level distribution refer to the amplitude distribution of data points corresponding to the theoretical highest and lowest levels in the actual received electrical signal, respectively. These distributions reflect amplitude fluctuations in the electrical signal caused by factors such as noise and interference.

[0094] Taking PAM-4 modulation and demodulation format as an example, the first electrical signal can be a PAM-4 signal. PAM-4 modulation maps the input digital signal (e.g., a binary bit stream) to four PAM-4 levels. Each symbol period can represent 2 bits of logical information (e.g., 00, 01, 10, 11). For example, these four levels can be represented as -3, -1, +1, and +3 (the unit can be volts or other suitable electrical units), corresponding to the four binary combinations 00, 01, 10, and 11, respectively. The +3 level is the highest level, and the -3 level is the lowest level. Corresponding pulse signals are generated based on the mapped symbols. These pulse signals have a fixed width in time (i.e., the symbol period), but the amplitude of the pulse signals depends on the mapped level values.

[0095] Understandably, in signal processing and data communication, although each level is defined as a precise theoretical value during modulation, the actual electrical signal level received by the receiving device will fluctuate around these theoretical values ​​due to factors such as channel noise and system nonlinearity. Therefore, in the first received electrical signal, the data points corresponding to the highest level (e.g., +3 level) will form a level distribution that fluctuates around this theoretical value, i.e., the highest level distribution; similarly, the data points corresponding to the lowest level (e.g., -3 level) will also form a similar distribution, i.e., the lowest level distribution.

[0096] S330. Based on the parameters of the first electrical signal, determine the information of the optical communication link, which is used to transmit the first optical signal; the parameters of the first electrical signal include at least one of the following: a comparison value of the highest level distribution and the lowest level distribution of the first electrical signal, and the frequency response curve characteristics of the first electrical signal; the information of the optical communication link includes at least one of the following: the intensity of multipath interference (MPI) noise, and the chirp coefficient; wherein, the intensity of the MPI noise is used to measure the magnitude of the influence of the MPI effect on the optical communication link, and the chirp coefficient is used to measure the magnitude of the influence of the chirp effect on the optical communication link.

[0097] The frequency response curve characteristics of the first electrical signal include at least one of the following: the curve characteristics of the frequency response curve of the first electrical signal itself, and the curve characteristics of the frequency response curve of the equalizer compensating for the first electrical signal.

[0098] In one approach, determining information about the optical communication link based on parameters of the first electrical signal includes: determining the intensity of MPI noise based on a comparison of the highest and lowest level distributions of the first electrical signal; and / or determining the chirp coefficient based on the frequency response curve characteristics of the first electrical signal.

[0099] In one approach, determining the intensity of MPI noise based on a comparison value of the highest and lowest level distributions of a first electrical signal includes: acquiring a first correspondence, the first correspondence including a correspondence between multiple comparison values ​​of the highest and lowest level distributions and the intensity of multiple MPI noises; and determining the intensity of multipath interference MPI noise corresponding to the comparison value of the highest and lowest level distributions of the first electrical signal based on the first correspondence, wherein the multiple comparison values ​​of the highest and lowest level distributions include the comparison value of the highest and lowest level distributions of the first electrical signal.

[0100] In one approach, the first correspondence is obtained based on simulations performed by an optical communication link simulation system used to simulate the MPI effect in an optical communication link.

[0101] The principle of determining the intensity of MPI noise by comparing the highest and lowest level distributions is given below.

[0102] First, a basic mathematical model of MPI is given. The electric field of the light signal emitted by the laser can be expressed by the following formula:

[0103]

[0104] Where ω0 is the center frequency of the optical carrier; It is laser phase noise; P sig (t) represents the luminous power, which includes amplitude modulation information. Amplitude modulation is a modulation technique that converts the amplitude variation of a modulating signal into the amplitude variation of a carrier signal, thereby achieving signal transmission. The modulating signal is the original signal carrying information, such as the first electrical signal mentioned above; the carrier signal is a high-frequency signal that does not carry information itself but is used to carry the information of the modulating signal during the modulation process. This carrier signal is usually a sine wave or a cosine wave, and the amplitude of the carrier signal changes according to the variation of the modulating signal.

[0105] The electric field of the optical signal after being affected by the MPI effect can be expressed by the following formula:

[0106]

[0107] Where, τ ijLet N represent the time delay of the reflection path formed by the i-th and j-th reflection points relative to the original signal, where N is the total number of reflection points. It can be seen that after the MPI effect, the electric field of the optical signal gains a term after the plus sign. Therefore, the value calculated from this latter term can be used to represent the intensity of the MPI noise, i.e., the magnitude of the MPI effect's influence on the optical signal. After detection by an intensity modulation and direct detection (IMDD) system, the current is expressed by the following formula:

[0108]

[0109] Where n(t) is white noise including receiver thermal noise, R i and R j These are the reflectivities of the i-th and j-th connectors, respectively. Since the proportion of higher-order terms greater than the second reflection is very small, they can be ignored. From the above equation (3), it can be seen that the intensity of MPI noise is proportional to the signal amplitude, expressed by the following formula:

[0110]

[0111] It is evident that the larger the level amplitude, the greater the intensity of the generated MPI noise. The change in level amplitude can be characterized by statistical analysis of the standard deviation / variance of the highest and lowest level distributions. Since the intensity of MPI noise varies with the degree of polarization alignment, this application uses simulation modeling to establish the correlation between the intensity of MPI noise and the comparison values ​​of the highest and lowest level distributions, thereby obtaining a feature relation library. This feature relation library is used to store the correspondence between the intensity of MPI noise and the comparison values ​​of the highest and lowest level distributions, so that subsequent receiving equipment can determine the intensity of the corresponding MPI noise based on the comparison values ​​of the highest and lowest level distributions.

[0112] In one possible approach, the comparison value between the highest level distribution and the lowest level distribution includes at least one of the following: the difference between the standard deviation of the highest level distribution and the standard deviation of the lowest level distribution, the ratio of the standard deviation of the highest level distribution to the standard deviation of the lowest level distribution, the difference between the variance of the highest level distribution and the variance of the lowest level distribution, and the ratio of the variance of the highest level distribution to the variance of the lowest level distribution.

[0113] It should be noted that the comparison value between the highest and lowest level distributions involved in this application refers to a value obtained by comparing the highest and lowest level distributions. This comparison value can be characterized by any of the values ​​listed above (e.g., standard deviation, difference / ratio, etc.). In other words, the comparison value between the highest and lowest level distributions in this application can be any of the values ​​listed above, or it can be the difference / ratio obtained by other calculations of the highest and lowest level distributions. The calculation methods are not limited to the standard deviation calculation and variance calculation mentioned above. Furthermore, the comparison value is not limited to the difference / ratio; it can also be other forms of value, such as the difference / ratio multiplied by a coefficient, or the difference / ratio raised to a power, etc., without limitation.

[0114] The following section details the construction of an optical communication link simulation system and the detection and quantification of the intensity of MPI noise in the optical communication link. It should be noted that quantifying the intensity of MPI noise in the optical communication link refers to using a quantity / value to measure the magnitude of the impact of the MPI effect on the optical communication link.

[0115] Step 1: Construct a signal transmission model through end-to-end simulation of the optical communication link to obtain the correspondence between the comparison values ​​of multiple highest and lowest level distributions and the intensity of multiple MPI noises. This system is called the optical communication link simulation system, which can simulate the MPI effect in the optical communication link. The correspondence between the comparison values ​​of multiple highest and lowest level distributions and the intensity of multiple MPI noises is an example of the first correspondence.

