Design And Characterizations Of Novel SOI Micro-Ring Optical Biosensors

Compared to the traditional optical system,the cost and complexity can be reduced heavily by realizing the photonics integrated circuits.To achieve the integration of silicon-based laser,silicon-based optical biosensor and photodetector on the same chip would be the future direction of optical sensing technology.Two important parts of integrated optical biosensors,lasers and optical biosensors,are studied in this paper.In terms of the lasers,due to the numerous advantages of quantum dot lasers,such as low threshold current,high characteristic temperature,wide modulation bandwidth,high gain and ease of integration,the characteristics of quantum dot lasers are studied as the potential of light sources of the future integrated optical biosensor system.First,based on the transition process of carriers between different levels of quantum dot lasers,the rate equations are established,and the equations are transformed into equivalent circuit equations through the equivalent transformation of the rate equations.Then,the simulation model is established to simulate the various characteristics of single mode and multi-mode quantum lasers to build the theoretical and modelling foundations.In terms of the optical biosensor devices,many optical biosensors have been designed based on micro-ring resonator(MRR)and one-dimensional photonic crystal cavity(1D-PhC)up to now.First,the influence of parameters of the single MRR on transmission characteristics is studied to optimize the structure of MRR,and the sensing characteristics of MRR are analyzed through simulation.And two different radius rings are connected in series to realize a double micro-ring sensor system,and the double micro-ring sensor can reduce the influence of noise on the sensors by the differential operation.Then,the idea of novel double-spiral-racetrack(DSR)shape composed of a single waveguide is proposed,and the sensing performance of the DSR has been greatly improved compared with the ordinary MRR.Secondly,the 1D-PhC formed by periodically etching some the uniform circular holes on planar straight waveguide is studied,and the influence of the main structural parameters of the 1D-PhC on the transmission characteristics is analyzed.Based on the uniform 1D-PhC,a non-uniform 1D-PhC biosensor is designed by changing the size of some specific holes on planar straight waveguide.After optimizing the structure,the sensing characteristics of the non-uniform 1D-Ph C biosensor is analyzedFinally,non-uniform circular holes are periodically etched on the MRR for realizing a novel MRR.And Autler-Townes splitting(ATS)formed by the novel MRR is used for sensing,because the spacing of two resonances splitting changes with the variation of the environmental refractive index,the sensing performance of the novel MRR is greatly improved.