Method and system for detecting faults occurring in optical transport network

Abstract

A system and a method for detecting a failure of an optical transport link (OTL) of an optical transport network (OTN) are provided, and a method for detecting a failure of an optical transport link (OTL) of an optical transport network (OTN) is provided. The method includes: receiving at least one multiplexed signal from the OTL, the at least one multiplexed signal having been generated by a multiplexing device from a first signal including a first set of optical channels and a second signal including a second set of signals; determining alternating current power and direct current power; determining a power ratio of the alternating current power to the direct current power; and determining a power ratio indicating a total number of optical channels in the first and second groups received at an output of the OTL at an optical power above a predetermined threshold.

Description

[0001] Cross-reference to related applications

[0002] This is the first application filed with respect to the technology disclosed herein. Technical Field

[0003] This disclosure relates generally to the field of optical communications, and more particularly to methods and systems for detecting faults occurring in the optical multiplexing section (OMS) of an optical transport network (OTN). Background Technology

[0004] Typical implementations of optical networks, such as dense wavelength division multiplexing (DWDM) networks, involve a large number of optical devices and optical communication lines, making standard surveillance systems inefficient. Most mesh optical networks include optical add-drop multiplexer (OADM) nodes, at which wavelength channels can be inserted / splittered / routed. During routing, any number of channels can be split and / or inserted at the OADM nodes.

[0005] At the output of an OADM node, optical power loss may occur. This can be caused by several factors, such as fiber breakage, fiber bending, and optical amplifier failure. Due to amplifier gain coupling and fiber nonlinearities (e.g., stimulated Raman scattering), power variations on some channels may affect other channels of the OADM. However, standard systems are not configured to determine whether power loss occurs on all channels of the OADM node or only on the local channel inserted at the OADM node. Distinguishing between these two scenarios can help provide customized response actions based on the type of optical power loss.

[0006] Therefore, it is desirable to detect one or more types of optical power loss at the output of the OADM. Summary of the Invention

[0007] One aspect of the present invention is to provide a method for detecting a fault in an optical transport link (OTL) of an optical transport network (OTN). The method includes receiving at least one multiplexed signal from the OTL, the at least one multiplexed signal having been generated by a multiplexing device from a first signal comprising a first group of optical channels and a second signal comprising a second group of signals. The method further includes: determining an AC power indicative of the bandwidth of the at least one multiplexed signal based on optical beat noise of the at least one multiplexed signal; determining a DC power representing the at least one multiplexed signal based on an average optical power of the at least one multiplexed signal; determining a power ratio of the AC power to the DC power; and determining a power ratio indicating the total number of optical channels in the first and second groups received at an optical power exceeding a predetermined threshold at the output of the OTL.

[0008] In some implementations, the first signal is received from the optical multiplexing section (OMS) of the OTN. The method also includes locally generating the second signal by a signal generation device communicatively connected to the multiplexing component.

[0009] In some implementations, the method further includes determining the loss of optical power of the second set of optical channels relative to the optical power of the first set of optical channels in response to determining the change in the power ratio.

[0010] In some implementations, determining the DC current includes: receiving the at least one multiplexed signal via a sensing device; amplifying the received at least one multiplexed signal via an electrical amplifier optically connected to the output of the sensing device; and calculating the DC current according to the following formula:

[0011] in, It is the responsivity of the sensing device, and It is the optical power of the at least one multiplexed signal, wherein, It is the optical power spectral density, and It is the frequency of light.

[0012] In some implementations, determining the DC power includes tapping the output of the optical amplifier through a low-pass filter and converting the output of the low-pass filter through an analog-to-digital converter.

[0013] In some implementations, determining optical power noise includes determining:

[0014] in, It is the optical power spectral density. It is the electrical frequency, and It is the detected electrical bandwidth.

[0015] In some implementations, determining the AC power further includes: tapping the output of the optical amplifier to a radio frequency power sensor; filtering the output of the radio frequency power sensor using a low-pass filter; and converting the output of the low-pass filter using an analog-to-digital converter.

[0016] In some implementations, the first optical inlet, the second optical inlet, and the multiplexing device are implemented in an optical add-drop multiplexer (OADM).

[0017] In some implementations, the method further includes: determining an overall power loss of the first group of optical channels and the second group of optical channels in response to the power ratio being equal to a predetermined value and the DC power being lower than a predetermined threshold; and determining a partial channel interruption in response to the power ratio being lower than the predetermined value, the partial channel interruption being defined by the loss of optical power of the second group of optical channels relative to the optical power of the first group of optical channels.

[0018] In some implementations, the method further includes inserting additional optical power into the multiplexed signal in response to determining that an overall power loss has occurred.

