Bidirectional loopback amplifier used for optical sensing applications

Abstract

To provide optical signal transmission methods and loopback bidirectional amplifiers used for optical sensing applications.SOLUTION: In a bidirectional optical sensing system, a repeater 531 comprises a bidirectional amplification device 530 communicatively coupled between a first communication terminal and a second communication terminal. The first and second communication terminals are communicatively coupled using an optical communication link. The bidirectional amplification device is configured to transmit and amplify one or more optical sensing signals 533, 539 transmitted in either direction between the first communication terminal and the second communication terminal. The one or more optical sensing signals indicate a status of one or more portions of the optical communication link.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates generally to optical communication systems, and more particularly to loopback bidirectional amplifiers for use in optical sensing applications. [Background technology]

[0002] Submarine optical cables are laid on the seabed or ocean floor between land-based terminals to carry optical signals across large oceans and marine areas. Optical cables typically comprise several optical fiber pairs and other components, such as strength members, power conductors, electrical insulators, and protective shields. The optical fibers may be single-mode or multimode optical fibers. A first optical fiber of the optical fiber pair can be coupled to a system for transmitting a signal in a first direction through the cable, and a second optical fiber of the optical fiber pair can be configured to transmit a signal in a second direction opposite the first direction through the cable, thereby supporting bidirectional communication. Some conventional systems use various amplification devices to amplify sensing signals that may be reflected along the optical communication path. The sensing signals can indicate various conditions along the path, such as cable breaks, interference, or seismic events. Typical systems use separate amplifiers to amplify the sensing signals transmitted in the reverse direction, which significantly increases the complexity and cost of the optical communication system's structure and function, and increases the risk of signal loss, signal errors, and other undesirable problems. Summary of the Invention

[0003] In some embodiments, the present subject matter relates to an apparatus for transmitting optical signals. The apparatus may include a bidirectional amplifying device communicatively coupled between a first communication terminal and a second communication terminal. The first and second communication terminals may be communicatively coupled by an optical communication link. The bidirectional amplifying device may be configured to transmit and amplify one or more optical sensing signals transmitted in either direction between the first communication terminal and the second communication terminal. The optical sensing signals may indicate a condition of one or more portions of the optical communication link.

[0004] In some embodiments, the present subject matter may include one or more of the following preferred features: The optical communications link may be configured to transmit one or more optical data signals.

[0005] In some embodiments, the bidirectional amplifying device may be configured to transmit a first optical sensing signal of the one or more optical sensing signals in a first direction from a first communication terminal to a second communication terminal and to amplify a first reflected optical sensing signal transmitted from the second communication terminal to the first communication terminal in a second direction. The device may be configured to transmit a second optical sensing signal of the one or more optical sensing signals in the second direction from the second communication terminal to the first communication terminal and to amplify a second reflected optical sensing signal transmitted from the first communication terminal to the second communication terminal in the first direction.

[0006] In some embodiments, the bidirectional amplifying device may include an active gain medium optical component. The active gain medium optical component may be configured to amplify at least one of the first reflected optical sensing signal, the second reflected optical sensing signal, the first optical sensing signal, the second optical sensing signal, and any combination thereof. The bidirectional amplifying device may include at least one of one or more isolators, one or more wavelength division multiplexing (WDM) optical components, one or more circulators, one or more bandpass filters, one or more optical couplers, and any combination thereof. The one or more WDM optical components may be coupled to one or more pumps. The one or more pumps may be laser pumps. The one or more isolators may be configured to isolate the one or more pumps from one or more optical signals backscattered from the active gain medium optical component.

[0007] In some embodiments, the active gain medium optical component may comprise at least one of one or more erbium-doped amplifiers, one or more doped fiber amplifiers, one or more Raman amplifiers, one or more semiconductor optical amplifiers, and any combination thereof.

[0008] In some embodiments, the bi-directional amplifying device may be communicatively coupled to one or more circulators that may be configured to direct transmission of at least one of the one or more optical sensing signals, the one or more optical sensing signals amplified by the bi-directional amplifying device, and any combination thereof to and / or away from the bi-directional amplifying device.

[0009] In some embodiments, the present subject matter relates to a method for transmitting optical signals, which may include providing a bidirectional amplifying device communicatively coupled between a first communication terminal and a second communication terminal, the first and second communication terminals being communicatively coupled by an optical communication link; amplifying, using the bidirectional amplifying device, one or more optical sensing signals transmitted in either direction between the first communication terminal and the second communication terminal, the one or more optical sensing signals being indicative of a condition of one or more portions of the optical communication link; and transmitting, using the bidirectional amplifying device, the one or more optical sensing signals amplified by the bidirectional amplifying device. The optical communication link may be configured to transmit one or more optical data signals.

[0010] In some embodiments, the method may further include transmitting, using the bidirectional amplifying device, a first optical sensing signal of the one or more optical sensing signals in a first direction from the first communication terminal to the second communication terminal and amplifying a first reflected optical sensing signal transmitted from the second communication terminal to the first communication terminal in a second direction. The method may further include transmitting, using the bidirectional amplifying device, a second optical sensing signal of the one or more optical sensing signals in the second direction from the second communication terminal to the first communication terminal and amplifying a second reflected optical sensing signal transmitted from the first communication terminal to the second communication terminal in the first direction.

[0011] Further described are non-transitory computer program products (i.e., physically implemented computer program products) that store instructions that, when executed by one or more data processors of one or more computing systems, cause at least one data processor to perform the operations described herein. Similarly, further described are computer systems that can include one or more data processors and memory coupled to the one or more data processors. The memory may temporarily or permanently store instructions that cause at least one processor to perform one or more operations described herein. Also, methods may be implemented by one or more data processors within a single computing system or one or more data processors distributed among two or more computing systems. Such computing systems may be connected and may exchange data and / or commands or other instructions, etc., via one or more connections, including, but not limited to, connections via a network (e.g., an Internet network, a wireless wide area network, a local area network, a wide area network, a wired network, etc.), direct connections between one or more of the computing systems, etc.

[0012] The details of one or more variations of the subject matter described herein are set forth in the drawings and the description below. Other features and advantages of the subject matter described herein will be apparent from the description, drawings, and claims. [Brief explanation of the drawings]

[0013] The drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the subject matter disclosed herein and, together with the description, aid in the understanding of certain principles related to the disclosed embodiments. [Figure 1] FIG. 1 illustrates an exemplary optical communication system. [Figure 2]FIG. 1 illustrates an example of a bidirectional optical sensing system used for bidirectionally amplified optical sensing signals, according to some embodiments of the current subject matter. [Figure 3] FIG. 1 illustrates an example of a bidirectional optical sensing system used for bidirectionally amplified optical sensing signals, according to some embodiments of the current subject matter. [Figure 4A] 1 illustrates an example of a bidirectional amplification system, according to some embodiments of the current subject matter. [Figure 4B] FIG. 10 illustrates another example of a bidirectional amplification system, according to some embodiments of the current subject matter. [Figure 5] FIG. 1 illustrates an example of an optical communication system that may be configured to perform bidirectional amplification of an optical sensing signal, according to some embodiments of the current subject matter. [Figure 6] 1 illustrates an exemplary system according to some embodiments of the current subject matter. DETAILED DESCRIPTION OF THE INVENTION

[0014] To address these and potential other shortcomings of currently available solutions, one or more embodiments of the current subject matter relate to methods, systems, products, etc. that can provide a loopback bidirectional amplifier for optical sensing applications, in addition to other possible advantages.

