Studies On The Photonic-assisted Broadband Microwave Analog Signal Processing Technologies

Photonic-assisted broadband microwave signal processing technology which takesadvantage of the photonic devices and subsystems with large bandwidth, high dynamicrange, low loss and easy integration, enables the processing of ultra-wideband (UWB)microwave signal by means of narrow-band analog optical signal processing. Hence, itshows great potential to meet the ever-increasing demand in many novel applicationsareas such as broadband wireless access, deep space exploration and national defenseand military. In this thesis, the UWB generation and modulation technology, highdynamic range microwave photonic (MWP) downconversion technology as well as theSOI based MWP signal processor are studied in detail.Firstly, in order to achieve more flexible access and reduce the system complexityin the future UWBoF application, a reconfigurable high-order UWB pulse generationand modulation method based on the symmetric PM-IM conversion architecture isproposed and a UWBoF system is also experimentally demonstrated. In the experiment,1Gbit/s excellent OOK, BPSK, OPPM and NPPM modulation formats for both the3rd-order and5th-order UWB pulses and transmission over a combined20km SMF and0.25m wireless link are successfully realized. Then to further achieve noninterferenceoperation with the global positioning system (GPS) and enhance the spectral powerefficiency of the UWB system, an optimization method for UWB temporal waveformand spectra simply based on a phase modulator is proposed and experimentally verified.In the experiment, a novel modified triplet pulse is generated with central frequency ofabout6.3GHz,10dB bandwidth of7.2GHz and power efficiency of52.6%, which hasa good agreement with the calculated results. In addition, an error-free transmission forboth the positive and negative triplet pulses after20km SMF transmission is achieved.In the high dynamic range MWP downconverting technology part, the noisesuppression and nonlinear distortion compensation method are studied. A novel all-optical downconversion scheme based on the cascaded intensity and phase modulationis proposed, and the LO-ASE noise can be suppressed thanks to the dual-output-portoptical sideband filtering and balanced detection. In the experiment, the SNR of thedownconverting system covering from X-to Ka-band, is improved by about2.6dB and the measured SFDR is higher than104.5dB-Hz2/3. As to the cancellation of the IMD, ahigh linear analog photonic link (APL) for the X-and K-band downconversion based onDSP post-compensation method is proposed. In the experiment, the IMD3is suppressedby more than21dB and the SFDR for both X-and K-band is improved by about8dB,and an SFDR as high as124.2dB-Hz2/3is achieved.For the research and applications mentioned above, the SOI based MWP filteringtechnology is also studied. The transfer functions of both the FIR and IIR filtering unitsare analyzed theoretically in the Z domain. In the experiment, three kinds of BPSKcoded UWB pulses are generated using a racetrack silicon microring resonator which isunder the critical coupling condition. Additionally, in the K-band analog photonic link,optical single sideband filtering is achieved by a SOI based narrow-band filter, of whichthe3dB bandwidth is about1.536GHz and the FSR is13.5GHz. The measured SFDRof the downconversion link is about104dB-Hz2/3.