Very-low-frequency disturbance perception positioning and high-capacity optical fiber communication fusion device

Abstract

The invention discloses a very-low-frequency disturbance sensing and positioning and high-capacity optical fiber communication fusion device, which is characterized in that sensing and positioning detection signals and digital subcarrier multiplexing (DSM) communication signals are fused through frequency division multiplexing, and the spectrum efficiency of an optical fiber communication system is improved; capacity expansion mechanisms such as space division multiplexing and wavelength division multiplexing are compatible, and high-capacity optical fiber communication can be realized; very-low-frequency disturbance sensing positioning is realized based on a direct detection distributed acoustic wave sensing (DAS) technology of chirped pulses; the method is suitable for all communication optical fibers including but not limited to single-mode optical fibers, multi-core optical fibers and multi-core few-mode optical fibers; while the performance advantages of a traditional DAS system are maintained, diversity reception of Rayleigh backscattering intensities of different fiber cores / modes is realized by using multi-dimensional multiplexing, so that the signal-to-noise ratio and sensitivity of a disturbance sensing positioning signal are improved.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber communication technology, and more specifically, to a fusion device of very low frequency disturbance sensing and positioning and large-capacity optical fiber communication. Background Art

[0002] With the rapid development of generative artificial intelligence, 5G, Internet of Things, cloud computing, etc., the demand for communication capacity has increased dramatically, while the traditional standard single-mode fiber (SSMF) is limited in its expansion. Space-division multiplexing (SDM) has the potential to solve the lack of expansion of traditional SSMF, and has the advantages of reducing system cost and improving energy efficiency. In recent years, the synaesthesia fusion has been achieved through multi-core fiber (MCF) and multi-core few-mode fiber (MC-FMF), giving the existing communication fiber sensing and positioning functions, which has aroused great interest. Distributed acoustic sensing (DAS) based on Rayleigh backscattering is widely used because of its high sensitivity and spatial resolution.

[0003] However, the existing communication optical fiber interaceptive fusion system has the following problems: 1. The peak power of the sensing detection pulse in the single-core optical fiber interaceptive fusion system is limited by the nonlinear effect of the optical fiber, resulting in a weak Rayleigh backscattering signal, so the signal-to-noise ratio and sensitivity of the disturbance sensing positioning signal are limited; 2. In the multi-core / few-mode optical fiber interaceptive fusion system, the communication signal and the sensing signal are transmitted independently in different cores / modes, sacrificing the spectrum efficiency of the communication system and resulting in limited expansion of the communication system; 3. Due to the phase noise and frequency drift of the laser, the coherent detection DAS system has poor sensing and positioning sensitivity in the very low frequency band, and existing research mainly focuses on sensing and positioning external disturbances above 10Hz. However, very low frequency disturbance sensing and positioning of 0.1Hz to 10Hz is crucial for applications such as optical cable monitoring, geological exploration, and natural disaster warning. Summary of the invention

[0004] In order to overcome the defect that the existing system cannot simultaneously realize the high-sensitivity very low frequency perception and the high-spectrum efficiency fusion of large-capacity communication, the present invention provides a fusion device of very low frequency disturbance perception positioning and large-capacity optical fiber communication.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0006] The present invention provides a fusion device of very low frequency disturbance sensing and positioning and large-capacity optical fiber communication, comprising a signal input unit, a signal ring unit, a communication optical fiber, a sensing unit and a communication unit;

[0007] The output end of the signal input unit is connected to the input end of the signal ring unit; the output end of the signal ring unit is connected to both the communication optical fiber and the input end of the sensor unit; the output end of the communication optical fiber is connected to the communication unit;

[0008] The signal input unit is used to generate a common-wavelength synaesthesia fusion signal; the signal ring unit is used to receive the common-wavelength synaesthesia fusion signal output by the signal input unit, and transmit the received backscattered synaesthesia fusion signal to the sensing unit and transmit the forward light to the communication unit through the communication optical fiber; the sensing unit is used to locate the very low frequency disturbance signal; and the communication unit is used for optical fiber communication.

[0009] Preferably, the signal input unit comprises a first laser, a first coupler, a second coupler, a chirped pulse generating module, a wavelength division multiplexer, a first optical amplification module, a first digital subcarrier multiplexing signal generating module and N digital subcarrier multiplexing signal generating units connected in sequence;

[0010] The digital subcarrier multiplexed signal generating unit comprises a narrow linewidth laser and a second digital subcarrier multiplexed signal generating module connected in sequence;

[0011] The output end of the first laser is connected to the input end of the first coupler; the output end of the first coupler is connected to the input ends of the chirped pulse generating module and the first digital subcarrier multiplexing signal generating module; the output ends of the chirped pulse generating module and the first digital subcarrier multiplexing signal generating module are connected to the input end of the second coupler; the output end of the second coupler is connected to the input end of the wavelength division multiplexer;

[0012] The input end of the wavelength division multiplexer is connected to the output end of the first digital subcarrier multiplexing signal generating unit; the output end of the Nth digital subcarrier multiplexing signal generating unit is connected to the input end of the wavelength division multiplexer; the output end of the wavelength division multiplexer is connected to the input end of the first optical amplification module;

[0013] The output end of the first optical amplification module is connected to the input end of the signal ring unit.

[0014] Preferably, the communication optical fiber includes but is not limited to single-mode optical fiber, multi-core optical fiber and multi-core few-mode optical fiber.

[0015] Preferably, when the communication optical fiber is a single-mode optical fiber, the sensing unit is a first sensing unit; the signal ring unit is a first signal ring unit; the communication unit is a first communication unit; the first signal ring unit includes a first circulator unit; the first circulator unit includes a first circulator, the output end of the first circulator is connected to the single-mode optical fiber and the input end of the first sensing unit; the output end of the single-mode optical fiber is connected to the input end of the first communication unit.

