Research On Filtering Characteristics Based On Microring Resonators Array

With the rapid development of the information industry,the traditional microelectronic technology can't meet the urgent needs of the information industry for high bandwidth capacity and flexible bandwidth allocation.In order to make use of the advantages of microelectronic technology and optoelectronic technology,silicon-based integrated optics integrating optoelectronic devices with large bandwidth into the chip.The microring resonator is compact and can be combined with other components to form a new functional device,which makes it a research focus in silicon-based integrated optics.In this thesis,the filter characteristics of the parallel microring array and the improved microring array are studied,and the optical device with excellent filtering performance is designed.Based on the parallel microring array,the filter characteristics of the resonator frequency band and the superimposed frequency band are studied,and a dense wavelength division multiplexer with high shape factor and a interleaver with multiple bandwidth ratio are researched,respectively.Accroding to the improved microring array,a method to realize the dynamic tuning filter channel is researched,and the tunable dense wavelength division multiplexer is simulated and analyzed.The main work is shown as follows:(1)Based on the working principle of microring resonator,the output function model of all-pass microring structure,add-drop microring structure and series double microring structure are established by using transfer matrix method.And the output spectrum characteristics of the three basic structures are simulated.The amplitude response,phase response and group delay response of all-pass microring under over-coupling,critical coupling and under-coupling are studied.The transmission coupling coefficient of the add-drop structure and the series structure are designed.(2)The output function of the parallel microring array is modeled by the transfer matrix method,and the output spectrum intensity is analyzed by Matlab simulation tool.The filter characteristics of the resonator frequency band and the superimposed frequency band are obtained by setting the ratio of microring spacing and microring circumference ratio to 0.25 and 0.5,respectively.By optimizing the transmission coupling coefficient,the system refractive index,the microring radius and the loss coefficient,the resonator frequency band with the shape factor over 0.85 and the stopband crosstalk less than-25 dB are obtained.By cascading four parallel microring arrays,a 1×4 dense wavelength division multiplexer is implemented.Based on the periodic characteristics of the superimposed frequency band,a scheme of an interleaver with multiple bandwidth ratio is studied.The output spectrums with four different bandwidth ratios are obtained,and the bandwidth ratios between the drop port and the throught port are 1: 1,1: 2,1: 3 and 1: 4,respectively.(3)In order to switch the filter channels of the parallel microring array flexibility,an improved microring array is researched,and the switching method of its filtering channel is studied.By controlling the coherent distance of the coupled resonator induced transparency(CRIT),the filter channels of the designed router and the dense wavelength division multiplexer can be switched flexibility.The dynamic tuning of the improved microring array filter channel is realized by changing the refractive index of the microring or adding the additional phase shift unit to the waveguide.The tunable dense wavelength division multiplexer is researched by using additional phase shift tuning.The device can not only multiplex the wavelength,but also can choose the wavelength of multiplexing.The improved microring array is more flexible than the parallel microring array.Because the filter channel can be switched and tuned dynamically,the improved microring array can enhance the flexibility of integrated optics significantly.