Hybrid sensing-communication optical systems and methods

Abstract

A hybrid sensing-communication system includes a multicore optical fiber (110) having first and second cores (302-1, 302-2), a first communication device (120) optically coupled with a first end of the first core (302-1) of the multicore optical fiber (110), a second communication device (140) optically coupled with a second end of the first core (302-1) of the multicore optical fiber (110), a first sensing device (130) optically coupled with a first end of the second core (302-2) of the multicore optical fiber (110), and a second sensing device (150) optically coupled with a second end of the second core (302-2) of the multicore optical fiber (110). The first and second communication devices exclusively exchange communication data along the first core, the first and second sensing devices exclusively exchange sensing data along the second core, and the communication data is different from the sensing data.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 001,788, filed on March 30, 2020, entitled “OPTICAL HYBRID SENSING-COMMUNICATION SYSTEM USING AMULTICORE FIBER”, the disclosure of which is incorporated herein by reference in its entirety. background Technical Field

[0004] The embodiments of the subject matter disclosed in this application generally relate to an optical system capable of simultaneous multi-channel communication and multi-parameter sensing, and more specifically, to a system using a multi-core optical fiber in which one or more cores are dedicated to communication and one or more of the remaining cores are dedicated to parameter sensing. Background Technology

[0006] Two main applications for optical fiber have been successfully identified: communication and sensing. Fiber optic communication is a mature technology that uses standard single-mode fiber (SMF) and multimode fiber (MMF) to transmit audio, video, telemetry, and more. In contrast, fiber optic sensing is a newer technology, but it has recently been incorporated into many industrial applications, such as the oil and gas industry and structural and health monitoring.

[0007] One area of ​​current interest in optical fiber is the integration of communication and sensing using a single fiber. Such hybrid systems are expected to be widely used in numerous applications because they save resources by avoiding the need to install a separate fiber for each use. Deploying synchronous communication and sensing systems (including a single core) using standard SMF / MMF introduces significant noise in both systems. This is because communication and sensing signals can interfere with each other in the time, wavelength, polarization, and spatial domains. Therefore, there is an urgent need to fabricate reliable hybrid sensing-communication systems using a single fiber.

[0008] The aforementioned challenges can be addressed by using Time Division Multiplexing (TDM), Wavelength Division Multiplexing (WDM), and / or Space Division Multiplexing (SDM) schemes. TDM and WDM are mature technologies; however, their use reduces throughput in communication channels, and given the rapid growth in current global bandwidth demands, this is not recommended.

[0009] Therefore, there is a need for new systems capable of transmitting communication and parameter measurements without interference and / or speed limitations. Summary of the Invention

[0010] According to an embodiment, a hybrid sensing-communication system is provided, comprising a multi-core optical fiber having first and second cores, a first communication device optically coupled to a first end of the first core of the multi-core optical fiber, a second communication device optically coupled to a second end of the first core of the multi-core optical fiber, a first sensing device optically coupled to a first end of the second core of the multi-core optical fiber, and a second sensing device optically coupled to a second end of the second core of the multi-core optical fiber. The first and second communication devices exchange communication data specifically along the first core, and the first and second sensing devices exchange sensing data specifically along the second core, wherein the communication data and the sensing data are different.

[0011] According to another embodiment, a coherent optical sensing and communication system is provided, the system comprising a multi-core optical fiber having first and second cores, a first communication device optically coupled to a first end of the first core of the multi-core optical fiber (the first communication device having a first local oscillator that generates a first local oscillator signal), and a second communication device optically coupled to a second end of the first core of the multi-core optical fiber (the second communication device having a second local oscillator signal that receives the first local oscillator signal). The first and second communication devices exchange communication data specifically along the first core, and the first and second local oscillators exchange the first local oscillator signal specifically along the second core.

