3x3 coupler scheme-based all-fiber interference type circumference security and protection system

Abstract

The invention relates to the field of fiber sensing and circumference security and protection, in particular to a 3x3 coupler scheme-based all-fiber interference type circumference security and protection system. The 3x3 coupler scheme-based all-fiber interference type circumference security and protection system is characterized by comprising a multi-wavelength single-frequency laser emission unit (1), a light source protection unit (2), a wavelength multiplexing unit (3), a pulse modulation unit (4), a power amplifier (5), a power distributor (6), a space division sensing array (7), a preamplification unit (8), a wavelength demultiplexing unit (9), an interference matching unit (10), a photoelectric conversion and demodulation unit (11) and a display and control unit (12), wherein the space division sensing array (7) comprises a transmission optical cable (701) and wavelength division sensing arrays (702); each group of wavelength division sensing array (702) comprises multiple groups of wavelength delete multiplexers (7021), wavelength increase multiplexers (7022) and interferometers (7023); each interferometer (7023) corresponds to a single-frequency light source wavelength; the COM (cluster communication) ports of the wavelength delete multiplexers (7021) are input ports.

Description

Technical field: [0001] The invention relates to the field of optical fiber sensing and perimeter security, in particular to an all-fiber interference type perimeter security system based on a 3×3 coupler scheme. Background technique: [0002] The perimeter security system based on optical fiber sensing technology is a new perimeter anti-intrusion technology gradually developed with the development of optical fiber communication technology. Compared with other types of monitoring technology, optical fiber sensing technology has remarkable characteristics. Optical fiber sensing uses optical fiber as the medium, light wave as the information carrier, and uses the one-dimensional spatial continuity of the optical fiber to sense and transmit external measurement signals. Optical fiber is both a sensing medium and a transmission medium, which greatly simplifies the structure of the sensing system. The optical fiber itself has electrical insulation, anti-electromagnetic interfer...

AI Technical Summary

Problems solved by technology

The positioning fiber optic perimeter security system relies on the Rayleigh scattering signal in the optical fiber as the original signal for signal demodulation. The Rayleigh scattering intensity is more than 50dB lower than the incident signal, which belongs to the field of weak signal detection. The sampling accuracy and hardware requirements of the system put forward very high requirements, which also caused the high cost of the system, which limited the further promotion and application of this solution

Although the current zone-type optical fiber perimeter security system adopts the interference method, which improves the sensitivity of intrusion detection and has a cost advantage, due to the limitation of the demodulation method, it can only analyze the frequency and intensity information of the intrusion signal, and does not analyze the phase information. The complete demodulation of the information will cause the correlation between the demodulated signal and the actual intrusion signal to be low, which will cause a large number of false alarms and missed alarms in practical applications. The application of this scheme has been greatly limited

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