Affiliation:
1. Huazhong University of Science and Technology
Abstract
A stepped-frequency (SF) radar waveform generation method based on Fourier domain mode-locking (FDML) period-one laser dynamics is proposed and demonstrated. By fast controlling the optical injection strength of a semiconductor laser through electro-optical modulation, a broadband SF signal is generated. By further introducing an optoelectronic feedback loop with its round trip time delay matched with the temporal period of the SF signal, FDML is enabled through which the frequency stability, accuracy, and in-band signal-to-noise ratio are greatly improved. In the experiment, SF signals with a bandwidth of 6 GHz (12–18 GHz) and a frequency step of 150 MHz are generated. By comparing the qualities of signals generated with and without FDML, advantages of the proposed SF signal generation method are verified. Based on the proposed SF signal generation method, high-resolution inverse synthetic aperture radar (ISAR) imaging is also demonstrated, in which the 2D imaging resolution reaches 2.6 cm × 3.82 cm.
Funder
National Key Research and Development Program of China
National Natural Science Foundation of China
Natural Science Foundation of Jiangsu Province
Open Project Program of Wuhan National Laboratory for Optoelectronics
Open Fund of State Key Laboratory of Advanced Optical Communication Systems and Networks
Fundamental Research Funds for the Central Universities
Fundamental Research Program for Young Student of National Key Laboratory of Microwave Photonics