Studies On Transmission Of Vector Siganal And Polarization Techniques In Optical Beam-forming Networks Based On Broadband Light Source

Microwave Photonics is a discipline focused on the interaction of optical signalsand electrical signals in the microwave and mm-wave band. The optical beam-formingnetworks (OBFN), as one of the important area in microwave photonics, is consideredto be a promising key technology for future smart antennas and wideband phased arrayantennas (PAAs). By controlling the phase difference or time delay between differentlinks in the array, the radiation from each microwave radiator has maximuminterference at far field in certain directions, to achieve directional emission (receive) ofthe signal. OBFN offers many outstanding advantages, such as small size, low loss,electromagnetic immunity, large bandwidth and squint-free array steering.Based on pratical architecture of OBFN designing, based on analysis ofpower-fading and delay-error induced by polarization mode dispersion (PMD), thisthesis proposed new methods in two sides. One is a novel subcarrier system utilizing inOBFN based on broadband lightwave source. The other is the study on the impact byPMD and the method on PMD compensation. These works are supported by theNational Natural Science Foundation, National Basic Research Program of China (973Program) and the National HighTechnology Research and Development Program (863Program).From the beginning with how to control the cost of the OBFN, improve the systemstability and utilize the OBFN, this thesis proposed a novel vector-signal transmissionsystem based on broadband lightwave system. This demonstration realized20kmtransmission and distribution in base sation of10Mbps64QAM signal at2.4GHz carrierwith no error. Meanwhile, signals in QPSK and16QAM with1.25Mbps,2Mbps,3.5Mbps supported by IEEE802.11have the same transmission results. Thisdemonstration realized20km transmission and distribution of16QAM OFDM signal at3.0GHz carrier with2Gbps. The number of the subcarriers is512.The research on PMD impact is devided into the parts. One is the power fadinginduced PMD, the other is delay error induced PMD. This thesis presents the relationsbetween the polarization of input light and the PMD vector. A PMD compensatonmethod based on FRM is demonstrated. The true time delay of the OBFN doubles from 407.1ps to833.2ps due to the FRM. The maximum residual PMD is0.164ps after theFRM compensaton.