[0019] In a second aspect of this technology, a multiplexing component for an optical transport network (OTN) is provided. The multiplexing component includes: a first optical inlet for receiving a first optical signal comprising a first set of optical channels; an optical amplifier at the first optical inlet for amplifying the first optical signal upon receipt by the multiplexing component; a second optical inlet for receiving a second optical signal comprising a second set of optical channels; a multiplexing device for multiplexing the first optical signal and the second optical signal; an optical outlet for outputting the multiplexed signal to an output optical transport link; and a processing module communicatively connected to the optical outlet for receiving the multiplexed signal from the output optical transport link. The processing module is configured to measure an AC power indicating the bandwidth of the multiplexed signal, measure a DC power representing the multiplexed signal, and determine a ratio of the AC power to the DC power, the ratio indicating the number of optical channels in the first and second sets received at the processing module at an optical power exceeding a predetermined threshold.

[0020] In some implementations, the first signal is received from the optical multiplexing section (OMS) of the OTN, and the second signal is generated locally by a signal generation device communicatively connected to the multiplexing component.

[0021] In some implementations, the processing module determines the change in the ratio, the change indicating the loss of optical power of the second set of optical channels relative to the optical power of the first set of optical channels.

[0022] In some implementations, the processing module includes a sensing device for receiving the multiplexed signal and an optical amplifier optically connected to the output of the sensing device. The processing module determines the direct current (DC) based on information received from the sensing device, wherein the DC current is:

[0023] in, It is the responsivity of the sensing device, and It is the optical power of the at least one multiplexed signal, wherein, It is the optical power spectral density, and It is the optical frequency, and the AC power is:

[0024] in, It is the optical power spectral density. It is the electrical frequency, and It is the detected electrical bandwidth.

[0025] In some implementations, the multiplexing component further includes a low-pass filter operatively connected to the output of the optical amplifier and an analog-to-digital converter (ADC) operatively connected to the low-pass filter. The processing module determines the DC current based on the signal from the ADC.

[0026] In some implementations, the multiplexing component further includes: a radio frequency power sensor operatively connected to the output of the optical amplifier, a second low-pass filter operatively connected to the radio frequency power sensor, and a second ADC operatively connected to the second low-pass filter. The processing module determines the AC power based on the signal from the second ADC.

[0027] In some implementations, the optical amplifier is a transient sensing amplifier.

[0028] In some implementations, the multiplexing device is a wavelength selective switch (WSS).

[0029] In some implementations, the first optical inlet, the second optical inlet, and the multiplexing device are implemented in an optical add-drop multiplexer (OADM). Attached Figure Description

[0030] The features and advantages of this disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which: Figure 1 This is a high-level diagram of an optical transport link (OTL) according to some embodiments of the present technology; Figure 2 yes Figure 1 A high-level diagram of OTL's Optical Add-Drop Multiplexer (OADM); Figure 3 This is a schematic representation of an optical amplifier according to some embodiments of the present technology; Figure 4 Is Figure 1 A representation of potential faults that may occur on the OTL; Figure 5 This is a block diagram of a monitoring system according to an embodiment of the present technology; Figure 6 yes Figure 5 A block diagram of the controller of the monitoring system; Figure 7 This is based on some embodiments of the present technology for detecting in Figure 1 A flowchart of the method for handling faults occurring on the optical multiplexing section (OMS) of the OTL; Figure 8 This indicates the power ratio response to OTL (e.g.) Figure 1 A graph showing the experimental results of how the number of optical channels present in the multiplexed signal of the OTL changes.

[0031] It should be understood that in all the drawings and corresponding descriptions, the same features are identified by the same reference numerals. Furthermore, it should be understood that the drawings and the following description are for illustrative purposes only, and such disclosure is not intended to limit the scope of the claims. Detailed Implementation

[0032] Various representative embodiments of the described technology will be described more fully below with reference to the accompanying drawings, which illustrate representative embodiments. However, the technical concept can be embodied in many different forms and should not be construed as limited to the representative embodiments described herein. In fact, these representative embodiments are provided so that this disclosure will be exhaustive and complete, and will fully convey the scope of the technology to those skilled in the art. In the drawings, the dimensions and relative dimensions of layers and regions may be enlarged for clarity. Throughout the specification, the same reference numerals refer to the same elements.

[0033] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. Therefore, without departing from the teachings of this art, the first element discussed below may be referred to as the second element. As used herein, the term "and / or" includes any and all combinations of one or more associated listed items.

[0034] It should be understood that when an element is referred to as "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. In contrast, when an element is referred to as "directly connected" or "directly coupled" to another element, there are no intermediate elements. Other terms used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.).