[0116] It should be noted that the first correspondence can be obtained through simulation by the receiving device's own simulation system, or it can be obtained by another device and sent to the receiving device. This application does not limit this.

[0117] The optical communication link simulation system covers as many parameters and devices involved in the optical communication link as possible.

[0118] Figure 4 This is a schematic diagram of the structure of an optical communication link simulation system. Figure 4 The optical communication link in the example is the wireless CRAN / DRAN fronthaul optical communication link, such as... Figure 4 As shown, the components included in this optical communication link simulation system and their corresponding main functions are as follows:

[0119] 1. Sequence Generation Module: Primarily used to generate pseudo-random binary sequences (PRBS) and custom sequences. In wireless communication systems, PRBS can be used to simulate and test the impact of MPI effects on signal transmission.

[0120] 2. Tx Optical Digital Signal Processor (oDSP): The transmitting end of the oDSP chip is part of the optical module and is mainly responsible for digital signal processing of electrical signals before optical signal transmission. It optimizes signal quality through encoding, modulation, filtering, and equalization, ensuring efficient, stable, and reliable signal transmission. In optical communication system simulation, the generated PRBS series can be Gray encoded and PAM-4 modulated. Gray encoding is a binary encoding method where adjacent values ​​differ by only one bit.

[0121] 3. Digital-to-analog converter (DAC): Primarily used to convert digital signals into analog signals. This converter can convert digital signals modulated by Tx oDSP into analog signals for transmission and processing. The quantization bit depth, sampling rate, and band-limiting effect in a DAC play important roles in signal transmission.

[0122] The quantization bit depth determines the resolution of a DAC, which is the smallest analog signal the DAC can distinguish. A higher quantization bit depth allows the DAC to generate more analog values, resulting in higher precision. Quantization bit depth is typically expressed in bits, such as 8-bit or 12-bit. In a DAC, quantization is the process of mapping discrete values ​​in a digital signal to continuous values ​​in an analog signal. The quantization bit depth determines the fineness of this mapping. For example, an 8-bit DAC can generate 8... 2 = 256 different analog levels.

[0123] The sampling rate refers to the sampling frequency of the digital signal input to a DAC, specifically the number of samples per second (SPS). The sampling rate determines the bandwidth that the DAC can process and the degree of distortion in the output signal. In digital signal processing, sampling is the process of converting a continuous-time signal into a discrete-time signal. A higher sampling rate means more data points are collected within the same time period, thus enabling a more accurate reconstruction of the original signal.

[0124] Band-limiting effect refers to the effect of bandwidth limitation on DAC during conversion, which causes attenuation or distortion of the output signal in the high-frequency range.

[0125] 4. Resampling module: It can be used to upsample and filter the analog signal obtained by DAC conversion.

[0126] 5. Driver: A driver provides the required output voltage. It also features gain adjustment to regulate the amplitude of the output signal. Furthermore, it can handle the peak-to-average power ratio (PAPR), which is the ratio of the signal's peak power to its average power and is an important indicator of signal fluctuation.

[0127] 6. Laser: It can be a directly modulated laser (DML), which modulates the phase and amplitude of the laser by directly injecting current. It can also be a Mach-Zehnder modulator (MZM), an external modulation technique that modulates the phase of the light signals on two waveguides by changing the refractive index of one of the two waveguides, causing the light signals on the two lines to have different phases at the intersection point. The laser can be used to set the laser wavelength, output power, extinction ratio, relative intensity noise (RIN), linewidth, chirp factor, and bias point. The extinction ratio is the ratio of the light power emitted when the laser emits all "1"s to the light power emitted when it emits all "0"s; RIN is the power noise normalized to average power, an important form of laser noise; the linewidth of the laser refers to the width of its output spectrum, usually expressed as frequency or wavelength; and the bias point is the set value of the drive current or voltage when the laser is operating normally.

[0128] For details on determining the chirp coefficient, please refer to the following explanation.

[0129] 7. Optical Link: Used to simulate and set the fiber length, information of multiple connectors (such as the location information of multiple connectors, the reflectivity of multiple connectors, insertion loss information), received optical power, and dispersion in an optical communication link. Among them, insertion loss is used to evaluate the optical power loss caused by the intervention of optical devices or fiber segments in the optical communication link, and dispersion is used to describe the dispersion phenomenon of optical signals during transmission due to the different transmission speeds or time delays of light of different frequencies or wavelengths.

[0130] 8. Photoelectric Converter: It contains a photodetector (PD), primarily used to convert light signals into electrical signals. It also contains an avalanche photodiode (APD), which utilizes the avalanche effect in semiconductors to enhance photoelectric conversion. It can be used to set responsivity, thermal noise / shot noise, and dark current. Responsivity is a physical quantity describing the photoelectric conversion capability of a photoelectric converter (such as a photodiode), reflecting the efficiency of the photoelectric converter in converting light signals into electrical signals. Thermal noise is caused by the thermal vibration of electrons in a conductor and exists in all electronic devices and transmission media. Thermal noise is also called resistive noise or Johnson noise, and its cause is the random thermal motion of electrons. Shot noise (also known as bullet noise) is caused by the photocurrent being a randomly generated current with irregular fluctuations in magnitude. These fluctuations are due to the random generation and recombination of photoelectrons and holes. Dark current refers to the current flowing in a photodetector (such as a solar cell, photodiode, etc.) in the absence of light illumination. It mainly consists of leakage current formed by defects on the surface of the crystal material and intrinsic dark current formed by thermal diffusion of charge carriers.

[0131] 9. Trans-impedance amplifier (TIA): Primarily used to convert weak current signals generated by photodetectors (such as photodiodes) into voltage signals. It can be used to set transimpedance values ​​and address band-limiting effects.

[0132] 10. Analog-to-digital converter (ADC): Primarily used to convert analog signals into digital signals. It can be used to set the quantization bits, sampling rate, and band-limiting effect.

[0133] 11. Filtering + Resampling Module: This module may include an anti-aliasing filter, used to remove or attenuate high-frequency information exceeding the sampling frequency before the analog signal is sampled, thus preventing aliasing. It may also include high-pass / low-pass / band-pass filters. This module can perform signal downsampling and signal synchronization.

[0134] 12. Rx oDSP: It includes a feed-forward equalizer (FFE), an equalization technique used at the receiver to compensate for channel loss. It can also calculate the bit error rate (BER), maximum likelihood sequence estimation (MLSE), signal-to-noise ratio (SNR), and spectrum of the received signal. BER, MLSE, SNR, and spectrum can all be used to evaluate the performance of optical communication systems. It can also be used to obtain the level distribution of electrical signals, demodulate them, and perform calculations such as standard deviation / variance.

[0135] In this optical communication link simulation system, key components may include an oDSP chip, a laser, and an optical link. The oDSP chip can be used for signal processing such as level distribution calculation, the laser can be used to set the chirp coefficient, and the optical link can be used to set the information of multiple connectors existing in the optical communication link.

[0136] Specifically, different MPI noise intensity values ​​are set in the optical communication link simulation system. After simulation by the optical communication link simulation system, the level distribution corresponding to the intensity value of the MPI noise is obtained at the receiving end. Since the MPI effect is caused by the superposition of signals from multiple reflection paths onto the signal of the main path, the intensity of MPI noise is the intensity of the superimposed signal minus the intensity of the original signal, that is, the term after the plus sign in formula (2). As can be seen from the formula, the intensity of MPI noise can be determined according to the distance between reflection points, the reflectivity of the connector, and the insertion loss information. The distance between reflection points will affect the time delay of the reflection path formed by the i-th reflection point and the j-th reflection point relative to the original signal.

