Optical transmission system and method

Abstract

To provide an optical transmission system and a method for determining whether the optical transmission system is functioning properly.SOLUTION: An optical transmission system includes a transceiver configured to output an optical signal to a first optical fiber core of a multicore fiber (MCF), a second optical fiber core proximate to the first optical fiber core within the MCF, configured to receive crosstalk of reflected portions of the optical signal from the first optical fiber core, a detector configured to receive the crosstalk of the reflected portions of the optical signal and generate detection data based on the crosstalk of the reflected portions of the optical signal, and a controller configured to receive information related to the detection data and determine whether the optical transmission system is functioning properly based on the detection data.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Optical transmission systems can be used to transmit data over long distances. In some cases, optical transmission systems are used for intercontinental data transmission via optical fibers laid along the seabed. In some cases, the monitoring of optical transmission systems is performed using the reflected light repeater output or optical time domain reflectometer (ODTR) technology. These systems utilize a circuit for returning a portion of the optical signal transmitted along the optical fiber to a detector at the source of the optical signal. The returned light is analyzed to determine whether the optical transmission system is functioning properly.

Background Art

[0002] Some optical transmission systems use single core fibers (SCFs) to carry optical signals. Some optical transmission systems use multi core fibers (MCFs) to carry optical signals. In some cases, in optical transmission systems that use MCFs to implement a circuit for returning a portion of the optical signal to a detector, a fan-in-fan-out (FIFO) structure is used.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Improvement in the technology for determining whether an optical transmission system is functioning properly is desired.

Means for Solving the Problems

[0004] One aspect of this specification is an optical transmission system comprising: a transceiver configured to output an optical signal to a first optical fiber core; a repeater connected to the first optical fiber core and configured to increase the intensity of the optical signal; a second optical fiber core located in close proximity to the first optical fiber core and configured to receive crosstalk from the first optical fiber core and to reflect a portion of the crosstalk of the optical signal back to the transceiver; a detector configured to receive the reflected portion of the crosstalk of the optical signal and to receive detection data based on the reflected portion of the crosstalk of the optical signal; and a controller configured to receive information about the detection data, to determine whether the optical transmission system is functioning properly based on the detection data, and to determine the location of a fault in the optical transmission system in response to a determination that the optical transmission system is not functioning properly.

[0005] One aspect of this specification is an optical transmission system comprising: a transceiver configured to output an optical signal to a first optical fiber core of a multicore fiber (MCF), wherein the first optical fiber core is configured to reflect a portion of the optical signal back to the transceiver; a second optical fiber core located adjacent to the first optical fiber core and within the MCF, and configured to receive crosstalk of the reflected portion of the optical signal from the first optical fiber core; a detector configured to receive the crosstalk of the reflected portion of the optical signal and to generate detection data based on the crosstalk of the reflected portion of the optical signal; and a controller configured to receive information about the detection data, to determine whether the optical transmission system is functioning properly based on the detection data, and to determine the location of a fault in the optical transmission system in response to a determination that the optical transmission system is not functioning properly.

[0006] One aspect of this specification is a method for determining the performance of an optical transmission system, comprising: transmitting an optical signal along a first optical fiber core; reflecting a portion of the optical signal; delivering the reflected portion of the optical signal to a second optical fiber core via crosstalk between the first and second optical fiber cores; detecting the crosstalk of the reflected portion of the optical signal and generating detection data; determining the performance of the optical transmission system based on the detection data; and identifying the location of a fault in the optical transmission system in response to a determination that the optical transmission system is not functioning properly. [Brief explanation of the drawing]

[0007] The aspects of this disclosure will be best understood from the following detailed description in conjunction with the attached drawings. Note that, in accordance with standard industry practice, various features are not depicted to scale. In fact, the dimensions of various features may be arbitrarily increased or decreased for clarity in the description. [Figure 1] This is a flowchart illustrating a method of using an optical transmission system according to several embodiments. [Figure 2A] This is a schematic diagram of an optical transmission system according to several embodiments. [Figure 2B] This is a graph of the detector output in an optical transmission system according to several embodiments. [Figure 3A] This is a schematic diagram of an optical transmission system according to several embodiments. [Figure 3B] This is a graph of the detector output in an optical transmission system according to several embodiments. [Figure 4] This is a schematic diagram of a fan-in-fan-out (FIFO) device according to several embodiments. [Figure 5A] This is a schematic diagram of an optical transmission system according to several embodiments. [Figure 5B] This is a graph of the detector output in an optical transmission system according to several embodiments. [Figure 6A] This is a schematic diagram of an optical transmission system according to several embodiments. [Figure 6B] This is a graph of the detector output in an optical transmission system according to several embodiments. [Figure 7] This is a block diagram of a controller usable in an optical transmission system, according to several embodiments. [Modes for carrying out the invention]

[0008] The following disclosure provides many different embodiments or examples for implementing different features of the subject matter provided. For the sake of brevity, specific examples of components, values, behaviors, materials, arrangements, etc. are described below. Of course, these are merely examples and are not intended to be limiting. Other components, values, behaviors, materials, arrangements, etc. are contemplated. For example, the formation of a first feature above or on top of a second feature in the following description may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which an additional feature may be formed between the first and second features so that the first and second features are not in direct contact. Furthermore, the disclosure may repeat reference numbers and / or letters in various examples. This repetition is for simplification and clarity and does not in itself prescribe relationships between the various embodiments and / or configurations described.

[0009] Furthermore, spatially relative terms such as “beneath,” “below,” “lower,” “above,” and “upper” may be used herein to facilitate descriptions of the relationship between one element or feature and another, as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation shown in the figures. The device may be oriented in other directions (it may be rotated 90 degrees or in other directions), and the spatially relative descriptors used herein may be interpreted accordingly.

[0010] Optical transmission systems are often used in hard-to-access locations. Accessing underground or along the seabed, such as optical transmission systems located on the seabed, to repair or replace components of an optical transmission system is difficult. Because access to parts of the optical transmission system is reduced, minimizing the number of components within the system helps lower operating costs and also reduces signal degradation associated with the failure to repair or replace faulty components. Furthermore, minimizing the number of components in an optical transmission system helps reduce the overall footprint of the system and lowers initial installation costs.

[0011] To help reduce the number of circuit and other components in optical transmission systems, this description utilizes inter-core crosstalk to monitor the performance of optical transmission systems. Crosstalk is the transmission of some of the optical signal from one core of an optical fiber to another core in the optical fiber. When an optical fiber contains multiple optical fiber cores, some degree of crosstalk is unavoidable. In some embodiments, crosstalk is amplified using a fan-in-fan-out (FIFO) device.

[0012] In some embodiments, this description utilizes back crosstalk to monitor the performance of the optical system. Back crosstalk is the reflection of a portion of an optical signal back to its source, where this reflected portion is transmitted to another optical fiber core within the optical fiber. In some embodiments, the reflection is a result of Rayleigh scattering of the optical signal as it propagates along the optical fiber core. In some embodiments, the reflection is a result of a grating introduced into the optical fiber core to cause the reflection of a portion of the optical signal.

