Abstract
Compared with well-developed free space polarization converters,polarization conversion between TE and TM modes in the waveguide is generally considered to be caused by shape birefringence,like curvature,morphology of waveguide cross section and scattering.Here,we study the polarization conversion mechanism in 1-THz-FSR X-cut lithium niobate microrings with multiple-resonance condition,that is the conversion can be implemented by birefringence of waveguides,which will also introduce an avoided-mode crossing.In the experiment,we find that this mode crossing results in severe suppression of one sideband in local nondegenerate four-wave mixing and disrupts the cascaded four-wave mixing on this side.Simultaneously,we propose one two-dimensional method to simulate the eigenmodes(TE and TM)in X-cut microrings,and the mode crossing point.This work will provide one approach to the design of polarization converters and simulation for monolithic photonics integrated circuits,and may be helpful to the studies of missed temporal dissipative soliton formation in X-cut lithium niobate rings.
基金项目
国家自然科学基金(12274462)
国家自然科学基金(11674396)
Department of Science and Technology of Hunan Province of China(2017RS3039)
Department of Science and Technology of Hunan Province of China(2018JJ1033)
Hunan Provincial Innovation Foundation for Postgraduate of China(QL20210006)
NETL
NSTL
万方数据