[0137] Therefore, in order to set different MPI noise intensities, the optical communication link simulation system sets different MPI noise intensities by setting different location information, reflectivity information, and insertion loss information of multiple reflection points in each simulation.

[0138] In each simulation, the simulation system sets different location, reflectivity, and insertion loss information for multiple reflection points. Combining this with the inherent loss coefficient of the optical fiber and the propagation speed of the optical signal, the 3*N matrix used for the location, reflectivity, and insertion loss information of multiple reflection points is transformed into a 5*N(N-1) / 2 matrix. For the 3*N matrix, the three rows represent the reflection point location, reflectivity, and insertion loss, respectively, and the N columns represent the N reflection points. For the 5*N(N-1) / 2 matrix, the five rows represent the distance between reflection points, the connector number between two reflection points, the secondary reflection coefficient under a single reflection path, and the corresponding time delay information superimposed on the main signal. Each column represents the reflected signal carried on a reflection path. The reflection points mentioned above can be understood as reflection connectors in an optical communication link.

[0139] Figure 5 This diagram illustrates an optical communication link and the MPI effect within it. Figure 5 As shown, this optical communication link is an actual optical fiber transmission link, including optical fibers, connectors, etc. Optical signals can be transmitted through a transmitting device and received through a receiving device. This link includes six reflection points, as shown in points 1 to 6. A new reflection path is formed between any two reflection points; that is, a new transmission path is formed after the signal is reflected by the two reflection points. For example, for reflection points 1 and 2, when the signal reaches reflection point 2, it cannot directly pass through transmitting point 1. Instead, it is reflected by reflection point 1, reaches reflection point 2, is reflected again by reflection point 2, and finally passes through reflection point 1 for transmission. The new path formed after reflection is R. 21 In other words, the signal can only be transmitted through reflection point 1 after being reflected twice, at reflection point 1 and reflection point 2.

[0140] Understandable, Figure 5 The diagram shows the reflection paths of all signals after reflection at the six reflection points, and the R value of each reflection path. ij Let R represent the multipath interference signal (hereinafter referred to as the reflected signal) between the i-th emission point and the j-th reflection point, for example, R. 21 R represents the reflected signal between reflection point 1 and reflection point 2. 32 This represents the reflected signal between reflection point 3 and reflection point 2. Therefore, as... Figure 5 As shown, there are a total of 15 reflected signals. Each reflected signal can be regarded as each column of a 5*N(N-1) / 2 matrix. The 5 rows of data in each column (i.e., the distance information between the reflection points, the serial number information of the two reflection points, the secondary reflection coefficient under a single reflection path, and the time delay information superimposed on the main signal) represent the information of each reflected signal.

[0141] In addition, from Figure 5The image also shows a service signal that is transmitted directly to the receiving device via a straight path without any reflection. This service signal can be an example of the main signal transmitted on the main path described in this application. The reflected signals from the 15 reflection paths are superimposed on this service signal. These 15 reflected signals are noise to the service signal, i.e., MPI noise. The receiving device receives the signal superimposed with the 15 reflected signals and analyzes it.

[0142] Finally, the simulation system superimposes the reflected signals from each column of a 5*N(N-1) / 2 matrix onto the corresponding main signal. After subsequent photoelectric conversion and signal processing, the level distribution is obtained. The system calculates and records the comparison value between the highest and lowest level distributions in each simulation. The intensity of the MPI noise in each simulation can be determined based on the position information, reflectivity information, and insertion loss information of multiple reflection points set during each simulation. Therefore, each simulation yields a correspondence between the intensity of an MPI noise and the comparison value between the highest and lowest level distributions. After multiple simulations, the correspondence between the intensity of multiple MPI noises and the comparison values ​​between multiple highest and lowest level distributions can be obtained. This correspondence can be presented in the form of a correspondence feature map (e.g., ...). Figure 6 (As shown).

[0143] The following example illustrates the comparison between the highest and lowest level distributions using the ratio of the difference in standard deviations between the highest and lowest level distributions to the standard deviations of the highest and lowest level distributions.

[0144] Figure 6 This diagram illustrates the difference / ratio of the standard deviations of the highest and lowest level distributions under different MPI noise intensities. As shown above, the intensity of MPI noise is determined based on the position information, reflectivity information, and insertion loss information of multiple reflection points. Therefore, different MPI noise intensities can be obtained by setting different position information, reflectivity information, and insertion loss information for each simulation. Since each simulation yields the signal level distribution, the difference between the standard deviations of the highest and lowest level distributions can be calculated and recorded to obtain the correspondence between the standard deviation difference of the highest and lowest level distributions and the MPI noise intensity; alternatively, the ratio of the standard deviations of the highest and lowest level distributions can be calculated and recorded to obtain the correspondence between the standard deviation ratio of the highest and lowest level distributions and the MPI noise intensity. Figure 6 As shown, the intensity range of MPI noise is -25dB to -45dB. Figure 6 Figure (a) shows the graphs showing the relationship between the intensity of multiple MPI noises and the standard deviation differences of multiple highest and lowest level distributions obtained after multiple simulations. Figure 6Figure (b) shows the graph showing the relationship between the intensity of multiple MPI noises and the ratio of the standard deviations of multiple highest and lowest level distributions obtained after multiple simulations.

[0145] The calculated and recorded standard deviation differences between multiple highest and lowest level distributions, along with the corresponding intensities of multiple MPI noises, and the ratios of the standard deviations of multiple highest and lowest level distributions to the corresponding intensities of multiple MPI noises, can also be stored in a feature parameter library. This feature parameter library is built upon a simulation system of the optical communication link. It is constructed by the simulation system forward-deriving the standard deviation differences / ratios of the highest and lowest level distributions based on the set MPI noise intensities, and then combining this with multiple real-world training and corrections.

[0146] Figure 6 Taking PAM-4 modulated signals as an example, σ4 represents the standard deviation of the highest level distribution, and σ1 represents the standard deviation of the lowest level distribution. The standard deviation of the highest level distribution reflects the dispersion of the signal amplitude value received at the highest level, and the standard deviation of the lowest level distribution reflects the dispersion of the signal amplitude value received at the lowest level. Figure 6 The data points in (a) are the standard deviation differences between the highest and lowest level distributions obtained from multiple measurements and calculations of the first electrical signal during each simulation. Figure 6 The data points in (b) represent the ratios of the standard deviations of the highest and lowest level distributions obtained from multiple measurements and calculations of the first electrical signal during each simulation. Each data point corresponds to multiple measurements and calculations. During each simulation, the data points are... Figure 6 Data points in (a) / Figure 6 By averaging the multiple data points in (b) in the diagram, we can obtain the result. Figure 6 (a) / Figure 6 The average value in (b) of the data.

[0147] It should be noted that the correspondence between the comparison values ​​of the highest and lowest level distributions and the intensity of MPI noise can be represented by a curve feature graph (e.g., Figure 7 The data can be stored in the form of a table, or in a table format. For example, the comparison values ​​of the highest and lowest level distributions obtained from each simulation and their corresponding MPI noise intensity can be recorded in a table. Alternatively, the data can be stored in the form of a database (e.g., a feature parameter library). This application does not limit the storage of the data in this way.

