Experimental Study On The Nanoimprinted On-Chip Polydimethylsiloxane Microring Resonator

Whispering gallery mode?WGM?resonators with ultra-high quality factor and ultra-small mode volume have potentials in sensing and detection,nonlinear optics,lasers and quantum information.Among them,on-chip WGM resonators can achieve compatibility and integration with other devices.Therefore,in order to improve the practical application of on-chip WGM resonators,it is necessary to ensure that the preparation method satisfies the requirements of mass production,high production efficiency and low cost.A new preparation scheme of polydimethylsiloxane?PDMS?optical microring resonator on MgF₂ substrate by nano-imprint lithography is proposed in this thesis.The main contents are as follows:?1?The mode field characteristics of the WGM microring resonator,the waveguide coupling theory and the characteristic parameters of the WGM resonator are firstly studied theoretically.Then,the influence of coupling distances and sizes of the PDMS optical microring on the resonator characteristics is simulated by finite difference time domain?FDTD?,which provides theoretical guidance for the size selection and characteristics of PDMS microring resonators.?2?Compared with the materials and methods of other on-chip WGM resonators,nano-imprint lithography is proposed to prepare the PDMS optical microring resonator on MgF₂ substrate,which is successfully fabricated by the design and preparation of the silicon mold,PDMS spin coating,imprinting,curing and demolding.?3?The tapered fiber is selected as the coupler,and the characteristics of PDMS optical microring resonator on MgF₂ substrate are studied by transmission spectrum test system.The measured quality factor of the resonator is in the order of 10⁴ in the C band and coupling distances and sizes of microring would affect its resonant wavelength.Moreover,we demonstrate that the resonant wavelength of such PDMS optical microring resonator on MgF₂ substrate is linear with temperature,and its temperature sensitivity is about-0.29 nm/?.