Research On One-dimensional Photonic Crystal Micro-ring Resonator For Refractive Index Sensing

Optical sensing technology is a comprehensive technology which integrates many important disciplines.It plays an important role in disease diagnosis,aerospace,biochemical anti-terrorism,environmental monitoring and other fields.With the development of various applications,miniaturized,low-cost and high-sensitivity optical sensors have become a research hotspot at home and abroad.In this paper,the refractive index sensing based on one-dimensional photonic crystal microring resonator is studied,including the sensing characteristics based on dielectric mode of one-dimensional slotted photonic crystal microring resonator,the air mode of one-dimensional bowtie photonic crystal microring resonator and one-dimensional photonic crystal microring resonator with dispersion.Firstly,the influences of air hole radius,waveguide width and slot width on the band gap position and band gap width of the one-dimensional slotted photonic crystal microring resonator are studied.The influences of bus waveguide width and coupling gap on its coupling characteristics are discussed.Then the transmission characteristics,optical field local conditions and quality factors of each dielectric mode are obtained.The dielectric mode sensitivity of the one-dimensional slotted photonic crystal microring resonator is discussed.The highest sensitivity is 495 nm / RIU.Then,for the bowtie-hole photonic crystal microring resonator,the influences of the width of the waveguide,the radius of the bowtie hole and the angle of the bowtie on the quality factor of the air mode are discussed.After optimization,the quality factor can reach 1.419 × 105.Taking the high quality factor air mode as the research object,the sensing sensitivity of 250 nm / RIU is obtained.Finally,by using the transfer matrix method,the expression of the microring resonator transmission spectrum is derived.It is found that the amplitude transfer factor,amplitude transmission coefficient and effective refractive index are all related to the wavelength.Therefore,the influence of dispersion on the transmission characteristics of one-dimensional photonic crystal microring resonator is studied.It is found that dispersion can make the transmission spectrum become envelope spectrum with unequal resonance intensity.Then,the influence of coupling length and coupling gap on the transmission spectrum is discussed.By selecting the critical coupling point,the sensitivity of the one-dimensional photonic crystal microring resonator with dispersion can reach 310 nm / RIU.The research work of this paper provides theoretical basis and innovative ideas for the development of miniaturization,low-cost and high sensitivity integrated refractive index sensor,and promotes the development of on-chip integrated sensing system.