Studies On Frequency Conversion Of The Microwave Photonics

Microwave photonics is a new interdisciplinary subject which combines photonics and microwave.In comparison with conventional electric parts,all-optical microwave components has got great concern due to the special advantages of wide bandwidth,light weight,and immunity to electromagnetic interference,and the microwave photonics has become a research hotspot in recent years.This paper focus on the technology of microwave photonics frequency conversion,and the research contents of this paper are as follows:(1)This study presents a microwave photonic mixer with the function of frequency up/down conversion based on a single dual-parallel Mach-Zehnder modulator.A radio frequency(RF)signal and a local oscillator(LO)signal drive two sub-MZMs to achieve the modulation of single side band.By adjusting the voltage of the parent MZM to introduce the 180? phase difference so that two optical carriers cancelled out.The output signal through the photodiode for beating frequency,the IF signal is obtained.(2)This study presents a microwave photonic mixer with the function of frequency up/down conversion and full range phase shift.In the proposed scheme,a radio frequency(RF)signal and a local oscillator(LO)drive two dual-parallel Mach-Zehnder modulators(DPMZM),respectively.By establishing the specific bias voltage of two DPMZMs,this scheme can implement the carrier suppressed single sideband(CS-SSB)modulation and +2nd-order single sideband modulation.By theoretically analyzes and demonstrates the proposed scheme,the system can realize both frequency conversion and 0?-360? phase shift.(3)A new frequency-sextupled microwave signal processor with full angle phase shift without using any filter is presented and demonstrated in this paper.A dual-polarization quadrature phase shift-keying(DP-QPSK)modulator is used to generate two 3rd-order sidebands which along the orthogonally polarization directions suppress the other sidebands.By adjusting the direct current(DC)voltage applied to the polarization modulator,the full angle phase shift is implemented.By beating the two 3rd-order sidebands at a photodetector(PD),a frequency-sextupled microwave signal with 0?-360? tunable phase shift is generated.