[0035] The terminology used herein is intended only to describe specific, representative embodiments and is not intended to limit the technology. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used herein are intended to include the plural forms as well. It should also be understood that when the terms “comprise” and / or “comprising” are used in this specification, they specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0036] Furthermore, all statements and specific examples of the principles, aspects, and implementations of this technology described herein are intended to encompass both structural and functional equivalents, whether such equivalents are currently known or will be developed in the future. Therefore, for example, those skilled in the art will understand that any block diagram herein represents a conceptual view of an illustrative circuit embodying the principles of this technology. Similarly, it should be understood that any flowchart, diagrammatic flowchart, state transition diagram, pseudocode, etc., represents various processes that can be substantially represented in a computer-readable medium and therefore executed by a computer or processor, whether or not such computer or processor is explicitly shown.

[0037] The functions of the various elements shown in the figures, including any functional blocks labeled "controller," "processor," or "processing unit," can be provided using dedicated hardware and hardware capable of executing software, combined with appropriate software and the methods described herein. When provided by a processor, these functions can be provided by a single dedicated processor, a single shared processor, or multiple independent processors, some of which may share resources. In some embodiments of this technology, the processor can be a general-purpose processor, such as a central processing unit (CPU), or a purpose-specific processing unit, such as a digital signal processor (DSP). Furthermore, the explicit use of the term "processor" should not be construed as referring only to hardware capable of executing software, but may implicitly include, but is not limited to, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), read-only memory (ROM), random access memory (RAM), and non-volatile memory for storing software. Other conventional and / or custom hardware may also be included.

[0038] A software module, or simply a module or unit (meaning software), may herein be represented as a flowchart element or any combination of other elements indicating the execution of process steps and / or textual descriptions. Such modules may be executed by hardware, explicitly or implicitly shown, adapted (manufactured, designed, or configured) to execute these modules. Furthermore, it should be understood that a module may include, for example, but not limited to, computer program logic, computer program instructions, software, stacks, firmware, hardware circuitry, or combinations thereof, providing the required capabilities.

[0039] In summary, this technology provides a system and method for detecting faults occurring on the optical multiplexing section (OMS) of an optical transport link (OTL) in an optical transport network (OTN). As will be described in more detail below, the system disclosed herein is capable of distinguishing between full-channel power attenuation and partial power attenuation. In the context of this disclosure, "full-channel power attenuation" occurs at the output of the OADM when optical power attenuation occurs on all output optical channels of the OADM, while "partial power attenuation" occurs when optical power attenuation occurs only on a subset of the output optical channels of the OADM. The disclosed technique can use a single photodetector to determine whether the power attenuation is full-channel or partial, thus providing a cost-effective way to determine the nature of potential power attenuation.

[0040] Based on these fundamental principles, we will now consider some non-limiting examples to illustrate various implementations of various aspects of this disclosure.

[0041] Now refer to the attached diagram, Figure 1 A conceptual diagram of an optical transport link (OTL) 90 that can be processed by the systems and methods presented herein is shown. As shown, the OTL 90 typically includes multiple optical multiplexing sections (OMS) 92 for transmitting optical signal 300. The OTL 90 may include conventional optical fibers, such as glass fibers wrapped with one or more coatings. The OTL 90 may include an optical fiber core for transmitting the optical signal 300, and an optical cladding that confines the optical signal within the optical fiber core. It should also be understood that the light defining the optical signal 300 may be single-polarized, double-polarized, or randomly polarized, and may have a specific polarization (e.g., linear, elliptical, or circular polarization). In this implementation, the wavelength of the optical signal 300 can be located in one or more of the following bands: E band (1400 nm to 1470 nm), S band (1470 nm to 1520 nm), C band (1520 nm to 1565 nm), L band (1565 nm to 1630 nm) and U band (1630 nm to 1680 nm).

[0042] Each OMS 92 includes an optical add-drop multiplexer (OADM), such as a reconfigurable optical add-drop multiplexer (ROADM) 94, each containing at least one wavelength selection switch (not shown). The ROADM 94 may include a transmitter labeled "Tx" and a receiver labeled "Rx" for inserting and extracting a given signal from the optical signal 300, respectively. Each OMS 92 can then be configured to insert, remove, and / or reroute wavelengths of the optical signal 300 via the ROADM 94. For example, and not limited to, each transmitter Tx may be a laser source with a corresponding wavelength and communicatively connected to a corresponding processing unit (not shown) of the ROADM 94. The laser source may be used to generate, emit, or radiate optical pulses with a specific pulse duration. In some implementations, one or more transmitters Tx, implemented as pulsed laser sources, may include one or more laser diodes, such as, but not limited to, Fabry-Perot laser diodes, quantum well lasers, distributed Bragg reflector (DBR) lasers, distributed feedback (DFB) lasers, or vertical-cavity surface-emitting lasers (VCSELs). For example, a given laser diode may be an aluminum-gallium-arsenide (AlGaAs) laser diode, an indium-gallium-arsenide (InGaAs) laser diode, or an indium-gallium-arsenide-phosphide (InGaAsP) laser diode, or any other suitable laser diode. ROADM 94 can be a passive multiplexer, such as, but not limited to, a prism-based or mirror-based multiplexer, or an active multiplexer based on a combination of passive components and tunable detectors, each detector being tuned to a specific frequency. Each OMS 92 is formed by multiple optical transport sections (OTS) 96, wherein the wavelength remains the same at each OTS 96.