[0015] In some embodiments, the present subject matter relates to an optical communication system that can be configured to provide bidirectional amplification for optical sensing signals, which may be transmitted over outgoing and / or incoming communication paths that communicatively couple one or more emitters (and / or transceivers) to one or more receivers (and / or transceivers). The system may include a bidirectional amplification device that may be communicatively coupled between a first communication terminal and a second communication terminal. The first and second communication terminals may be communicatively coupled by an optical communication link. The communication terminals may include transmitting and / or receiving components and / or may be capable of transmitting and receiving both various optical sensing signals (e.g., optical signals for detecting the status of the optical communication link) and / or optical data signals (e.g., optical signals for transmitting data, information, etc.). The bidirectional amplification device may be configured to transmit and amplify one or more optical sensing signals transmitted in either direction between the first communication terminal and the second communication terminal.

[0016] In some embodiments, the bidirectional amplification device may be configured to transmit a first optical sensing signal in a first direction (e.g., from a first communication terminal to a second communication terminal) and amplify a first reflected optical sensing signal transmitted in a second direction (e.g., from the second communication terminal to the first communication terminal). The first reflected optical sensing signal may be an optical signal reflected from the optical communication link in response to a detected condition in the link (e.g., a cable break, interference, a seismic event, etc.). The first reflected optical sensing signal may be a reflection of the first optical sensing signal and / or any other signal.

[0017] In some embodiments, the bidirectional amplifying device may transmit a second optical sensing signal in a second direction from the second communication terminal to the first communication terminal. It may amplify a second reflected optical sensing signal transmitted in the first direction from the first communication terminal to the second communication terminal. The second reflected optical sensing signal may be a reflection of the second optical sensing signal and / or any other signal. It may be an optical signal reflected in the optical communication link in response to a condition in the link being detected.

[0018] To amplify the optical sensing signal, the bidirectional amplifying device may include an active gain medium optical component. The active gain medium optical component may be configured to amplify at least one of the first reflected optical sensing signal, the second reflected optical sensing signal, the first optical sensing signal, the second optical sensing signal, and any combination thereof. The bidirectional amplifying device may further include at least one of one or more isolators, one or more wavelength division multiplexing (WDM) optical components, and any combination thereof. The WDM optical component may be coupled to one or more pumps, which may be laser pumps. The isolator may also be configured to isolate the one or more pumps from one or more optical signals backscattered from the active gain medium optical component. The active gain medium optical component may also include at least one of one or more doped fiber amplifiers, one or more erbium-doped fiber amplifiers, one or more Raman amplifiers, one or more semiconductor optical amplifiers, and any combination thereof.

[0019] In some embodiments, the bi-directional amplifying device may be communicatively coupled to one or more circulators. The circulators may be configured to direct transmission of at least one of one or more optical sensing signals, one or more optical sensing signals amplified by the bi-directional amplifying device, and any combination thereof. The circulators may direct such signals to and / or away from the bi-directional amplifying device.

[0020] 1 illustrates an exemplary optical communication system 100. The system 100 can transmit and receive large amounts of data over long distances using high-bandwidth optical fibers. The bidirectional optical communication system 100 may also be referred to as a long-distance optical communication system. Bidirectional data transmission may be achieved by establishing optical fiber pairs within an optical cable and / or by each optical fiber pair transmitting one or more channels (e.g., wavelength division multiplexed channels).

[0021] System 100 may include terminals 103 and 105 that are communicatively coupled using (e.g., unidirectional) optical paths 111 and 121. Terminal 103 may include a transmitter 113 and a receiver 123. Similarly, terminal 105 may include a receiver 115 and a transmitter 125. The transmitter 113 of terminal 103 may be communicatively coupled to the receiver 115 of terminal 105 via path 111. The transmitter 125 of terminal 105 may be communicatively coupled to the receiver 123 of terminal 103 via communication path 121. Paths 111 and 121 may form a bidirectional optical fiber pair. For example, optical path 111 may transmit one or more signals, data, information, etc., and / or any combination thereof in one direction (e.g., from transmitter 113 to receiver 115). Optical path 121 may transmit one or more signals, data, information, etc., and / or any combination thereof in another direction (e.g., from transmitter 125 to receiver 123).

[0022] Thus, with respect to terminal 103, optical path 111 may be referred to as the outgoing path, and optical path 121 may be referred to as the incoming path. Optical path 111 may comprise one or more optical fibers 117-1 through 117-n and one or more optical amplifiers 119-1 through 119-n, backed up into corresponding repeaters 131-1 through 131-n. Similarly, optical path 121 may comprise one or more optical fibers 127-1 through 127-n and one or more optical amplifiers 129-1 through 129-n, backed up into corresponding repeaters 131-1 through 131-n. Optical fibers 117-1 through 117-n and 127-1 through 127-2 may correspondingly be separate bands of a single optical fiber 117 and / or a single optical fiber 127, which may be formed by combining amplifiers and optical fibers 117 and 127, as shown in FIG. 1 .

[0023] For example, one or more of optical amplifiers 119-1 through 119-n and / or 129-1 through 129-n may be erbium-doped fiber amplifiers (EDFAs) and / or any other optical amplifiers. Also, while transmitters 113, 115 and receivers 123, 125 are shown as separate components, it can be understood that transmitter 113 and / or receiver 123 may be housed together in a single housing and form a transponder and / or transceiver in terminal 103. Similarly, transmitter 115 and receiver 125 may be housed together in a single housing and form a transponder and / or transceiver in terminal 105.

[0024] As noted above, optical path pairs (e.g., optical paths 111, 121) may be configured to be communicatively coupled to a set of amplifier pairs 119-1 to 119-n and 129-1 to 129-n within one of repeaters 131-1 to 131-n using optical fiber pairs 117 (e.g., using optical fibers 117-1 to 117-n) and 127 (e.g., using optical fibers 127-1 to 127-n), and optical fibers 117 and 127 may be included in an optical fiber cable along with other optical fibers and / or optical fiber pairs supporting additional path pairs. As discussed above and shown in FIG. 1, for example, each repeater 131-1 to 131-n may include at least one corresponding pair of amplifiers 119-1 to 119-n, 129-1 to 129-n for each path pair and / or may include additional amplifiers for additional path pairs. As shown in FIG. 1, for example, repeater 131-1 may include amplifiers 119-1 and 129-1.