[0013] Using crosstalk signals to monitor the performance of optical transmission systems reduces the number of components within the optical transmission system. The use of crosstalk signals also helps to minimize or eliminate circuits within the optical transmission system. Because accessing parts of optical transmission systems underground or along the seabed is difficult, the costs associated with repairing or replacing parts of the optical transmission system are very high. Reducing the number of components, especially circuits, within the optical transmission system helps to reduce the costs associated with repairing or replacing those components. Reducing the number of components also reduces the number of potential points of failure in the optical transmission system, which helps to minimize or reduce the degradation of the optical signal transmitted by the optical transmission system when a component fails or begins to fail. Furthermore, the reduction in the number of components reduces the overall size of the optical transmission system, lowering installation and manufacturing costs.

[0014] Figure 1 is a flowchart of Method 100, which uses an optical transmission system, in several embodiments. Method 100 can be used in optical transmission systems installed in various locations, such as underground, along the seabed, or other suitable locations. Method 100 is configured to use crosstalk between cores in an optical fiber to determine whether the optical transmission system is functioning correctly and to generate instructions to repair the optical transmission system if it is not functioning correctly. Method 100 can be used in optical transmission systems including single-core fiber (SCF) and multi-core fiber (MCF). Method 100 can be used in optical transmission systems that utilize Rayleigh scattering, gratings, or other suitable reflective devices. Method 100 can be used in optical transmission systems including fan-in-fan-out (FIFO) devices and in optical transmission systems that do not include FIFO devices.

[0015] In operation 105, an optical signal is transmitted along a first optical fiber core of an optical transmission system. In some embodiments, the first optical fiber core is located in an SCF. In some embodiments, the first optical fiber core is located in an MCF. In some embodiments, the transmitter converts an electrical signal into an optical signal. In some embodiments, the optical signal is available for data delivery along the optical fiber core. In some embodiments, the optical signal includes a pulsed signal. In some embodiments, the optical signal includes random pulses. In some embodiments, the optical signal is transmitted from a transmitter that does not include a detector. In some embodiments, the optical signal is transmitted from a transmitter that includes a detector.

[0016] In operation 110, a portion of the transmitted signal is reflected. This portion is less than the total signal propagating along the optical fiber core. In some embodiments, this portion accounts for about 5% to about 20% of the intensity of the signal propagating along the optical fiber core. In some embodiments, this portion accounts for about 10% of the intensity of the signal propagating along the optical fiber core. In some embodiments, the reflection is a result of Rayleigh scattering within the optical fiber core. In some embodiments, if the reflection is a result of Rayleigh scattering, this portion is about 0.05%. In some embodiments, the reflection is a result of the signal propagating through the FIFO device. In some embodiments, the reflection is a result of the signal encountering a grating, such as a Bragg grating, within the optical fiber core.

[0017] In operation 115, the reflected portion of the signal is transmitted to a second optical fiber core within the optical transmission system. The second optical fiber core is different from the first optical fiber core. The second optical fiber core is part of the same optical fiber as the first optical fiber core. In some embodiments, the second optical fiber core is within an SCF. In some embodiments, the second optical fiber core is within an MCF. In some embodiments, the second optical fiber core is adjacent to the first optical fiber core. In some embodiments, the second optical fiber core is in physical contact with the first optical fiber core. In some embodiments, the transmission of the reflected portion is a result of crosstalk between the first optical fiber core and the second optical fiber core. In some embodiments, the transmission is a result of the reflected portion passing through a FIFO device.

[0018] In operation 120, the reflected portion of the signal from the second optical fiber core is detected. The detector converts the detected reflected portion of the signal into an electrical signal for processing and analysis. In some embodiments, the reflected portion is detected using a detector incorporated into the same device as the transmitter. In some embodiments, the reflected portion is detected using a detector separate from the transmitter.

[0019] In operation 125, the detected reflected portion of the signal is analyzed to determine the state of the optical transmission system. Analysis of the intensity of the reflected portion of the signal over time can be used to determine whether the optical transmission system is functioning within the tolerances of the design specifications. Analysis of the intensity of the reflected portion can also be used to identify the potential location of faults in the optical transmission system. By comparing the detection time of the intensity peak of the reflected portion with the time since the optical signal was first transmitted to the first optical fiber core, it is possible to determine how far the optical signal has traveled along the optical transmission system. The distance traveled can be used to identify the location of potential faults in the optical transmission system. In some embodiments, optical time-domain reflectometry (OTDR) is used to identify the location of potential faults. In some embodiments, coherent OTDR (COTDR) is used to identify the location of potential faults. In some embodiments, the detected reflected portion of the signal is used to generate a graph for analyzing the state of the optical transmission system. In some embodiments, the analysis is performed using a controller to automatically identify potential faults in the optical transmission system. In some embodiments, the controller uses a trained neural network (NN) to analyze detected reflected portions of the signal and determine the state of the optical transmission system. In some embodiments, the controller is configured to automatically generate a notification to the operator of the optical transmission system in response to the detection of a potential fault in the optical transmission system. In some embodiments, the notification includes an audible or visual notification to the operator. In some embodiments, the notification is transmitted to a terminal device accessible to the operator using a wireless or wired connection. In some embodiments, the notification includes information related to recommendations for addressing a potential fault in the optical transmission system. In some embodiments, the controller is configured to receive commands from the operator for further analysis of the detected reflected portions of the signal.In some embodiments, the additional analysis includes a reexamination of the historical data, a reexamination of the environmental factors surrounding the optical transmission system, a reexamination of the repair options for the optical transmission system, or other suitable analysis.

[0020] In operation 130, a determination is made as to whether the optical transmission system is functioning properly. Functioning properly means operating within the error tolerance of the optical transmission system. The determination of whether it is functioning properly is made based on an analysis of the intensity of the reflected portion of the detected signal. In some embodiments, a threshold is used to determine whether an anomaly within the detected reflected portion of the signal is likely to be a fault within the optical transmission system. In some embodiments, the identification of a potential fault is transmitted to an operator of the optical transmission system via a wireless or wired connection for verification before completing the determination that it is not functioning properly. In some embodiments, the determination that it is not functioning properly is made automatically without verification from an operator of the optical transmission system.

[0021] In response to the determination that the optical transmission system is functioning properly, method 100 returns to operation 105 and continues to transmit the optical signal and monitor the performance of the optical transmission system. In response to the determination that the optical transmission system is not functioning properly, method 100 proceeds to operation 135. In some embodiments, if the fact that the optical transmission system is not functioning properly is less than a second threshold of the variance from the expected operation, method 100 performs both proceeding to operation 135 and returning to operation 105, enabling the optical transmission system to continue operating while the fault is being repaired or corrected. Utilizing the second threshold helps to avoid situations where the optical transmission system is prevented from continuing to operate in a state where it is still usable despite a reduction in accuracy or precision.

[0022] In operation 135, a repair command is generated to repair the optical transmission system. The repair command includes information related to recommendations on how to resolve or mitigate one or more faults determined to affect the performance of the optical transmission system. In some embodiments, operation 135 is performed using the same controller as at least one of operation 125 or operation 130. In some embodiments, operation 135 is performed using a different controller than those used in both operations 125 and 130. In some embodiments, the repair command includes the location of each of the one or more faults. In some embodiments, the repair command includes recommendations on whether a component of the optical transmission system should be repaired or replaced. In some embodiments, the repair command is transmitted to the operator of the optical transmission system via a wireless or wired connection for verification before transmitting the repair command to a repair technician. In some embodiments, the repair command is transmitted to the repair technician without verification by the operator. In some embodiments, verification by the operator is required based on the type of repair recommended by the repair command. For example, in some embodiments where the type of repair involves restarting or rebooting a component of the optical transmission system, the repair command is transmitted to the repair technician or directly to the component of the optical transmission system that should be restarted or rebooted without verification. In some embodiments where the type of repair involves physical interaction with the optical transmission system, for example, by repairing or replacing components, the repair command is validated before being transmitted to the repair technician.

