The theoretical study of dielectric-chiral photonic crystal fiber （PCF） with an elliptical hollow core is presented. The band structure of chiral photonic crystal （PhC） is calculated by using a modified plane-wave...The theoretical study of dielectric-chiral photonic crystal fiber （PCF） with an elliptical hollow core is presented. The band structure of chiral photonic crystal （PhC） is calculated by using a modified plane-wave expansion （PWE） method. By examining the out-of-plane photonic bandgaps （PBGs） of chiral PhC, a kind of chiral PCF with a hollow core is designed and their eigenstates are calculated. The distributions of mode field and polarization state are demonstrated, and how the structural asymmetry of the core together with the chirality in the background affects the modal polarization is discussed. The dependences of birefringence on chirality for different ellipticities of core are investigated.展开更多
By means of the weakly guiding approximation, the mode spot sizes Wx and Wy of the fundamental mode along the semimajor （x-direction） and semiminor （y-direction） axes of the fiber core in elliptical core two- mode...By means of the weakly guiding approximation, the mode spot sizes Wx and Wy of the fundamental mode along the semimajor （x-direction） and semiminor （y-direction） axes of the fiber core in elliptical core two- mode fiber are discussed. The variation of their ratio value Wx/W9 with the operation wavelength A and the length ratio a/b between the semimajor axis and the semiminor axis of the fiber core is analyzed. Based on this analysis, the distribution figures of two-lobe interferential mode patterns are evaluated and simulated quantitatively for different phase difference changes between LP01 and LP~~n modes. The two-lobe interferential mode patterns have the same profile and distribute symmetrically when the phase difference equals ~r/2. Their central distance S becomes larger when W~：/W~ augments gradually. F^rthermore, the equation about the central distance S of the two-lobe interferential mode patterns is given when the operation wavelength varies between 0.65 and 1.31 #m, which is important to applications shuch as sensors and coupling devices between different fibers.展开更多
A refractive index(RI)sensor based on elliptical core photonic crystal fiber(EC-PCF)has been proposed.The asymmetric elliptical core introduces the polarization-dependent characteristics of the fiber core modes.The pe...A refractive index(RI)sensor based on elliptical core photonic crystal fiber(EC-PCF)has been proposed.The asymmetric elliptical core introduces the polarization-dependent characteristics of the fiber core modes.The performances of intermodal interference between the intrinsic polarization fiber core modes are investigated by contrast in two interferometers based on the Mach-Zehnder(M-Z)and Sagnac interference model.In addition,the RI sensing characteristics of the two interferometers are studied by successively filling the three layers air holes closest to the elliptical core in the cladding.The results show that the M-Z interference between LP_(01)and LP_(11)mode in the same polarized direction is featured with the incremental RI sensing sensitivity as the decreasing interference length,and the infilled scope around the elliptical core has a weak correlation with the RI sensing sensitivity.Due to the high birefringence of LP11 mode,the Sagnac interferometer has better RI sensing performance,the maximum RI sensing sensitivity of 12000 nm/RIU is achieved under the innermost one layer air holes infilled with RI matching liquid of RI=1.39 at the pre-setting EC-PCF length of 12 cm,which is two orders of magnitude higher than the M-Z interferometer with the same fiber length.The series of theoretical optimized analysis would provide guidance for the applications in the field of biochemical sensing.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.60977032)
文摘The theoretical study of dielectric-chiral photonic crystal fiber （PCF） with an elliptical hollow core is presented. The band structure of chiral photonic crystal （PhC） is calculated by using a modified plane-wave expansion （PWE） method. By examining the out-of-plane photonic bandgaps （PBGs） of chiral PhC, a kind of chiral PCF with a hollow core is designed and their eigenstates are calculated. The distributions of mode field and polarization state are demonstrated, and how the structural asymmetry of the core together with the chirality in the background affects the modal polarization is discussed. The dependences of birefringence on chirality for different ellipticities of core are investigated.
基金National Basic Research Program of China under Grant No.2006CB806001.
文摘By means of the weakly guiding approximation, the mode spot sizes Wx and Wy of the fundamental mode along the semimajor （x-direction） and semiminor （y-direction） axes of the fiber core in elliptical core two- mode fiber are discussed. The variation of their ratio value Wx/W9 with the operation wavelength A and the length ratio a/b between the semimajor axis and the semiminor axis of the fiber core is analyzed. Based on this analysis, the distribution figures of two-lobe interferential mode patterns are evaluated and simulated quantitatively for different phase difference changes between LP01 and LP~~n modes. The two-lobe interferential mode patterns have the same profile and distribute symmetrically when the phase difference equals ~r/2. Their central distance S becomes larger when W~：/W~ augments gradually. F^rthermore, the equation about the central distance S of the two-lobe interferential mode patterns is given when the operation wavelength varies between 0.65 and 1.31 #m, which is important to applications shuch as sensors and coupling devices between different fibers.
基金jointly supported by the Tianjin Natural Science Foundation(No.18JCQNJC71300)the National Natural Science Foundation of China(Nos.11804250,11904262 and 11704283)+1 种基金the Tianjin Education Commission Scientific Research Project(No.2018KJ146)the Opening Foundation of Tianjin Key Laboratory of Optoelectronic Detection Technology and Systems(No.2019LODTS004)。
文摘A refractive index(RI)sensor based on elliptical core photonic crystal fiber(EC-PCF)has been proposed.The asymmetric elliptical core introduces the polarization-dependent characteristics of the fiber core modes.The performances of intermodal interference between the intrinsic polarization fiber core modes are investigated by contrast in two interferometers based on the Mach-Zehnder(M-Z)and Sagnac interference model.In addition,the RI sensing characteristics of the two interferometers are studied by successively filling the three layers air holes closest to the elliptical core in the cladding.The results show that the M-Z interference between LP_(01)and LP_(11)mode in the same polarized direction is featured with the incremental RI sensing sensitivity as the decreasing interference length,and the infilled scope around the elliptical core has a weak correlation with the RI sensing sensitivity.Due to the high birefringence of LP11 mode,the Sagnac interferometer has better RI sensing performance,the maximum RI sensing sensitivity of 12000 nm/RIU is achieved under the innermost one layer air holes infilled with RI matching liquid of RI=1.39 at the pre-setting EC-PCF length of 12 cm,which is two orders of magnitude higher than the M-Z interferometer with the same fiber length.The series of theoretical optimized analysis would provide guidance for the applications in the field of biochemical sensing.
