Reconfigurable Microwave-Photonic Filter Based On Cascaded Coupling-Modulated Ring Resonators

With the increasing demand for transmission capacity in wireless networks,the traditional electronic circuit is not capable of providing high-speed,broadband,low power and low latency signal processing to maximize the carrying capacity.To resolve these issues,microwave photonic?MWP?processing has attracted considerable interests recently due to its key merits of broadband,light weight,low power consumption,compact structure,flexible reconfigurability and immunity to electromagnetic interference.Compared to other filtering technologies,photonics-assisted microwave filtering is an elegant approach to have flexible reconfigurability and tunability,and can achieve various filtering functions with a full control over the ring resonators'magnitude and phase responses,such as bandpass and bandstop filers.The photonic approach has shown superior reconfigurability,low cost,low power consumption and high integration capability compared to their electrical counterparts.This thesis is focused on the design and realization of a programmable microwave photonic filter built of cascased coupling-modulated ring resonators on the Si₃N₄ waveguide platform.Firstly,A transfer matrix model is established for the filter.The influence of the design parameters of the basic components on the performance of the device is analyzed.Secondly,the structure and the working principle of the basic components used in the device are introduced and discussed.Thirdly,the principle of the system to realize optical filtering and the microwave filtering is introduced and experimentally verified.The filter bandwidth tuning range is 790 MHz-7.9 GHz.The microwave filtering is realized by mapping filtering function from the optical domain to the microwave domain.The bandwidth tuning range of microwave filter is 1.15 GHz-8.87GHz.The device is realized on the low-loss Si₃N₄/SiO₂ platform.The silicon nitride waveguide propagation loss is less than 0.5 dB/cm,in favor of implementating a narrow-band filter.