Frequency Matching Methods In Silicon Nitride Microrings And Their Applications For Nonlinear Optics

Silicon nitride photonic chip has the advantages of low loss,high transmission bandwidth and high nonlinear coefficient,and is an excellent platform for integrated photonic chip.Microring resonator is an important element on chip,which can enhance the light field greatly.In order to meet the needs of nonlinear frequency conversion in silicon nitride microring,we propose two methods of frequency matching theoretically,and test their resonance and tuning performance.The thesis mainly includes:(1)A microring resonator coupled with a single/double Mach Zehnder interferometer is designed and fabricated experimentally.Experimental results show that single interferometer coupling microring can realize the tuning of coupling state and quality factor,and double interferometer coupling microring can realize the tuning of coupling state,quality factor and quality factor under critical coupling.(2)A tunable frequency matching method of four-wave mixing Bragg scattering in silicon nitride microring is proposed and designed.An interferometer loop is used as the reflector of the microring to adjust the reflectivity from 0 to 1,thus achieving the tunability of the splitting effect of resonance mode.Based on this adjustable mode splitting method,we propose a frequency matching method for four-wave mixing Bragg scattering in a microring.Numerical simulation shows that the designed structure has a wide frequency matching range and is suitable for waveguides of different wavelengths and sizes.(3)A frequency matching method based on coupled tunable double microrings is proposed and designed.The coupling between microrings is realized by Mach Zehnder interferometer,and the tunability of splitting effect of resonance mode is realized by adjusting the coupling coefficient between microrings.It is proved that the design can be used for wide frequency tuning of the four-wave mixing process.