[0025] Optical amplifiers 119-1 through 119-n, 129-1 through 129-n may comprise EDFAs and / or other rare-earth doped fiber amplifiers, Raman amplifiers, semiconductor optical amplifiers (SOAs), and / or other types of amplifiers. Each repeater 131-1 through 131-n may comprise a corresponding coupling path 133-1 through 133-n that may be communicatively coupled between optical paths 111, 121. As used herein, the terms "coupled" and / or "coupled" or "communicatively coupled" may broadly refer to any connection, positive connection, coupling, link and / or positive link, direct and / or indirect and / or wired and / or wireless connection, etc., but may be understood to not necessarily mean that coupled components and / or elements are directly connected to one another.

[0026] Underwater fiber optic cables transmit and receive optical flow of several terabits. Sensing applications can use deployed optical fibers for intrusion detection, cable cuts, and faults, minimizing restoration efforts. Optical data flows bidirectionally in these networks. Sensing applications may be configured to monitor each span in both directions. The sensing signal reflected after Rayleigh scattering may need to be amplified to recover power and return it to the sensing receiver. Conventional systems typically require two separate optical amplifiers to amplify one or more sensing signals from opposite spans and transmit the signal to the receiver.

[0027] In some embodiments, the current subject matter provides a bidirectional optical fiber amplifier for use in multi-span underwater optical network sensing. The bidirectional loopback amplifier may be configured to amplify reflected sensing signal wavelengths propagated from opposite spans.

[0028] 2 illustrates an example of a bidirectional optical sensing system 200 used for bidirectional amplified optical sensing signals, according to some embodiments of the present subject matter. System 200 may include terminals 203 and 205 communicatively coupled using (e.g., unidirectional) optical paths 211 and 221, where terminals 203 and 205 may include corresponding transmitters 213 and 215 and corresponding receivers 223 and 225. Transmitter 213 and receiver 215 may be communicatively coupled using optical communication path 211, and transmitter 225 and receiver 223 may be communicatively coupled using optical communication path 221. Optical paths 211 and 221 may transmit one or more signals, data, information, etc., and / or any combination thereof, in one direction (e.g., path 211 is from transmitter 213 to receiver 215, and path 221 is from transmitter 225 to receiver 223).

[0029] One or more repeaters 231-1 through 231-n may be positioned along optical paths 211 and 221. Repeater 231 may include corresponding amplifiers (e.g., erbium-doped fiber amplifiers (EDFAs)) 219-1 through 219-n and 229-1 through 229-n for amplifying optical signals transmitted along paths 211 and 221. For example, repeater 231-1 may include EDFA 219-1 for amplifying signals transmitted along optical communication path 217-1, repeater 231-2 may include EDFA 219-2 for amplifying signals transmitted along optical communication path 217-2, etc. Also, repeater 231-1 may include EDFA 229-1 for amplifying signals transmitted along optical communication path 227-1, repeater 231-2 may include EDFA 229-2 for amplifying signals transmitted along optical communication path 227-2, etc.

[0030] Repeater 231 may also include corresponding optical sensing signal amplifiers 233-1 through 233-n (e.g., repeater 231-1 may include amplifier 233-1, etc.). Amplifier 233 may be configured as a bidirectional amplifier and configured to amplify a corresponding reflected or returned optical sensing signal 235. For example, repeater 231-1 may include amplifier 233-1, which may be configured to amplify reflected signal 237-1, which is reflected back in response to an optical sensing signal transmitted from transmitter 213 to receiver 215 and / or as a result of an event and / or condition (e.g., a break, damage, interference, etc. in the optical communication path) detected on optical communication path 217-2 (e.g., due to Rayleigh scattering in the optical fiber, etc.). The sensing optical signal may be transmitted (in either direction) on an optical communication path for transmitting optical data signals and / or on a separate optical communication path dedicated to transmitting optical sensing signals. The optical sensing signal may be transmitted using a transmitter similar to the transmitter transmitting the optical data signal (e.g., transmitter 213) and / or a separate optical sensing signal transmitter. Similarly, amplifier 233-1 may be configured to amplify reflected signal 235-1, which is reflected back in response to the optical sensing signal transmitted from transmitter 225 to receiver 223 and / or as a result of events and / or conditions detected on optical communication path 227-1 (e.g., due to Rayleigh scattering in optical fiber, etc.). As described herein, amplifier 233 may be configured to bidirectionally amplify the reflected / returned optical sensing signal in both directions, thereby eliminating the need for a separate amplifier and reducing the amount of hardware, power, etc. that may be required. In some embodiments, the present subject matter may monitor any and / or all reflected signals (e.g., continuously, periodically, etc.). One or more (or none) such signals may be amplified (e.g., by one or more amplifiers discussed herein) for transmission. Any such change in the signal may correspond to a change in the phase, amplitude, polarization and / or any other signal parameter and / or any combination of parameters of the reflected signal.

[0031] For example, one or more of optical amplifiers 219-1 through 219-n and / or 229-1 through 229-n may be erbium-doped fiber amplifiers (EDFAs), other rare-earth doped fiber amplifiers, Raman amplifiers, semiconductor optical amplifiers (SOAs), and / or any other optical amplifiers. Also, while transmitters 213, 215 and receivers 223, 225 are shown as separate components, it can be understood that transmitter 213 and / or receiver 223 may be housed together in a single housing and form a transponder and / or transceiver in terminal 203. Similarly, transmitter 215 and receiver 225 may be housed together in a single housing and form a transponder and / or transceiver in terminal 205.

[0032] 2, optical paths 211, 221 may be configured as corresponding amplifier pairs 219, 229 in corresponding repeaters 231 that are communicatively coupled using corresponding optical fiber pairs 217, 227. Optical fibers 217, 227 may be included in a fiber optic cable along with other optical fibers and / or optical fiber pairs that support additional path pairs.

[0033] 3 illustrates an example of a bidirectional optical sensing system 300 used for bidirectionally amplified optical sensing signals, according to some embodiments of the present subject matter. System 300 may be part of system 200 shown in FIG. 2. System 300 may include one or more repeaters 331-1, 331-2, . . . , 331-n, which may be communicatively coupled using optical communication path spans 317 (317-0, 317-1, 317-2, . . . , 317-n) and 327 (327-0, 327-1, 327-2, . . . , 327-n). Path 317 may be configured to be used to transmit an optical sensing signal between sensing signal source 302 (via wavelength division multiplexer (WDM) 303) to receiver 306 (via filter 307), and path 327 may be configured to be used to transmit an optical sensing signal between sensing signal source 304 (via WDM 305) to receiver 308 (via filter 309). By transmitting sensing signal 302, one or more conditions in optical transmission path 211 (shown as 311 in the continuation of FIG. 3) and / or span 317 shown in FIG. 2 can be determined. By transmitting sensing signal 304, one or more conditions in optical transmission path 221 (shown as 321 in the continuation of FIG. 3) and / or span 327 shown in FIG. 2 can be determined. It can be understood that a single source or multiple sources of sensing signals may be used to transmit the sensing signals.