[0148] It should also be noted that the -25dB to -45dB range mentioned above is only an example of the MPI noise intensity range. The MPI noise intensity range can also be other ranges, depending on the actual optical communication link, and is not limited thereto. Furthermore, the MPI noise intensity within the 25dB to -45dB range, as an example, reflects both normal and abnormal conditions of the optical communication link. For instance, when the MPI noise intensity is in the range of -25dB to -30dB, the optical communication link can be determined to be abnormal; when the MPI noise intensity is in the range of -30dB to -45dB, the optical communication link can be determined to be normal. In other words, the MPI noise intensity can be used to determine whether the optical communication link is abnormal (or whether there is damage), so as to determine whether the optical communication link needs to be repaired / optimized.

[0149] Step 2: The receiving device detects the first electrical signal to obtain the first level distribution corresponding to the first electrical signal. The first level distribution includes the highest level distribution and the lowest level distribution. Based on the correspondence between the comparison values ​​of the multiple highest and lowest level distributions obtained in Step 1 and the intensity of multiple MPI noises, the intensity of the MPI noise corresponding to the comparison values ​​of the highest and lowest level distributions of the first electrical signal is determined. The multiple comparison values ​​of the highest and lowest level distributions include the comparison values ​​of the highest and lowest level distributions of the first electrical signal.

[0150] In one approach, the receiving device performs multiple measurements on the first electrical signal to obtain multiple first level distributions corresponding to the first electrical signal, i.e., multiple highest level distributions and multiple lowest level distributions, meaning there is a one-to-one correspondence between the multiple measurements and the multiple highest and lowest level distributions. For each measurement, the standard deviation difference / ratio of the corresponding highest and lowest level distributions is calculated. This process is repeated multiple times to obtain the standard deviation difference / ratio of the multiple highest and lowest level distributions. These standard deviation differences / ratios are then averaged to obtain a homogenized standard deviation difference / ratio. This homogenized standard deviation difference / ratio is then compared with the standard deviation differences / ratios of the highest and lowest level distributions stored in the feature parameter library from step one to determine the intensity of the MPI noise corresponding to the homogenized standard deviation difference / ratio. This homogenized standard deviation difference / ratio is one example of a comparison value between the highest and lowest level distributions of the first electrical signal.

[0151] In one approach, the oDSP chip in the optical module collects histogram statistics of a predefined length data stream, which represents a first electrical signal. The amplitude value of each data point in the data stream is assigned to different intervals, each interval corresponding to a voltage level. When the first electrical signal is a PAM-4 signal, four voltage levels correspond to four intervals. The histogram statistics include multiple data points in the interval corresponding to the highest voltage level and multiple data points in the interval corresponding to the lowest voltage level. Based on these histogram statistics, the highest and lowest voltage level distributions of the first electrical signal can be obtained, and the standard deviations of the highest and lowest voltage level distributions can be calculated. The difference / ratio of the standard deviations of the highest and lowest voltage level distributions is calculated in the oDSP chip or the host computer. This difference / ratio is then stored in a register and reported, or directly compared in the host computer with the difference / ratio of the standard deviations of the highest and lowest voltage level distributions stored in a feature parameter library, and the corresponding MPI noise intensity is returned.

[0152] In one approach, the data stream is sampled for a predefined length using an oDSP chip within the optical module. The aforementioned simulations and calculations can be directly inherited from the microcontroller unit (MCU) chip within the optical module. For example, the feature parameter library mentioned above can also be trained using the MCU chip within the optical module. Furthermore, the calculation of the standard deviation difference / ratio of the highest and lowest level distributions, the averaging of the standard deviation differences / ratios of multiple highest and lowest level distributions, and the comparison of the standard deviation differences / ratios with the feature parameter library to obtain the intensity of the MPI noise corresponding to the standard deviation difference / ratio can also be implemented using the MCU chip within the optical module.

[0153] In the above scheme, the method of comparing the comparison values ​​of the highest and lowest level distributions with the feature parameter library, that is, based on the correspondence between the comparison values ​​of the highest and lowest level distributions and the intensity of MPI noise, obtains the intensity of MPI noise corresponding to the comparison values ​​of the highest and lowest level distributions of the electrical signal. The intensity of this MPI noise is used to measure the magnitude of the impact of the MPI effect on the optical communication link. This not only allows for the real-time acquisition of the magnitude of the impact of the MPI effect on the optical communication link (i.e., the intensity of the MPI noise), but also enables the determination of whether the optical communication link is damaged and whether subsequent link repair is needed based on the intensity of the MPI noise. This does not require interruption of current services and does not require additional hardware devices for detection, resulting in low cost.

[0154] It should be noted that the above describes a method for correlating the comparison values ​​of the highest and lowest level distributions of the first electrical signal with the intensity of MPI noise. Since the intensity of MPI noise is related to the amplitude of the level, in addition to using the comparison values ​​of the highest and lowest level distributions to characterize the amplitude of the level, other levels of the first electrical signal can also be correlated with the intensity of MPI noise, such as correlating any two or more levels in PAM-4 modulation with the intensity of MPI noise, etc. This application does not limit this.

[0155] In one approach, determining the chirp coefficient based on the frequency response curve characteristics of a first electrical signal includes: obtaining a second correspondence, the second correspondence including a correspondence between multiple frequency response curve characteristics and multiple chirp coefficients; and determining the chirp coefficient corresponding to the frequency response curve characteristics of the first electrical signal based on the second correspondence, the multiple frequency response curve characteristics including the frequency response curve characteristics of the first electrical signal.

[0156] In one approach, the second correspondence is obtained based on simulations performed by an optical communication link simulation system, which is used to simulate the chirp effect in an optical communication link.

[0157] The principle of determining the chirp coefficient by utilizing the characteristics of the frequency response curve of an electrical signal is given below.

[0158] The effect of chirp on first optical communication can be expressed by the following equation (5):

[0159]

[0160] Where α is the linewidth enhancement factor (an example of the chirp coefficient), κ is the adiabatic chirp parameter, P(t) is the laser output power, and P bias This is the output power at the bias current. The first term before the plus sign in parentheses is called transient chirp, and the second term after the plus sign is called adiabatic chirp. In a system based on a directly modulated laser, the frequency response under the influence of chirp can be expressed by the following formula:

[0161]

[0162] Where γ=πDλ 2 / c, the first term before the plus sign is the frequency response caused by transient chirp, the second term after the plus sign is the frequency response caused by adiabatic chirp, f is the frequency, L is the transmission distance, I is the bias current, P is the laser output power, D is the fiber dispersion parameter, and c is the speed of light in vacuum.

[0163] Therefore, different chirp effects result in different frequency responses, and these different frequency responses are determined by different linewidth enhancement factors. Since the linewidth enhancement factor affects both transient and adiabatic chirp, it can be used to quantify the impact of chirp on the optical communication link; that is, the linewidth enhancement factor α can be used as the chirp coefficient. Chirp degradation can be defined as degradation of the linewidth enhancement factor.

[0164] The following section details the construction of an optical communication link simulation system, as well as the detection and quantification of chirp effects and chirp degradation in optical communication links. It should be noted that quantifying the chirp effect in an optical communication link refers to using a quantity / value to measure the magnitude of the chirp effect's impact on the optical communication link.

[0165] Step 1: Construct a mirror network of the optical communication link using the aforementioned end-to-end simulation system, obtaining the correspondence between multiple frequency response curve characteristics and multiple chirp coefficients. The optical communication link simulation system described in Step 1 can also simulate the chirp effect in the optical communication link. The correspondence between multiple frequency response curve characteristics and multiple chirp coefficients is an example of a second correspondence.