[0023] Those skilled in the art will recognize that modifications to Method 100 are within the scope of this description. In some embodiments, at least one operation of Method 100 is omitted. For example, in some embodiments, operation 135 is omitted, and the operator determines the type of repair of the optical transmission system in response to the identified fault. In some embodiments, at least one additional operation is included in Method 100. For example, in some embodiments, in response to the identification of a potential fault, the optical transmission system transmits a probe signal for further diagnosis of the potential fault. In some embodiments, the order of operations of Method 100 is changed. For example, in some embodiments, operation 115 is performed before operation 110. In optical transmission systems including a FIFO device, the FIFO device may induce crosstalk between optical fiber cores. As a result, crosstalk induced by the FIFO device may occur before the reflection of some of the optical signal.

[0024] Method 100 can be used to monitor the performance of an optical transmission system. Compared to other methods, the optical transmission system can avoid introducing additional components into the optical transmission system, such as optical circuits for returning the reflected portion of the optical signal to the detector. As a result, the complexity of the optical transmission system is reduced compared to other methods. Furthermore, the number of potential fault points in the optical transmission system is reduced, and the cost of repairing and installing the optical transmission system is reduced compared to other methods.

[0025] Figure 2A is a schematic diagram of an optical transmission system 200 according to several embodiments. In some embodiments, the optical transmission system 200 can be used to perform method 100 (Figure 1). In some embodiments, the optical transmission system 200 can be used to perform methods other than method 100. The optical transmission system 200 includes a transceiver 205 configured to transmit an optical signal along an optical fiber 210 and to receive reflected signals from the optical fiber 210. The optical transmission system 200 further includes a plurality of spaced repeaters 215 along the optical fiber 210 to increase the intensity of the optical signal. The optical transmission system 200 further includes a transceiver 225 at the end of the optical fiber 210 opposite to the transceiver 205. In some embodiments, the transceiver 225 has the same or similar structure as the transceiver 205. In some embodiments, at least one of the transceiver 205 or the transceiver 225 is configured to communicate with a controller, such as a controller 700 (Figure 7), for analyzing the performance of the optical transmission system 200. For simplicity, the propagation direction from transceiver 205 to transceiver 225 is called the forward direction, and the propagation direction from transceiver 225 to transceiver 205 is called the reverse direction. Those skilled in the art will understand that this description applies to either transceiver 205 or transceiver 225, which is the source of the optical signal, and that the directions described above are used simply to clarify the description.

[0026] The transceiver 205 includes a transmitter configured to output an optical signal received by the optical fiber 210. The transmitter is configured to convert an electrical signal into an optical signal. In some embodiments, the optical signal is a pulsed signal. In some embodiments, the transmitter is configured to perform operation 105 of method 100 (Figure 1). The transceiver 205 further includes a detector configured to receive the reflected portion of the optical signal from the optical fiber 210. The detector is configured to convert the received reflected portion of the optical signal into an electrical signal. In some embodiments, the detector is configured to perform operation 120 of method 100 (Figure 1). The transceiver 205 is configured to provide the electrical signal from the detector to a controller such as a controller 700 (Figure 7) for analyzing the performance of the optical transmission system 200. In some embodiments, the controller is integrated into the transceiver 205. In some embodiments, the controller is separate from the transceiver 205.

[0027] The optical fiber 210 is configured to deliver an optical signal from transceiver 205 to transceiver 225. The optical fiber 210 includes a plurality of optical fiber cores housed within it. In some embodiments, the optical fiber 210 includes two optical fiber cores. In some embodiments, the optical fiber includes three or more optical fiber cores. In some embodiments, the optical fiber 210 includes an SCF optical fiber core. In some embodiments, the optical fiber 210 includes an MCF optical fiber core. The optical fiber cores in the optical fiber 210 are in close proximity to each other, allowing for crosstalk between the optical fiber cores. In some embodiments, at least two of the optical fiber cores in the optical fiber 210 are in direct physical contact.

[0028] The optical transmission system 200 further includes repeaters 215 spaced apart along the optical fiber 210. The repeaters 215 are configured to increase the intensity of the optical signal propagating along the optical fiber 210. As the optical signal propagates along the optical fiber 210, the intensity of the optical signal decreases due to reflection, crosstalk, diffusion, or other interactions that reduce the intensity of the optical signal. If the intensity of the optical signal is too low when it reaches the transceiver 225, the transceiver 225 will have difficulty accurately converting the optical signal into an electrical signal. The repeaters 215 are configured to increase the intensity of the optical signal toward the initial intensity of the optical signal, so that when it reaches the transceiver 225, the transceiver 225 can reliably detect the optical signal and convert it into a usable electrical signal.

[0029] The repeater 215 includes a plurality of optical amplifiers 220a, 220b. In some embodiments, each of the optical amplifiers 220a and 220b includes an erbium-doped fiber (EDF). In some embodiments, each of the optical amplifiers 220a and 220b includes a multicore EDF, where the first optical fiber core 212 and the second optical fiber core 214 are MCFs. In some embodiments, each of the optical amplifiers 220a and 220b includes a single-core EDF, where the first optical fiber core 212 and the second optical fiber core 214 are SCFs. The repeater 215 in Figure 2A includes one optical amplifier 220a for forward propagation and one optical amplifier 220b for backward propagation. Those skilled in the art will recognize that additional optical amplifiers are within the scope of this description.

[0030] The optical transmission system 200 further includes a transceiver 225. The transceiver 225 is configured to receive the optical signal output by the transceiver 205. In some embodiments, the transceiver 225 includes the same or similar structure as the transceiver 205.

[0031] Figure 2A includes enlarged portions of the optical fiber 210 and repeater 215. These enlarged portions provide additional details of the optical fiber 210 and repeater 215 to aid in understanding this description. The optical fiber 210 includes a first optical fiber core 212 configured to carry the optical signal during forward propagation. The optical fiber 210 includes a second optical fiber core 214 configured to carry the optical signal during backward propagation. Those skilled in the art will understand that three or more optical fiber cores within the optical fiber 210 are contemplated by this description. An optical amplifier 220a is connected to the first optical fiber core 212 to enhance the intensity of the optical signal as the optical signal propagates along the first optical fiber core 212. An optical amplifier 220b is connected to the second optical fiber core 214 to enhance the intensity of the optical signal as the optical signal propagates along the second optical fiber core 214.

[0032] During the operation of the optical transmission system 200, a portion of the optical signal propagating along the first optical fiber core 212 is reflected backward and returned to the transceiver 205. In some cases, this reflection is a result of Rayleigh scattering. In some embodiments, this reflection is a result of the optical signal encountering the interface between the first optical fiber core 212 and the optical amplifier 220a. The reflected portion of the optical signal is conceptually shown in Figure 2A by an arrow indicating a change in direction but remaining within the first optical fiber core 212.