[0034] Repeater 331 may be repeater 231 and / or may be coupled to repeater 231 shown in Figure 2. Each of repeaters 331 may have a similar or similar structure and / or one or more functions. Thus, for ease of explanation and description, repeater 331-1 will be discussed below, which can be understood to apply to the remaining repeaters 331-2, ... 331-n.

[0035] Repeater 331-1 may include one or more sensing signal branches 336 and 338 communicatively coupled to each other via bidirectional optical amplification device 330. Branch 336 may be configured to transmit and process sensing signal 302 and reflected optical sensing signals in optical communication paths 317, which may be reflected in response to sensing signal 302 encountering a reflection point (e.g., interference, break, damage, and / or any other reflective event) in one or more of optical communication paths 317 (e.g., due to Rayleigh scattering in optical fiber, etc.). As described above, one or more reflected signals may be monitored (e.g., continuously, periodically, etc.), whereupon one or more (or none) such signals are amplified (e.g., by one or more amplifiers as discussed herein). The phase, amplitude, polarization, and / or any other signal parameter and / or any combination of parameters of one or more reflected signals may be determined to determine any changes in the reflected signals. Branch 338 may be configured to be used to transmit and process sensing signal 304 and reflected optical sensing signals in optical communication paths 327, which may be reflected in response to sensing signal 304 encountering a reflection point (e.g., interference, break, damage, and / or any other reflection event) in one or more of optical communication paths 327.

[0036] Branch 336 may include circulators 341, 349, bandpass filters 342, 343, a coupler (e.g., WDM) 345, and an inline EDFA amplifier 347. Each of circulators 341, 349 may include one or more ports (marked “1,” “2,” and “3”) that may be configured to transmit the optical sensing signal and / or the reflected optical sensing signal to optical communication components that may be coupled thereto. In particular, at port 1, circulator 341 may be communicatively coupled to bandpass filter 343; at port 2, circulator 341 may be communicatively coupled to bidirectional amplifying device 330; and at port 3, circulator 341 may be communicatively coupled to filter 342, which may in turn be communicatively coupled to coupler 345. Coupler 345 may be configured to receive optical sensing signal 302 over span or optical communication path 317-0 and may be communicatively coupled to an input of EDFA 347. An output of EDFA 347 may be communicatively coupled to port 1 of circulator 349. Port 2 of circulator 349 may be communicatively coupled to optical communication path 317-1 and configured to receive the reflected optical sensing signal transmitted over path 317-1 towards repeater 331-1. Port 3 of circulator 349 may be communicatively coupled to bandpass filter 343. Circulators 341, 349 may be configured to direct transmission of the optical sensing signal in a counterclockwise direction. It may be understood that circulators 341, 349 may be positioned and configured to direct transmission of the optical sensing signal in any desired direction.

[0037] Similarly, branch 338 may include circulators 351, 359, bandpass filters 353, 358, a coupler (e.g., WDM) 355, and an in-line EDFA amplifier 357. Branch 338 may be configured to receive a signal from source 304 and transmit it to receiver 309. It may be configured to receive a reflected signal and transmit it to branch 336 for transmission to receiver 306. Each of circulators 351, 359 may include one or more ports (marked “1,” “2,” and “3”), which may be configured to transmit the optical sensing signal and / or the reflected optical sensing signal to optical communication components that may be coupled thereto. In particular, at port 1, circulator 351 may be communicatively coupled to bandpass filter 353. At port 2, circulator 351 may be communicatively coupled to bidirectional amplifying device 330. At port 3, circulator 351 may be communicatively coupled to bandpass filter 358, which may in turn be communicatively coupled to coupler 355. Coupler 355 may be configured to receive optical sensing signal 304, which may be communicatively coupled to an input of EDFA 357. The output of EDFA 357 may be communicatively coupled to port 1 of circulator 359. Port 2 of circulator 359 may be communicatively coupled to optical communication path 327-0 and configured to receive the reflected optical sensing signal transmitted on path 327-1 towards repeater 331-1. Port 3 of circulator 359 may be communicatively coupled to bandpass filter 353. Circulators 351, 359 may be configured to direct transmission of the optical sensing signal in a counterclockwise direction. It may be understood that circulators 351, 359 may be positioned and configured to direct transmission of the optical sensing signal in any desired direction.

[0038] During transmission of the optical sensing signal (e.g., to determine the state of an optical communication path (e.g., the optical sensing path and / or the optical data path)), the optical sensing signal 302 may be transmitted to repeater 331-1 via communication path 317-0 and received by coupler 345. Coupler 345 may then transmit the sensing signal to EDFA 347, which may amplify and transmit the signal to port 1 of circulator 349. Circulator 349 may then direct the amplified sensing signal to port 2, which may transmit the signal as an output to optical communication path 317-1. The signal may then be received by a coupler (similar to coupler 345) of repeater 331-2.

[0039] If a reflective event (e.g., an interruption, break, seismic event, etc.) is encountered in one of the optical communication paths (e.g., path 317-1), the sensing signal may be reflected back to repeater 331-1. As described above, one or more reflected signals may be continuously monitored (e.g., regardless of whether any event occurs and / or is encountered). The reflected optical signal may be received at port 2 of circulator 349. Circulator 349 may then direct the reflected sensing signal to its port 3, which may then transmit it to bandpass filter 343. Bandpass filter 343 may filter out noise and / or limit the bandwidth of the reflected sensing signal, and / or perform any other signal processing function. The processed reflected sensing signal may then be received at port 1 of circulator 341. Circulator 341 may then direct the reflected sensing signal via its port 2 to bidirectional amplification device 330. Amplification device 330 may amplify the reflected sensing signal and transmit it to port 2 of circulator 351.

[0040] Circulator 351 may then direct the amplified reflected sensing signal to its port 3, through bandpass filter 358 (which may filter out noise and / or limit the bandwidth of the reflected sensing signal, etc.) and to coupler 355. Coupler 355 may provide this signal to EDFA 357. EDFA 357 may further amplify the amplified reflected sensing signal. Such signal may then be transmitted via circulator 359 (from its port 1 to port 2) and communication path 327-0 towards receiver 309, where it may finally be received by receiver 309.

[0041] The processing of sensing signal 304 and any reflected signals thereof is similar to the processing of sensing signal 302. Specifically, optical sensing signal 304 may be transmitted to repeater 331-1 and received by coupler 355. Coupler 355 may then transmit the sensing signal to EDFA 357. EDFA 357 may amplify the signal and transmit it to port 1 of circulator 359, which directs the amplified sensing signal to port 2, which transmits the amplified sensing signal as an output to optical communication path 327-0, where it may be further received by receiver 309.

[0042] Any reflected optical sensing signal in one or more paths 327 can be received at port 2 of circulator 359, for example, from communication path 327-0 (and / or, in the case of repeater 331-2, e.g., communication path 327-1), which can direct the transmission of the reflected sensing signal to its port 3 and transmit it to bandpass filter 353 for processing. The processed reflected sensing signal can be received at port 1 of circulator 351, which can direct the reflected sensing signal via its port 2 to bidirectional amplification device 330. Amplification device 330 can amplify the reflected sensing signal and transmit it to port 2 of circulator 341.

