Photonics-assisted joint communication-radar system based on a QPSK-sliced linearly frequency-modulated signal
Shi Wang, Dingding Liang, Yang Chen
Abstract
A photonics-assisted joint communication-radar system is proposed by introducing a quadrature phase-shift keying (QPSK)-sliced linearly frequency-modulated (LFM) signal. An LFM signal is carrier-suppressed single-sideband modulated onto the optical carrier in one dual-parallel Mach–Zehnder modulator (DPMZM) of a dual-polarization dual-parallel Mach–Zehnder modulator (DPol-DPMZM). The other DPMZM is biased as an IQ modulator to implement QPSK modulation on the optical carrier. The polarization orthogonal optical signals from the DPol-DPMZM are further combined and detected in a photodetector to generate the QPSK-sliced LFM signal. The QPSK-sliced LFM signal is used to realize efficient data transmission and high-performance radar functions including ranging and imaging. An experiment is performed. Radar range detection with an error of less than 4 cm, inverse synthetic aperture radar imaging with a resolution of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>14.99</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">c</mml:mi> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:mrow> <mml:mo>×</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>3.25</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">c</mml:mi> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:mrow> </mml:math> , and communication with a data rate of 105.26 or 210.52 Mbit/s are successfully verified.