[0016] Preferably, the first sensing unit includes a second optical amplification module, a first optical filter module, a first photoelectric detection module and a first signal demodulation module connected in sequence; the output end of the first circulator is connected to the input end of the second optical amplification module; the first communication unit includes a first wavelength division multiplexer, a first local oscillator laser, a first signal receiving module and a second signal demodulation module; the output end of the single-mode optical fiber is connected to the input end of the first wavelength division multiplexer; the output ends of the first wavelength division multiplexer and the first local oscillator laser are both connected to the input end of the first signal receiving module; the output end of the first signal receiving module is connected to the input end of the second signal demodulation module.

[0017] Preferably, when the communication optical fiber is a multi-core optical fiber, the sensing unit is a second sensing unit; the signal ring unit is a second signal ring unit; the communication unit is a second communication unit; the second signal ring unit includes a second circulator unit and a first fan-in fan-out unit; the second circulator unit includes a first circulator array composed of a plurality of second circulators connected in sequence; the output end of each second circulator in the first circulator array is connected to the input end of the first fan-in fan-out unit; the output end of each second circulator in the first circulator array is connected to the input end of the second sensing unit; the output end of the first fan-in fan-out unit is connected to the input end of the second communication unit.

[0018] Preferably, the second sensing unit includes a first optical combiner, a third optical amplification module, a second optical filtering module, a second photoelectric detection module and a third signal demodulation module connected in sequence; the output end of each second circulator of the first circulator array is connected to the input end of the first optical combiner; the second communication unit includes a second fan-in fan-out unit, a second wavelength division multiplexer, a second local oscillator laser, a second signal receiving module and a fourth signal demodulation module; the output end of the multi-core optical fiber is connected to the input end of the second fan-in fan-out unit; the output end of the second fan-in fan-out unit is connected to the input end of the second wavelength division multiplexer; the output end of the second wavelength division multiplexer and the second local oscillator laser is connected to the input end of the second signal receiving module; the output end of the second signal receiving module is connected to the input end of the fourth signal demodulation module.

[0019] Preferably, when the communication optical fiber is a multi-core few-mode optical fiber, the sensing unit is a third sensing unit; the signal ring unit is a third signal ring unit; the communication unit is a third communication unit; the third signal ring unit includes a third circulator unit, a mode multiplexer and a third fan-in and fan-out unit connected in sequence; the third device unit includes a second circulator array composed of a plurality of third circulators connected in sequence; the output end of each third circulator of the second circulator array is connected to the input end of the mode multiplexer; the output end of each second circulator of the second circulator array is connected to the input end of the third sensing unit; the output end of the third fan-in and fan-out unit is connected to the input end of the third communication unit.

[0020] Preferably, the third sensing unit includes a second optical combiner, a fourth optical amplification module, a third optical filtering module, a third photoelectric detection module and a fifth signal demodulation module connected in sequence; the output end of each second circulator of the second circulator array is connected to the input end of the second optical combiner; the third communication unit includes a fourth fan-in and fan-out unit, a mode demultiplexer, a third wave splitter, a third local oscillator laser, a third signal receiving module and a sixth signal demodulation module; the output end of the multi-core few-mode optical fiber is connected to the input end of the fourth fan-in and fan-out unit; the output end of the fourth fan-in and fan-out unit is connected to the input end of the mode demultiplexer; the output end of the mode demultiplexer is connected to the input end of the third wave splitter; the output ends of the third wave splitter and the third local oscillator laser are both connected to the input end of the third signal receiving module; the output end of the third signal receiving module is connected to the input end of the sixth signal demodulation module.

[0021] Preferably, when the peak power of the common-wavelength synaesthesia fusion signal exceeds a preset threshold, stimulated Brillouin scattering (SBS) will cause degradation of the signal-to-noise ratio of the very low frequency disturbance signal; the preset threshold is:

[0022]

[0023] Among them, A eff is the effective area of ​​the communication optical fiber, g B is the SBS gain coefficient, L eff is the effective length of the communication optical fiber.

[0024] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0025] The present invention proposes a fusion device of very low frequency disturbance perception and positioning and large-capacity optical fiber communication. The signal input unit generates a common wavelength interaceptive fusion signal through frequency division multiplexing, which can make full use of optical fiber space resources and spectrum resources and improve the capacity of the communication system. Under the coordinated action of the communication unit and the sensor unit, the very low frequency disturbance signal can be located while realizing optical fiber communication. Very low frequency disturbance perception and positioning are realized by direct detection and intensity cross-correlation demodulation, and high-sensitivity very low frequency disturbance perception and positioning and large-capacity optical fiber communication can be realized simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of the fusion device of very low frequency disturbance sensing and positioning and large-capacity optical fiber communication described in Example 1;

[0027] Figure 2 This is a schematic diagram of the structure of the common wavelength synaesthesia fusion signal generating device described in Example 3;

[0028] Figure 3 This is a schematic diagram of the structure of the fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication based on single-mode optical fiber described in Example 3;

[0029] Figure 4 It is a schematic diagram of the structure of the fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication based on multi-core optical fiber described in Example 3;

[0030] Figure 5 It is a schematic diagram of the structure of the fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication based on multi-core few-mode optical fiber described in Example 3;

[0031] Figure 6 A schematic diagram of the working principle of the DAS system described in Example 3;

[0032] Figure 7 Schematic diagram of the spectrum of the multi-wavelength synaesthesia fusion signal described in Example 3;

[0033] Figure 8 Schematic diagram of the spectrum of the common-wavelength synaesthesia fusion signal under different system parameters described in Example 3. DETAILED DESCRIPTION

[0034] The drawings are for illustrative purposes only and should not be construed as limiting the present patent;

[0035] In order to better illustrate the present embodiment, some parts in the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product;

[0036] It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0037] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0038] Example 1

[0039] This embodiment provides a fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication, such as Figure 1 As shown, it includes a signal input unit, a signal ring unit, a communication optical fiber, a sensing unit and a communication unit;

[0040] The output end of the signal input unit is connected to the input end of the signal ring unit; the output end of the signal ring unit is connected to both the communication optical fiber and the input end of the sensor unit; the output end of the communication optical fiber is connected to the communication unit;

[0041] The signal input unit is used to generate a common-wavelength synaesthesia fusion signal; the signal ring unit is used to receive the common-wavelength synaesthesia fusion signal output by the signal input unit, and transmit the backscattered synaesthesia fusion signal to the sensing unit and transmit the forward light to the communication unit through the communication optical fiber; the sensing unit is used to locate the very low frequency disturbance signal; and the communication unit is used for optical fiber communication.