[0043] Circulator 341 may then direct the amplified reflected sensing signal to its port 3, via bandpass filter 342, and to coupler 345. Bandpass filter 342 (and similar bandpass filter 358) may be configured to filter noise and / or limit the bandwidth of the reflected sensing signal, etc. Coupler 345 may provide this signal to EDFA 347. EDFA 347 may further amplify the amplified reflected sensing signal. This signal may then be transmitted via circulator 349 (from its port 1 to port 2) and communication path 317 towards receiver 306. It may be understood that this signal may be amplified by one or more EDFAs in repeater 331 (e.g., similar to EDFA 347 in repeater 331-1).

[0044] 4A illustrates an example of a bidirectional amplification system 400 according to some embodiments of the present subject matter. One or more components of system 400 and / or system 400 as a whole may be included in and / or coupled to one or more repeaters 331 shown in FIG. 3. System 400 may be used for bidirectional amplification of an optical sensing signal, which may be reflected when encountering a reflection event in response to an optical sensing signal that may be transmitted from either source of the optical sensing signal (e.g., source 302 as shown in FIG. 3 and / or 304 as shown in FIG. 3 (continued)), and / or performing continuous monitoring of the reflection signal (regardless of any event or condition).

[0045] System 400 may include a bidirectional optical amplification device 330 that may be communicatively coupled to circulators 351 and 341 (as shown in FIG. 3 ). Circulator 351 may be configured to receive reflected optical sensing signal 304 (e.g., “west sensing signal”) and direct / redirect transmissions of the reflected optical sensing signal (e.g., reflected in a direction opposite to that of optical sensing signal 304) to eastern sensing receiver 306 (as shown in FIG. 3 (continued)). Similarly, circulator 341 may be configured to receive reflected optical sensing signal 302 (e.g., “east sensing signal”) and direct / redirect transmissions of the reflected optical sensing signal (e.g., reflected in a direction opposite to that of optical sensing signal 302) to western sensing receiver 308 (as shown in FIG. 3 ). It may be understood that the designations “eastern” and “western” provided herein are used for descriptive purposes only, without limiting the scope of the current subject matter.

[0046] The bidirectional optical amplification device 330 may include an active gain medium 402 that may be communicatively coupled between WDM1 404 and WDM2 406. WDM1 404 may be communicatively coupled to a circulator 351 and an isolator (“Iso 1”) 408. WDM2 406 may be communicatively coupled to a circulator 341 and an isolator (“Iso 2”) 410. The isolators 408 and 410 may be coupled to a coupler 412, which may in turn be communicatively coupled to lasers L1 414 (“Laser 1”) and L2 416 (“Laser 2”). The lasers 414 and 416 may be coupled to a laser actuator 418. The lasers 414 and 416 may be pump lasers that are driven by the laser actuator 418 and coupled together using a coupler 412, which may be a fused optical fiber coupler and / or any other type of coupler. The isolators 408 , 410 may be configured to protect the lasers 414 , 416 from the effects of high pump power and / or high power back reflections passing through the active gain medium 402 .

[0047] In operation, the reflected optical sensing signal 304 may be routed by circulator 351 from its port 1 to port 2 and configured to be sent to WDM1 404, which may multiplex one or more reflected optical sensing signals 304 that may be commonly propagated in either direction (e.g., from east to west or from west to east) using one or more lasers 414, 416. The multiplexed optical sensing signals may be provided to active gain medium 402 for amplification. Active gain medium 402 may comprise a rare-earth doped fiber amplifier, a Raman amplifier, a semiconductor optical amplifier (SOA), and / or any other optical amplifier, which may be configured to amplify the multiplexed optical signal before passing it to WDM2 406. The output of WDM2 406 may be sent to circulator 341 and received at its port 2. Circulator 341 may then transmit these signals to receiver 308 (e.g., "west sensing signal") by directing them to port 3.

[0048] Similarly, the reflected optical sensing signals 302 can be routed from port 1 to port 2 by circulator 341 and transmitted to WDM2 406. WDM2 406 can multiplex these optical sensing signals using one or more pump lasers 414, 416. The signals can similarly propagate commonly in either direction (e.g., from east to west or from west to east). The multiplexed optical sensing signals can be amplified and transmitted to WDM1 404 using an active gain medium 402. WDM1 404 can transmit the amplified signals to port 2 of circulator 351. Circulator 351 can then direct these signals to its port 3 for transmission to receiver 306 (e.g., "Eastern Sensing Signals").

[0049] In some embodiments, a single laser (414 or 416) may be used for pump WDM1 404 and WDM2 406. Alternatively or additionally, each WDM may be operated by a specific laser 414, 416 and / or any laser.

[0050] In some embodiments, the bidirectional optical amplification device 330 may be configured to include circulators 341 and 351, as shown in the system 401 in FIG. 4B, in addition to the components shown in FIG. 4A. Thus, the circulators 341 and 351 can form part of the bidirectional optical amplification device 330 in FIG. 4B, without the circulators 341 and 351 being communicatively coupled to the bidirectional optical amplification device 330 in FIG. 4A (through corresponding WDM2 406 and WDM1 404). The connections between the circulators 341 and 351 and components within and outside the bidirectional optical amplification device 330 are similar to those discussed with respect to FIG. 4A above. Similarly, the operation (e.g., optical signal processing) of the bidirectional optical amplification device 330 including the circulators 341 and 351 may be similar to the operation of the components in the system 400 shown in FIG. 4A.

[0051] 5 illustrates an example of an optical communication system 500 that may be configured to perform bidirectional amplification of an optical sensing signal, according to some embodiments of the present subject matter. System 500 may be similar to the systems discussed with reference to FIGS. 1-4B above.

[0052] System 500 may include a west side sensing transmitter 502 configured to transmit one or more optical sensing signals to an east side sensing receiver 506, and an east side sensing transmitter 508 configured to transmit one or more optical sensing signals to a west side sensing receiver 504. The transmitter 502 and receiver 506 may be communicatively coupled using an optical communication path 511, which may be configured to transmit one or more optical sensing signals and / or one or more optical data signals. The communication path 511 may include one or more repeaters (e.g., one or more repeaters 531) located thereon (e.g., at predetermined distances (e.g., 50 km, 100 km, etc.)), which may include one or more amplifiers (e.g., EDFAs, etc.) 519-1, 519-2, 519-3, etc. (for convenience, only three amplifiers are shown in FIG. 5 ) to amplify optical signals transmitted over spans or portions 517-1, 517-2, 517-3, etc. of the communication path 511. Similarly, communication path 521 may include one or more repeaters (e.g., one or more repeaters 531) located thereon (e.g., at predetermined distances (e.g., 50 km, 100 km, etc.)), which may include one or more amplifiers (e.g., EDFAs, etc.) 529-1, 529-2, 529-3, etc. (again, for convenience, only three amplifiers are shown in FIG. 5 ) to amplify optical signals transmitted over spans or portions 527-1, 527-2, 527-3, etc. Also, similar repeater housings (e.g., the housing of repeater 531) may be located throughout communication paths 511 and 521. It will be understood that corresponding amplifiers 519 (e.g., 519-1) and 529 (e.g., 529-1) may be included in similar corresponding repeater housings 531 (e.g., as shown in FIGS. 1-3 ) and / or in separate housings, which may form a repeater. 5, the housing of repeater 531 may include amplifier 519-2 located on communication line 511 and amplifier 529-2 located on communication line 521. Transmitter 502 and receiver 504 may also be located in a common housing.Similarly, a common housing may be used to house the receiver 506 and the transmitter 508. Alternatively or additionally, the transmitter and receiver on each side may be housed separately from each other.

