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Asymmetric light transmission effect based on an evolutionary optimized semi-Dirac cone dispersion photonic structure
摘要： In this paper, we present the numerical and experimental demonstration of asymmetric light transmission by a compact photonic crystal (PC) structure, which sustains semi-Dirac cone dispersion. The semi-Dirac point is obtained by exploiting plane-wave expansion method in a rectangular unit cell of a cylindrical dielectric rod, forming a PC structure. The preselected part of the corresponding PC structure is optimized via differential evolution to maximize the transmission efficiency in one direction, and to minimize in the opposite direction. In this regard, finite-difference time-domain method is integrated with the optimization algorithm to numerically design a compact PC structure with asymmetric light transmission effect. The detailed numerical investigation of the optimized PC structure is represented, and the experiments in the microwave regime are performed to verify the numerical results. The experimentally measured transmission efficiency reaches 78% for one direction, whereas in the opposite direction it reduces to 11%. The physical mechanism of asymmetric light transmission is related to differences of the projection of the wave incident from both directions into the eigenmodes of the photonic structure.
关键词： asymmetric light transmission,semi-Dirac cone dispersion,photonic crystal,differential evolution,finite-difference time-domain method
更新于2025-09-04 15:30:14
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Passive Integrated Optical Gyroscope Based on Photonic Crystal Ring Resonator for Angular Velocity Sensing
摘要： In this paper, we investigated the concept of the Sagnac effect in passive integrated optical gyroscope base photonic crystal ring resonator for angular velocity sensing. This configuration utilizes one 3 dB coupler, two Bus waveguides, and five ring resonators for rotation sensing. The structure has been designed using dielectric silicon rods which are embedded in air. The transmission efficiency of the photonic crystal ring resonator at 1551 nm is about 96% with quality factor and bandwidth values equal to 4326 and 0.35 nm, respectively. By measuring the power of the output port, it is possible to estimate the phase shift and then to measure the rotation rate. The central wavelength of structure is assumed to be equal to 1569.9 nm. The structure characteristics have been investigated by using the two-dimensional finite-difference time-domain method. The footprint of the structure is approximately 279 μm2.
关键词： Photonic crystal,Angular velocity sensing,Ring resonator,Optical gyroscope
更新于2025-09-04 15:30:14
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Role of structural anisotropy in geometric birefringence of high-birefringence index-guiding PCFs: analysis by moment of inertia
摘要： We have studied the role of structural anisotropy on the geometric birefringence of four typical high-birefringence (HB) index-guiding photonic crystal fibers (PCFs) with the same air-silica structure and circular, ellipse, and rectangle air holes, respectively. The normalized difference between the moment of inertia ΔI in x and y direction of the PCF structure is utilized to quantificationally describe the structural anisotropy. We demonstrate that the phase birefringence B increases monotonously when the normalized ΔI rises in different cases of PCFs structures. In order to obtain high birefringence B, it can be an effective method to optimize the parameters of the structure to increase the normalized ΔI. This work can be not only a reference of founding the essence of geometric birefringence and proposing the optimal design of HB-IG-PCFs, but also an enlightenment for bringing the different method (compared to the finite element) into the investigation of PCFs.
关键词： Photonic crystal fiber (PCF),Polarization maintenance,Structural anisotropy,Geometric birefringence,Birefringence,Moment of inertia
更新于2025-09-04 15:30:14
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[IEEE 2018 Photonics North (PN) - Montreal, QC, Canada (2018.6.5-2018.6.7)] 2018 Photonics North (PN) - Bloch Surface Wave Based Biosensing
摘要： An integrated biosensing platform exploiting the properties of Bloch surface waves on all-dielectric thin film stacks is described. It combines label-free sensing based on tracking with surface wave enhanced angular resonance fluorescence and detection. Detailed design considerations reveal a system with defined attenuation to improve resolution limits in both modes.
关键词： label-free detection,biosensor,Bloch surface wave,1D photonic crystal,surface wave enhanced fluorescence
更新于2025-09-04 15:30:14