[0012] According to yet another exemplary embodiment, a method for synchronizing communication and sensing devices in a network is provided, the method comprising generating a first local oscillation signal at a first local oscillator; generating communication data at a first communication device (the first communication device having a first local oscillator that generates the first local oscillation signal) optically coupled to a first end of a first core of a multi-core optical fiber; transmitting the communication data along the first core of the multi-core optical fiber; transmitting the first local oscillation signal along a second core of the multi-core optical fiber; receiving the communication data at a second communication device optically coupled to a second end of the first core of the multi-core optical fiber; receiving the first local oscillation signal at a second local oscillator that is part of the second communication device; and using the first local oscillator signal to decode the communication data. The first and second communication devices exchange communication data specifically along the first core, and the first and second local oscillators exchange the first local oscillation signal specifically along the second core. Attached Figure Description

[0013] To gain a more complete understanding of the present invention, reference is now made to the following description in conjunction with the accompanying drawings, wherein:

[0014] Figure 1 This is a schematic diagram of a hybrid sensing-communication system using multi-core optical fibers;

[0015] Figure 2 A cross-section through a multi-core optical fiber is shown;

[0016] Figure 3 An implementation of a hybrid sensing-communication system using multi-core optical fiber is shown;

[0017] Figure 4 The configuration of the communication device as part of a hybrid sensing-communication system is shown;

[0018] Figure 5 The configuration of the sensing device as part of a hybrid sensing-communication system is shown;

[0019] Figure 6 Another implementation of a hybrid sensing-communication system using multi-core optical fibers is shown;

[0020] Figure 7 This demonstrates yet another implementation of a hybrid sensing-communication system using multi-core optical fibers, and

[0021] Figure 8 This is a flowchart of a synchronization method for a hybrid sensing-communication system using multi-core optical fibers. Detailed Implementation

[0022] The following description of the embodiments refers to the accompanying drawings. The same reference numerals in the different drawings denote the same or similar elements. The following detailed description does not limit the invention. Rather, the scope of the invention is defined by the appended claims. For simplicity, the following embodiments concerning multi-core optical fibers (MCFs) that simultaneously transmit communication data and parameter measurements along different cores are discussed. However, the embodiments discussed below are not limited to transmitting communication data and parameter measurements, but can be used to transmit any data.

[0023] Throughout this specification, references to "an embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic associated with the embodiment is included in at least one embodiment of the disclosed subject matter. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing in various places throughout the specification do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0024] According to an embodiment, multi-core optical fibers used for optical sensing and communication are used simultaneously with communication and measurement devices to exchange communication and measurement data concurrently. Communication data is routed along one or more cores that are different from the measurement data. MCF (Multi-Core Fiber) is a special type of optical fiber containing multiple cores that can be arranged in a loop around the fiber's longitudinal axis or on a two-dimensional grid. In one application, each core in the MCF acts as a separate waveguide, allowing light to propagate independently through these cores. In one embodiment, each core in the MCF is used for sensing or communication, such that their signals are well separated in space. In this case, the MCF can provide simultaneous multi-channel communication and multi-parameter sensing.

[0025] More specifically, according to Figure 1In the illustrated embodiment, the hybrid sensing-communication system 100 includes an MCF 110 connected between a first optical coupler C1 112 and a second optical coupler C2 114. The first coupler 112 and the second coupler 114 are configured to separate multiple cores of the MCF 110 and connect each core to a different device. For example, as... Figure 1 As shown, the first coupler 112 connects the first core of the MCF 110 to the communication device 120 and the second core of the MCF to the sensing unit SU 130.

[0026] The figure also schematically illustrates that the communication device 120 can include a transmitter Tx and / or a receiver Rx (as is typically seen in optical devices such as optical routers, optical servers, optical nodes, etc.). The communication device 120 can be capable of sending and / or receiving communication data using optical signals. The sensing unit 130 can be any device capable of (1) receiving optical signals from the MFC 110 and reading measurements stored in the optical signals, or (2) generating optical signals carrying one or more parameter measurements. In one application, the sensing unit is a light-emitting diode or a photodetector diode.

[0027] The second coupler 114 is also configured to connect the first core of the MCF 110 to the communication device 140 and the second core of the MCF to the sensing unit SU 150. The figure schematically illustrates that the communication device 140 may include a transmitter Tx and / or a receiver Rx, as commonly found in optical devices such as optical routers, optical servers, optical nodes, etc. The communication device 140 may be capable of transmitting and / or receiving communication data using optical signals. The sensing unit 150 may be any device capable of (1) receiving optical signals from the MFC 110 and reading measurements stored in the optical signals or (2) generating optical signals carrying one or more parameter measurements.