[0043] It should be noted that the OTL 90 may include additional optical components, which may include active components / modules and / or passive components / modules, including but not limited to: optical amplifiers, filters, wavelength selective switches, arrayed waveguide gratings, optical transmitters, optical receivers, processors, and other suitable components. However, for simplicity, [the following has been omitted]. Figure 1 These components have been omitted.

[0044] Each optical transmission segment 96, also known as link 96, includes an optical amplifier (e.g., an erbium-doped fiber amplifier (EDFA)) and a section of optical fiber 97. The optical fiber can be of any suitable type, such as single-mode fiber, multimode fiber, standard single-mode fiber (SSMF), large effective area fiber (LEAF), etc.

[0045] In alternative implementations, it may also be considered to use one or more additional optical network elements and modules (which may include active elements / modules and / or passive elements / modules) on the OTL 90, such as filters, arrayed waveguide gratings, optical transmitting devices, optical receiving devices, processors and other suitable components.

[0046] It should be noted that a given ROADM 94 can receive more than one optical signal (e.g., two optical signals), each of which is received at its corresponding optical input. For example, Figure 2 This is a schematic diagram of a ROADM 94 according to a non-limiting implementation of the present technology. In this illustrative example, the ROADM 94 includes a first optical input 210 for receiving a first optical signal 202 from a first OMS (denoted as OMS-A), and a second optical input 220 for receiving a second optical signal 204 from a second OMS (denoted as OMS-B). More specifically, the first signal 202 includes a first set of optical channels, and the second signal 204 includes a second set of optical channels, such as... Figure 2 As shown.

[0047] ROADM 94 also includes a transmitter 230 for locally inserting the third optical signal 206 into the output signal of ROADM 94. In use, ROADM 94 includes a multiplexing device 240 for multiplexing the first optical signal 202, the second optical signal 204, and the third optical signal 206. In this implementation, the multiplexing device 240 is a wavelength selective switch (WSS). More specifically, ROADM 94 includes a first optical amplifier 210 for applying power amplification to the first optical signal 202. AAnd a second optical amplifier 210 for applying power amplification to the second optical signal 204. B The amplified first optical signal 202 and second optical signal 204 are then guided to WSS 240.

[0048] ROADM 94 may also include an output optical amplifier 240. A It receives the multiplexed signal from WSS 240 before the optical signal is output from the optical output terminal 240 of ROADM 94. In this implementation, the optical output terminal 240 is optically connected to a third OMS (denoted as OMS-C). More specifically, OMS-C defines the optical input terminal at the optical output terminal 240 of OMS 94 and defines the optical output terminal 302. In addition, OMS-C includes an optical amplifier 301 at the optical output terminal 302. In this implementation, WSS 304 is configured to receive the multiplexed signal 290 at the optical output terminal 302 of OMS-C.

[0049] Figure 3 This is a schematic diagram of an optical amplifier 310 according to some non-limiting implementations of the present technology. In some implementations, the optical amplifier 210 a 220 A Optical amplifier 310 is implemented as optical amplifier 301. Optical amplifier 310 defines an optical input 311 for receiving optical signals. The optical signals can be carried through multiple optical channels received at optical input 311. Optical amplifier 310 also includes an optical signal generation device 312, which is configured to generate a placeholder optical signal or "virtual optical signal," which has optical power but does not carry information. In general, a virtual optical signal can be inserted at the beginning of the OMS and terminated at the end of the OMS to stabilize the OTN. The virtual optical signal is then directed to a variable optical attenuator (VOA) 314. VOA 314 can be used to adjust the gain level of the virtual optical signal by attenuating the virtual optical signal propagating therein. A signal combiner 316 (e.g., a coupler) further combines the attenuated virtual optical signal with the optical signal received at optical input 311. The combined optical signal is further guided through the local optical amplifier 318 and then output from the optical output terminal 319 of the optical amplifier 310.

