Photonic heterodyne generation of phase-coded terahertz signals

Abstract In this paper, we propose and experimentally demonstrate a photonic scheme of generating phase-coded signals in the terahertz (THz) band, based on an optical frequency combs (OFC) and optical heterodyne. In the proposed scheme, the optical modulation is implemented by using a dual-parallel Mach–Zehnder modulator (DPMZM), which is simultaneously driven by a radio frequency and a phase-coding sequence to ensure the stability. In the experiment, a 13-bit Barker-code phase-coded THz signal centered at 357 GHz is successfully generated with a record coding rate of up to 15 Gbit/s, which can potentially enable a range resolution of 1.57 cm. This work, for the first time to our knowledge, reveals the high potential of phase-coded THz signals in high resolution pulse compression radar.