Abstract: The present disclosure provides a Brillouin optical time domain reflectometer with an ultra-high spatial resolution based on bipolar differential phase encoding, including a narrow-linewidth laser, a polarization maintaining coupler, a differential encoder, a Mach-Zehnder modulator, an optical pulse amplifier, an optical circulator and a sensing fiber, an optical amplifier, a coherent optoelectronic receiver, a sideband demultiplexer, and a result measurement module. By implementing the present disclosure, a spatial resolution for measuring a Brillouin scattering spectrum can be effectively improved, and measurement precision can be effectively improved by increasing a quantity of times of superposition and averaging. In addition, measurement performance can be effectively improved by directly using a bipolar encoding sequence.

Abstract: The present disclosure provides a Brillouin optical time domain reflectometer with an ultra-high spatial resolution based on bipolar differential phase encoding, including a narrow-linewidth laser, a polarization maintaining coupler, a differential encoder, a Mach-Zehnder modulator, an optical pulse amplifier, an optical circulator and a sensing fiber, an optical amplifier, a coherent optoelectronic receiver, a sideband demultiplexer, and a result measurement module. By implementing the present disclosure, a spatial resolution for measuring a Brillouin scattering spectrum can be effectively improved, and measurement precision can be effectively improved by increasing a quantity of times of superposition and averaging. In addition, measurement performance can be effectively improved by directly using a bipolar encoding sequence.

Abstract: Embodiments of the present invention relate to a signal transmission method, transmitter, and signal transmission system. The method includes: obtaining, by a sending end, information about a power fading point of a fiber channel between the sending end and a receiving end; determining, by the sending end and according to the information about the power fading point, a subcarrier that is used to send a service signal to the receiving end on the fiber channel, where a frequency of the determined subcarrier is different from that of the power fading point; and sending, by the sending end, a service signal to the receiving end by using the determined subcarrier. According to the embodiments of the present invention, validity of a signal spectrum is ensured, and therefore it is ensured that transmitted data can be effectively recovered at a receiving end.

Abstract: Embodiments of the present invention relate to a signal transmission method, transmitter, and signal transmission system. The method includes: obtaining, by a sending end, information about a power fading point of a fiber channel between the sending end and a receiving end; determining, by the sending end and according to the information about the power fading point, a subcarrier that is used to send a service signal to the receiving end on the fiber channel, where a frequency of the determined subcarrier is different from that of the power fading point; and sending, by the sending end, a service signal to the receiving end by using the determined subcarrier. According to the embodiments of the present invention, validity of a signal spectrum is ensured, and therefore it is ensured that transmitted data can be effectively recovered at a receiving end.

Abstract: A method for implementing Polarization Division Multiplexing Binary Phase Shift Keying (PDM-BPSK) modulation and Quadrature Phase Shift Keying (QPSK) modulation in a compatible manner includes: dividing a direct current (DC) light into a first channel of light and a second channel of light with the same power; separately performing optoelectrical modulation on the first channel of light and the second channel of light and correspondingly outputting a first optical signal and a second optical signal in a Binary Phase Shift Keying (BPSK) format; performing polarization state control on the first optical signal; performing a phase shift on the first optical signal or the second optical signal; and performing optical signal combination with the polarization state preserved on the first optical signal and the second optical signal after the polarization state control and the phase shift, and outputting a PDM-BPSK modulation optical signal or a QPSK modulation optical signal.

Abstract: A method for implementing Polarization Division Multiplexing Binary Phase Shift Keying (PDM-BPSK) modulation and Quadrature Phase Shift Keying (QPSK) modulation in a compatible manner includes: dividing a direct current (DC) light into a first channel of light and a second channel of light with the same power; separately performing optoelectrical modulation on the first channel of light and the second channel of light and correspondingly outputting a first optical signal and a second optical signal in a Binary Phase Shift Keying (BPSK) format; performing polarization state control on the first optical signal; performing a phase shift on the first optical signal or the second optical signal; and performing optical signal combination with the polarization state preserved on the first optical signal and the second optical signal after the polarization state control and the phase shift, and outputting a PDM-BPSK modulation optical signal or a QPSK modulation optical signal.