[0033] Furthermore, during the operation of the optical transmission system 200, a portion of the reflected light signal propagating backward through the first optical fiber core 212 is transmitted to the second optical fiber core 214 due to crosstalk. Crosstalk occurs between the first optical fiber core 212 and the second optical fiber core 214 due to the proximity of the optical fiber cores and the optical coupling between them. The crosstalk portion of the optical fiber cores is conceptually shown in Figure 2A by an arrow exiting the first optical fiber core 212 and entering the second optical fiber core 214.

[0034] The detector in the transceiver 205 is configured to detect the crosstalk portion of the reflected optical signal from the second optical fiber core 214. Analyzing the output of the detection of the crosstalk portion of the reflected optical signal helps determine the performance of the optical transmission system 200. In some embodiments, the analysis of the crosstalk portion of the reflected optical signal is performed as described above with respect to method 100 (Figure 1). In some embodiments, the analysis of the crosstalk portion of the reflected optical signal is performed using a method other than method 100 (Figure 1).

[0035] Figure 2B is a graph 250 of the detector output in an optical transmission system according to several embodiments. Graph 250 includes a plot 255 of the intensity of the crosstalk portion of the reflected light signal as a function of distance from the transceiver 205 of the optical transmission system 200. Plot 255 shows spikes in intensity, followed by a decrease in intensity until the next intensity spike. The intensity spikes indicate the locations of the repeaters 215 along the optical fiber 210. The decrease in intensity shows how the intensity of the optical signal decreases as it propagates along the optical fiber 210 between the repeaters 215. Plot 255 shows the design performance of the optical transmission system 200. Plot 255 includes peaks with consistent heights that indicate the proper performance of the repeaters 215. Plot 255 further includes steady-state intensity decreases between the repeaters 215, showing the predicted intensity loss due to the propagation of the optical signal along the optical fiber 210.

[0036] Graph 250 further includes a potential fault plot 260. The potential fault plot 260 is a sharp drop in intensity, indicating a potential fault within the optical transmission system 200. This sharp drop in intensity indicates a possible break in the optical fiber 210. Using Graph 250, the presence and location of potential faults can be identified as distance from the transceiver 205. Other potential faults that can be identified using Graph 250 include repeater faults, which have a lower amplitude intensity peak or a U-shaped or N-shaped peak indicating that the intensity change occurred over a longer distance.

[0037] By analyzing the data in Graph 250, both the type and location of potential faults can be identified. In some embodiments, a controller, such as Controller 700 (Figure 7), can then generate recommendations for resolving potential faults, as described above with respect to Method 100 (Figure 1).

[0038] The optical transmission system 200 can detect its performance without including components such as optical circuits or FIFO devices. Furthermore, being able to determine not only the presence of a fault but also its location and type helps determine what repairs can be performed to improve the performance of the optical transmission system 200, if any. This helps reduce the complexity of the optical transmission system 200 compared to other methods, as well as the installation and maintenance costs of the optical transmission system 200 compared to other methods.

[0039] Figure 2A includes an optical transmission system 200 that transmits optical signals between two transceivers 205 and 225, but those skilled in the art will understand that the optical transmission system 200 may include additional components in some embodiments. These additional components may include features such as gratings, multiplexers, optical couplers, or other suitable components, or components that guide optical signals to intended locations throughout the optical transmission network.

[0040] Figure 3A is a schematic diagram of an optical transmission system 300 according to several embodiments. In some embodiments, the optical transmission system 300 can be used to perform method 100 (Figure 1). In some embodiments, the optical transmission system 300 can be used to perform methods other than method 100. The optical transmission system 300 includes a transceiver 305 configured to transmit an optical signal along an optical fiber 210 and to receive reflected signals from the optical fiber 210. In some embodiments, the optical fiber 210 is an MCF. The optical transmission system 300 further includes a plurality of spaced repeaters 315 along the optical fiber 210 to increase the intensity of the optical signal. The optical transmission system 300 further includes a transceiver 325 at the end of the optical fiber 210 opposite to the transceiver 305. In some embodiments, the transceiver 325 has the same or similar structure as the transceiver 305. In some embodiments, at least one of the transceivers 305 or 325 is configured to communicate with a controller, such as a controller 700 (Figure 7), for analyzing the performance of the optical transmission system 300. For simplicity, the propagation direction from transceiver 305 to transceiver 325 is referred to as the forward direction, and the propagation direction from transceiver 325 to transceiver 305 is referred to as the reverse direction. Those skilled in the art will understand that this description applies to either transceiver 305 or transceiver 325, which is the source of the optical signal, and that the directions described above are used simply to clarify the description.

[0041] Transceiver 305 is the same as transceiver 205 (Figure 2A), and will not be described in detail for the sake of brevity. Optical fiber 210 is the same as optical fiber 210 (Figure 2A), and will not be described in detail for the sake of brevity.

[0042] The optical transmission system 300 further includes repeaters 315 spaced apart along the optical fiber 210. The repeaters 315 are configured to increase the intensity of the optical signal propagating along the optical fiber 210. Compared to the repeater 215 (Figure 2A), the repeater 315 includes a FIFO device 330 at the interface between the repeater 315 and the optical fiber 210. Details of the FIFO device 330 are described below in Figure 4 according to several embodiments. The FIFO device 330 helps to connect the MCF of the optical fiber 210 to the single-core EDF of the repeater 315. By including FIFO devices 330 on both sides of the repeater 315, the optical signal is transitioned from the MCF of the optical fiber 210 to the single-core EDF of the repeater 315 for both forward and backward propagation.

[0043] Repeater 315 includes a plurality of optical amplifiers 320a, 320b. Optical amplifiers 320a and 320b are similar to optical amplifiers 220a and 220b (Figure 2A) and will not be described in detail for brevity. Repeater 315 in Figure 3A includes one optical amplifier 320a for forward propagation and one optical amplifier 320b for back propagation. Those skilled in the art will recognize that additional optical amplifiers are within the scope of this description.

[0044] The optical transmission system 300 further includes a transceiver 325. The transceiver 325 is configured to receive the optical signal output by the transceiver 305. In some embodiments, the transceiver 325 includes the same or similar structure as the transceiver 305.

[0045] Figure 3A includes enlarged portions of the optical fiber 210 and repeater 315. These enlarged portions provide additional details of the optical fiber 210 and repeater 315 to aid in understanding this description. The optical fiber 210 includes a first optical fiber core 212 configured to carry the optical signal during forward propagation. The optical fiber 210 includes a second optical fiber core 214 configured to carry the optical signal during backward propagation. Those skilled in the art will understand that three or more optical fiber cores in the optical fiber 210 are contemplated by this description. An optical amplifier 320a is connected to the first optical fiber core 212 to enhance the intensity of the optical signal as the optical signal propagates along the first optical fiber core 212. An optical amplifier 320b is connected to the second optical fiber core 214 to enhance the intensity of the optical signal as the optical signal propagates along the second optical fiber core 214. A FIFO device 330 can be used to optically connect the first optical fiber core 212 to the optical amplifier 320a and to connect the second optical fiber core 214 to the optical amplifier 320b.