[0050] When optical amplifier 310 is implemented at the end or "tail" of the OMS, VOA 314 is set to its maximum value during normal operation, completely blocking the virtual optical signal without affecting the service channel (i.e., the optical signal received at optical input 311). If a fiber break occurs in the OMS, the power of all optical channels will decrease. Local optical amplifier 318 operates in constant output power mode, so that in the event of a fiber break in the OMS, local optical amplifier 318 will increase its gain to maintain output power. This may help maintain the integrity of the OMS and OTN. If the input power attenuation exceeds a certain threshold, the attenuation of VOA 314 will decrease to insert power from the virtual optical signal. In this way, the output optical power of optical amplifier 310 can be maintained. In some implementations, the power attenuation threshold is selected to be between 6 dB and 10 dB.

[0051] More specifically, the total power from the channels remains constant, allowing channel replacement operations to be performed in response to faults occurring in the OTN. Maintaining the total optical power enables operators to perform transient-free switching, i.e., virtually no transients occur during replacement operations, thus allowing all channels to be replaced in a single operation. Therefore, it is unnecessary to divide optical channels into replacement groups.

[0052] This technology addresses the need to separately identify two types of faults occurring in OTN: full channel interruption and partial channel interruption. For example... Figure 4 As shown, a fiber breakage fault occurring on the OMS-C is denoted as "Fault A". This results in a complete channel interruption at WSS 304. More specifically, all optical channels of the OMS-C experience optical power attenuation, with substantially the same attenuation across all channels. Another type of fault is a local fault occurring at transmitter 230 of ROADM 94, denoted as "Fault B", which results in a partial channel interruption. More specifically, only the optical channel inserted by transmitter 230, or the "local channel," experiences power attenuation during transmission through the OMS-C. In other words, in the case of "Fault B", only a subset of optical channels experiences optical power attenuation, the subset corresponding to the local channel inserted by transmitter 320. In one aspect, this technique can be used to distinguish between complete channel interruption and partial channel interruption.

[0053] Figure 5This is a schematic diagram of a monitoring system 500 according to some non-limiting implementations of the present technology. For example, and not as a limitation, the monitoring device 500 may be implemented at the tail of the OMS-C (e.g., its optical output terminal 302) to distinguish between full-channel interruption and partial-channel interruption. In use, the monitoring system 500 includes a sensing module 510 that can receive multiplexed signals 290 from the OMS-C. In this implementation, the sensing module 510 includes a single sensing device 512, which may be a photodetector, such as a Ge photodiode, InGaAs photodiode, etc. In this implementation, the sensing device 512 is a square-law detector. The sensing module 510 also includes an amplifier 514 at the output of the sensing device 512. For example, the amplifier 514 may be a transient sensing amplifier.

[0054] In summary, once the sensing module 510 receives the multiplexed signal 290, the monitoring system 500 can determine whether the fault is full-channel power attenuation or partial-channel power attenuation. On one hand, the average photocurrent (or equivalent voltage) output by the sensing module 510 is proportional to the input optical power received by the multiplexed signal 290. On the other hand, different spectral components in the optical signal or ASE noise spectrum generate beat frequency noise during optical detection. Beat frequency noise is AC, and the DC-normalized AC power depends on the spectral width of its input, or equivalently, on the number of channels in the input.

[0055] Therefore, a power detector can be used to measure the input optical power (i.e., AC power) of the multiplexed signal 290. An analog-to-digital converter (ADC) can be used to convert the DC and AC power into the digital domain, and then the AC / DC power ratio can be calculated. Therefore, the monitoring system 500 can use the AC / DC power ratio to monitor changes in the number of optical channels in the multiplexed signal 290. The AC / DC power ratio indicates the total number of optical channels received at WSS 304 that have not experienced power loss (i.e., have optical power above a predetermined threshold).

[0056] To this end, the monitoring system 500 includes: a low-pass filter (LPF) 536, receiving the output of the amplifier 514 to improve measurement quality; and an analog-to-digital converter (ADC) 538, which receives the output of the LPF 536 and outputs a DC current 539. The DC current 539 is given by the following formula:

[0057] Where Resp is the photodetector responsivity. It is the optical power of at least one multiplexed signal, wherein, It is the optical power spectral density, and It is the frequency of light. This refers to optical bandwidth. Also note the frequency. The power density of the spontaneous beat frequency noise at a given location can be written as:

[0058] Among them, if ,but ;if ,but .

[0059] The monitoring system 500 includes a DC module 522 that receives the output of the sensing module 510. In use, the DC module 522 prevents the presence of DC frequencies in the electrical signal. For example, the DC module 522 includes capacitors and conductors. The DC module 522 can remove the DC frequency component of the original signal, allowing only AC frequencies to pass through. The monitoring system 500 also includes a radio frequency (RF) power module 524 for determining the RF power level of the photocurrent generated by the sensing module 510. The monitoring system 500 also includes: a second LPF 526 that receives the output of the RF power module 524 to improve measurement quality; and a second ADC 528 that receives the output of the second LPF 526 and outputs AC power 529.

