Method and device for testing optical link based on optical frequency domain reflectometry

A method for testing an optical link based on optical frequency domain reflectometry, comprising:

• measuring and demodulating, by a frequency domain reflectometer, a return optical signal of a probe optical signal from the frequency domain reflectometer in an optical link in an initial state, to obtain a first signal, wherein the return optical signal carries information of an amplitude and a phase of an optical field at a node to-be-tested in the optical link in the initial state;
• adjusting and controlling a photoelectric control unit in the optical link to change a state of the optical link, and measuring and demodulating, by the frequency domain reflectometer, a return optical signal of the probe optical signal from the frequency domain reflectometer in the optical link in the changed state, to obtain a second signal, wherein the return optical signal carries information of an amplitude and a phase of an optical field at the node to-be-tested in the optical link in the changed state;
• performing a fast Fourier transform on the first signal and the second signal, respectively, to obtain a frequency domain signal of the first signal and a frequency domain signal of the second signal;
• performing an inverse fast Fourier transform on a signal segment of the frequency domain signal of the first signal and a signal segment of the frequency domain signal of the second signal, respectively, to obtain a time domain signal of the first signal and a time domain signal of the second signal, whereby obtaining a relationship curve between a distance from the frequency domain reflectometer to the node to-be-tested in the optical link and a frequency shift;
• performing a cross-correlation calculation on the time domain signal of the first signal and the time domain signal of the second signal to obtain a Rayleigh scattering frequency shift at each node to-be-tested in the entire optical link;
• and
• performing a calculation based on a coefficient to obtain a curve between the distance from the frequency domain reflectometer to the node to-be-tested in the optical link and a power distribution, whereby obtaining a phase and amplitude modulation result of the return optical signal after passing through the optical link.