[0046] During the operation of the optical transmission system 300, a portion of the optical signal propagating along the first optical fiber core 212 is reflected backward and returned to the transceiver 305. In some cases, this reflection is a result of Rayleigh scattering. In some embodiments, this reflection is a result of the optical signal encountering the interface between the first optical fiber core 212 and the optical amplifier 320a. In some embodiments, this reflection is a result of the optical signal encountering the interface between the first optical fiber core 212 and the FIFO device 330. The reflected portion of the optical signal is conceptually shown in Figure 3A by arrows indicating a change in direction but remaining within the first optical fiber core 212.

[0047] Furthermore, during the operation of the optical transmission system 300, a portion of the reflected light signal propagating backward through the first optical fiber core 212 is transmitted to the second optical fiber core 214 by crosstalk. Crosstalk occurs between the first optical fiber core 212 and the second optical fiber core 214 due to the proximity of the optical fiber cores and the optical coupling between them. The crosstalk portion of the optical fiber cores is conceptually shown in Figure 3A by an arrow exiting the first optical fiber core 212 and entering the second optical fiber core 214. In addition, in some cases, crosstalk is introduced by the FIFO device 330 at the interface between the FIFO device 330 and the optical fiber 210.

[0048] The detector in the transceiver 305 is configured to detect the crosstalk portion of the reflected optical signal from the second optical fiber core 214. Analyzing the output of the detection of the crosstalk portion of the reflected optical signal helps determine the performance of the optical transmission system 300. In some embodiments, the analysis of the crosstalk portion of the reflected optical signal is performed as described above with respect to method 100 (Figure 1). In some embodiments, the analysis of the crosstalk portion of the reflected optical signal is performed using a method other than method 100 (Figure 1).

[0049] Figure 3B is a graph 350 of the detector output in an optical transmission system according to several embodiments. Graph 350 includes a plot 355 of the intensity of the crosstalk portion of the reflected light signal as a function of distance from the transceiver 305 of the optical transmission system 300. Graph 350 further includes a potential fault plot 360. The analysis of graph 350 is similar to the analysis of graph 250 (Figure 2B) and will not be described in detail for brevity.

[0050] The optical transmission system 300 can detect its performance without including components such as optical circuits. Furthermore, being able to determine not only the presence of a fault but also its location and type helps determine what repairs can be performed to improve the performance of the optical transmission system 300, if any. This helps reduce the complexity of the optical transmission system 300 compared to other methods, as well as the installation and maintenance costs of the optical transmission system 300 compared to other methods.

[0051] Figure 3A includes an optical transmission system 300 that transmits optical signals between two transceivers 305 and 325, but those skilled in the art will understand that the optical transmission system 300 may include additional components in some embodiments. These additional components may include features such as gratings, multiplexers, optical couplers, or other suitable components, or components that guide optical signals to intended locations throughout the optical transmission network.

[0052] Figure 4 is a schematic diagram of a fan-in-fan-out (FIFO) device 400 according to several embodiments. The FIFO device 400 is configured to receive a signal from a first optical fiber core 405 and transmit the optical signal to a second optical fiber core 420. The FIFO device 400 is further configured to receive an optical signal from a third optical fiber core 425 and transmit the optical signal to a fourth optical fiber core 410. The FIFO device 400 includes a spatial multiplexer or demultiplexer 415. In some embodiments, the spatial multiplexer or demultiplexer 415 is configured to facilitate the transition between SCF and MCF for bidirectional optical signal propagation. In some embodiments, the spatial multiplexer or demultiplexer 415 is configured to multiplex or demultiplex the optical signal based on the frequency of the optical signal. In some embodiments, the spatial multiplexer or demultiplexer 415 is configured to multiplex or demultiplex the optical signal based on time. In some cases, during multiplexing or demultiplexing, the spatial multiplexer or demultiplexer 415 generates crosstalk 430 due to some of the optical signal being directed toward an unintended output. The FIFO device 400 can be used in different embodiments of this description to enable connections between SCF and MCF components of an optical transmission system.

[0053] Figure 5A is a schematic diagram of an optical transmission system 500 according to several embodiments. In some embodiments, the optical transmission system 500 can be used to perform method 100 (Figure 1). In some embodiments, the optical transmission system 500 can be used to perform methods other than method 100. The optical transmission system 500 includes a transceiver 505 configured to transmit an optical signal along an optical fiber core 312 and to receive a reflected signal from an optical fiber core 314. The optical transmission system 500 further includes a plurality of repeaters 215 spaced apart along the optical fiber cores 312 and 314 to increase the intensity of the optical signal. The optical transmission system 500 further includes a transceiver 525 at the end of the optical fiber 312 opposite to the transceiver 505. In some embodiments, the transceiver 525 has the same or similar structure as the transceiver 505. In some embodiments, at least one of the transceivers 505 or 525 is configured to communicate with a controller, such as a controller 700 (Figure 7), for analyzing the performance of the optical transmission system 500. For simplicity, the propagation direction from transceiver 505 to transceiver 525 is referred to as the forward direction, and the propagation direction from transceiver 525 to transceiver 505 is referred to as the reverse direction. Those skilled in the art will understand that this description applies to either transceiver 505 or transceiver 525, which is the source of the optical signal, and that the directions described above are used simply to clarify the description.

[0054] Transceiver 505 is similar to transceiver 205 (Figure 2A) and will not be described in detail for brevity. Optical fiber cores 212 and 214 are similar to optical fiber core 210 of optical transmission system 300 (Figure 3A) and will not be described in detail for brevity.

[0055] The optical transmission system 500 further includes repeaters 215 spaced apart along the optical fiber cores 312 and 314. The repeaters 215 are described above with respect to the optical transmission system 200 (Figure 2A). Compared to the optical transmission system 200 (Figure 2A) and the optical transmission system 300 (Figure 3A), the optical transmission system 500 includes a FIFO device 330 between the repeaters 215 and the optical fiber cores 312. The FIFO device 330 is also present between the repeaters 215 and the optical fiber cores 314. Details of the FIFO device 330 are described above in Figure 4 according to several embodiments. The FIFO device 330 helps to connect the SCF, i.e., the optical fiber cores 312 or 314, to the multicore EDF of the repeaters 215. By including FIFO devices 330 on both sides of repeater 215, the optical signal transitions from the SCF of optical fiber cores 312 and 314 to the multicore EDF of repeater 215 for both forward and backward propagation.

[0056] The optical transmission system 500 further includes a transceiver 525. The transceiver 525 is configured to receive the optical signal output by the transceiver 505. In some embodiments, the transceiver 525 includes the same or similar structure as the transceiver 505.

[0057] Figure 5A includes enlarged portions of the optical fiber cores 312 and 314 and the repeater 215. These enlarged portions provide further details of the optical fiber cores 312 and 314 and the repeater 215 to aid in understanding this description. The optical fiber core 312 is configured to carry the optical signal during forward propagation. The optical fiber core 314 is configured to carry the optical signal during backward propagation. Those skilled in the art will understand that three or more optical fiber cores are contemplated by this description. An optical amplifier 220a is connected to the first optical fiber core 312 to enhance the intensity of the optical signal as the optical signal propagates along the first optical fiber core 312. An optical amplifier 220b is connected to the second optical fiber core 314 to enhance the intensity of the optical signal as the optical signal propagates along the second optical fiber core 314. A FIFO device 330 can be used to optically connect the first optical fiber core 312 to the optical amplifier 220a and to connect the second optical fiber core 314 to the optical amplifier 220b.