[0028] although Figure 1 The diagram shows that MFC 110 has only two cores, but MFC may have I different cores, where I is an integer equal to or greater than 2. As a representative example, a seven-core fiber with six cores located at the edges of a hexagon and a central core in the middle... Figure 2 As shown in the image. Note that... Figure 2 The MFC 110 shown has multiple cores 204-I distributed within the cladding material 206 and a sheath 202 that protects both the cores and the cladding material. Optical signals propagate only through the cores 204-I. One or more tension cables 210 may be disposed inside or outside the sheath 202 to provide mechanical strength to the MFC 110. Each core 204-I is used for sensing or communication to avoid noise in both subsystems due to interference from optical signals. For example, consider... Figure 2 The MCF 110 shown has three cores that can be used as independent communication channels, and four other cores for multi-parameter sensing applications.

[0029] Figures 3 to 5 A more detailed implementation of the system 100 discussed above is shown. Figure 3 The diagram illustrates MFC fiber 110 connected to a fan-in / fan-out coupler 112, which connects MFC fiber 110 to individual individual fibers 302-J, where J is an integer equal to or greater than 2. In one embodiment, the number of individual fibers J is equal to the number of cores I in the MFC 110. However, in one embodiment, J is less than I. For simplicity, Figure 3 The example shown illustrates only four single optical fibers 302-J. A greater number of single optical fibers can be used. Two single optical fibers 302-1 and 302-2 are connected to the corresponding communication devices 120 and 122, respectively, while two additional single optical fibers are connected to the corresponding sensing units 130 and 132, respectively. The transmitter / receiver (Tx / Rx) of the sensing units and communication devices injects light into / receives light from MCF 110. Light injection into / receiving from the individual cores of the MCF is performed via fan-in / fan-out couplers.

[0030] One possible internal configuration of the communication device 120 is as follows: Figure 4 As shown. The communication device 120 may have a housing 402 that carries an optical generator 404, such as a laser, that generates continuous wave (CW) light 405. The CW light 405 is modulated by an electro-optic (EO) modulator 406, which is driven by an electronic driver 408 based on an electronic signal (e.g., radio frequency (RF) signal / information). The EO modulator 406 is capable of generating any type of modulation, such as amplitude modulation, phase modulation, frequency modulation, etc. The modulated light 407 can be amplified using an erbium-doped fiber amplifier (EDFA) 410, and the amplified light 411 is guided through a circulator 412 to a fan-in / fan-out coupler 112. The circulator 412 in the figure has three ports 1-3: one for receiving the amplified light 411; one connected to the corresponding single fiber 302-1 for transmitting or receiving optical signals; and a demodulation arm connected to the communication device 120, which will be discussed later. Note that the optical circulator is a structure that receives an optical signal at one port and outputs the signal at the next port.

[0031] The optical signal 413 received at port 2 is directed from the fan-in / fan-out coupler 112 through port 3 of the circulator 412 to another EDFA 414 for possible amplification. The amplified received signal 415 is then detected by detector 416 and demodulated at demodulator 418 to extract the information carried by the optical signal 413. This configuration of the communication device can be placed at only one end of the MCF or at both ends for bidirectional communication. The structure of the communication device 120 can be modified to add more electronics to stabilize the signal and further improve its accuracy. In one application, the communication device may also include a power supply 420 for providing electrical power to the components carried by the housing 120. The power supply 420 may be an autonomous power source (e.g., a battery) or connected to an external power source. In addition, the communication device may include a processor 422 for coordinating the activities of the aforementioned components, and an RF communication module 424 configured to control the driver 408. This RF communication module can communicate with the RF signal source used to modulate the CW light 405 in a wired or wireless manner. As previously mentioned, the communication device 120 may be a router, server, network component, cell tower, or similar device that uses optical signals to encode and / or decode data.

[0032] In one embodiment, the communication device 120 differs from the sensing unit 130 in that the communication device is capable of modulating optical signals with a driver 408 to encode commands or communication data, and is also capable of demodulating received optical signals with a demodulator 418 to extract commands or communication data received from another communication device. In this application, communication data is defined as data associated with voice, images, video, written text, or any other data that is not merely a measurement of parameters of an object, person, animal, or plant (i.e., a living organism). In other words, communication data relates to logical processes performed by humans. Sensing data received or transmitted by the sensing unit 130 is associated with the measurement of a parameter of an object or living organism, but this parameter is not related to logical processes. For example, the sensing unit may measure the light intensity of a cell, where light intensity is a parameter and a natural phenomenon. However, taking an image of the same cell related to its light intensity constitutes communication data because the image of the cell involves a logical process of putting together the various parts of the cell and their light intensities to construct a final image of the cell. In one example, sensor data is defined as relating to one or more measured parameters of the environment, while communication data relates to non-measured data. While these examples are intended to provide an understanding of the differences between communication data and parameter data, those skilled in the art will understand from this discussion that other differences may exist between these two types of data, and that communication data involves more than simply measuring parameters and transmitting them via the MCF 110.

