The invention discloses a phase-
frequency noise characteristic measurement technique for a weak
laser signal, the phase-
frequency noise characteristic measurement technique for the weak
laser signal comprises a to-be-measured weak
laser light source, an
erbium-doped
fiber amplifier, a coupler, a 120-degree
phase difference interferometer and an industrial
personal computer; the to-be-measured weaklaser
light source amplifies a
weak signal of the
light source through the
erbium-doped
fiber amplifier, the amplified
signal of the light source is split into two light sources by the coupler, the
first light source is used for testing the phase-
frequency noise characteristic of the to-be-measured weak
laser light source, the second light source is used for feeding back the amplified signal of the light source to a power detection unit, and the laser power incident on the 120-degree
phase difference interferometer is kept on the same level; and the
first light source is incident on the 120-degree
phase difference interferometer, the 120-degree phase difference interferometer is used for demodulating
differential phase information of the signal of the
first light source, and the
differential phase information is transmitted to the industrial
personal computer to be analyzed. The phase-frequency
noise characteristic of the
weak signal is tested, and the phase-frequency
noise characteristic measurement technique is favorable for studying the influence of the
weak signal on the whole
system performance.