A Continuously Tunable and Filter-Less QPSK Modulated Millimeter-Wave Signal Generation with Frequency Quadrupling Just Based on an MZM

Abstract

In this paper, we propose a new frequency quadrupling scheme to generate a quadrature phase shift keying (QPSK) modulated vector millimeter-wave signal, in which an optical filter is not necessary. To eliminate constellation overlapping of the generated vector millimeter-wave signal caused by phase multiplication in the process of frequency multiplication, a precoding assisted technique is adopted. The principle and feasibility of the proposed scheme is deduced by a detailed mathematical formula. Simulations are carried out to generate 40 GHz QPSK modulated vector millimeter-wave signals using a 10 GHz radio frequency source and the BER performance is analyzed in detail. The results show that BER of the generated 5/10-Gbaud vector millimeter-wave signal is below 3.8 × 10−3, when the input optical power for into photo-detector is higher than −20.67 dBm.