Simultaneous frequency upconversion and phase coding of a radio-frequency signal for photonic radars

We report a photonic approach to simultaneously realize frequency upconversion and phase coding of a radiofrequency (RF) signal based on polarization manipulation of optical signals. An intermediate frequency (IF) signal is upconverted to the local frequency (LO) band using a dualpolarization dual-parallel Mach - Zehnder modulator, while a high-speed polarization modulator is used to realize highspeed phase coding of the upconverted signal. The key advantage of the proposed method is that no optical or electrical filters are required to remove the residual IF, LO, and undesired downconverted signals, which ensures a broad operation bandwidth, excellent isolation, and wide tunability. The proposed scheme is theoretically analyzed and experimentally verified. (C) 2018 Optical Society of America