Research On Microwave Photonic Signal Processing Technology Based On Waveguide Microring

Microwave photonic technology is a new technology by the cross integration of microwave technology and photonic technology,which has many advantages such as large bandwidth,low loss,and anti-photoelectric interference.It has broad application prospects in the fields of radio frequency signal generation,processing and transmission.Integrated microwave photonic signal processing is one of the important developing directions of the microwave photonic technology.In this thesis,the microwave photonic filtering and delay characteristics based on the integrated waveguide microring are studied,and its application in the optical beamforming network and the radio frequency(RF)interference cancellation system for full-duplex communication is investigated.The main work of the thesis is as follows:The filtering and delay response characteristics of the integrated waveguide microring are analyzed theoretically and simulated.On the basis,for the application of Ka-band(30GHz)optically controlled phased array antenna,the optical delay network structure of four-element sub-phased array antenna is designed by virtue of the low loss and large bandwidth properties of the waveguide micro-ring at the anti-resonance.In the optical delay network the RF signal is converted from the electrical domain to the optical domain by phase modulation.The RF signal carried optical signal is processed with time delay and sideband filtering in the optical domain,and detected by the balanced photo detector.The RF signal is transmitted to the antenna transmitting unit to perform the beam scanning function.Time delay and sideband filter processing units based on microrings are used in optical signal processing.The integrated waveguide optical delay network system is established and the structural parameters of each functional unit are simulated and optimized.The tunable range of each delay path is 0-24.9 ps,and the bandwidth of each dealy path is larger than 4GHz within the allowable range of delay fluctuation.The beam scanning angle with the range of ±30° is realized.An optical filter with a double-ring-assisted Mach-Zehnder interferometer(MZI)structure is designed for sideband filtering the phase-modulated optical signal.The filter has a stopband rejection of 25 dB,a passband bandwidth of 19.16 GHz and an edge steepness of 23.9dB/GHz.The gain and noise figure of the optical delay network link are analyzed and simulated,and the performance of the optical delay network system in practical applications is evaluated.For the RF self-interference in the full-duplex communication system,a photonic integrated RF self-interference cancellation chip was designed on the basis of the previous work on the self-interference cancellation system of discrete optoelectronic devices by our group.The integrated waveguide microring is used for the time delay and filter processing.The tunable optical delay line is constructed by two cascaded microrings with the delay range of 0-10 ps by optimal design,and the delay jitter within the 30 GHz bandwidth is less than 0.1ps.The delay unit adopts triple-ring-assisted MZI structure,and the filtering response obtained by optimizing the structural parameters are as follows: the stopband rejection is 36.5dB,the passband bandwidth is 60.6GHz,and the edge steepness is 9.2dB/GHz.On this basis,the layout of photonic integrated RF self-interference cancellation chip is completed.The theoretical model of the photonic integrated chip RF self-interference cancellation system is established,and the RF self-interference cancellation performance for the single frequency signal and broadband signal are simulated,the results show that the suppression ratio of the system is-45.3 dB.Finally,the influence of the optical delay line and the attenuator on the system suppression in the integrated chip is analyzed.