[0042] The device includes a signal input unit, a signal ring unit, a communication optical fiber, a sensing unit and a communication unit. The signal input unit is responsible for generating a common wavelength interaceptive fusion signal and outputting the signal to the signal ring unit. As an intermediate link, the signal ring unit receives the common wavelength interaceptive fusion signal from the signal input unit, and the scattered light is directly sent to the sensing unit, and the forward light is sent to the communication unit through the communication optical fiber. The function of the sensing unit is to detect and locate extremely low frequency disturbance signals, while the communication unit is responsible for performing optical fiber communication tasks. Such a design enables the system to simultaneously perform very low frequency sensing detection and large-capacity data communication, thereby improving the comprehensive performance and efficiency of the system.

[0043] Compared with the traditional multi-core / few-mode optical fiber synaesthesia fusion technology, this device can more effectively utilize the spatial and spectral resources of optical fiber by multiplexing the communication signal and the sensing signal under the common wavelength channel, thereby improving the capacity of the communication system. Compared with the existing single-core optical fiber synaesthesia fusion scheme, this device enhances the intensity of the Rayleigh backscattering signal at the receiving end through space division multiplexing, which helps to improve the signal-to-noise ratio and sensitivity of the very low frequency disturbance perception and positioning signal. In addition, compared with the existing synaesthesia fusion scheme, the present invention adopts direct detection and intensity cross-correlation demodulation technology, which can simultaneously realize high-sensitivity very low frequency disturbance perception and positioning and large-capacity optical fiber communication, providing an innovative solution that takes into account both very low frequency perception and positioning and large communication capacity.

[0044] Example 2

[0045] This embodiment provides a fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication, including a signal input unit, a signal ring unit, a communication optical fiber, a sensing unit and a communication unit;

[0046] The output end of the signal input unit is connected to the input end of the signal ring unit; the output end of the signal ring unit is connected to both the communication optical fiber and the input end of the sensor unit; the output end of the communication optical fiber is connected to the communication unit;

[0047] The signal input unit is used to generate a common-wavelength synaesthesia fusion signal; the signal ring unit is used to receive the common-wavelength synaesthesia fusion signal output by the signal input unit, and transmit the received backscattered synaesthesia fusion signal to the sensing unit and transmit the forward light to the communication unit through the communication optical fiber; the sensing unit is used to locate the very low frequency disturbance signal; and the communication unit is used for optical fiber communication.

[0048] The device includes a signal input unit, a signal ring unit, a communication optical fiber, a sensing unit and a communication unit. The signal input unit is responsible for generating a common wavelength interaceptive fusion signal and outputting the signal to the signal ring unit. As an intermediate link, the signal ring unit receives the common wavelength interaceptive fusion signal from the signal input unit, and the scattered light is directly sent to the sensing unit, and the forward light is sent to the communication unit through the communication optical fiber. The function of the sensing unit is to detect and locate extremely low frequency disturbance signals, while the communication unit is responsible for performing optical fiber communication tasks. Such a design enables the system to simultaneously perform very low frequency sensing detection and large-capacity data communication, thereby improving the comprehensive performance and efficiency of the system.

[0049] Compared with the traditional multi-core / few-mode optical fiber synaesthesia fusion technology, this device can more effectively utilize the spatial and spectral resources of optical fiber by multiplexing the communication signal and the sensing signal under the common wavelength channel, thereby improving the capacity of the communication system. Compared with the existing single-core optical fiber synaesthesia fusion scheme, this device enhances the intensity of the Rayleigh backscattering signal at the receiving end through space division multiplexing, which helps to improve the signal-to-noise ratio and sensitivity of the very low frequency disturbance perception and positioning signal. In addition, compared with the existing synaesthesia fusion scheme, the present invention adopts direct detection and intensity cross-correlation demodulation technology, which can simultaneously realize high-sensitivity very low frequency disturbance perception and positioning and large-capacity optical fiber communication, providing an innovative solution that takes into account both very low frequency perception and positioning and communication capacity.

[0050] The signal input unit includes a first laser, a first coupler, a second coupler, a chirped pulse generating module, a wavelength division multiplexer, a first optical amplification module, a first digital subcarrier multiplexing signal generating module and N digital subcarrier multiplexing signal generating units connected in sequence;

[0051] The digital subcarrier multiplexed signal generating unit comprises a narrow linewidth laser and a second digital subcarrier multiplexed signal generating module connected in sequence;

[0052] The output end of the first laser is connected to the input end of the first coupler; the output end of the first coupler is connected to the input ends of the chirped pulse generating module and the first digital subcarrier multiplexing signal generating module; the output ends of the chirped pulse generating module and the first digital subcarrier multiplexing signal generating module are connected to the input end of the second coupler; the output end of the second coupler is connected to the input end of the wavelength division multiplexer;

[0053] The input end of the wavelength division multiplexer is connected to the output end of the first digital subcarrier multiplexing signal generating unit; the output end of the Nth digital subcarrier multiplexing signal generating unit is connected to the input end of the wavelength division multiplexer; the output end of the wavelength division multiplexer is connected to the input end of the first optical amplification module;

[0054] The output end of the first optical amplification module is connected to the input end of the signal ring unit.