[0060] For electrical bandwidths less than a few GHz (e.g., hundreds of MHz to a few GHz), optical bandwidths are typically greater than 10 GHz. Multiple optical channels can occupy several THz. Therefore, spontaneous-spontaneous beat noise is generally flat. Thus, the bandwidth... The total beat frequency noise power (AC power) within the range can be written as:

[0061] in, It is the optical power spectral density. It is the electrical frequency, and The electrical bandwidth of the detector is much smaller than the optical bandwidth. The equation can be approximated as:

[0062] in, It is the effective optical bandwidth defined by the multiplexed signal.

[0063] DC power is proportional to the square of the photocurrent of the sensing module 510; therefore, the AC / DC power ratio is... It is directly proportional to the bandwidth ratio:

[0064] Therefore, AC / DC power ratio With optical bandwidth Inversely proportional. Under full-channel power attenuation, optical bandwidth... Unchanged. However, with partial channel power attenuation, the effective optical bandwidth... It will decrease. Since the optical bandwidth is proportional to the number of optical channels present in the multiplexed signal 290, the monitoring system 500 can provide an indication of the change in the number of optical channels effectively present in the multiplexed signal 290, thereby distinguishing between full-channel power attenuation scenarios and partial-channel power attenuation scenarios.

[0065] Figure 8 This is a chart showing the AC / DC power ratio. Experimental results showing variation in response to changes in the number of optical channels present in the multiplexed signal 290 (i.e., optical channels with corresponding optical powers above a given power threshold). In the experiment, the spectral width of each optical channel was 50 GHz. Power ratio. The measurement was based on the number of optical channels in the multiplexed signal 290. A sampling oscilloscope was used to measure the AC waveform and DC level. The detection bandwidth was approximately 130 MHz, and the sampling rate was 500 MHz. Each measurement used 100,000 samples at a 1 GHz sampling rate for a duration of 100 microseconds. The theoretical curve for the bandwidth ratio is also shown.

[0066] For example, the loss of optical power in the optical channel set of the third optical signal 206 relative to the optical power of the optical channel set of the first optical signal 202 and / or the second optical signal 204 (i.e., partial channel power attenuation) can be determined in response to the power ratio. The power ratio is determined by the variation. For example, if a known number of optical channels (e.g., 70 optical channels) are expected to exist at WSS 304, the power ratio can be determined. The corresponding expected value, for example, for 70 expected optical channels, is approximately 0.000037. If the power ratio... If the current value differs from the expected value, it can be determined that a partial channel outage has occurred. For example, if the power ratio... If the current value is approximately 0.000043, then it can be determined that 10 out of 70 optical channels are experiencing optical power loss.

[0067] During use, the DC current 539 and AC power 529 are received by the processing module 540, which determines the AC / DC power ratio. .For example, Figure 6This is a schematic block diagram of a controller 600 of a processing module 540 according to an embodiment of the present technology. The controller 600 includes one or more processors (represented as processor 604 for simplicity), one or more memory devices (represented as memory device 610 for simplicity), and an input / output interface 602 that enables the controller 600 to communicate with other components of the monitoring system 500 and / or other components that remotely communicate with the monitoring system 500. The processor 604 is operatively connected to the memory device 610 and the input / output interface 602. The memory device 610 includes storage elements for storing parameters 614. The memory device 610 may include a non-transitory computer-readable medium for storing code instructions 612 that the processor 604 can execute to cause the controller 600 to perform various tasks assigned to the controller 600 in the methods described herein.

[0068] The controller 600 is operatively connected to the ADCs 528 and 538 via the input / output interface 602. The controller 600 executes code instructions 612 stored in the memory device 610 to implement various of the aforementioned functions that may exist in certain implementations. As shown in the figure, Figure 6 This is a non-limiting embodiment illustrating the operation of the controller 602 coordination processing module 540. This particular embodiment is not intended to limit the scope of this disclosure, but is provided for illustrative purposes.

[0069] Figure 7 This is a flowchart of a method 700 for detecting a fault occurring on an optical multiplexing section (OMS) (e.g., OMS-C). In one or more aspects, method 700 is performed by a monitoring system 500 communicatively and operatively connected to the tail of the OMS-C, but some implementation details of system 500 may differ in different embodiments. In some implementations, one or more operations of method 700 may be implemented wholly or partially by a device implemented by another computer. It is also conceivable that method 700 or one or more of its operations may be embodied in computer-executable instructions stored in a computer-readable medium (e.g., a non-transitory mass storage device), loaded into memory, and executed by a processor (e.g., controller 600). Some operations or parts of the operations in the flowchart may be performed simultaneously, omitted, or reordered.

