A novel 2-bit photonic digital-to-analog converter based on quadrature phase modulation and differential demodulation

A novel 2-bit PDAC based on quadrature phase modulation and differential demodulation together with balanced detection is proposed and experimentally demonstrated at sampling rates of 2.5GS/s and 10GS/s. The simulation results of expanded 4-bit PDAC from the 2-bit PDAC unit by using two channels of incoherent light with different wavelength are presented. This PDAC scheme is simple, compact and effective with high expansibility. Compared with other approaches, this method´s output signal has a greater dynamic range and a higher noise margin.