Abstract: A measurement device for polarization-maintaining optical fiber spindle difference delay is provided. The measurement device comprises a polarization-maintaining fiber (PM) Sagnac interferometer, a signal generator, a microwave detector, a microprocessor. The PM Sagnac interferometer comprises a laser, a photoelectric modulator, and a PM fiber coupler that are connected in sequence. The PM Sagnac interferometer further comprises an optical fiber interface J1 and an optical fiber interface J2 arranged at the two output ends of the PM fiber coupler, a PM fiber to be measured located between the fiber interface J1 and the fiber interface J2, and a photodetector arranged at the other output end of the PM fiber coupler.

Abstract: A measurement device for polarization-maintaining optical fiber spindle difference delay is provided. The measurement device comprises a polarization-maintaining fiber (PM) Sagnac interferometer, a signal generator, a microwave detector, a microprocessor. The PM Sagnac interferometer comprises a laser, a photoelectric modulator, and a PM fiber coupler that are connected in sequence. The PM Sagnac interferometer further comprises an optical fiber interface J1 and an optical fiber interface J2 arranged at the two output ends of the PM fiber coupler, a PM fiber to be measured located between the fiber interface J1 and the fiber interface J2, and a photodetector arranged at the other output end of the PM fiber coupler.

Abstract: A frequency chirp correction method for the photonic time-stretch system comprises acquiring the stretching signal, i.e. acquiring the time-domain data after the time-domain stretching. First, the time-domain data of the stretching signal is Fourier transformed to obtain the spectral distribution. The spectral distribution is then convoluted with the first frequency-domain correction factor, and then multiplied with the second frequency-domain correction factor to obtain the modified frequency spectrum. Finally, the modified frequency spectrum is performed by the inverse Fourier transform to obtain the time-domain signal after the frequency chirp correction.

Abstract: A frequency chirp correction method for the photonic time-stretch system comprises acquiring the stretching signal, i.e. acquiring the time-domain data after the time-domain stretching. First, the time-domain data of the stretching signal is Fourier transformed to obtain the spectral distribution. The spectral distribution is then convoluted with the first frequency-domain correction factor, and then multiplied with the second frequency-domain correction factor to obtain the modified frequency spectrum. Finally, the modified frequency spectrum is performed by the inverse Fourier transform to obtain the time-domain signal after the frequency chirp correction.

Abstract: An optical sensing device applicable to two dimensional electric field, includes sequentially connected input polarization maintaining fibers, a sensing unit, an output single mode fiber, a photodetector and a signal processing unit, the sensing unit includes a lithium niobate substrate; a first Y optical waveguide and two Mach Zehnder structure optical waveguides are arranged on the lithium niobate substrate; the input of the first Y optical waveguide is connected with the output of the laser source, the output is respectively connected to the inputs of the two Mach Zehnder structure optical waveguides; the outputs of the two Mach Zehnder structure optical waveguides are connected to the photodetector; dipole antenna is arranged at any single waveguide arm of each Mach Zehnder structure optical waveguide, the polarization directions of the two dipole antennas are in orthogonality with each other.

Abstract: An optical sensing device applicable to two dimensional electric field, includes sequentially connected input polarization maintaining fibers, a sensing unit, an output single mode fiber, a photodetector and a signal processing unit, the sensing unit includes a lithium niobate substrate; a first Y optical waveguide and two Mach Zehnder structure optical waveguides are arranged on the lithium niobate substrate; the input of the first Y optical waveguide is connected with the output of the laser source, the output is respectively connected to the inputs of the two Mach Zehnder structure optical waveguides; the outputs of the two Mach Zehnder structure optical waveguides are connected to the photodetector; dipole antenna is arranged at any single waveguide arm of each Mach Zehnder structure optical waveguide, the polarization directions of the two dipole antennas are in orthogonality with each other.

Abstract: A traveling-wave loop antenna based on a metal ring cavity for generating a radio frequency OAM beam includes a main structure which is the metal ring cavity whose top surface has an annular slot circumferentially opened. Two openings, ¼ of a perimeter of the metal ring cavity apart, are two excitation source ports of the antenna, for connecting a metal waveguide. When the two ports are inputted with microwave sources having the same frequency and a phase difference of ±90°, an electromagnetic field in the metal ring cavity exhibits a traveling-wave distribution propagating circumferentially clockwise or counterclockwise. The annular slot constitutes the antenna. A reasonable design of a size of the metal ring cavity and a position of the annular slot realizes a conversion from a microwave guided-wave mode to an OAM mode and a generation of the radio frequency OAM beams with different orders l in free space.

Abstract: A traveling-wave loop antenna based on a metal ring cavity for generating a radio frequency OAM beam includes a main structure which is the metal ring cavity whose top surface has an annular slot circumferentially opened. Two openings ¼ of a perimeter of the metal ring cavity apart, are two excitation source ports of the antenna, for connecting a metal waveguide. When the two ports are inputted with microwave sources having the same frequency and a phase difference of ±90°, an electromagnetic field in the metal ring cavity exhibits a traveling-wave distribution propagating circumferentially clockwise or counterclockwise. The annular slot constitutes the antenna. A reasonable design of a size of the metal ring cavity and a position of the annular slot realizes a conversion from a microwave guided-wave mode to an OAM mode and a generation of the radio frequency OAM beams with different orders l in free space.