The MBC-DPIQ bias voltage controller from Plugtech is a high-performance automatic bias voltage controller specifically designed for Electro-Optic (EO) dual-polarization IQ modulators. Its principle involves injecting dither signals of different frequencies, analyzing the working point errors of the I, Q, and P arms for both polarizations, and adjusting the six output bias voltages accordingly to keep the modulator in optimal working condition. Based on a specially optimized control algorithm, the MBC-DPIQ controller supports QPSK, QAM-x, SSB, and ODFM applications. Users can easily achieve these applications without parameter settings or manual calibration.