All-fiber-photonics-based ultralow-noise agile frequency synthesizer for X-band radars
We propose and demonstrate an agile X-band signal synthesizer with ultralow phase noise based on all-fiber-photonic techniques for radar applications. It shows phase noise of ?145 dBc/Hz (?152 dBc/Hz) at 10 kHz (100 kHz) offset frequency for 10 GHz carrier frequency with integrated RMS timing jitter between 7.6 and 9.1 fs (integration bandwidth: 10 Hz–10 MHz) for frequencies from 9 to 11 GHz. Its frequency switching time is evaluated to be 135 ns with a 135 pHz frequency tuning resolution. In addition, the X-band linear-frequency-modulated signal generated by the proposed synthesizer shows a good pulse compression ratio approximating the theoretical value. In addition to the ultrastable X-band signals, the proposed synthesizer can also provide 0–1 GHz ultralow-jitter clocks for analog-to-digital converters (ADC) and digital-to-analog converters (DAC) in radar systems and ultralow-jitter optical pulse trains for photonic ADC in photonic radar systems. The proposed X-band synthesizer shows great performance in phase stability, switching speed, and modulation capability with robustness and potential low cost, which is enabled by an all-fiber-photonics platform and can be a compelling technology suitable for future X-band radars.
基金项目：National Research Foundation of Korea (NRF)10.13039/501100003725 (2012R1A2A2A01005544); China Scholarship Council (CSC)10.13039/501100004543.
Dohyeon Kwon：School of Mechanical and Aerospace Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
Shuangyou Zhang：School of Mechanical and Aerospace Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
Shilong Pan：Key Laboratory of Radar Imaging and Microwave Photonics, Ministry of Education, Nanjing University of Aeronautics and Astronautics (NUAA), Nanjing 210016, Chinae-mail: email@example.com
Jungwon Kim：School of Mechanical and Aerospace Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
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Juan Wei, Dohyeon Kwon, Shuangyou Zhang, Shilong Pan, and Jungwon Kim, "All-fiber-photonics-based ultralow-noise agile frequency synthesizer for X-band radars," Photonics Research 6(1), 12 (2018)