[0055] The communication optical fiber includes but is not limited to single-mode optical fiber, multi-core optical fiber and multi-core few-mode optical fiber.

[0056] When the communication optical fiber is a single-mode optical fiber, the sensing unit is a first sensing unit; the signal ring unit is a first signal ring unit; the communication unit is a first communication unit; the first signal ring unit includes a first circulator unit; the first circulator unit includes a first circulator, the output end of the first circulator is connected to the single-mode optical fiber and the input end of the first sensing unit; the output end of the single-mode optical fiber is connected to the input end of the first communication unit.

[0057] The first sensing unit includes a second optical amplifier module, a first optical filter module, a first photoelectric detection module and a first signal demodulation module which are connected in sequence; the output end of the first circulator is connected to the input end of the second optical amplifier module; the first communication unit includes a first wavelength division multiplexer, a first local oscillator laser, a first signal receiving module and a second signal demodulation module; the output end of the single-mode optical fiber is connected to the input end of the first wavelength division multiplexer; the output ends of the first wavelength division multiplexer and the first local oscillator laser are both connected to the input end of the first signal receiving module; the output end of the first signal receiving module is connected to the input end of the second signal demodulation module.

[0058] When the communication optical fiber is a multi-core optical fiber, the sensing unit is a second sensing unit; the signal ring unit is a second signal ring unit; the communication unit is a second communication unit; the second signal ring unit includes a second circulator unit and a first fan-in fan-out unit; the second circulator unit includes a first circulator array composed of a plurality of second circulators connected in sequence; the output end of each second circulator in the first circulator array is connected to the input end of the first fan-in fan-out unit; the output end of each second circulator in the first circulator array is connected to the input end of the second sensing unit; the output end of the first fan-in fan-out unit is connected to the input end of the second communication unit.

[0059] The second sensing unit includes a first optical combiner, a third optical amplification module, a second optical filtering module, a second photoelectric detection module and a third signal demodulation module connected in sequence; the output end of each second circulator of the first circulator array is connected to the input end of the first optical combiner; the second communication unit includes a second fan-in fan-out unit, a second wavelength division multiplexer, a second local oscillator laser, a second signal receiving module, and a fourth signal demodulation module; the output end of the multi-core optical fiber is connected to the input end of the second fan-in fan-out unit; the output end of the second fan-in fan-out unit is connected to the input end of the second wavelength division multiplexer; the output ends of the second wavelength division multiplexer and the second local oscillator laser are connected to the input end of the second signal receiving module; the output end of the second signal receiving module is connected to the input end of the fourth signal demodulation module.

[0060] When the communication optical fiber is a multi-core few-mode optical fiber, the sensing unit is a third sensing unit; the signal ring unit is a third signal ring unit; the communication unit is a third communication unit; the third signal ring unit includes a third circulator unit, a mode multiplexer and a third fan-in and fan-out unit connected in sequence; the third device unit includes a second circulator array composed of a plurality of third circulators connected in sequence; the output end of each third circulator of the second circulator array is connected to the input end of the mode multiplexer; the output end of each second circulator of the second circulator array is connected to the input end of the third sensing unit; the output end of the third fan-in and fan-out unit is connected to the input end of the third communication unit.

[0061] The third sensing unit includes a second optical combiner, a fourth optical amplification module, a third optical filtering module, a third photoelectric detection module and a fifth signal demodulation module connected in sequence; the output end of each second circulator of the second circulator array is connected to the input end of the second optical combiner; the third communication unit includes a fourth fan-in fan-out unit, a mode demultiplexer, a third wave splitter, a third local oscillator laser, a third signal receiving module and a sixth signal demodulation module; the output end of the multi-core few-mode optical fiber is connected to the input end of the fourth fan-in fan-out unit; the output end of the fourth fan-in fan-out unit is connected to the input end of the mode demultiplexer; the output end of the mode demultiplexer is connected to the input end of the third wave splitter; the output ends of the third wave splitter and the third local oscillator laser are both connected to the input end of the third signal receiving module; the output end of the third signal receiving module is connected to the input end of the sixth signal demodulation module.

[0062] When the peak power of the common wavelength synaesthesia fusion signal exceeds a preset threshold, stimulated Brillouin scattering (SBS) will cause the signal-to-noise ratio of the very low frequency disturbance signal to deteriorate; the preset threshold is:

[0063]

[0064] Among them, A eff is the effective area of ​​the communication optical fiber, g B is the SBS gain coefficient, L eff is the effective length of the communication optical fiber.

