<div style="text-align:justify;"> Currently, coupled mode theory (CMT) is widely used for calculating the coupling coefficient of twin-core fibers (TCFs) that are used in a broad range of important app...<div style="text-align:justify;"> Currently, coupled mode theory (CMT) is widely used for calculating the coupling coefficient of twin-core fibers (TCFs) that are used in a broad range of important applications. This approach is highly accurate for scenarios with weak coupling between the cores but shows significant errors in the strong coupling scenarios, necessitating the use of a more accurate method for coupling coefficient calculations. Therefore, in this work, we calculate the coupling coefficients of TCFs using the supermode theory with finite element method (FEM) that has higher accuracy than CMT, particularly for the strong coupling TCF. To investigate the origin of the differences between the results obtained by these two methods, the modal field distributions of the supermodes of TCF are simulated and analyzed in detail. </div>展开更多
A novel Mach–Zehnder interferometer(MZI)sensor based on multiple supermode interferences that can be used for dualparameter measurements of temperature and strain is proposed and demonstrated.The MZI is made by splic...A novel Mach–Zehnder interferometer(MZI)sensor based on multiple supermode interferences that can be used for dualparameter measurements of temperature and strain is proposed and demonstrated.The MZI is made by splicing a coupled four-core sapphire-derived fiber(FSDF)between two single-mode fibers,utilizing the differences in temperature response and strain response of different supermodes in the FSDF to realize the simultaneous measurement of the two parameters.Experimental results demonstrate that the proposed MZI can achieve up to 1600μεand 1000℃ measurements with a temperature-strain cross-sensitivity of approximately 0.075℃/με.展开更多
Polarization of photons plays a key role in quantum optics and light-matter interactions,however,it is difficult to control in nanosystems since the eigenstate of a nanophotonic cavity is usually fixed and linearly po...Polarization of photons plays a key role in quantum optics and light-matter interactions,however,it is difficult to control in nanosystems since the eigenstate of a nanophotonic cavity is usually fixed and linearly polarized.Here,we reveal the polarization control of photons using photonic molecules(PMs)that host supermodes of two coupled nanobeam cavities.In contrast to conventional PMs in a 2D photonic crystal slab,for the two 1D photonic crystal nanobeam cavities the shift and gap between them can be tuned continuously.With an ultra subwavelength gap,the coupling between the two cavities is dominated by the evanescent wave coupling in the surrounding environment,rather not the emission wave coupling for conventional PMs.As such,the non-Hermiticity of the system becomes pronounced,and the supermodes consist of a non-trivial phase difference between bare eigenstates that supports elliptical polarization.We observe that both the polarization degree and polarization angle of the antisymmetric mode strongly depend on the shift and gap between the two cavities,exhibiting polarization states from linear to circular.This full polarization control indicates the great potential of PMs in quantum optical devices and spin-resolved cavity quantum electrodynamics.展开更多
文摘<div style="text-align:justify;"> Currently, coupled mode theory (CMT) is widely used for calculating the coupling coefficient of twin-core fibers (TCFs) that are used in a broad range of important applications. This approach is highly accurate for scenarios with weak coupling between the cores but shows significant errors in the strong coupling scenarios, necessitating the use of a more accurate method for coupling coefficient calculations. Therefore, in this work, we calculate the coupling coefficients of TCFs using the supermode theory with finite element method (FEM) that has higher accuracy than CMT, particularly for the strong coupling TCF. To investigate the origin of the differences between the results obtained by these two methods, the modal field distributions of the supermodes of TCF are simulated and analyzed in detail. </div>
基金supported by the National Key Research and Development Program of China(No.2023YFB3209500)the National Natural Science Foundation of China(No.U2241237)+1 种基金the China Postdoctoral Science Foundation(No.2024M751934)the Postdoctoral Fellowship Program of CPSF(No.GZC20240973)。
文摘A novel Mach–Zehnder interferometer(MZI)sensor based on multiple supermode interferences that can be used for dualparameter measurements of temperature and strain is proposed and demonstrated.The MZI is made by splicing a coupled four-core sapphire-derived fiber(FSDF)between two single-mode fibers,utilizing the differences in temperature response and strain response of different supermodes in the FSDF to realize the simultaneous measurement of the two parameters.Experimental results demonstrate that the proposed MZI can achieve up to 1600μεand 1000℃ measurements with a temperature-strain cross-sensitivity of approximately 0.075℃/με.
基金supported by the National Key Research and Development Program of China(Grant no.2021YFA1400700)the National Natural Science Foundation of China(Grants Nos.62025507,12494600,12494601,12494603,92250301,22461142143,62175254,12174437,12204020 and 12474096).
文摘Polarization of photons plays a key role in quantum optics and light-matter interactions,however,it is difficult to control in nanosystems since the eigenstate of a nanophotonic cavity is usually fixed and linearly polarized.Here,we reveal the polarization control of photons using photonic molecules(PMs)that host supermodes of two coupled nanobeam cavities.In contrast to conventional PMs in a 2D photonic crystal slab,for the two 1D photonic crystal nanobeam cavities the shift and gap between them can be tuned continuously.With an ultra subwavelength gap,the coupling between the two cavities is dominated by the evanescent wave coupling in the surrounding environment,rather not the emission wave coupling for conventional PMs.As such,the non-Hermiticity of the system becomes pronounced,and the supermodes consist of a non-trivial phase difference between bare eigenstates that supports elliptical polarization.We observe that both the polarization degree and polarization angle of the antisymmetric mode strongly depend on the shift and gap between the two cavities,exhibiting polarization states from linear to circular.This full polarization control indicates the great potential of PMs in quantum optical devices and spin-resolved cavity quantum electrodynamics.