[0053] In some embodiments, as shown in FIG. 5, a bidirectional amplifying device 530 may be communicatively coupled to one or more of amplifiers 519-2 and 529-2 to perform bidirectional amplification of the optical sensing signal (including the reflected optical sensing signal). The other amplifiers 519 and 529 may similarly be communicatively coupled using corresponding bidirectional amplifying devices 530 provided in the repeater housing. As shown in FIG. 5, a bidirectional amplifying device 530 may be communicatively coupled to the output of amplifier 529-2 and the input of amplifier 519-2. Also, a bidirectional amplifying device 530 may be communicatively coupled to the output of amplifier 519-2 and the input of amplifier 529-2.

[0054] 3-4B and may include a bidirectional amplifier 534 (e.g., similar to the active gain medium 402 shown in FIGS. 4A and 4B). Preferably, the bidirectional amplifying device 530 may include one or more bandpass filter combinations 532a and 532b, which may be communicatively coupled to the bidirectional amplifier 534 and may process the optical sensing input and / or output signals processed by the corresponding amplifiers 519, 529 and bidirectional amplifier 534.

[0055] During operation, as shown in FIG. 5 , optical sensing signal 539 may be preferably processed by a filter in combination 532b and amplified by bidirectional amplifier 534, or may be preferably processed by a filter in combination 532a and output by bidirectional amplification device 530 as amplified optical sensing signal 535, which may then be input to amplifier 519-2. Optical sensing signal 539 may include a reflected optical sensing signal, which may be a reflected optical sensing signal output by amplifier 529-2 or may be due to encountering a reflective event (e.g., a break, interference, etc.). Amplified optical sensing signal 535 may be multiplexed with one or more optical sensing signals (and / or optical data signals) that may be input to amplifier 519-2 and transmitted to sensing receiver 506. As noted above, if desired, one or more reflected signals may be continuously monitored and / or amplified (e.g., despite any reflective event(s)).

[0056] Similarly, optical sensing signal 533 may preferably be processed by a filter in combination 532a and amplified by bi-directional amplifier 534, and may preferably be processed by a filter in combination 532b and output by bi-directional amplification device 530 as amplified optical sensing signal 537. Optical sensing signal 533 may include a reflected optical sensing signal, which may be a reflected optical sensing signal output by amplifier 519-2, may be the result of encountering a reflective event (e.g., a break, interference, etc.), and / or may be continuously monitored (e.g., regardless of a reflective event). Amplified optical sensing signal 537 may be multiplexed with one or more optical sensing signals (and / or optical data signals), which may be input to amplifier 529-2 and transmitted to sensing receiver 504.

[0057] In some embodiments, the present subject matter may be configured to provide various technical advantages over conventional systems. In particular, conventional amplifier designs typically require two separate optical fiber amplifiers to amplify counter-propagating sensing signals as loopback amplifiers. This is problematic because it requires additional hardware and connections, complex signal routing, and the like, which can lead to signal loss, incorrect readings, and other issues. The present subject matter provides bidirectional loopback amplification, which solves the above problems by completely eliminating the need for additional amplifiers. Furthermore, the bidirectional amplification systems of the present subject matter can address the issue of signal-to-signal crosstalk by using only passive wavelength-sensing filters, which is a problem for some bidirectional amplifiers. Furthermore, the active gain medium may comprise rare-earth doped optical fiber, Raman gain optical fiber, semiconductor optical amplifier (SOA) devices, and / or any other optical fiber amplifier. For unidirectional signal amplification, bidirectional means may also be used for unidirectional amplification only. The present subject matter also eliminates the need for an additional pump by using a single pump laser, simplifying the structural components.

[0058] Figure 6 illustrates an exemplary system 600 for processing and / or controlling the operation of one or more of the systems shown in Figures 2-5. For example, as shown in Figure 5, system 600 may be coupled to one or more of sensing receivers 504, 506 and / or sensing transmitters 502, 508 and / or one or more repeaters 531. Alternatively or additionally, system 600 may be coupled to one or more separately provided devices and / or components, which may be configured to provide control functions to one or more of the optical communication systems shown in Figures 2-5. It may be understood that system 600 may be coupled to any other devices and / or components.

[0059] As shown in FIG. 6 , processing system 600 may include an input / output (I / O) device 601, a processor 603, a memory 605, a storage device 607, and one or more communication components 611. Each of components 601-607 may be connected to one another using a system bus 609. Processor 603 may be configured to process instructions for execution within system 600. In some embodiments, processor 603 may be a single-threaded processor. Alternatively or additionally, processor 603 may be a multi-threaded processor. Processor 603 may further be configured to process instructions stored in memory 605 and / or storage device 607, including, but not limited to, receiving or transmitting information via I / O device 601. Memory 605 may store information within system 600. In some embodiments, memory 605 may be a computer-readable medium. Alternatively or additionally, memory 605 may be a volatile memory unit. In some embodiments, memory 605 may be a non-volatile memory unit. The storage device 607 may provide mass storage for the system 600. In some embodiments, the storage device 607 may be a computer-readable medium. Alternatively or additionally, the storage device 607 may be a floppy disk device, a hard disk device, an optical disk device, a tape device, a non-volatile solid-state memory, or any other type of storage device. The I / O device 601 may provide input / output operations to the system 600. In some embodiments, the I / O device 601 may include a keyboard and / or a pointing device. Alternatively or additionally, the I / O device 601 may include a display unit for displaying a graphical user interface.

[0060] In some exemplary embodiments, one or more components of system 600 may comprise any combination of hardware and / or software. In some embodiments, one or more components of system 600 may reside on one or more computing devices, such as one or more servers, one or more databases, one or more personal computers, one or more laptops, one or more mobile phones, one or more smartphones, one or more tablets, virtual reality devices, and / or any other computing device, and / or any combination thereof. In some exemplary embodiments, one or more components of system 600 may reside on a single computing device and / or be part of a single communications network. Alternatively or additionally, such services may be located separately from one another.