[0065] Example 3

[0066] This embodiment provides a fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication, including a signal input unit, a signal ring unit, a communication optical fiber, a sensing unit and a communication unit; the signal input unit is a common wavelength synaesthesia common wavelength synaesthesia fusion signal generating device; the signal ring unit is a space division multiplexing signal transceiver array; the communication optical fiber is an optical fiber link; the communication unit is a communication signal receiving and demodulating device; the sensing unit is a sensing signal receiving and demodulating device; Figure 2As shown, the common-wavelength interacuity common-wavelength interacuity fusion signal generating device comprises an ultra-narrow linewidth laser (101), a narrow linewidth laser (102-10N), a coupler (201, 202), a chirped pulse generating module (300), a digital subcarrier multiplexing signal generating module (401-40N), a wavelength division multiplexer (500), and an optical amplification module (601); the ultra-narrow linewidth laser (101) is used to provide a high-coherence light source; the narrow linewidth laser (102-10N) is used to provide a wavelength division multiplexed continuous optical signal; the coupler (201) is used to split the continuous light generated by the ultra-narrow linewidth laser (101) into two, one for disturbance perception positioning, and the other for optical fiber communication; the chirped pulse generating module (300) is used to generate a chirped pulse suitable for perception positioning; the digital subcarrier multiplexing signal generating module (401) comprises a modulator, an arbitrary waveform generator, The invention discloses a digital signal processing device for generating a digital subcarrier multiplexed communication signal with a reserved guard interval; the digital subcarrier multiplexed signal generating module (402-40N) for generating a digital subcarrier multiplexed communication signal without a reserved guard interval; the coupler (202) for multiplexing the sensing detection signal into the digital subcarrier multiplexed communication signal with a reserved guard interval; the wavelength division multiplexer (500) for multiplexing the multi-wavelength modulation signal to form a synaesthesia fusion transmission signal; the optical amplifier module (601) for amplifying the synaesthesia fusion transmission signal; the common wavelength synaesthesia common wavelength synaesthesia fusion signal generating device outputs a common wavelength synaesthesia fusion signal with high spectrum efficiency; the invention is compatible with the existing communication system expansion mechanism, and only uses communication optical cables, including but not limited to single-mode optical fiber (800), multi-core optical fiber (1800), and multi-core few-mode optical fiber (2100), to realize the fusion of very low frequency disturbance perception positioning and large-capacity optical fiber communication; Figure 7 and Figure 8 As shown, the system performance is optimized by changing the parameters of the communication signal or the sensing signal (occupied frequency band, frequency protection interval, communication signal baud rate, power ratio of the sensing signal, etc.).

[0067] like Figure 3 As shown, the device comprises a common wavelength interaceptive fusion signal generating device, a communication signal receiving and demodulating device, a sensor signal receiving and demodulating device, and a single-mode optical fiber (800). The common wavelength interaceptive fusion signal generating device, the single-mode optical fiber (800), the communication signal receiving and demodulating device, and the sensor signal receiving and demodulating device are connected in sequence to achieve the fusion of very low frequency disturbance perception positioning based on single-mode optical fiber and large-capacity optical fiber communication.

[0068] The common-wavelength interacuity fusion signal generating device comprises an ultra-narrow linewidth laser (101), a narrow linewidth laser (102-10N), a coupler (201, 202), a chirped pulse generating module (300), a digital subcarrier multiplexing signal generating module (401-40N), a wavelength division multiplexer (500), and an optical amplification module (601); the common-wavelength interacuity fusion signal generating device outputs a common-wavelength interacuity fusion signal with high spectrum efficiency;

[0069] The communication signal receiving and demodulating device comprises a wavelength division multiplexer (900), a local oscillator laser (1000), a coherent receiving module (1100), and a communication signal demodulating module (1200); the output signal of the single-mode optical fiber (800) is demultiplexed by the wavelength division multiplexer (900), and the multi-wavelength signals are received and demodulated in sequence;

[0070] The sensor signal receiving and demodulating device comprises an optical amplifying module (602), an optical filtering module (1300), a photoelectric detection module (1400), and a sensor signal demodulating module (1500) which are connected in sequence; the optical filtering module (1300) is used to filter out communication signals and amplify spontaneous radiation noise; Figure 6 As shown in the figure, a direct detection architecture is adopted to weaken the influence of phase noise and realize accurate positioning of very low frequency disturbance signals; an intensity cross-correlation demodulation scheme is adopted to further improve the perception sensitivity of very low frequency disturbances;

[0071] like Figure 4 As shown, the device includes a common wavelength interaceptive fusion signal generating device, a communication signal receiving and demodulating device, and a sensor signal receiving and demodulating device, and also includes a space division multiplexing signal transceiver array and a multi-core optical fiber (1800). The common wavelength interaceptive fusion signal generating device, the space division multiplexing signal transceiver array, the multi-core optical fiber (1800), the communication signal receiving and demodulating device, and the sensor signal receiving and demodulating device are connected in sequence to achieve the fusion of high-sensitivity very low frequency disturbance perception positioning and large-capacity optical fiber communication based on multi-core optical fiber.

[0072] The common wavelength interaural fusion signal generating device comprises an ultra-narrow linewidth laser (101), a narrow linewidth laser (102-10N), a coupler (201, 202), a chirped pulse generating module (300), a digital subcarrier multiplexing signal generating module (401-40N), a wavelength division multiplexer (500), an optical amplification module (601), and a signal beam splitter (1600); the signal beam splitter is used to split light into multiple input signals; and the system performance is optimized by changing the parameters of the communication signal or the sensor signal;

[0073] The space-division multiplexing signal transceiver array comprises a circulator array (700) and a fan-in fan-out (1701); the synaesthesia fusion signal output by the common wavelength synaesthesia fusion signal generating device is output from port 1 to port 2 of the circulator array (700), and then enters the multi-core optical fiber (1800) through the fan-in fan-out (1701); the forward light in the multi-core optical fiber (1800) reaches the communication signal receiving and demodulating device; the Rayleigh backscattered light in the multi-core optical fiber (1800) reaches the sensing signal receiving and demodulating device from the fan-in fan-out (1701) through port 3 of the circulator array (700);

[0074] The communication signal receiving and demodulating device comprises a fan-in and fan-out (1702), a wavelength division multiplexer (900), a local oscillator laser (1000), a coherent receiving module (1100), and a communication signal demodulating module (1200). The output signal of the fan-in and fan-out (1702) is demultiplexed by the wavelength division multiplexer (900), and the multi-wavelength signals of different fiber cores are received and demodulated in sequence.

[0075] The sensing signal receiving and demodulating device comprises a photosynthesizer (1900), an optical amplifying module (602), an optical filtering module (1300), a photoelectric detection module (1400), and a sensing signal demodulating module (1500) which are connected in sequence; Rayleigh backscattered light of different fiber cores is transmitted from a space division multiplexing signal transceiver array to the photosynthesizer (1900), so that the intensity of the Rayleigh backscattered light is superimposed, thereby improving the signal-to-noise ratio and sensitivity of the disturbance sensing positioning signal.

