High-performance digital-to-analog conversion based on dual-electrode Mach–Zehnder modulators

Abstract

A unique high-performance digital to analog conversion (DAC) approach based on dual-electrode Mach–Zehnder modulators (DEMZMs) is proposed and experimentally demonstrated. According to the modulation transfer characteristics of DEMZM, the output waveform can be edited in-line by properly adjusting the input digital signals. In our design, a 2-bit photonic DAC module can be realized by using only one DEMZM, which is biased at the minimum transmission point. The scheme is extendable, i.e., a 4-bit DAC system can be achieved by using two parallel DEMZMs, and an 8-bit system can be obtained with four DEMZMs. As few modulators are employed and the system configuration is simplified, the proposed approach can greatly improve the bit resolution with less complexity. A proof-of-concept experiment of a 4-bit DAC system is successfully carried out, which fully verifies the feasibility of the proposed approach. Moreover, the system performance in terms of integral nonlinearity and differential nonlinearity is also discussed. The proposed scheme provides a potential solution for high-bandwidth and high-resolution photonic DAC.