[0166] It should be noted that the second correspondence can be obtained through simulation by the receiving device's own simulation system, or it can be obtained by another device and sent to the receiving device. This application does not limit this.

[0167] Specifically, multiple sets of frequency response curves are obtained by setting multiple different chirp coefficients in the optical communication link simulation system. The curve features of the frequency response curve corresponding to each chirp coefficient (called "frequency response curve features") are identified and recorded. The correspondence between the frequency response curve features and the chirp coefficients is obtained. The frequency response curve features and the corresponding chirp coefficients are stored in the feature parameter library for subsequent detection.

[0168] In one approach, the frequency response curve features include at least one of the following: stationary point information of the frequency response curve, slope information between stationary points of the frequency response curve, degree of curvature of the frequency response curve, and location information of concave and convex points of the frequency response curve.

[0169] For example, the frequency response curve is characterized by its stationary point information. This requires the frequency response curve to contain at least one stationary point, which is a point where the derivative is 0. This establishes the correspondence between the stationary point information and the chirp coefficient. Whether a point is a possible stationary point can be determined by judging the magnitude of the frequency spectral density values ​​of points within a certain range before and after it. This certain range is determined by the sampling accuracy.

[0170] It should be noted that the multiple frequency response curve features represent the curve features of multiple frequency response curves, with each frequency response curve corresponding to an electrical signal. This does not refer to the multiple feature information included in the frequency response curve features. For example, the frequency response curve features of the first electrical signal may include the stationary point information of the frequency response curve and the slope information between the stationary points of the frequency response curve. In this case, the frequency response curve features of the first electrical signal corresponding to the chirp coefficient represent the stationary point information of the frequency response curve of the first electrical signal, the slope information between the stationary points of the frequency response curve, and the chirp coefficient.

[0171] The following example uses the linewidth enhancement factor α as the chirp coefficient.

[0172] Figure 7 These are the frequency response curves under different linewidth enhancement factors α (alpha). Figure 7 As shown in (a), there are two frequency response curves: one for the signal at the transmitting end (Tx) and the other for the signal at the receiving end (Rx) before FFE. It can be seen that when the linewidth enhancement factor α is 1, the frequency response curve of the received signal at Rx changes after the transmitted signal is affected by the chirp effect in the optical communication link. Similarly, Figure 7 Figure (b) shows the frequency response curve of the received signal for the same transmitted signal when the linewidth enhancement factor α is 2. Figure 7 As shown, the chirp effect affects the same transmitted signal differently under different linewidth enhancement factors α. Therefore, the linewidth enhancement factor α can be used as a chirp coefficient to measure the magnitude of the chirp effect on the optical communication link.

[0173] Furthermore, to reflect the frequency response curves under different linewidth enhancement factors α, stagnation point information can be used to represent the frequency response curve corresponding to α. For example, in Figure 7 In (a) of the diagram, the stationary point information of the frequency response curve corresponding to α = 1 includes the stationary point coordinates (x, y) = (15.918, -107.713). α = 1 and the corresponding (x, y) = (15.918, -107.713) can be stored in the feature parameter library. For example, in... Figure 7 In (b), the stationary point information of the frequency response curve corresponding to α=2 includes stationary point coordinates (x,y)=(13.2812,-109.304) and (x,y)=(22.5586,-105.18). α=2 and the corresponding (x,y)=(13.2812,-109.304) and (x,y)=(22.5586,-105.18) can be stored in the feature parameter library so that the corresponding linewidth enhancement factor α can be determined later based on the stationary point coordinates.

[0174] It should be noted that frequency response curve characteristics are not limited to the stagnation point information, slope information between stagnation points, degree of curvature, and location information of concave and convex points mentioned above. Any information used to reflect / describe / represent the frequency response curve can be called a frequency response curve characteristic. There are many frequency response curve characteristics used to describe the frequency response curve. In addition to the information listed above, frequency response curve characteristics can also include the gain of the frequency response curve, the bandwidth of the frequency response curve, etc. For the sake of brevity, they will not be listed one by one here.

[0175] Step 2: Receive the second optical signal and perform photoelectric conversion on it to obtain a second electrical signal. The first optical signal corresponds to a first time point, and the second optical signal corresponds to a second time point, which is after the first time point. Based on the frequency response curve characteristics of the second electrical signal and the first electrical signal, determine whether there is chirp degradation in the optical communication link. The optical communication link is also used to transmit the second optical signal. The first and second optical signals are the same optical signal transmitted by the transmitting device at different times.

[0176] The frequency response curve characteristics of the second electrical signal include at least one of the following: the curve characteristics of the frequency response curve of the second electrical signal itself, and the curve characteristics of the frequency response curve of the equalizer compensating for the second electrical signal.

[0177] It should be understood that when determining whether there is chirp degradation in the optical communication link based on the frequency response curve characteristics of the second electrical signal and the first electrical signal, the frequency response curve characteristics of the second electrical signal and the first electrical signal are the same type of frequency response curve characteristics. That is, the frequency response curve characteristics of the second electrical signal and the first electrical signal are both the curve characteristics of the frequency response curves of the first and second electrical signals themselves, or the frequency response curve characteristics of the second electrical signal and the first electrical signal are both the curve characteristics of the frequency response curves of the equalizer compensating for the first and second electrical signals.

[0178] In one approach, the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal is determined according to a second correspondence, wherein the multiple frequency response curve features include the frequency response curve feature of the second electrical signal; and the presence of chirp degradation in the optical communication link is determined based on the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal and the chirp coefficient corresponding to the frequency response curve feature of the first electrical signal.

[0179] The following example uses the characteristics of the frequency response curve as the coordinates of the stationary point.

[0180] For example, the transmitting device transmits a first optical signal and a second optical signal at two time points, respectively. Correspondingly, the receiving device receives the first optical signal and the second optical signal at two time points, respectively. The first optical signal and the second optical signal are the same optical signal transmitted by the transmitting device at different times. For ease of explanation, the first optical signal is transmitted at a first time point, and the second optical signal is transmitted at a second time point. Accordingly, the receiving device receives the first optical signal at the first time point and the second optical signal at the second time point, with the first time point preceding the second time point.

[0181] The receiving device can also perform photoelectric conversion on the first optical signal and the second optical signal respectively to obtain a first electrical signal corresponding to the first optical signal and a second electrical signal corresponding to the second optical signal; detect the first electrical signal and the second electrical signal respectively to obtain the frequency response curves of the first electrical signal and the second electrical signal, and the detection can be online detection; differentiate the frequency response curves of the first electrical signal and the second electrical signal respectively to obtain the stationary point coordinates of the first electrical signal and the second electrical signal, and determine whether there is chirp degradation in the optical communication link based on the stationary point coordinates of the first electrical signal and the second electrical signal.

[0182] For example, if the stationary point coordinates corresponding to the second electrical signal are closer to the center point than the stationary point coordinates corresponding to the first electrical signal, it can be determined that the optical communication link suffers from chirp degradation. Figure 7 As shown, Figure 7 If the signal in Rx in (a) is considered as the first electrical signal, then the coordinates of the stationary point corresponding to the first electrical signal are (x, y) = (15.918, -107.713). Figure 7 If the signal in Rx in (b) is considered as the second electrical signal, then the stationary point coordinates corresponding to the second electrical signal are (x,y)=(13.2812,-109.304). It can be seen that the stationary point coordinates corresponding to the second electrical signal are closer to the center than the stationary point coordinates corresponding to the first electrical signal, which can be used to determine that there is chirp degradation in the optical communication link.

