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The cross-correlation technology is applied to decrease the noise figure of microwave photonic link(MPL) for the first time in this paper. Firstly, both effects of the intensity of the laser and the bias voltage of the EOM on the noise figure of MPL are analyzed and optimized. Then, a cascaded low-noise amplifier is added in front of MPL for lower noise figure. Finally, the double laser - double detector structure based on cross-correlation technology is used to offset different kinds of uncorrelated noise in the link and experiments show that the noise figure is further reduced by 3 dB.

A new type of structure for opto-electronic oscillator (OEO) is proposed and verified by experiments in this paper. Probing-signal control method for the long-term stability of opto-electronic oscillator (OEO) is proposed firstly and this new method is used to enhance long-term stability of OEO. Using this new method, a low-frequency signal is used as a reference source, getting through the microwave photonic link in OEO and extracting the time-delay fluctuation information and compensated ultimately. In addition, the long-fiber based OEO is injection-locked by a microwave source for suppressing side modes. Results show that the side mode suppression ratio characteristics are improved obviously after microwave source injection and the long-term stability is greatly enhanced by this probing-frequency method and the Allen Deviation of oscillation signal is reduced to 2.7 × 10−12 during 1 s.

In this paper, the theory model of phase noise for microwave photonic link is derived and verified by experiments first, considering both types of flicker and white noises. In order to decrease the phase noise of link, low-phase noise amplifier and high-linear photodiode is applied in microwave photonic link. Based on this model, the effect of phase noise of microwave photonic link on the OEO is also analyzed and we found the lower-phase noise microwave photonic link results in better-characteristics OEO.

A novel model of injection-locked dual optoelectronic oscillator (ILD-OEO) is proposed and verified by experiments in this article. We not only built an accurate model for ILD-OEO but also analyzed the influence of fiber length on the white noise-limited phase noise of ILD-OEO. Results show that the single sideband (SSB) phase noise would increase when fiber delay line is long enough. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2568–2571, 2013

A new method for measuring the alternating current (AC) half-wave voltage of a Mach-Zehnder modulator is proposed and verified by experiment in this paper. Based on the opto-electronic self-oscillation technology, the physical relationship between the saturation output power of the oscillating signal and the AC half-wave voltage is revealed, and the value of the AC half-wave voltage is solved by measuring the saturation output power of the oscillating signal. The experimental results show that the measured data of this new method involved are in agreement with a traditional method, and not only an external microwave signal source but also the calibration for different frequency measurements is not needed in our new method. The measuring process is simplified with this new method on the premise of ensuring the accuracy of measurement, and it owns good practical value.

A intelligent integrated control method of double close loop is used for advanced static var generator (ASVG). The outer loop based on traditional PI control and the inner loop based on variable structure neural network fuzzy control are presented. Observed signals are firstly collected to input and output signals of FLC for inner loop, and initial fuzzy rules are fast obtained by fuzzy toolbox of MATLAB. A kind of variable structure neural network algorithm is adopted to adjust fuzzy rules, and improves the ability of self-studying and self-adjusting in fuzzy control rules. The result of simulation shows: the method which is applied in ASVG controller can improve comprehensive ability of the controller and strengthen control effect to the power system.