Signal frequency-mixing device and method suitable for optical fibre transmission

The embodiment of the invention provides a signal frequency-mixing device and method suitable for optical fibre transmission. The device comprises a first electrooptical modulator and a second electrooptical modulator; the first electrooptical modulator is used for receiving a laser signal, receiving an intrinsic signal, and performing suppressed carrier double-sideband modulation of the laser signal by utilizing the intrinsic signal to obtain a first modulated signal; and the second electrooptical modulator is used for receiving the first modulated signal, dividing the first modulated signal into two same signals including a first shunt signal and a second shunt signal, receiving a microwave signal, performing suppressed carrier double-sideband modulation of the first shunt signal by utilizing the microwave signal to obtain a second modulated signal, shifting the phase of the second shunt signal by responding to the phase adjusting operation input by a user, combining the phase-shifted second shunt signal wi