[0033] One possible structure of the sensing unit 130 is as follows: Figure 5 As shown, it includes a housing 502 that carries a light source 504, such as a laser source, configured to generate CW light 505. Light 505 can optionally be modulated using an EO modulator 506 driven by a function generator 508. Note that the function generator 508 differs from the driver 408 of the communication device 120 because the function generator 508 can modulate light 505 using one or more predefined functions, while the driver 408 uses a signal storing information to modulate light 405. In other words, the function generator 508 is limited to generating only functions, while the driver 408 is not. If desired, the modulated light 507 is amplified by an EDFA 510, and then the amplified light 511 is passed through another single fiber 302-J via a circulator 512 to a fan-in / fan-out coupler 112. The received light 513 from the fan-in / fan-out coupler 112 is directed via the circulator 512 to an EDFA 514 for further amplification, and then detected at a detector 516. Circulator 512 may have the configuration of circulator 412 discussed above. Sensing unit 130 can be located at one end or both ends of the MCF for bidirectional sensing. Each sensing unit can detect / measure / monitor one or more parameters and materials, including but not limited to temperature, pressure, stress, vibration, gas, oil, contamination, etc. As mentioned above, the parameters monitored by the sensing units and the data generated from these parameters are different from communication data. At least in some sense, parameter-related data does not describe logical processes, while communication data involves describing logical processes, such as capturing video, writing text, speaking, or putting measured parameters together to generate an image.

[0034] Now about Figure 6 This paper discusses one possible application of system 100, and relates it to coherent optical sensing and communication system 600. In conventional coherent optical sensing and communication systems, the local oscillator (LO) signal is mixed with the received light to improve the system's signal-to-noise ratio (SNR). However, such coherent systems are susceptible to frequency-temporal instability and phase discrepancies between the received signal and the LO signal. This occurs because the transmitter and LO source are never exactly identical. Note that a local oscillator is an electronic circuit that generates a periodically oscillating electronic signal. Numerous sophisticated digital signal processing (DSP) techniques are required to synchronize the transmitter and LO to compensate for frequency and phase noise.

[0035] However, by using Figure 6In the configuration shown, communication signal 620 can be transmitted through one core 602-1 of MCF 110, and its corresponding LO signal 624 is transmitted through another core 602-2. The LO signal 624 is generated by LO 622 located next to or as part of communication device 120. Thus, the signal 640 received at receiving communication equipment 140 (which may be the transmitted signal 620) and the signal 644 received at receiving LO 642 (which is the LO signal 624) both come from the same source, but are transmitted on different cores of MCF 110. Figure 6 Communication devices 120 and 140 are shown at the end of MCF 110, utilizing a first optical fiber or core 602-1 and LO devices 622 and 642, which communicate via a second optical fiber or core 602-2. This method ensures that the receiving communication device 140 always receives the original transmitted signal and its LO from the same source, without any phase and / or frequency noise. Similarly, the transmitting sensing unit 130 can use different cores 602-3 and 602-4 to transmit optical signal 630 and LO signal 634 from the same source (which includes sensing unit 130 and LO 632), and the receiving sensing unit 150 and the corresponding LO 652 receive optical signal 650 (which corresponds to optical signal 630) and LO signal 654 (which corresponds to optical signal 634) along separate cores, without any phase and / or frequency noise. Note that the LO unit may be part of the communication device and / or the sensing unit.

