Microwave Photonics|2 Article(s)
Microwave frequency upconversion employing a coupling-modulated ring resonator
Yiming Zhong, Linjie Zhou, Yanyang Zhou, Yujie Xia, Siqi Liu, Liangjun Lu, Jianping Chen, and Xingjun Wang
We present a method to generate a frequency-doubled microwave signal by employing a coupling-modulated ring resonator. Critical coupling is achieved when the resonator intrinsic loss is perfectly balanced by the external coupling enabled by a Mach–Zehnder interferometer coupler. The high suppression of the carrier leads to a clean two-tone optical signal with the frequency interval two times larger than that of the input microwave frequency. The beating of the two-tone signal at a photodiode generates the frequency upconverted microwave signal. A theoretical model is established to analyze the modulation process and the microwave signal generation. Experimental results show that the electrical harmonic suppression ratio is around ~20 dB (29 dB) for an input microwave signal with 5 dBm (10 dBm) power.
Photonics Research
  • Publication Date: Oct. 17, 2017
  • Vol. 5, Issue 6, 06000689 (2017)
All-fiber-photonics-based ultralow-noise agile frequency synthesizer for X-band radars
Juan Wei, Dohyeon Kwon, Shuangyou Zhang, Shilong Pan, and Jungwon Kim
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.
Photonics Research
  • Publication Date: Jan. 01, 2018
  • Vol. 6, Issue 1, 01000012 (2018)