[0070] Method 700 begins at operation 710 by receiving at least one multiplexed signal from the OMS. In use, the multiplexed signal has been generated by the multiplexing device from a first signal comprising a first set of optical channels and a second signal comprising a second set of signals. In this implementation, the multiplexed signal is multiplexed signal 290 generated by WSS 240 from the optical channels of the first optical signal 202 and / or the second optical signal 204 multiplexed with the third optical signal 230.

[0071] In some implementations, the first signal is received from another OMS (e.g., OMS-A) of the OTN, and the second signal is generated locally by a signal generation device (e.g., transmitter 230) communicatively connected to the multiplexing component.

[0072] Method 700 continues at operation 720 by determining the AC power indicating the bandwidth of at least one multiplexed signal. In this implementation, the AC power is AC power 529.

[0073] Method 700 continues at operation 730 by determining the DC power representing at least one multiplexed signal. In this implementation, the DC power is generated due to DC current 539. For example, and not limited to, determining the DC power may include a sensing device (e.g., sensing device 512) receiving at least one multiplexed signal. The received at least one multiplexed signal, or a signal indicating said at least one multiplexed signal (e.g., photocurrent), may be amplified by an amplifier communicatively connected to the output of the sensing device. The DC power can then be calculated according to the following formula:

[0074] in, It is the responsiveness of the sensing device, and It is the optical power of at least one multiplexed signal, wherein, It is the optical power spectral density, and It is the optical frequency. In some implementations, determining the DC power involves tapping the output of the optical amplifier through a low-pass filter and converting the output of the low-pass filter through an analog-to-digital converter (ADC).

[0075] In some implementations, the DC current is determined by tapping the output of the optical amplifier with a low-pass filter and converting the output of the low-pass filter with an ADC.

[0076] Method 700 continues by determining the power ratio of AC power to DC power at operation 740. In this implementation, the power ratio is the AC / DC power ratio. The power ratio indicates the number of optical channels in the first and second groups received at the output of the OMS with optical power above a predetermined threshold.

[0077] In some implementations, method 700 continues to determine the loss of optical power of the second set of optical channels relative to the optical power of the first set of optical channels in response to a change in the power ratio.

[0078] It should be understood that at least some operations of method 700 can also be executed by computer programs, which can exist in various forms, including both active and inactive forms. For example, a computer program can exist as one or more software programs including source code, object code, executable code, or program instructions in other formats. All of the above can be embodied in compressed or uncompressed form on a computer-readable medium including storage devices and signals. Representative computer-readable storage devices include conventional computer system random access memory (RAM), read-only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), and magnetic disks, optical disks, or magnetic tapes. Representative computer-readable signals, whether or not carrier modulation is used, are signals that a computer system hosting or running a computer program can be configured to access, including signals downloaded via the Internet or other networks. Specific examples of the above include programs downloaded and distributed on CD-ROMs or via the Internet. In a sense, the Internet itself, as an abstract entity, is a computer-readable medium. The same is true in general for computer networks.

[0079] Although the above implementation has been described and illustrated in conjunction with specific operations performed in a particular order, it should be understood that these steps can be combined, subdivided, or reordered without departing from the teachings of this art. At least some of these steps can be performed in parallel or sequentially. Therefore, the order and grouping of these steps are not a limitation of this art.

[0080] It should be understood that the operation and function of the monitoring system 500, its components, and associated processes can be implemented by any one or more hardware-based, software-based, and firmware-based elements. Such operational alternatives do not limit the scope of this disclosure in any way.

[0081] It should be clearly understood that not all the technical effects mentioned in this article need to be implemented in every implementation of this technology.

[0082] Modifications and improvements to the above implementation of this technology will be apparent to those skilled in the art. The above description is intended to be exemplary and not limiting. Therefore, the scope of this technology is intended to be limited only by the scope of the appended claims.

Claims

1. A method for detecting faults in an optical transport link (OTL) of an optical transport network (OTN), the method comprising: At least one multiplexed signal is received from the OTL, the at least one multiplexed signal having been generated by the multiplexing device from a first signal comprising a first set of optical channels and a second signal comprising a second set of optical channels; Based on the optical beat noise of the at least one multiplexed signal, determine the AC power indicating the bandwidth of the at least one multiplexed signal; Based on the average optical power of the at least one multiplexed signal, determine the DC power representing the at least one multiplexed signal; Determine the power ratio of the AC power to the DC power; as well as A power ratio is determined, which indicates the total number of optical channels in the first and second groups received at the output of the OTL with an optical power higher than a predetermined threshold.

2. The method according to claim 1, wherein, The first signal is received from the optical multiplexing section (OMS) of the OTN, and the method further includes: The second signal is generated locally by a signal generation device that can be communicatively connected to the multiplexing component.