[0058] During the operation of the optical transmission system 500, a portion of the optical signal propagating along the first optical fiber core 312 is reflected backward and returned to the transceiver 505. In some cases, this reflection is a result of Rayleigh scattering. In some embodiments, this reflection is a result of the optical signal encountering the interface between the first optical fiber core 312 and the optical amplifier 220a. In some embodiments, this reflection is a result of the optical signal encountering the interface between the first optical fiber core 312 and the FIFO device 330. The reflected portion of the optical signal is similar to that described above and is not conceptually shown in Figure 5A for clarity in the drawings.

[0059] Furthermore, during the operation of the optical transmission system 500, in some cases, crosstalk is introduced by the FIFO device 330 at the interface between the FIFO device 330 and the optical fiber cores 312 and 314. The crosstalk portion of the optical signal is similar to that described above and is not conceptually shown in Figure 5A for clarity.

[0060] The detector in the transceiver 505 is configured to detect the crosstalk portion of the reflected optical signal from the second optical fiber core 314. Analyzing the output of the detection of the crosstalk portion of the reflected optical signal helps determine the performance of the optical transmission system 500. In some embodiments, the analysis of the crosstalk portion of the reflected optical signal is performed as described above with respect to method 100 (Figure 1). In some embodiments, the analysis of the crosstalk portion of the reflected optical signal is performed using a method other than method 100 (Figure 1).

[0061] Figure 5B is a graph 550 of the detector output in an optical transmission system according to several embodiments. Graph 500 includes a plot 555 of the intensity of the crosstalk portion of the reflected light signal as a function of distance from the transceiver 505 of the optical transmission system 500. Compared to graph 250 (Figure 2B), plot 555 does not include the intensity drop between repeaters. Identification of potential faults in the optical transmission system 500 is possible based on whether the peaks in plot 555 are n-shaped or U-shaped. Potential defects can also be identified based on the magnitude of the peaks in plot 555 being smaller than the other peaks in plot 555.

[0062] The optical transmission system 500 can detect its performance without including components such as optical circuits. Furthermore, being able to determine not only the presence of a fault but also its location and type helps determine what repairs can be performed to improve the performance of the optical transmission system 500, if any. This helps reduce the complexity of the optical transmission system 500 compared to other methods, as well as the installation and maintenance costs of the optical transmission system 500 compared to other methods.

[0063] Figure 5A includes an optical transmission system 500 that transmits optical signals between two transceivers 505 and 525, but those skilled in the art will understand that in some embodiments the optical transmission system 500 includes additional components. These additional components include features such as gratings, multiplexers, optical couplers, or other suitable components, or components that guide optical signals to intended locations throughout the optical transmission network.

[0064] Figure 6A is a schematic diagram of an optical transmission system 600 according to several embodiments. In some embodiments, the optical transmission system 600 can be used to perform method 100 (Figure 1). In some embodiments, the optical transmission system 600 can be used to perform methods other than method 100. The optical transmission system 600 includes a transceiver 205 configured to transmit an optical signal along an optical fiber 210 and to receive reflected signals from the optical fiber 210. The optical transmission system 600 further includes a plurality of spaced repeaters 215 along the optical fiber 210 to increase the intensity of the optical signal. The optical transmission system 600 further includes a transceiver 225 at the end of the optical fiber 210 opposite to the transceiver 205. In some embodiments, the transceiver 225 has the same or similar structure as the transceiver 205. In some embodiments, at least one of the transceiver 205 or the transceiver 225 is configured to communicate with a controller, such as a controller 700 (Figure 7), for analyzing the performance of the optical transmission system 600. For simplicity, the propagation direction from transceiver 205 to transceiver 225 is called the forward direction, and the propagation direction from transceiver 225 to transceiver 205 is called the reverse direction. Those skilled in the art will understand that this description applies to either transceiver 205 or transceiver 225, which is the source of the optical signal, and that the directions described above are used simply to clarify the description.

[0065] Transceiver 205 is described above in relation to the optical transmission system 200 (Figure 2A). Optical fiber 210 is described above in relation to the optical transmission system 200 (Figure 2A). Repeater 215 is described above in relation to the optical transmission system 200 (Figure 2A). Transceiver 225 is described above in relation to the optical transmission system 200 (Figure 2A).

[0066] Compared to optical transmission system 200 (Figure 2A), optical transmission system 600 includes a grating 630. In some embodiments, the grating 630 is located within a first optical fiber core 212. In some embodiments, the grating 630 is located within a second optical fiber core 214. In some embodiments, the grating 630 is located in both the first optical fiber core 212 and the second optical fiber core 214. Figure 6A includes the grating 630 at a single location along the optical fiber 210. In some embodiments, the grating 630 is located at various locations along the optical fiber 210, within one of the optical fiber cores in the optical fiber 210.

[0067] Figure 6A includes several enlarged sections of the optical fiber 210 and repeater 215. These enlarged sections provide additional details of the optical fiber 210 and repeater 215 to aid in understanding this description. The optical fiber 210 includes a first optical fiber core 212 configured to carry the optical signal during forward propagation. The optical fiber 210 includes a second optical fiber core 214 configured to carry the optical signal during backward propagation. Those skilled in the art will understand that three or more optical fiber cores in the optical fiber 210 are contemplated by this description. An optical amplifier 220a is connected to the first optical fiber core 212 to enhance the intensity of the optical signal as the optical signal propagates along the first optical fiber core 212. An optical amplifier 220b is connected to the second optical fiber core 214 to enhance the intensity of the optical signal as the optical signal propagates along the second optical fiber core 214. The enlarged sections include examples of the location of the grating 630. Those skilled in the art will understand that these locations are merely examples and that other locations and additional gratings 630 are within the scope of this description.

[0068] During the operation of the optical transmission system 600, a portion of the optical signal propagating along the first optical fiber core 212 is reflected backward and returned to the transceiver 205. In some cases, this reflection is a result of Rayleigh scattering. In some embodiments, this reflection is a result of the optical signal encountering the interface between the first optical fiber core 212 and the optical amplifier 220a. In some embodiments, this reflection is a result of the optical signal encountering the grating 630. The reflected portion of the optical signal is conceptually shown in Figure 6A by arrows indicating a change in direction but remaining within the first optical fiber core 212. In some embodiments, forward crosstalk occurs as the optical signal propagates along the first optical fiber core 212, and this forward crosstalk is reflected by the grating 630 in the second optical fiber core 214 and returned to the transceiver 205.

[0069] Furthermore, during the operation of the optical transmission system 600, a portion of the reflected light signal propagating backward through the first optical fiber core 212 is transmitted to the second optical fiber core 214 due to crosstalk. Crosstalk occurs between the first optical fiber core 212 and the second optical fiber core 214 due to the proximity of the optical fiber cores and the optical coupling between them. The crosstalk portion of the optical fiber cores is conceptually shown in Figure 6A by an arrow exiting the first optical fiber core 212 and entering the second optical fiber core 214.

[0070] The detector in the transceiver 205 is configured to detect the crosstalk portion of the reflected optical signal from the second optical fiber core 214. Analyzing the output of the detection of the crosstalk portion of the reflected optical signal helps determine the performance of the optical transmission system 600. In some embodiments, the analysis of the crosstalk portion of the reflected optical signal is performed as described above with respect to method 100 (Figure 1). In some embodiments, the analysis of the crosstalk portion of the reflected optical signal is performed using a method other than method 100 (Figure 1).