[0061] In some embodiments, one or more components of system 600 may comprise a computer supporting a network. As described herein, a computer supporting a network may include, but is not limited to, a computing or communications device, such as a server, a network device, a personal computer, a workstation, a telephone, a smartphone, a handheld PC, a personal digital assistant, a thin client, a fat client, an Internet browser, or other device. One or more components of system 600 may be a mobile computing device, such as an Apple® iPhone®, iPod®, iPad®, and / or any other compatible device running the Apple® iOS® operating system, any device running the Microsoft® Windows® mobile operating system, any device running the Google® Android® operating system, and / or any other compatible mobile computing device, such as a smartphone, tablet, or similar wearable mobile device.

[0062] One or more components of system 600 may comprise a processor and memory, and it can be understood that processing circuitry may comprise additional components necessary to perform the functions described herein, including processors, memory, error and parity / CRC checkers, data encoders, anti-collision algorithms, controllers, command decoders, security primitives, and tamper-proof hardware. One or more components of system 600 may further comprise one or more displays and / or one or more input devices. A display is any type of device for presenting visual information (e.g., computer monitors, flat panel displays, and mobile device screens) and may include liquid crystal displays, light-emitting diode displays, plasma panels, and cathode ray tube displays. An input device may comprise any device for inputting information into a user device, such as a touchscreen, keyboard, mouse, cursor control device, touchscreen, microphone, digital camera, video recorder, or portable video camera, that is available and supported by the user device. These devices may be used to input information and interact with the software and other devices described herein.

[0063] In some exemplary embodiments, one or more components of system 600 may execute one or more applications (e.g., software applications), which may, for example, be in network communication with one or more components of system 600 to send and / or receive data.

[0064] One or more components of system 600 may comprise one or more servers and / or may communicate with one or more servers via one or more networks and may operate as a front-end to back-end pair corresponding to one or more servers. One or more components of system 600 may send one or more requests to one or more servers, for example, from a mobile device application (e.g., executing on one or more user devices, components, etc.). These requests may be associated with retrieving data from the servers. A server may receive requests from components of system 600. Based on these requests, the server may be configured to retrieve the requested data from one or more databases. Based on receiving the requested data from the databases, the server may be configured to transmit the received data to one or more components of system 600 that are responsive to the one or more requests.

[0065] System 600 may comprise and / or be communicatively coupled to one or more networks. In some embodiments, the networks may be one or more of a wireless network, a wired network, or any combination of a wireless network and a wired network, and may be configured to connect components of system 600 and / or components of system 600 to one or more servers. For example, the network may include one or more of an optical fiber network, a passive optical network, a cable network, an Internet network, a satellite network, a wireless local area network (LAN), a metro network (MAN), a wide area network (WAN), a virtual local area network (VLAN), an extranet, an intranet, a global mobile communications system, a personal communication service, a personal area network, a wireless application protocol, a multimedia messaging service, an enhanced messaging service, a short message service, a time division multiplexing based system, a code division multiple access based system, D-AMPS, Wi-Fi®, fixed wireless data, IEEE 802.11b, 802.15.1, 802.11n and 802.11g, Bluetooth®, NFC, radio frequency identification (RFID), Wi-Fi®, and / or any other type of network and / or any combination thereof.

[0066] A network may also include, but is not limited to, a telephone line, optical fiber, IEEE Ethernet 802.3, a wide area network, a wireless personal area network, a LAN, or a global network such as the Internet network. A network may also support an Internet network, a wireless communication network, a cellular network, or the like, or any combination thereof. A network may further include one or any number of the exemplary types of networks listed above, operating as a standalone network or in cooperation with one another. A network may utilize one or more protocols of one or more network elements to which they are communicatively coupled. A network may convert one or more protocols of network devices to and from other protocols. A network may include multiple networks connected to one another, such as the Internet network, a service provider's network, a cable television network, an enterprise network, and a home network.

[0067] System 600 may include one or more servers and / or may be communicatively coupled to one or more servers, which may include one or more processors, which may be coupled to memory. The server may be configured as a central system, server, or platform to control and access various data at different times to perform multiple workflow actions. The server may be configured to connect to one or more databases. The server may be integrated into and / or communicatively coupled to at least one component of system 600.

[0068] 2-5 may include various hardware elements, software elements, or a combination of both. Examples of hardware elements may include devices, logic devices, components, processors, microprocessors, circuits, processors, circuit elements (e.g., transistors, resistors, capacitors, inductors, etc.), integrated circuits, application specific integrated circuits (ASICs), programmable logic devices (PLDs), digital signal processors (DSPs), field programmable gate arrays (FPGAs), memory units, logic gates, registers, semiconductor devices, chips, microchips, chipsets, etc. Examples of software elements may include software components, programs, applications, computer programs, application programs, system programs, software development programs, device programs, operating system software, middleware, firmware, software modules, routines, subroutines, functions, methods, procedures, software interfaces, application program interfaces (APIs), instruction sets, computing code, computer code, code segments, computer code segments, words, values, symbols, or any combination thereof. However, determining whether an embodiment is implemented using hardware and / or software elements can vary depending on many factors, such as desired computation rates, power levels, thermal tolerances, processing cycle budgets, input data rates, output data rates, memory resources, data bus speeds, and other design or performance constraints desired according to a given implementation.

[0069] One or more aspects of at least one embodiment may be implemented by representative instructions stored on a machine-readable medium, which represent various logic within a processor and, when read by a machine, cause the machine to assemble the logic to perform the techniques described herein. Such expressions, referred to as "IP cores," may be stored on tangible machine-readable media and supplied to various customers or manufacturing facilities to be loaded into manufacturing equipment that produces the logic or processors. In some embodiments, the embodiments may be implemented using a machine-readable medium or article of manufacture capable of storing instructions or sets of instructions that, when executed by the machine, cause the machine to perform methods and / or operations according to embodiments. Such an apparatus may include, for example, any suitable processing platform, computing platform, computing device, processing device, computing system, processing system, computer, processor, etc., and may be implemented using any suitable combination of hardware and / or software. The machine-readable medium or product may include, for example, any suitable type of memory unit, memory device, memory product, memory medium, storage device, storage product, storage medium and / or storage unit, such as memory, removable or non-removable media, erasable or non-erasable media, writable or rewritable media, digital or analog media, hard disk, floppy disk, Compact Disk Read Only Memory (CD-ROM), Compact Disk Recordable (CD-R), Compact Disk Rewriteable (CD-RW), optical disk, magnetic media, magneto-optical media, removable memory cards or disks, various types of Digital Versatile Disks (DVDs), tapes, cassettes, etc.The instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, encrypted code, etc., implemented using any suitable high-level, low-level, object-oriented, visual, compiled and / or interpreted programming language.

[0070] Components and features of the devices may be implemented using any combination of discrete circuits, application specific integrated circuits (ASICs), logic gates, and / or single-chip architectures. Also, where appropriate, device features may be implemented using microcontrollers, programmable logic arrays, and / or microprocessors, or any combination of the above. Note that hardware, firmware, and / or software elements may be collectively or individually referred to herein as "logic" or "circuitry."

[0071] It can be understood that the exemplary device shown in the above block diagram may represent one functional description example of many potential embodiments. Thus, the division, omission, or inclusion of functions in the blocks shown in the figures does not necessarily mean that the hardware components, circuits, software, and / or elements for implementing those functions are necessarily divided, omitted, or included in the embodiments.