[0076] like Figure 5 As shown, the device includes a common wavelength interaceptive fusion signal generating device, a communication signal receiving and demodulating device, a sensor signal receiving and demodulating device, and also includes a space division multiplexing signal transceiver array and a multi-core few-mode optical fiber (2100). The common wavelength interaceptive fusion signal generating device, the space division multiplexing signal transceiver array, the multi-core few-mode optical fiber (2100), the communication signal receiving and demodulating device, and the sensor signal receiving and demodulating device are connected in sequence to realize the fusion of high-sensitivity very low frequency disturbance perception positioning and large-capacity optical fiber communication based on the multi-core few-mode optical fiber.

[0077] The common wavelength interaural fusion signal generating device comprises an ultra-narrow linewidth laser (101-10K), a narrow linewidth laser (10K+1-10N), a coupler (200), a chirped pulse generating module (300), a digital subcarrier multiplexing signal generating module (401-40N), a wavelength division multiplexer (500), an optical amplification module (601), and a signal beam splitter (1600); the system performance is optimized by changing the parameters of the communication signal or the sensor signal;

[0078] The space division multiplexing signal transceiver array comprises a circulator array (700), a mode multiplexer (2001) and a fan-in fan-out (1701); the multi-wavelength interaceptive fusion signal output by the common wavelength interaceptive fusion signal generating device is output from port 1 to port 2 of the circulator array (700), and then enters the multi-core few-mode optical fiber (2100) through the mode multiplexer (2001) and the fan-in fan-out (1701); the forward light in the multi-core few-mode optical fiber (2100) reaches the communication signal receiving and demodulating device, and the Rayleigh backscattered light in the multi-core few-mode optical fiber (2100) reaches the sensing signal receiving and demodulating device from the mode multiplexer (2001) through port 3 of the circulator array (700);

[0079] The communication signal receiving and demodulating device comprises a fan-in and fan-out (1702), a mode demultiplexer (2002), a wavelength division multiplexer (900), a local oscillator laser (1000), a coherent receiving module (1100), and a communication signal demodulating module (1200). The output signal of the mode demultiplexer (2002) is demultiplexed by the wavelength division multiplexer (900), and multi-wavelength signals of different fiber cores and different modes are received and demodulated in sequence.

[0080] The sensing signal receiving and demodulating device comprises a photosynthetic beam combiner (1900), an optical amplification module (602), an optical filtering module (1300), a photoelectric detection module (1400), and a sensing signal demodulation module (1500) which are connected in sequence; Rayleigh backscattered light of different fiber cores and different modes is transmitted from a signal space division transceiver array to the photosynthetic beam combiner (1900), so as to realize the intensity superposition of the Rayleigh backscattered light in the optical domain, thereby improving the signal-to-noise ratio and sensitivity of the disturbance sensing positioning signal; the scheme is also applicable to multi-wavelength sensing signals, and the sensitivity is improved by superposition of Rayleigh backscattered light of different wavelengths.

[0081] External disturbance signals will locally change the length and refractive index of the communication optical fiber. When using the direct detection mode based on chirped pulses, the change in refractive index will cause frequency changes. Due to the time-frequency mapping relationship of the chirped pulse, the external disturbance signal will cause a local delay in the intensity curve, and the delay amount is linearly related to the external disturbance amount. The external disturbance signal can be quantitatively measured through intensity cross-correlation demodulation, and the disturbance can be located by the time-of-flight method. The relationship between the disturbance amount and the local delay amount is:

[0082]

[0083] Among them, Δn g is the local refractive index change caused by the disturbance signal, n g is the refractive index of the optical fiber, Δv is the frequency shift caused by the disturbance signal, v0 is the center frequency of the detection pulse, δv p is the sweep bandwidth of the chirped pulse, τ pis the duration of the chirped pulse, Δt is the local time delay of the intensity curve caused by the disturbance signal, and Δε is the strain.

[0084] (1) Intensity cross-correlation demodulation algorithm 1:

[0085] T1(t)=max(correlation[E i (t-τ corr ,t+τ corr ),E i+1 (t-τ corr ,t+τ corr )]) (2)

[0086] Where T1(t) is the local delay obtained by the intensity cross-correlation demodulation algorithm 1; correlation is the cross-correlation function; E i is the i-th Rayleigh scattering intensity curve, i = 1:n-1, n is the number of intensity curves; t is the sampling time; τ corr is the cross-correlation time window. The local cross-correlation delay of two consecutive intensity curves can be obtained by Algorithm 1, by combining [E1, E2], [E2, E3], ..., [E n-1 ,E n The cross-correlation value can measure the change of strain over time. When the local delay is small, due to the quantization error, the delay estimated by two consecutive strength curves also has errors, resulting in poor demodulation effect.

[0087] (2) Intensity cross-correlation demodulation algorithm 2:

[0088] T2(t)=max(correlation[E1(t-τ corr ,t+τ corr ),E i+1 (t-τ corr ,t+τ corr )]) (3)

[0089] Where T2(t) is the local delay obtained by the intensity cross-correlation demodulation algorithm 2; correlation is the cross-correlation function; E i is the i-th Rayleigh scattering intensity curve, i = 1:n-1, n is the number of intensity curves; t is the sampling time; τ corr is the cross-correlation time window. The local cross-correlation delay between the first and the i-th intensity curves can be obtained by Algorithm 2, by combining [E1, E2], [E1, E3], ..., [E1, E n ] The value obtained by cross-correlation can measure the change of strain over time. Compared with Algorithm 1, when the local delay is small, due to the small quantization error, the delay error estimated between the first and i-th intensity curves is smaller, resulting in a better demodulation effect.