[0071] Figure 6B is a graph 650 of the detector output in an optical transmission system according to several embodiments. Graph 650 includes a plot 655 of the intensity of the crosstalk portion of the reflected light signal as a function of distance from the transceiver 205 of the optical transmission system 600. Graph 650 further includes a potential fault plot 660. The analysis of graph 650 is similar to the analysis of graph 250 (Figure 2B) and will not be described in detail for brevity.

[0072] The optical transmission system 600 can detect its performance without including components such as optical circuits or FIFO devices. Furthermore, being able to determine not only the presence of a fault but also its location and type helps determine what repairs can be performed to improve the performance of the optical transmission system 600, if any. This helps reduce the complexity of the optical transmission system 600 compared to other methods, as well as the installation and maintenance costs of the optical transmission system 600 compared to other methods.

[0073] Figure 6A includes an optical transmission system 600 that transmits optical signals between two transceivers 205 and 225, but those skilled in the art will understand that in some embodiments the optical transmission system 600 includes additional components. These additional components include features such as gratings, multiplexers, optical couplers, or other suitable components, or components that guide optical signals to intended locations throughout the optical transmission network.

[0074] Furthermore, while the optical transmission system 600 includes elements similar to those of the optical transmission system 200 (Figure 2A), those skilled in the art will recognize that the inclusion of a grating 630 or similar structure is also applicable to the optical transmission system 300 (Figure 3A) and the optical transmission system 500 (Figure 5A).

[0075] Figure 7 is a block diagram of a controller 700 usable in an optical transmission system according to several embodiments. The controller 700 includes a hardware processor 702 and a non-temporary computer-readable storage medium 704 that stores a set of executable instructions, encoded in computer program code 706, i.e., a set of executable instructions. The computer-readable storage medium 704 is also encoded in instructions 707 for interfacing with external devices. The processor 702 is electrically coupled to the computer-readable storage medium 704 via a bus 708. The processor 702 is also electrically coupled to an input / output (I / O) interface 710 via the bus 708. A network interface 712 is also electrically connected to the processor 702 via the bus 708. The network interface 712 is connected to a network 714 so that the processor 702 and the computer-readable storage medium 704 can connect to external elements via the network 714. The processor 702 is configured to execute computer program code 706 encoded in a computer-readable storage medium 704 in order to enable the controller 700 to perform some or all of the operations described in Method 100 (Figure 1), Optical Transmission System 200 (Figure 2A), Optical Transmission System 300 (Figure 3A), Optical Transmission System 500 (Figure 5A), or Optical Transmission System 600 (Figure 6A).

[0076] In some embodiments, the processor 602 is a central processing unit (CPU), a multiprocessor, a distributed processing system, an application-specific integrated circuit (ASIC), and / or a suitable processing unit.

[0077] In some embodiments, the computer-readable storage medium 704 is an electronic, magnetic, optical, electromagnetic, infrared, and / or semiconductor system (or apparatus or device). For example, the computer-readable storage medium 704 includes semiconductor or solid-state memory, magnetic tape, removable computer diskette, random access memory (RAM), read-only memory (ROM), rigid magnetic disk, and / or optical disk. In some embodiments using optical disks, the computer-readable storage medium 504 includes compact disc read-only memory (CD-ROM), compact disc read / write (CD-R / W), and / or digital video disc (DVD).

[0078] In some embodiments, the storage medium 704 stores computer program code 706 configured to cause the controller 700 to execute some or all of the operations described in Method 100 (Figure 1), Optical Transmission System 200 (Figure 2A), Optical Transmission System 300 (Figure 3A), Optical Transmission System 500 (Figure 5A), or Optical Transmission System 600 (Figure 6A). In some embodiments, the storage medium 704 also stores information used to execute some or all of the operations described in Method 100 (Figure 1), Optical Transmission System 200 (Figure 2A), Optical Transmission System 300 (Figure 3A), Optical Transmission System 500 (Figure 5A), or Optical Transmission System 600 (Figure 6A), and information used to execute some or all of the operations described in Method 100 (Figure 1), Optical Transmission System 200 (Figure 2A), Optical Transmission System 300 (Figure 3A), Optical Transmission System 500 (Figure 5A), or Optical Transmission System 600 (Figure 6A). It stores information generated during the execution of some or all of the operations described above, such as the position data parameter 716, the threshold parameter 718, the detector data parameter 720, the repair command parameter 722, and / or a set of executable commands for executing some or all of the operations described in Method 100 (Figure 1), Optical Transmission System 200 (Figure 2A), Optical Transmission System 300 (Figure 3A), Optical Transmission System 500 (Figure 5A), or Optical Transmission System 600 (Figure 6A).

[0079] In some embodiments, the storage medium 704 stores instructions 707 for interfacing with an external device, such as a terminal device accessible by an operator or repair technician. The instructions 707 enable the processor 702 to generate manufacturing instructions readable by the external device in order to effectively implement some or all of the operations described in Method 100 (Figure 1), Optical Transmission System 200 (Figure 2A), Optical Transmission System 300 (Figure 3A), Optical Transmission System 500 (Figure 5A), or Optical Transmission System 600 (Figure 6A).

[0080] The controller 700 includes an I / O interface 710, which is coupled to external circuitry. In some embodiments, the I / O interface 710 includes a keyboard, keypad, mouse, trackball, trackpad, and / or cursor directional keys for communicating information and commands to the processor 702.

[0081] The controller 700 also includes a network interface 712 coupled to the processor 702. The network interface 712 enables the controller 700 to communicate with a network 714 to which one or more other computer systems are connected. The network interface 712 includes wireless network interfaces such as BLUETOOTH®, WIFI, WiMAX, GPRS, or WCDMA®, or wired network interfaces such as ETHERNET, USB, or IEEE-1394. In some embodiments, some or all of the operations described in Method 100 (Figure 1), Optical Transmission System 200 (Figure 2A), Optical Transmission System 300 (Figure 3A), Optical Transmission System 500 (Figure 5A), or Optical Transmission System 600 (Figure 6A) are implemented in two or more controllers 700, and information such as position data, thresholds, detector data, and repair commands is exchanged between different controllers 700 via the network 714.

[0082] Some or all of the above embodiments may also be described as follows, but are not limited to the following.

[0083] (Note 1) It is an optical transmission system, A transceiver configured to output an optical signal to a first optical fiber core, A repeater connected to the first optical fiber core and configured to increase the intensity of the optical signal, A second optical fiber core is located adjacent to the first optical fiber core and configured to receive crosstalk from the first optical fiber core, and is also configured to reflect a portion of the crosstalk of the optical signal back to the transceiver, A detector configured to receive the reflected portion of the crosstalk of the optical signal and to receive detection data based on the reflected portion of the crosstalk of the optical signal, To receive information regarding the aforementioned detection data, Based on the detection data, it is determined whether the optical transmission system is functioning properly, In response to the determination that the optical transmission system is not functioning properly, the location of the fault in the optical transmission system is determined. The configured controller and An optical transmission system equipped with [the necessary components].

[0084] (Note 2) The optical transmission system according to Appendix 1, further comprising a repeater connected to the first optical fiber core and the second optical fiber core, wherein the repeater is configured to increase the intensity of the optical signal.

[0085] (Note 3) The optical transmission system described in Appendix 2, wherein the repeater is a multicore erbium-doped fiber (EDF).

