84 GHz millimeter-wave PAM4 signal generation based on one PDM-MZM modulator and one polarizer without DAC and filters

In this paper, a novel scheme to employ one external polarization division multiplexing Mach–Zehnder Modulator (PDM-MZM) and one polarizer to generate millimeter-wave four-level pulse amplitude modulation (PAM4) signal is proposed without the usage of expensive and power hungry digital-to-analog converter (DAC). Firstly, we theoretically derive the generation conditions for the mm-wave PAM4 signal scheme. Based on this cost-effective scheme, 6 Gbaud PAM4 signal carried by 84 GHz millimeter-wave transmission over 15 km single-mode fiber (SMF-28) with only 0.5 dB power penalty without any CD compensation is experimentally demonstrated. Furthermore, VPI simulation software is employed to numerically simulate the mm-wave PAM4 signal generation and explore the influences of polarization rotation of the polarizer and direct current (DC)-Bias on the performance of generated W-band signals. In a word, it would be a promising scheme for future 5G short-reach intensity modulation and direct detection (IM/DD) system.