The present invention discloses a distributed pulsed light amplifier based on optical fiber parameter amplification, comprising a pump pulsed light source, a sensing pulsed light source, a synchronization device, a two-in-one optical coupler, an optical circulator, a parameter amplification optical fiber, a first optical filter, a photoelectric detector and a signal acquisition device. According to the distributed pulsed light amplifier, high-power pulsed light is used as pump light to generate an optical fiber parameter amplification effect near a zero-dispersion wavelength of an optical fiber, thereby amplifying a power of another sensing pulsed light. Meanwhile, due to the fact that effective optical fiber parameter amplification cannot be achieved through low-power light leakage outside a duration interval of the pump pulsed light, leaked light from the sensing pulsed light cannot be amplified, and the effect of amplifying a pulse extinction ratio can be achieved at the same time.

Disclosed is a method for reconstructing an electromagnetic vector wave backscattered in all or part of an optical fiber. According to an embodiment of the method a light signal of a frequency v.sub.0 or v.sub.0+v.sub.A is injected into the optical fiber. A step of polarization-resolved heterodyne optical detection includes the generation of at least two orthogonally polarized backscattered light signals, producing a beat preferably of a frequency v.sub.A. At least one photodetector converts the orthogonally polarized backscattered light signals into initial analog signals. Electrical homodyne detection is performed by an IQ demodulator so as to generate I and Q demodulated analog signals. A processing module reconstructs the electromagnetic vector wave backscattered in all or part of the optical fiber.

An arrangement for high rate fiber optical distributed acoustic sensing includes an optical fiber, a light launch module adapted to inject a first coherent light pattern into the optical fiber and to inject a second coherent light pattern into the optical fiber while first Rayleigh backscatter light of the first light pattern is propagating in the optical fiber, wherein the first coherent light pattern and the second coherent light pattern have a light pattern power above a nonlinear effect related power limit; and a detector adapted to detect the first Rayleigh backscatter light and to detect second Rayleigh backscatter light of the second light pattern.

The present invention aims to provide a vibration detection method, a signal processing device, and a program according to which it is possible to accurately detect vibration physically applied to an optical fiber, using a simple determination reference. In a vibration detection method according to the present invention, scattered light of a given target segment of a measurement target fiber is indicated by vectors of an in-phase component and a quadrature component, and a triangular shape constituted by a near-end-side vector of the target segment and a far-end-side vector is used as a physical amount to be tracked. That is, it is determined whether or not there is vibration based on a change in shape of the triangular shape with respect to a reference state. This is a detection method in which DAS-I and DAS-P are combined, a simple determination reference such as shape change of a triangular shape is employed, and overlooking of vibration detection can be reduced.

Aspects of the present disclosure describe systems methods and structures for avoiding saturation caused phase jump in systems that extract information from the phase of a complex sequence and exhibit an overflow or “spike” in the output of a high-pass filter. Operationally, during phase unwrapping—when an output signal exceeds a supported range—it is adjusted to be back in range by adding N.Math.2π, to a phase where N is negative or positive integer, depending on the direction to be adjusted.

Aspects of the present disclosure describe DAS/DVS DFOS systems, methods, and structures that advantageously enable/provide OTDR measurement(s).

In some implementations, a device may obtain responsivity data for segments of a fiber optic cable. The device may receive, from a sensor device, vibration data associated with the fiber optic cable, the vibration data being produced by a vibration source in or on soil associated with the fiber optic cable. The device may normalize, based on the responsivity data, the vibration data. The device may determine, based on the normalized vibration data, a distance of the vibration source from the fiber optic cable. The device may perform one or more actions based on the distance satisfying a distance threshold.

In some examples, a temperature distribution sensor may include a laser source to emit a laser beam that is tunable to a first wavelength and a second wavelength for injection into a device under test (DUT). A first wavelength optical receiver may convert a return signal corresponding to the first wavelength with respect to Rayleigh backscatter or Raman backscatter Anti-Stokes. A second wavelength optical receiver may convert the return signal corresponding to the second wavelength with respect to Rayleigh backscatter or Raman backscatter Stokes. Bending loss associated with the DUT may be determined by utilizing the Rayleigh backscatter signal corresponding to the first wavelength and the Rayleigh backscatter signal corresponding to the second wavelength. Further, temperature distribution associated with the DUT may be determined by utilizing the Raman backscatter Anti-Stokes signal corresponding to the first wavelength and the Raman backscatter Stokes signal corresponding to the second wavelength.

Aspects of the present disclosure describe the localization of a utility pole by distributed fiber sensing of aerial fiber cable suspended from the utility pole.

The present application provides a continuous spatial synchronization monitoring device for an ocean temperature and pressure. Broadband light output by a broadband light source is converted into broadband pulsed light by using a pulse controller; then, the broadband pulsed light is demodulated by using a phase shifted fiber bragg grating unit to obtain pulsed light having multiple different wave-lengths; the pulsed light is incident to a sensing optical fiber in seawater by means of a wavelength division multiplexer; according to a Rayleigh scattering principle, backward Rayleigh scattering light returns to a control demodulation module by means of the wavelength division multiplexer; the control demodulation module performs demodulation on the backward Rayleigh scattering light, analyzes a dynamic pressure according to a phase change of a light signal, and analyzes a seawater temperature according to a wavelength change, thereby simultaneously monitoring both the pressure and temperature.