[0086] (Note 4) The optical transmission system as described in Appendix 2, wherein the repeater is a single-core erbium-doped fiber (EDF).

[0087] (Note 5) The optical transmission system according to Appendix 1 or 2, further comprising a grating on at least one of the first optical fiber core or the second optical fiber core.

[0088] (Note 6) The optical transmission system according to any one of appendices 2 to 5, further comprising a fan-in-fan-out (FIFO) device between the first optical fiber core and the repeater.

[0089] (Note 7) The optical transmission system according to any one of appendices 2 to 6, wherein the interface between the first optical fiber core and the repeater is configured to reflect the portion of the optical signal.

[0090] (Note 8) The first optical fiber core and the second optical fiber core are located within a multicore fiber (MCF) and are part of an optical transmission system as described in any one of the appendices 1 to 7.

[0091] (Note 9) The first optical fiber core is located within a single-core fiber (SCF) in the optical transmission system described in Appendix 3.

[0092] (Note 10) The optical transmission system according to any one of the appendices 1 to 9, wherein the intensity of the reflected portion is less than approximately 20% of the intensity of the optical signal.

[0093] (Note 11) The optical transmission system according to any one of appendices 1 to 10, further comprising a grating within the first optical fiber core, wherein the grating is configured to reflect the portion of the optical signal.

[0094] (Note 12) The optical transmission system described in any one of the appendices 1 to 11, wherein the optical transmission system does not include an optical circuit.

[0095] (Note 13) The optical transmission system is a submarine optical transmission system, or an optical transmission system described in any one of the appendices 1 to 13.

[0096] (Note 14) The optical transmission system according to Appendix 1, wherein the first optical fiber core is part of a multicore fiber (MCF), and the repeater is a multicore erbium-doped fiber (EDF).

[0097] (Note 15) The optical transmission system according to Appendix 1, wherein the first optical fiber core is part of an MCF and the repeater is a single-core EDF.

[0098] (Note 16) The optical transmission system according to Appendix 1, wherein the first optical fiber core is a single-core fiber (SCF) and the repeater is a multi-core EDF.

[0099] (Note 17) The optical transmission system according to any one of appendices 1, 14, and 15, further comprising a fan-in-fan-out (FIFO) device between the first optical fiber core and the repeater.

[0100] (Note 18) The optical transmission system according to any one of appendices 1 and 14 to 16, wherein the interface between the first optical fiber core and the repeater is configured to reflect the portion of the optical signal.

[0101] (Note 19) The optical transmission system according to any one of appendices 1 and 14 to 17, further comprising a grating on the first optical fiber core, wherein the grating is configured to partially reflect the optical signal.

[0102] (Note 20) The optical transmission system according to any one of appendices 1 and 14 to 18, further comprising a grating on the second optical fiber core, wherein the grating is configured to reflect the portion of the crosstalk of the optical signal.

[0103] (Note 21) A method for determining the performance of an optical transmission system, Transmitting an optical signal along the first optical fiber core, Reflecting a portion of the aforementioned optical signal, The reflected portion of the optical signal is transmitted to the second optical fiber core via crosstalk between the first optical fiber core and the second optical fiber core. The process involves detecting the crosstalk of the reflected portion of the optical signal and generating detection data. The performance of the optical transmission system is determined based on the detection data, In response to a determination that the optical transmission system is not functioning properly, to identify the location of a fault in the optical transmission system. Methods that include...

[0104] The above outlines some features of embodiments so that those skilled in the art may better understand aspects of the disclosure. Those skilled in the art will understand that the disclosure can be readily used as a basis for designing or modifying other processes and structures to perform the same purposes and / or achieve the same advantages as the embodiments introduced herein. Those skilled in the art will also understand that such equivalent configurations do not deviate from the spirit and scope of the disclosure, and that various changes, substitutions, and alternatives can be made herein without departing from the spirit and scope of the disclosure.

[0105] This application claims priority based on U.S. Patent Application No. 18 / 616,059, filed on 25 March 2024, and incorporates all of its disclosures herein. [Explanation of Symbols]

[0106] 200 Optical Transmission Systems 205 Transceiver 210 optical fibers 212 First optical fiber core 214 Second optical fiber core 215 Repeat Customers 220a Optical Amplifier 220b Optical Amplifier 225 Transceiver 300 Optical Transmission Systems 305 Transceiver 312 Fiber Optic Cores 314 Fiber Optic Core 315 Repeat Customers 320a Optical Amplifier 320b Optical Amplifier 325 Transceiver 330 FIFO devices 400 Fan-In / Fan-Out (FIFO) Devices 405 First Optical Fiber Core 410 Fourth Optical Fiber Core 415 Spatial multiplexer or demultiplexer 420 Second optical fiber core 425 Third Fiber Optic Core 500 Optical Transmission Systems 505 Transceiver 525 Transceiver 600 Optical Transmission Systems 602 Processors 630 Grating 700 Controllers 702 Hardware Processors 704 Non-temporary computer-readable storage medium 706 Computer program code 707 Command 708 Bus 710 Input / Output (I / O) Interfaces 712 Network Interfaces 714 Network 716 Location data parameters 718 Threshold parameters 720 Detector Data Parameters 722 Repair Instruction Parameters

Claims

1. It is an optical transmission system, A transceiver configured to output an optical signal to a first optical fiber core, A repeater connected to the first optical fiber core and configured to increase the intensity of the optical signal, A second optical fiber core is located adjacent to the first optical fiber core and configured to receive crosstalk from the first optical fiber core, and is also configured to reflect a portion of the crosstalk of the optical signal back to the transceiver, A detector configured to receive the reflected portion of the crosstalk of the optical signal and to receive detection data based on the reflected portion of the crosstalk of the optical signal, To receive information regarding the aforementioned detection data, Based on the detection data, it is determined whether the optical transmission system is functioning properly, In response to the determination that the optical transmission system is not functioning properly, the location of the fault in the optical transmission system is determined. The configured controller and A grating introduced into the first optical fiber core and causing reflection of a portion of the optical signal, An optical transmission system equipped with [the necessary components].

2. The optical transmission system according to claim 1, further comprising a repeater connected to the first optical fiber core, wherein the repeater is configured to increase the intensity of the optical signal.

3. The optical transmission system according to claim 2, wherein the repeater is a multicore erbium-doped fiber (EDF).

4. The optical transmission system according to claim 2, wherein the repeater is a single-core erbium-doped fiber (EDF).

5. The optical transmission system according to claim 1, wherein the first optical fiber core and the second optical fiber core are located within a multicore fiber (MCF).

6. The optical transmission system according to claim 3, wherein the first optical fiber core is located within a single-core fiber (SCF).

7. A method for determining the performance of an optical transmission system, Transmitting an optical signal along the first optical fiber core, Reflecting a portion of the aforementioned optical signal, The reflected portion of the optical signal is transmitted to the second optical fiber core via crosstalk between the first optical fiber core and the second optical fiber core. The process involves detecting the crosstalk of the reflected portion of the optical signal and generating detection data. The performance of the optical transmission system is determined based on the detection data, In response to a determination that the optical transmission system is not functioning properly, to identify the location of a fault in the optical transmission system. Includes, A method wherein a grating introduced into the first optical fiber core causes reflection of a portion of the optical signal.

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