[0183] In one approach, the receiving device determines the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal according to a second correspondence, wherein the multiple frequency response curve features include the frequency response curve feature of the second electrical signal; and determines whether there is chirp degradation in the optical communication link based on the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal and the chirp coefficient corresponding to the frequency response curve feature of the first electrical signal.

[0184] In one approach, when the chirp coefficient corresponding to the frequency response curve characteristics of the second electrical signal is greater than the chirp coefficient corresponding to the frequency response curve characteristics of the first electrical signal, the optical communication link suffers from chirp degradation.

[0185] In one approach, the receiving device determines a chirp degradation value based on the chirp coefficient corresponding to the frequency response curve characteristics of the second electrical signal and the chirp coefficient corresponding to the frequency response curve characteristics of the first signal. The chirp degradation value is used to measure the degree of chirp degradation.

[0186] For example, such as Figure 7 As shown in (a), when the stationary point coordinates of the first electrical signal are (x,y) = (15.918, -107.713) or the stationary point coordinates of the first electrical signal are within a certain range of coordinates (x,y) = (15.918, -107.713), then the linewidth enhancement factor α = 1 corresponding to the stationary point coordinates of the first electrical signal can be determined; for example, if the stationary point coordinates of the second electrical signal are (x,y) = (13.2812, -109.304) and (x,y) = ( (22.5586, -105.18) By comparing the stationary point coordinates of the second electrical signal, which is closer to the center, with the stationary point coordinates of the first electrical signal, if the stationary point coordinates of the second electrical signal are (x,y) = (13.2812, -109.304) or within a certain range of (x,y) = (13.2812, -109.304), then the linewidth enhancement factor α = 2 corresponding to the stationary point coordinates of the second electrical signal can be determined. Since α = 2 is greater than α = 1, it can be determined that there is chirp degradation in the optical communication link.

[0187] Furthermore, the linewidth enhancement factor α = 2 can be compared with the linewidth enhancement factor α = 1 to obtain a comparison value of the linewidth enhancement factor. For example, the difference between α = 2 and α = 1 can be used to measure the degree of chirp degradation. The linewidth enhancement factor difference of 1 is an example of a chirp degradation value.

[0188] It should be noted that the chirp degradation value can be the difference between chirp coefficients, the ratio of chirp coefficients, or other forms of comparison of chirp coefficients; this application does not limit it.

[0189] In one approach, the receiving device uses an oDSP chip to acquire a data stream of a predefined length, and performs a Fourier transform on the data stream using the oDSP chip or a host computer (e.g., a server / computer) to obtain the frequency response curve information corresponding to the data stream. The receiving device then reports this frequency response curve information using a register, for example, through an inter-integrated circuit (IIC) interface, or the host computer directly processes the frequency response curve information to obtain frequency response curve features. These features are then compared with frequency response curve features in a feature parameter library to obtain the chirp coefficient corresponding to the frequency response curve features of the data stream. The presence of chirp degradation is determined by comparing the chirp coefficients at different times. The predefined length data stream is a representation of either a first electrical signal or a second electrical signal.

[0190] For example, the frequency response curve obtained by performing a Fourier transform on the data stream using an oDSP chip or a host computer (e.g., a server / computer) can be as follows: Figure 8 The curve corresponding to the signal in Rx before FFE is shown in (b) of the diagram. Therefore, the frequency response curve features obtained by directly processing the frequency domain information using the host computer can be the stationary point coordinates (x,y) = (13.2812, -109.304) and (x,y) = (22.5586, -105.18). By comparing the stationary point coordinates stored in the feature parameter library, the chirp coefficient corresponding to the frequency response curve features of the data stream of the predefined length can be obtained, that is, the linewidth enhancement factor α = 2 corresponding to the stationary point coordinates.

[0191] The frequency response curve of the first or second electrical signal obtained in this way is characterized by the frequency response curve of the first or second electrical signal itself (e.g., ...). Figure 8 The curve characteristics of the frequency response curve shown are given. The first or second electrical signal is the original electrical signal (which can be understood as an electrical signal without any processing). Therefore, this application can obtain the correspondence between the curve characteristics of the frequency response curve of the original first or second electrical signal and the chirp coefficient.

[0192] In one approach, the receiving device uses an oDSP chip to acquire a data stream of a predefined length. Utilizing the oDSP chip's adaptive equalization function, which fills in the bumps and dips in the frequency response curve of the electrical signal, this data stream is input directly to the equalizer's frequency response curve (or "equalization compensation curve"). The device then reports this frequency response curve information using a register, for example, via an inter-integrated circuit (IIC) interface, or by having a host computer directly process the equalizer's frequency response curve information to obtain frequency response curve characteristics. These characteristics are then compared with those in a feature parameter library to obtain the chirp coefficient corresponding to the data stream's frequency response curve characteristics. Comparing the chirp coefficients at different times determines whether chirp degradation exists. The equalizer's frequency response characteristics can be optimized by adjusting parameters (such as tap coefficients).

[0193] For example, the equalizer is a least mean square (LMS) equalizer. Figure 8 The graph shows the frequency response curves of the LMS equalizer under different chirp coefficients, where the chirp coefficient is the linewidth enhancement factor α. Figure 9 As shown, the curvature of the frequency response curves corresponding to different chirp coefficients varies. The frequency response curve of the LMS equalizer for a chirped signal exhibits a more pronounced curvature, with the convex portion closer to the center (i.e., the position corresponding to a normalized frequency of 0). For example, the frequency response curve corresponding to α=3 is more pronounced than that corresponding to α=2, with the convex portion closer to the center; similarly, the frequency response curve corresponding to α=2 is more pronounced than that corresponding to α=1, with the convex portion closer to the center; and again, the frequency response curve corresponding to α=1 is more pronounced than that corresponding to α=0, with the convex portion closer to the center. If α=0, α=1, α=2, and α=3 correspond to the frequency response curves obtained by the LMS equalizer from multiple electrical signals received by the receiving device through the optical communication link at different times, and these multiple electrical signals are obtained from multiple optical signals through photoelectric conversion, and these multiple optical signals are the same optical signal transmitted by the transmitting device at different times, then chirp degradation in the optical communication link can be determined by comparing the chirp coefficients at different times.

[0194] The frequency response curve of the first or second electrical signal obtained in this way is characterized by the frequency response curve of the first or second electrical signal compensated by the equalizer (e.g., Figure 9The curve characteristics of the frequency response curve shown are as follows: the first electrical signal or the second electrical signal is the original electrical signal (which can be understood as an electrical signal without any processing). The frequency response curve of the equalizer compensating for the first electrical signal or the second electrical signal can be understood as the frequency response curve of the equalizer obtained by inputting the first electrical signal or the second electrical signal into the equalizer. Therefore, this application can also obtain the correspondence between the curve characteristics of the frequency response curve of the equalizer compensating for the original first electrical signal or the second electrical signal and the chirp coefficient.

[0195] In one approach, the data stream is sampled for a predefined length using an oDSP chip within the optical module. The aforementioned data processing can be directly inherited by the microcontroller unit (MCU) chip within the optical module. The sampled and processed data is the frequency response curve of an electrical signal. For example, the feature parameter library mentioned above can also be trained using the MCU chip within the optical module. Furthermore, the frequency response curve of the first electrical signal obtained through processing, and the chirp coefficient corresponding to the frequency response curve features obtained by comparing the curve features of this frequency response curve with the feature parameter library, can also be implemented using the MCU chip within the optical module.