3. The method according to claim 1 or 2, further comprising: In response to determining the change in the power ratio, the optical power loss of the second set of optical channels relative to the optical power of the first set of optical channels is determined.

4. The method according to any one of claims 1 to 3, wherein, Determining DC power includes: The at least one multiplexed signal is received by a sensing device; The received at least one multiplexed signal is amplified by an electrical amplifier optically connected to the output of the sensing device; and Calculate direct current using the following formula: in, It is the responsivity of the sensing device, and It is the optical power of the at least one multiplexed signal, wherein, It is the optical power spectral density, and It is the frequency of light.

5. The reuse component according to claim 4, wherein, Determining the DC power includes converting the output of the low-pass filter to the output of the optical amplifier, and converting the output of the low-pass filter to an analog-to-digital converter.

6. The method according to claim 4 or 5, wherein, Determining the AC power includes determining: in, It is the optical power spectral density, It is the electrical frequency, and It is the detected electrical bandwidth.

7. The method according to claim 6, wherein, Determining the AC power also includes: The output of the optical amplifier is tapped to the radio frequency power sensor; The output of the radio frequency power sensor is filtered by a low-pass filter; and The output of the low-pass filter is converted by an analog-to-digital converter.

8. The method according to any one of claims 1 to 7, wherein, The first optical input, the second optical input, and the multiplexing device are implemented in an optical add-drop multiplexer (OADM).

9. The method according to any one of claims 1 to 8, further comprising: In response to the power ratio being equal to a predetermined value and the DC power being lower than a predetermined threshold, it is determined that an overall power loss has occurred in the first group of optical channels and the second group of optical channels. as well as In response to the power ratio being lower than the predetermined value, a partial channel interruption is determined to have occurred, the partial channel interruption being defined by the loss of optical power of the second group of optical channels relative to the optical power of the first group of optical channels.

10. The method of claim 9, further comprising inserting additional optical power into the multiplexed signal in response to determining that an overall power loss has occurred.

11. A multiplexing component for an optical transport network (OTN), the multiplexing component comprising: The first optical input is used to receive the first optical signal, which includes the first set of optical channels; The optical amplifier at the first optical inlet is used to amplify the first optical signal when it is received through the multiplexing component; The second optical input is used to receive a second optical signal, including a second set of optical channels; A multiplexing device for multiplexing the first optical signal and the second optical signal into a multiplexed signal; Optical output, used to output the multiplexed signal to the output optical transmission link; as well as A processing module communicatively connected to the optical output, configured to receive the multiplexed signal from the output optical transmission link, is configured to: The AC power is measured to indicate the bandwidth of the multiplexed signal. The measurement represents the DC power of the multiplexed signal, and Determine the ratio of the AC power to the DC power, the ratio indicating the number of optical channels in the first and second groups received at the processing module at an optical power higher than a predetermined threshold.

12. The multiplexing component according to claim 11, wherein: The first signal is received from the optical multiplexing section (OMS) of the OTN; and The second signal is generated locally by a signal generation device that is communicatively connected to the multiplexing component.

13. The multiplexing component according to claim 11 or 12, wherein, The processing module is configured to determine the change in the ratio, the change indicating the loss of optical power of the second set of optical channels relative to the optical power of the first set of optical channels.

14. The reuse component according to any one of claims 11 to 13, wherein, The processing module includes: Sensing device for receiving the multiplexed signal; and An optical amplifier, with light connected to the output of the sensing device. The processing module is further configured to determine a direct current based on information received from the sensing device, wherein the direct current is: in, It is the responsivity of the sensing device, and It is the optical power of the at least one multiplexed signal, wherein, It is the optical power spectral density, and It is the light frequency, The AC power is: in, It is the optical power spectral density, It is the electrical frequency, and It is the detected electrical bandwidth.

15. The multiplexing component of claim 14, further comprising: A low-pass filter is operatively connected to the output of the optical amplifier; as well as An analog-to-digital converter (ADC) is operatively connected to the low-pass filter. The processing module is also configured to determine the DC current based on the signal from the ADC.

16. The multiplexing component according to claim 14 or 15, further comprising: A radio frequency power sensor is operatively connected to the output of the optical amplifier; A second low-pass filter is operatively connected to the radio frequency power sensor; as well as The second ADC is operatively connected to the second low-pass filter. The processing module is also configured to determine the AC power based on the signal from the second ADC.

17. The reuse component according to any one of claims 14 to 16, wherein, The optical amplifier is a transient induction amplifier.

18. The reuse component according to any one of claims 11 to 17, wherein, The multiplexing device is a wavelength selective switch (WSS).

19. The reuse component according to any one of claims 11 to 18, wherein, The first optical input, the second optical input, and the multiplexing device are implemented in an optical add-drop multiplexer (OADM).

Images