The invention discloses a
control system of bias
voltage of an IQ
optical modulator and a control method of the bias
voltage of the IQ
optical modulator. The
control system comprises a
laser optical source, a
polarization controller, the IQ
optical modulator, an
optical coupler, a photoelectric
detector and a
data processing module, which are connected in sequence, wherein the output of the IP optical modulator is divided by the
optical coupler, and then is connected to the photoelectric
detector; the output of the IP optical modulator is connected with the input of the
data processing module; three outputs of the
data processing module are respectively sent to the
direct current bias
voltage input ports of three subsidiary modulators of the IQ optical modulator. The control method comprises the steps of optimizing the bias voltage of a subsidiary phase modulator by measuring the maximum value and the adjacent minimum value of an output
optical power, loading the minimum value of search
optical power of a path of low-frequency square
signal onto two subsidiary intensity modulators in sequence to optimize the bias voltages of the two subsidiary intensity modulators on that basis, and finally realizing the control and locking on each subsidiary modulator working point of the IQ optical modulator. By applying the
control system and the control method, the perfect bias point of the IQ optical modulator can be rapidly and automatically controlled.