[0196] In the above scheme, the method of comparing the frequency response curve features with the feature parameter library, that is, obtaining the chirp coefficient corresponding to the frequency response curve features of the electrical signal based on the correspondence between the frequency response curve features and the chirp coefficient, is used to measure the impact of chirp effect on the optical communication link. Furthermore, the frequency response curve features or the chirp coefficient corresponding to the frequency response curve features at different times can be compared to determine whether there is chirp degradation in the optical communication link. This method can not only obtain the chirp changes in the optical communication link in real time without interrupting the current service, but also does not require additional hardware devices for detection, resulting in low cost.

[0197] The method embodiments of this application have been described above. The corresponding device embodiments will be described below.

[0198] In order to realize the functions of the communication devices (e.g., receiving devices, transmitting devices, etc.) in the embodiments of this application, each device can realize the corresponding functions through hardware structure, software module, or hardware structure plus software module.

[0199] Figure 11 This is a schematic block diagram of the optical communication link detection device 1000 provided in an embodiment of this application. Figure 11As shown, the device 1000 may include a transceiver unit 1010 and a processing unit 1020. The transceiver unit 1010 can communicate with the outside world, and the processing unit 1020 is used for data processing. The transceiver unit 1010 may also be referred to as a communication interface or transceiver unit. The processing unit 1020 can be used for processing.

[0200] Optionally, the device 1000 may further include a storage unit, which can be used to store instructions and / or data, and the processing unit 1020 can read the instructions and / or data in the storage unit to enable the device to implement the aforementioned method embodiments.

[0201] For example, the device 1000 is a receiving device, which may be an AAU or a BBU, or it may be a device applied to or used in conjunction with the receiving device to implement the method executed by the receiving device, such as a chip, chip system, or circuit. See details below. Figure 10 The chip system shown is described in detail.

[0202] For example, the device 1000 is a transmitting device, which may be an AAU or a BBU, or it may be a device applied to or used in conjunction with a transmitting device to implement a method executed by the transmitting device, such as a chip, chip system, or circuit. See details below. Figure 10 The chip system shown is described in detail.

[0203] In one possible design, the device 1000 can implement the steps or processes corresponding to those performed by the receiving device in the above method embodiments, wherein the processing unit 1020 is used to perform processing-related operations of the receiving device in the above method embodiments, and the transceiver unit 1010 is used to perform transceiver-related operations of the first device in the above method embodiments.

[0204] For example, the transceiver unit 1010 is used to receive a first optical signal; the processing unit 1020 is used to determine the information of the optical communication link based on the parameters of the first electrical signal, the optical communication link being used to transmit the first optical signal; the parameters of the first electrical signal include at least one of the following: a comparison value of the highest level distribution and the lowest level distribution of the first electrical signal, and the frequency response curve characteristics of the first electrical signal; the information of the optical communication link includes at least one of the following: the intensity of multipath interference (MPI) noise, and the chirp coefficient; wherein, the intensity of the MPI noise is used to measure the magnitude of the influence of the MPI effect on the optical communication link, and the chirp coefficient is used to measure the magnitude of the influence of the chirp effect on the optical communication link.

[0205] In another possible design, the device 1000 can implement the steps or processes corresponding to those performed by the transmitting device in the above method embodiments, wherein the transceiver unit 1010 is used to perform the transceiver-related operations of the transmitting device in the above method embodiments, and the processing unit 1020 is used to perform the processing-related operations of the transmitting device in the above method embodiments.

[0206] For example, the transceiver unit 1010 is used to transmit a first optical signal.

[0207] It should be understood that the device 1000 here is embodied in the form of a functional unit. The term "unit" here can refer to an application-specific integrated circuit (ASIC), electronic circuitry, a processor (e.g., a shared processor, a proprietary processor, or a group processor, etc.) and memory for executing one or more software or firmware programs, integrated logic circuitry, and / or other suitable components supporting the described functions. In an alternative example, those skilled in the art will understand that the device 1000 may specifically be the transmitting end in the above embodiments, used to execute the various processes and / or steps corresponding to the transmitting end in the above method embodiments; or, the device 1000 may specifically be the receiving end in the above embodiments, used to execute the various processes and / or steps corresponding to the receiving end in the above method embodiments. To avoid repetition, further details are omitted here.

[0208] The apparatus 1000 of each of the above-described schemes has the function of implementing the corresponding steps performed by the transmitting end in the above-described method, or the apparatus 1000 of each of the above-described schemes has the function of implementing the corresponding steps performed by the receiving end in the above-described method. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions; for example, the transceiver unit can be replaced by a transceiver (e.g., the transmitting unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiver), and other units, such as processing units, can be replaced by processors, respectively executing the transceiver operations and related processing operations in each method embodiment.

[0209] Furthermore, the aforementioned transceiver unit can also be a transceiver circuit (e.g., it may include a receiving circuit and a transmitting circuit), and the processing unit can be a processing circuit. In embodiments of this application, the aforementioned optical communication link detection device can be the receiving device or transmitting device in the foregoing embodiments, or it can be a chip or a chip system, such as an MCU chip or a system-on-a-chip (SoC). The transceiver unit can be an input / output circuit or a communication interface. The processing unit is a processor, microprocessor, or integrated circuit integrated on the chip. No limitations are imposed here.

[0210] Figure 11 This is a schematic block diagram of the optical communication link detection device 2000 provided in an embodiment of this application. Figure 11 As shown, the device 2000 includes a processor 2010 and a transceiver 2020. The processor 2010 and the transceiver 2020 communicate with each other through an internal connection path. The processor 2010 is used to execute instructions to control the transceiver 2020 to transmit and / or receive signals.

[0211] Optionally, the device 2000 may further include a memory 2030, which communicates with the processor 2010 and the transceiver 2020 via an internal connection path. The memory 2030 is used to store instructions, and the processor 2010 can execute the instructions stored in the memory 2030.

[0212] For example, the device 2000 is a transmitting device, which may be an AAU or a BBU, or it may be a device applied to or used in conjunction with a transmitting device to implement a method executed by the transmitting device, such as a chip, chip system, or circuit. See details below. Figure 11 The chip system shown is described in detail.

[0213] For example, the device 2000 is a receiving device, which may be an AAU or a BBU, or it may be a device applied to or used in conjunction with a receiving device to implement a method executed by the receiving device, such as a chip, chip system, or circuit. See details below. Figure 11 The chip system shown is described in detail.

[0214] In one possible implementation, the apparatus 2000 is used to implement the various processes and steps corresponding to the transmitting device in the above method embodiments.

[0215] In another possible implementation, the apparatus 2000 is used to implement the various processes and steps corresponding to the receiving device in the above method embodiments.

[0216] Optionally, the memory 2030 may include read-only memory and random access memory, and provide instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. For example, the memory may also store device type information. The processor 2010 may be used to execute instructions stored in the memory, and when the processor 2010 executes instructions stored in the memory, the processor 2010 is used to perform the various steps and / or processes of the method embodiments corresponding to the sending end or receiving end described above.