[0072] At least one computer-readable storage medium may contain instructions that, when executed, cause the system to perform any computer-implemented method described herein.

[0073] Some embodiments may be described using the phrase "one embodiment" or "embodiment" and their derivatives. These terms mean that a particular feature, structure, or characteristic described in connection with this embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" in different places in the specification do not necessarily all refer to the same embodiment. Furthermore, it is contemplated that the above features can be used in any combination unless otherwise stated. Thus, any features discussed individually can be used in combination with each other unless it is noted that these features are incompatible with each other.

[0074] It is emphasized that the Abstract of the Disclosure is provided solely to allow the reader to quickly ascertain the nature of the technical disclosure. This document is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Furthermore, in the foregoing Detailed Description, various features may be combined into a single embodiment for the purpose of simplifying the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments sought to be protected require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in fewer than all features of a single disclosed embodiment. Accordingly, the following claims are incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment. In the appended claims, the terms "comprising" and "wherein" are used as the pure English equivalents of the respective terms "including" and "wherein." Furthermore, the terms "first," "second," "third," etc. are used as labels only and are not intended to impose numerical requirements on their objects.

[0075] The foregoing includes examples of the disclosed architecture. Of course, it is not possible to describe every conceivable combination of components and / or methodologies, and one of ordinary skill in the art will recognize that many more combinations and permutations are possible. Accordingly, the novel architecture is intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.

[0076] The foregoing description of exemplary embodiments has been presented for purposes of illustration and description. It is not intended to limit or restrict the disclosure to the precise form disclosed. Many modifications and variations are possible in accordance with this disclosure. It is intended that the scope of the disclosure be limited not by this detailed description, but rather by the appended claims. Future applications claiming priority to this application may claim the disclosed subject matter differently and may generally include any set of one or more limitations disclosed or otherwise established herein.

Claims

1. a bidirectional amplifying device communicatively coupled between a first communication terminal and a second communication terminal, the first communication terminal and the second communication terminal being communicatively coupled by an optical communication link; the bidirectional amplification device is configured to transmit and amplify one or more optical sensing signals transmitted in either direction between the first communication terminal and the second communication terminal; the one or more optical sensing signals indicate a condition of one or more portions of the optical communication link; A device for transmitting optical signals.

2. the optical communication link is configured to transmit one or more optical data signals; 10. The apparatus of claim 1.

3. The bidirectional amplification device includes: configured to transmit a first optical sensing signal of the one or more optical sensing signals from the first communication terminal to the second communication terminal in a first direction, and to amplify a first reflected optical sensing signal transmitted from the second communication terminal to the first communication terminal in a second direction; configured to transmit a second optical sensing signal of the one or more optical sensing signals from the second communication terminal to the first communication terminal in the second direction, and to amplify a second reflected optical sensing signal transmitted from the first communication terminal to the second communication terminal in the first direction.

10. The apparatus of claim 1.

4. the bidirectional amplifying device comprises an active gain medium optical component; the active gain medium optical component is configured to amplify at least one of the first reflected optical sensing signal, the second reflected optical sensing signal, the first optical sensing signal, the second optical sensing signal, and any combination thereof; 4. The apparatus of claim 3.

5. the bidirectional amplifying device comprises at least one of one or more isolators, one or more wavelength division multiplexing (WDM) optical components, one or more circulators, one or more bandpass filters, one or more optical couplers, and any combination thereof; 5. The apparatus of claim 4.

6. the one or more WDM optical components are coupled to one or more pumps; 6. The apparatus of claim 5.

7. the one or more pumps are laser pumps; 7. The apparatus of claim 6.

8. the one or more isolators are configured to isolate the one or more pumps from one or more optical signals backscattered from the active gain medium optical component.

8. The apparatus of claim 7.

9. the active gain medium optical component comprises at least one of one or more erbium-doped amplifiers, one or more doped fiber amplifiers, one or more Raman amplifiers, one or more semiconductor optical amplifiers, and any combination thereof; 5. The apparatus of claim 4.

10. the bidirectional amplifying device is communicatively coupled to one or more circulators; the one or more circulators are configured to direct transmission of at least one of the one or more optical sensing signals, the one or more optical sensing signals amplified by the bidirectional amplifying device, and any combination thereof, to and / or away from the bidirectional amplifying device.

10. An apparatus according to any one of claims 1 to 9.

11. providing a bidirectional amplifying device communicatively coupled between a first communication terminal and a second communication terminal, the first communication terminal and the second communication terminal being communicatively coupled by an optical communication link; using the bidirectional amplifying device to amplify one or more optical sensing signals transmitted in either direction between the first communication terminal and the second communication terminal, the one or more optical sensing signals indicating a state of one or more portions of the optical communication link; and transmitting, using the bidirectional amplifying device, the one or more optical sensing signals amplified by the bidirectional amplifying device. A method for transmitting optical signals.

12. the optical communication link is configured to transmit one or more optical data signals; The method of claim 11.

13. Using the bidirectional amplifying device, transmit a first optical sensing signal of the one or more optical sensing signals in a first direction from the first communication terminal to the second communication terminal, and amplify a first reflected optical sensing signal transmitted in a second direction from the second communication terminal to the first communication terminal; using the bidirectional amplifying device to transmit a second optical sensing signal of the one or more optical sensing signals in the second direction from the second communication terminal to the first communication terminal, and amplifying a second reflected optical sensing signal transmitted in the first direction from the first communication terminal to the second communication terminal. The method of claim 11.

14. the bidirectional amplifying device comprises an active gain medium optical component; the active gain medium optical component is configured to amplify at least one of the first reflected optical sensing signal, the second reflected optical sensing signal, the first optical sensing signal, the second optical sensing signal, and any combination thereof; The method of claim 13.

15. the bidirectional amplifying device comprises at least one of one or more isolators, one or more wavelength division multiplexing (WDM) optical components, one or more circulators, one or more bandpass filters, one or more optical couplers, and any combination thereof; 15. The method of claim 14.

16. the one or more WDM optical components are coupled to one or more pumps; 16. The method of claim 15.

17. the one or more pumps are laser pumps; 17. The method of claim 16.

18. the one or more isolators are configured to isolate the one or more pumps from one or more optical signals backscattered from the active gain medium optical component.

18. The method of claim 17.

19. the active gain medium optical component comprises at least one of one or more Raman amplifiers, one or more erbium-doped fiber amplifiers, one or more doped fiber amplifiers, one or more semiconductor optical amplifiers, and any combination thereof; 15. The method of claim 14.

20. the bidirectional amplifying device is communicatively coupled to one or more circulators; the one or more circulators are configured to direct transmission of at least one of the one or more optical sensing signals, the one or more optical sensing signals amplified by the bidirectional amplifying device, and any combination thereof, to and / or away from the bidirectional amplifying device.

20. The method of any one of claims 11 to 19.

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