Slow Light Characteristics And Sensing Application Of Two-Dimensional Photonic Crystal Microcavity Coupled Waveguide

As a kind of periodic microstructure,photonic crystal has received wide attention in recent years since its advantages of high performance,integration and room temperature operation.A new direction and possibility is offered by the method of producing slow light effect through photonic crystal for optical buffer and delay technology,which is very important in information technology.Secondly,the research on many applications derived from photonic crystal,such as low loss waveguide,optical sensor,optical switching and laser devices,has also made great progress.In the research of this article,slow light waveguide and the sensing application based on 2-D photonic crystal microcavity coupled waveguide are studied.Through theoretical analysis and numerical simulation,high performance slow light and high sensitivity mid infrared refractive index sensor structures are obtained respectively.The main contents of this article are as follows:1.A two-dimensional photonic crystal microcavity coupled waveguide structure which replacing the base material with a nonlinear organic polymer for slow light transmission is obtained。Combined with optimization of the radius dimension of the central dielectric column and length of the microcavity in static state,the normalized delay-bandwidth product value achieves an excellent performance of 0.809,moreover,the group-velocity dispersion value was only on the order of 10~4(ps~2/km).Futhermore,since the polymer is used as substrate,the refractive index of the polymer changes with the change of the external pump laser power,which makes the slow light performance of the waveguide dynamically controllable.The results show that in this structure,the working frequency range of slow light can be adjusted to a certain extent,and in the process of adjustment,the high performance of slow light can be maintained,which has great potential in optical buffer and optical delay.2.Based on the coupled waveguide with microcavity,a kind of photonic crystal waveguide is designed to act as refractive index sensing devices at mid-infrared wavelengths around 4μm.To realize a high sensitivity,the shape of the cavity,the width of the waveguide and the size of the central dielectric column are adjusted.Theoretical analysis and numerical simulation results show that a high-sensitivity refractive index sensor based on the optimized photonic crystal microcavity coupled waveguide(PC-MCW)was then proposed and a sensitivity of～2620 nm/RIU was obtained in the refractive index range of 1.0-1.4,and the high sensitivity of more than 2400 nm/RIU can always be maintained in the measurement range.