[0217] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly implemented by a hardware processor, or by a combination of hardware and software modules in the processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0218] It should be noted that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiments can be completed by the integrated logic circuitry in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, digital signal processor, application-specific integrated circuit, field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, or, as mentioned above, a CPU, other general-purpose processor, DSP, ASIC, FPGA or other codeable logic device, or a portion of the circuitry in another chip used for processing functions. The processor in the embodiments of this application can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied as being executed by a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above method.

[0219] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0220] In the embodiments of this application, the method described above can be executed by a transmitting device or a receiving device, or by a chip, chip system, or circuit of the transmitting device or receiving device, which can be installed in the transmitting device or receiving device. Below, in conjunction with... Figure 11 The following explanation uses the chip system of the transmitting or receiving device as an example.

[0221] ​ This is a schematic block diagram of the chip system 3000 provided in an embodiment of this application. ​ As shown, the chip system 3000 (or processing system) includes logic circuitry 3010 and input / output interface 3020.

[0222] The logic circuit 3010 can be a processing circuit in the chip system 3000. The logic circuit 3010 can be coupled to a memory unit, calling instructions from the memory unit, enabling the chip system 3000 to implement the methods and functions of the embodiments of this application. The input / output interface 3020 can be an input / output circuit in the chip system 3000, outputting processed information from the chip system 3000, or inputting data or signaling information to be processed into the chip system 3000 for processing.

[0223] As one approach, the chip system 3000 is used to implement the operations performed by the transmitting or receiving device in the various method embodiments described above.

[0224] For example, logic circuit 3010 is used to implement processing-related operations performed by the transmitting device in the above method embodiments, such as the processing-related operations performed by the transmitting device in the above embodiments; input / output interface 3020 is used to implement sending and / or receiving-related operations performed by the transmitting device in the above method embodiments, such as the sending and / or receiving-related operations performed by the transmitting device in the above embodiments.

[0225] For example, logic circuit 3010 is used to implement processing-related operations performed by the receiving device in the above method embodiments, such as the processing-related operations performed by the receiving device in the above embodiments; input / output interface 3020 is used to implement sending and / or receiving-related operations performed by the receiving device in the above method embodiments, such as the sending and / or receiving-related operations performed by the receiving device in the above embodiments.

[0226] This application also provides a computer-readable storage medium storing computer instructions for implementing the methods executed by the transmitting or receiving device in the above-described method embodiments.

[0227] This application also provides a computer program product comprising instructions which, when executed by a computer, implement the methods described above by the transmitting or receiving device.

[0228] This application also provides a communication system, which includes the transmitting device or receiving device in the above embodiments.

[0229] The explanations and beneficial effects of the relevant contents in any of the devices provided above can be found in the corresponding method embodiments provided above, and will not be repeated here.

[0230] In this application, examples may reference each other without logical contradiction. For example, methods and / or terms between method embodiments may reference each other, functions and / or terms between device embodiments may reference each other, and functions and / or terms between device examples and method examples may reference each other.

[0231] In the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0232] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0233] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0234] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0235] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0236] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0237] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0238] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the 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 optical communication link detection, the method comprising: The method comprises: receiving a first optical signal and photoelectrically converting the first optical signal to obtain a first electrical signal; determining information of an optical communication link according to a parameter of the first electrical signal, the optical communication link being used for transmitting the first optical signal; the parameter of the first electrical signal comprises at least one of: a comparison value of a highest level distribution and a lowest level distribution of the first electrical signal, and a frequency response curve feature of the first electrical signal; the information of the optical communication link comprises at least one of: an intensity of multipath interference (MPI) noise, and a chirp coefficient; wherein the intensity of the MPI noise is used to measure the influence of MPI effect on the optical communication link, and the chirp coefficient is used to measure the influence of chirp effect on the optical communication link.

2. The method of claim 1, wherein, The method further comprises: determining the information of the optical communication link according to the parameter of the first electrical signal comprises: determining the intensity of the MPI noise according to the comparison value of the highest level distribution and the lowest level distribution of the first electrical signal; and / or 3. The method of claim 2, wherein, determining the chirp coefficient according to the frequency response curve feature of the first electrical signal. The method further comprises: determining the intensity of the MPI noise according to the comparison value of the highest level distribution and the lowest level distribution of the first electrical signal comprises:

4. The method according to any one of claims 1 to 3, characterized in that, obtaining a first correspondence relationship, the first correspondence relationship comprising a correspondence relationship between a plurality of comparison values of highest level distribution and lowest level distribution and a plurality of intensities of MPI noise; determining, according to the first correspondence relationship, the intensity of the multipath interference (MPI) noise corresponding to the comparison value of the highest level distribution and the lowest level distribution of the first electrical signal, the plurality of comparison values of highest level distribution and lowest level distribution comprising the comparison value of the highest level distribution and the lowest level distribution of the first electrical signal.

5. The method of claim 2, wherein, The comparison value of the highest level distribution and the lowest level distribution comprises at least one of: a standard deviation difference value of the highest level distribution and the lowest level distribution, a standard deviation ratio value of the highest level distribution and the lowest level distribution, a variance difference value of the highest level distribution and the lowest level distribution, and a variance ratio value of the highest level distribution and the lowest level distribution. The method further comprises:

6. The method of claim 5, wherein, determining the chirp coefficient according to the frequency response curve feature of the first electrical signal comprises: obtaining a second correspondence relationship, the second correspondence relationship comprising a correspondence relationship between a plurality of frequency response curve features and a plurality of chirp coefficients; determining, according to the second correspondence relationship, the chirp coefficient corresponding to the frequency response curve feature of the first electrical signal, the plurality of frequency response curve features comprising the frequency response curve feature of the first electrical signal.

7. The method of claim 6, wherein, The method further comprises: receiving a second optical signal and photoelectrically converting the second optical signal to obtain a second electrical signal, the first optical signal corresponding to a first time, and the second optical signal corresponding to a second time, the second time being after the first time; determining whether the optical communication link has chirp degradation according to the frequency response curve feature of the second electrical signal and the frequency response curve feature of the first electrical signal, the optical communication link also being used for transmitting the second optical signal. The method further comprises: According to the second correspondence relationship, determine the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal, the plurality of frequency response curve features including the frequency response curve feature of the second electrical signal; According to the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal and the chirp coefficient corresponding to the frequency response curve feature of the first electrical signal, determine whether the optical communication link has chirp degradation.

8. The method of claim 7, wherein, When the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal is greater than the chirp coefficient corresponding to the frequency response curve feature of the first electrical signal, the optical communication link has chirp degradation.

9. The method according to claim 7 or 8, characterized in that, The method further comprises: According to the chirp coefficient corresponding to the frequency response curve feature of the second electrical signal and the chirp coefficient corresponding to the frequency response curve feature of the first signal, determine a chirp degradation value, the chirp degradation value being used to measure the degree of the chirp degradation.

10. The method according to any one of claims 5-9, characterized in that, The frequency response curve feature includes at least one of: The inflection point information of the frequency response curve, the slope information between the inflection points of the frequency response curve, the bending degree of the frequency response curve, and the position information of the concave-convex of the frequency response curve.

11. An apparatus, comprising: The apparatus comprises units or modules for performing the method of any one of claims 1 to 10.

12. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program or instructions, when the computer program or instructions are run on a computer, the method as claimed in any one of claims 1 to 10 is executed.

13. A chip, characterized by Comprise: The processor is used to call and run the computer program from the memory, so that the method as claimed in any one of claims 1 to 10 is executed.

14. A computer program product, characterised in that, When the computer program product is run on the computer, the method as claimed in any one of claims 1 to 10 is executed.

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