[0036] Figure 6 The diagram illustrates how, for two communication devices 120 and 140, the MFC 110 uses two different cores to give the LO signal its own core. The diagram also shows how, for two sensing units 130 and 150, two additional cores of the MFC 110 are used to give the LO signal its own core. This means that adding any pair of communication devices or sensing units requires two additional cores, one for communication / sensing data transmission and the other for the LO signal, ensuring the system is coherent without any phase and / or frequency noise. Note that... Figure 6 The system shown requires a dedicated chip for the LO signals of communication devices 120 and 140 or for the LO signals of sensing units 130 and 150, but not simultaneously for the LO signals of 120 and 140, or 130 and 150. If enhanced system consistency is required, each pair of communication devices and / or sensing units may have its own dedicated LO signal chip. Although Figure 6 A pair of communication devices and a pair of sensing units are shown, but those skilled in the art should understand that any number of N pairs of communication devices and any number of M pairs of sensing units can be connected to a given MFC. The only limitation is the number of cores available in the MFC, i.e., N + M = the number of cores in the MFC, where N and M are integers equal to or greater than 1.

[0037] For simplicity, the embodiments discussed above show that each pair of devices connected to the same core of the MCF is identical or similar. However, it is also possible for two different devices to be connected to opposite ends of the same core of the MCF, for example, a sensing unit and a processing device, where the sensing unit measures parameters, sends the parameters to the processing device, and the processing device processes the received data and provides the parameter values ​​to the user. Other combinations of devices are possible for a given core of the MCF; for example, one communication device is generating text while another is consuming content. In other words, two devices connected to the same core of the MCF do not have to be exactly the same.

[0038] Another application of System 100 is in the management of complex optical sensor networks. For optical sensor networks containing thousands of sensors, synchronization between the sensors is essential. Furthermore, the large amounts of data generated by these sensors should be transmitted to any end of the network. If System 100 is used... Figure 7 Implemented in the configuration shown, such a system 700 would have a synchronization device 710, such as a processor, configured to synchronize sensing units. In this case, some cores 702-2 and 702-3 of the MCF 110 are used for sensing applications along with sensing units 130 and 132, while one or more other cores 702-1 transmit synchronization signals. Furthermore, one or more other cores 702-4 can be used to connect to a communication device 120, allowing communication data to also be exchanged via the MCF 110. Any number of cores can be used for synchronizing, sensing, or communicating data, provided at least one core is dedicated to the synchronization function.

[0039] about Figure 8A method for synchronizing devices in a network is discussed. The method includes: step 800 of generating a first local oscillator signal at a first local oscillator 622; step 802 of generating communication data 620 at a first communication device 120 optically coupled to a first end of a first core 302-1 of a multi-core optical fiber 110, the first communication device 120 including a first local oscillator 622 generating the first local oscillator signal 624; step 804 of transmitting the communication data along the first core 302-1 of the multi-core optical fiber 110; step 806 of transmitting the first local oscillator signal 624 along a second core 302-2 of the multi-core optical fiber 110; step 808 of receiving the communication data 620 at a second communication device 140 optically coupled to a second end of the first core 302-1 of the multi-core optical fiber 110; step 810 of receiving the first local oscillator signal 624 at a second local oscillator 642, which is part of the second communication device 140; and step 812 of using the first local oscillator signal 624 to decode the communication data 620. In this final step, the second local oscillator 642 can use the first local oscillator signal 624 to correct / adjust its local oscillation time, thereby synchronizing the first local oscillator 622 and the second local oscillator 642. The first and second communication devices exchange communication data specifically along the first core, and the first and second local oscillators exchange the first local oscillator signal specifically along the second core.

[0040] The disclosed embodiments provide a hybrid sensing-communication system utilizing multi-core optical fibers to simultaneously transmit communication data and sensing data along different cores of the fibers. It should be understood that this description is not intended to limit the invention. Rather, the embodiments are intended to cover alternatives, modifications, and equivalents included within the spirit and scope of the invention as defined by the appended claims. Furthermore, numerous specific details are set forth in the detailed description of the embodiments to provide a comprehensive understanding of the claimed invention. However, those skilled in the art will understand that various embodiments can be implemented without these specific details.

[0041] Although the features and elements of this embodiment are described in specific combinations in the embodiments, each feature or element may be used alone without the other features and elements of the embodiment, or in combination with or without the other features and elements disclosed herein, or in various combinations with or without the other features and elements disclosed herein.

[0042] This written description uses examples of the disclosed subject matter to enable any person skilled in the art to practice examples of the disclosed subject matter, including making and using any device or system and performing any incorporated methods. The patent scope of this subject matter is defined by the claims and may include other examples that would occur to a person skilled in the art. Such other examples are intended to be within the scope of these claims.