[0090] (3) Improved intensity cross-correlation demodulation algorithm 3:

[0091] T3(t)=max(correlation[E i (t-τ corr ,t+τ corr ),E k (t-τ corr ,t+τ corr )]) (4)

[0092] Where T3(t) is the local delay obtained by the intensity cross-correlation demodulation algorithm 3; correlation is the cross-correlation function; E i is the i-th Rayleigh scattering intensity curve, i = 1:n-1, k = (i+1):n, n is the number of intensity curves; t is the sampling time; τ corr is the cross-correlation time window. The difference from Algorithm 2 is that: Algorithm 2 fixes the first curve as the reference curve, and the remaining curves are cross-correlated with the first curve respectively; while Algorithm 3 reduces the error by changing the reference curve and averaging multiple estimates. In the first stage, the first curve is fixed as the reference curve, and the 2nd to nth curves are cross-correlated with it respectively; in the second stage, the second curve is fixed as the reference curve, and the 3rd to nth curves are cross-correlated with it respectively; ..., in the last stage, the n-1th curve is fixed as the reference curve, and the n-1th curve is cross-correlated with the nth curve. Compared with Algorithm 2, the local delay between the first curve and the remaining curves in Algorithm 3 is estimated multiple times, and the estimation error can be reduced by averaging, thereby improving the demodulation effect.

[0093] Generally speaking, the Rayleigh backscatter signal power is weak, resulting in a low signal-to-noise ratio of the DAS system and limiting the spatial resolution of distributed sensing. The Rayleigh backscatter signal strength can be increased by increasing the pulse duration, but since the pulse duration is inversely proportional to the spatial resolution, an increase in pulse duration will result in worse spatial resolution. The intensity of the Rayleigh backscatter signal can also be increased by increasing the peak power of the pulse, but the peak power is limited by the nonlinear effect of the fiber. When the peak power exceeds the threshold, stimulated Brillouin scattering (SBS) will cause the signal-to-noise ratio of the very low frequency disturbance signal to deteriorate. The estimation formula for the SBS threshold is as follows:

[0094]

[0095] Among them, A eff is the effective area of ​​the optical fiber, g B is the SBS gain coefficient, L eff is the effective length of the optical fiber, α=0.2dB / km, and w is the mode field radius.

[0096] The present invention detects the Rayleigh backscattered light of each fiber core / mode through spatial division multiplexing diversity detection, breaking the limitation that the peak power of the single-core DAS system is restricted by the nonlinear threshold of the optical fiber, increasing the intensity of the Rayleigh backscattered signal at the receiving end, thereby improving the signal-to-noise ratio and further improving the sensitivity. The noise floor of the disturbance amplitude spectrum density (ASD) is

[0097]

[0098] Among them, SNR electrical is the electrical noise ratio, v0 is the center frequency of the laser detection pulse, δv p is the sweep bandwidth of the chirped pulse, τ corr is the cross-correlation time window, f s,ac is the pulse repetition frequency (i.e., the disturbance sampling rate). From Equation 6, it can be seen that when the signal-to-noise ratio of the signal is larger, the noise floor is smaller, thus improving the sensitivity of the DAS system.

[0099] Compared with the traditional multi-core / few-mode optical fiber synaesthesia fusion scheme that uses different fiber cores / modes to transmit communication signals and sensor signals respectively, this embodiment can make full use of optical fiber space resources and spectrum resources and improve the capacity of the communication system by multiplexing communication signals and sensor signals under the common wavelength channel; compared with the existing single-core optical fiber synaesthesia fusion scheme, this embodiment increases the intensity of the Rayleigh backscattering signal at the receiving end through space division multiplexing, thereby improving the signal-to-noise ratio and sensitivity of the very low frequency disturbance perception and positioning signal; compared with the existing synaesthesia fusion scheme, this embodiment uses direct detection and intensity cross-correlation demodulation to achieve very low frequency disturbance perception and positioning, and can simultaneously achieve high-sensitivity very low frequency disturbance perception and positioning and large-capacity optical fiber communication.

[0100] The same or similar reference numerals correspond to the same or similar components;

[0101] The terms used in the drawings to describe positional relationships are only used for illustrative purposes and should not be construed as limiting this patent;

[0102] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A device for integrating very low frequency disturbance sensing and positioning with large-capacity optical fiber communication, characterized in that: It includes a signal input unit, a signal ring unit, a communication optical fiber, a sensing unit and a communication unit; The output end of the signal input unit is connected to the input end of the signal ring unit; the output end of the signal ring unit is connected to both the communication optical fiber and the input end of the sensor unit; the output end of the communication optical fiber is connected to the communication unit; The signal input unit is used to generate a common-wavelength synaesthesia fusion signal; the signal ring unit is used to receive the common-wavelength synaesthesia fusion signal output by the signal input unit, and transmit the backscattered synaesthesia fusion signal to the sensing unit and transmit the forward light to the communication unit through the communication optical fiber; the sensing unit is used to locate the very low frequency disturbance signal; and the communication unit is used for optical fiber communication.

2. The fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication according to claim 1 is characterized in that: The signal input unit includes a first laser, a first coupler, a second coupler, a chirped pulse generating module, a wavelength division multiplexer, a first optical amplification module, a first digital subcarrier multiplexing signal generating module and N digital subcarrier multiplexing signal generating units connected in sequence; The digital subcarrier multiplexed signal generating unit comprises a narrow linewidth laser and a second digital subcarrier multiplexed signal generating module connected in sequence; The output end of the first laser is connected to the input end of the first coupler; the output end of the first coupler is connected to the input ends of the chirped pulse generating module and the first digital subcarrier multiplexing signal generating module; the output ends of the chirped pulse generating module and the first digital subcarrier multiplexing signal generating module are connected to the input end of the second coupler; the output end of the second coupler is connected to the input end of the wavelength division multiplexer; The input end of the wavelength division multiplexer is connected to the output end of the first digital subcarrier multiplexing signal generating unit; the output end of the Nth digital subcarrier multiplexing signal generating unit is connected to the input end of the wavelength division multiplexer; the output end of the wavelength division multiplexer is connected to the input end of the first optical amplifier module; the signal input unit is used to generate a common wavelength interaceptive fusion signal, which is compatible with the existing expansion mechanism; The output end of the first optical amplification module is connected to the input end of the signal ring unit.

3. The fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication according to claim 1 is characterized in that: The communication optical fiber includes but is not limited to single-mode optical fiber, multi-core optical fiber and multi-core few-mode optical fiber.

4. The fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication according to claim 3 is characterized in that: When the communication optical fiber is a single-mode optical fiber, the sensing unit is a first sensing unit; the signal ring unit is a first signal ring unit; the communication unit is a first communication unit; the first signal ring unit includes a first circulator unit; the first circulator unit includes a first circulator, the output end of the first circulator is connected to the single-mode optical fiber and the input end of the first sensing unit; the output end of the single-mode optical fiber is connected to the input end of the first communication unit.

5. The fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication according to claim 4 is characterized in that: The first sensing unit comprises a second optical amplification module, a first optical filter module, a first photoelectric detection module and a first signal demodulation module which are connected in sequence; the output end of the first circulator is connected to the input end of the second optical amplification module; the first sensing unit adopts direct detection and cross-correlation demodulation to realize very low frequency perception; The first communication unit includes a first wavelength division multiplexer, a first local oscillator laser, a first signal receiving module and a second signal demodulation module; the output end of the single-mode optical fiber is connected to the input end of the first wavelength division multiplexer; the output ends of the first wavelength division multiplexer and the first local oscillator laser are both connected to the input end of the first signal receiving module; the output end of the first signal receiving module is connected to the input end of the second signal demodulation module; the first communication unit is used to receive and demodulate the multi-wavelength signals in sequence.

6. The fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication according to claim 3 is characterized in that: When the communication optical fiber is a multi-core optical fiber, the sensing unit is a second sensing unit; the signal ring unit is a second signal ring unit; the communication unit is a second communication unit; the second signal ring unit includes a second circulator unit and a first fan-in fan-out unit; the second circulator unit includes a first circulator array composed of a plurality of second circulators connected in sequence; the output end of each second circulator in the first circulator array is connected to the input end of the first fan-in fan-out unit; the output end of each second circulator in the first circulator array is connected to the input end of the second sensing unit; the output end of the first fan-in fan-out unit is connected to the input end of the second communication unit.

7. The fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication according to claim 6 is characterized in that: The second sensing unit comprises a first optical beam combiner, a third optical amplification module, a second optical filtering module, a second photoelectric detection module and a third signal demodulation module connected in sequence; the output end of each second circulator of the first circulator array is connected to the input end of the first optical beam combiner; the second sensing unit adopts direct detection and cross-correlation demodulation to realize very low frequency perception; The second communication unit includes a second fan-in fan-out unit, a second wavelength division multiplexer, a second local oscillator laser, a second signal receiving module, and a fourth signal demodulation module; the output end of the multi-core optical fiber is connected to the input end of the second fan-in fan-out unit; the output end of the second fan-in fan-out unit is connected to the input end of the second wavelength division multiplexer; the output ends of the second wavelength division multiplexer and the second local oscillator laser are connected to the input end of the second signal receiving module; The output end of the second signal receiving module is connected to the input end of the fourth signal demodulation module; the second communication unit is used to receive and demodulate the multi-wavelength signals of different fiber cores in sequence.

8. The device for integrating very low frequency disturbance sensing and positioning with large-capacity optical fiber communication according to claim 3 is characterized in that: When the communication optical fiber is a multi-core few-mode optical fiber, the sensing unit is a third sensing unit; the signal ring unit is a third signal ring unit; the communication unit is a third communication unit; the third signal ring unit includes a third circulator unit, a mode multiplexer and a third fan-in and fan-out unit connected in sequence; the third device unit includes a second circulator array composed of a plurality of third circulators connected in sequence; the output end of each third circulator of the second circulator array is connected to the input end of the mode multiplexer; the output end of each second circulator of the second circulator array is connected to the input end of the third sensing unit; the output end of the third fan-in and fan-out unit is connected to the input end of the third communication unit.

9. The fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication according to claim 8 is characterized in that: The third sensing unit comprises a second optical combiner, a fourth optical amplification module, a third optical filtering module, a third photoelectric detection module and a fifth signal demodulation module connected in sequence; the output end of each second circulator of the second circulator array is connected to the input end of the second optical combiner; the third sensing unit adopts direct detection and cross-correlation demodulation to realize very low frequency perception; The third communication unit includes a fourth fan-in and fan-out unit, a mode demultiplexer, a third wave division multiplexer, a third local oscillator laser, a third signal receiving module and a sixth signal demodulation module; the output end of the multi-core few-mode optical fiber is connected to the input end of the fourth fan-in and fan-out unit; the output end of the fourth fan-in and fan-out unit is connected to the input end of the mode demultiplexer; the output end of the mode demultiplexer is connected to the input end of the third wave division multiplexer; the output ends of the third wave division multiplexer and the third local oscillator laser are both connected to the input end of the third signal receiving module; the output end of the third signal receiving module is connected to the input end of the sixth signal demodulation module; the third communication unit is used to sequentially receive and demodulate multi-wavelength signals of different cores and different modes.

10. The fusion device of very low frequency disturbance sensing positioning and large-capacity optical fiber communication according to claim 1 is characterized in that: When the peak power of the common-wavelength synaesthesia fusion signal exceeds a preset threshold, stimulated Brillouin scattering will cause the signal-to-noise ratio of the very low frequency disturbance signal to deteriorate; the preset threshold is: Among them, A eff is the effective area of ​​the communication optical fiber, g B is the SBS gain coefficient, L eff is the effective length of the communication optical fiber.

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