Claims

1. A coherent optical sensing and communication system (600), comprising: A multi-core optical fiber (110) comprising a first core (302-1) and a second core (302-2); A first communication device (120) is optically coupled to a first end of a first core (302-1) of the multi-core optical fiber (110), and the first communication device (120) has a first local oscillator (622) that generates a first local oscillation signal (624). as well as The second communication device (140) is optically coupled to the second end of the first core (302-1) of the multi-core optical fiber (110), and the second communication device (140) has a second local oscillator (642) that receives a first local oscillator signal (624). A first sensing device (130) is optically coupled to the first end of the third core of the multi-core optical fiber (110), and the first sensing device (130) has a third local oscillator (632) that generates a second local oscillation signal (634). as well as The second sensing device (150) is optically coupled to the second end of the third core of the multi-core optical fiber (110), and the second sensing device (150) has a fourth local oscillator (652) for receiving a second local oscillator signal (634). The first communication device and the second communication device exchange communication data specifically along the first core. The first local oscillator and the second local oscillator specifically exchange the first local oscillation signal along the second core. The first and second sensing devices exchange sensing data along the third core, and The third and fourth local oscillators specifically exchange the second local oscillation signal along the fourth core of the multi-core optical fiber.

2. The system of claim 1, wherein the first sensing device and the second sensing device are configured to measure parameters of the environment.

3. The system of claim 2, wherein the parameter is at least one of temperature, pressure, light intensity, stress, vibration, gas, and oil.

4. The system of claim 1, wherein the first communication device and the second communication device are configured to exchange non-measurement data.

5. The system of claim 1, wherein the first communication device is a router, and the first sensing device is a photodetector diode.

6. The system of claim 1, further comprising: A first optical coupler optically connects the first end of the multi-core optical fiber to the first communication device, the first local oscillator, the first sensing device, and the third local oscillator. and A second optical coupler optically connects the second end of the multi-core optical fiber to the second communication device, the second local oscillator, the second sensing device, and the fourth local oscillator.

7. The system of claim 6, wherein the first communication device comprises: light source; An optical modulator, which is optically connected to a light source and configured to modulate light from the light source to encode communication data; An optical amplifier, optically connected to an optical modulator; A circulator configured to receive amplified light from an optical amplifier and transmit the amplified light to the first optical coupler; A photodetector configured to receive light from a circulator; as well as A demodulator, configured to demodulate the light received from the photodetector and extract communication data.

8. The system of claim 7, wherein the first communication device further comprises: An electronic driver that encodes communication data into light by controlling a modulator.

9. The system of claim 8, wherein the first sensing device is identical to the first communication device, except that the electronic driver is replaced by a function generator and the first sensing device does not have a demodulator.

10. A method for synchronizing communication devices and sensing devices in a network, the method comprising: A first local oscillation signal (624) is generated at the first local oscillator (622); Communication data (620) is generated at a first communication device (120) optically coupled to the first end of the first core (302-1) of a multi-core optical fiber (110), the first communication device (120) having a first local oscillator (622) that generates a first local oscillation signal (624). Communication data is transmitted along the first core (302-1) of the multi-core optical fiber (110); A first local oscillation signal (624) is transmitted along the second core (302-2) of the multi-core optical fiber (110); Communication data (620) is received at a second communication device (140) optically coupled to the second end of the first core (302-1) of the multi-core optical fiber (110). The first local oscillation signal (624) is received at the second local oscillator (642), which is part of the second communication device (140); as well as The first local oscillator signal (624) is used to decode the communication data (620); Sensing data is transmitted using a first sensing device, which is optically coupled to the first end of the third core of the multi-core optical fiber, and the first sensing device has a third local oscillator that generates a second local oscillation signal. A second local oscillation signal is transmitted along the fourth core of the multi-core optical fiber; Sensing data is received at a second sensing device, which is optically coupled to the second end of the third core of the multi-core optical fiber. The second sensing device has a fourth local oscillator that receives a second local oscillator signal along the fourth core of the multi-core optical fiber. The first communication device and the second communication device exchange communication data specifically along the first core, and The first local oscillator and the second local oscillator specifically exchange the first local oscillation signal along the second core. The first and second sensing devices exchange sensing data along the third core, and The third and fourth local oscillators specifically exchange the second local oscillation signal along the fourth core.

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