Using electromagnetic field theory of dielectric in a cylindrical coordinates system,the theoretical analysis and calculation for a rotatory optic fiber are presented in this paper.
A special optical fiber is investigated, which has a helical core in the cylindrical cladding. The beam propagation method （BPM） is used for analyzing the impacts of the geometric and physical parameters on the prop...A special optical fiber is investigated, which has a helical core in the cylindrical cladding. The beam propagation method （BPM） is used for analyzing the impacts of the geometric and physical parameters on the properties of mode losses of the helical-core fiber. The propagation loss is 0.32 dB/m for the fundamental mode and the propagation loss is 20.95 dB/m for the LPu mode in the wavelength range of 1050-1065 nm when the core diameter is 19 μm, the pitch of the core＇s helix is 2.66 mm, and the offset of the helix core from the center of the fiber axis is 31 μm. The core diameter of the single-mode helical-core fiber well exceeds that of the conventional large-mode-area fiber. The helical-core fiber can provide the effec- tive large-mode-area single-mode operation without coiling fiber or selecting excitation mode.展开更多
The mode theory is the main way to study the propagation characteristics of light in fiber so far,but it is not suitable for analysis of light in duct.By using ray-tracing method,the rotary propagation characteristics...The mode theory is the main way to study the propagation characteristics of light in fiber so far,but it is not suitable for analysis of light in duct.By using ray-tracing method,the rotary propagation characteristics of light in multimode-single mode-multimode(MSM) fiber structures are analyzed in this paper.Firstly,the light ray in fiber can propagate around an inscribed circle,and the central axis of this fiber is the propagation axis.Secondly,the radius of the inscribed circle is decided by both incident angle and incident position,and its variation is between 0 and RM,where RM is the radius of the multimode fiber.Lastly,the bigger the ratio of core and cladding diameter is,the higher the propagation efficiency is.展开更多
An effective and flexible rotation and compensation scheme is designed to improve the accuracy of rotating inertial navigation system （RINS）. The accuracy of single-axial R1NS is limited by the errors on the rotatin...An effective and flexible rotation and compensation scheme is designed to improve the accuracy of rotating inertial navigation system （RINS）. The accuracy of single-axial R1NS is limited by the errors on the rotating axis. A novel inertial measurement unit （IMU） scheme with error compensation for the rotating axis of fiber optic gyros （FOG） RINS is presented. In the scheme, two couples of inertial sensors with similar error characteristics are mounted oppositely on the rotating axes to compensate the sensors error. Without any change for the rotation cycle, this scheme improves the system＇s precision and reliability, and also offers the redundancy for the system. The results of 36 h navigation simulation prove that the accuracy of the system is improved notably compared with normal strapdown INS, besides the heading accuracy is increased by 3 times compared with single-axial RINS, and the position accuracy is improved by 1 order of magnitude.展开更多
The influence of the linear birefringence on magneto-optical property measurement for optical fibers is investigated theoretically and experimentally. The evolution of polarization in fibers is simulated by the Jones ...The influence of the linear birefringence on magneto-optical property measurement for optical fibers is investigated theoretically and experimentally. The evolution of polarization in fibers is simulated by the Jones matrix. To verify this theoretical model, a magneto-optical system is built to measure the input azimuth, output azimuth and ellipticity. The Faraday rotation of spun fibers with different pitches is measured. The Verdet constant increases, while the linear birefringence decreases as the pitch becomes smaller. For spun fibers with 1 mm pitch, the Verdet constant can be enhanced by about 20.7% at 660 nm, compared with that of the unspun fiber. The results indicate that smaller linear birefringence can provide more accurate Faraday rotation measurement.展开更多
文摘Using electromagnetic field theory of dielectric in a cylindrical coordinates system,the theoretical analysis and calculation for a rotatory optic fiber are presented in this paper.
基金supported by the National Natural Science Foundation of China(Nos.11104043,61107069,60927008)the Natural Science Foundation of Heilongjiang Provincein China(No.LC201006)
文摘A special optical fiber is investigated, which has a helical core in the cylindrical cladding. The beam propagation method （BPM） is used for analyzing the impacts of the geometric and physical parameters on the properties of mode losses of the helical-core fiber. The propagation loss is 0.32 dB/m for the fundamental mode and the propagation loss is 20.95 dB/m for the LPu mode in the wavelength range of 1050-1065 nm when the core diameter is 19 μm, the pitch of the core＇s helix is 2.66 mm, and the offset of the helix core from the center of the fiber axis is 31 μm. The core diameter of the single-mode helical-core fiber well exceeds that of the conventional large-mode-area fiber. The helical-core fiber can provide the effec- tive large-mode-area single-mode operation without coiling fiber or selecting excitation mode.
基金supported by the National Natural Science Foundation of China(No.61177076)the Fundamental Research Funds for the Central Universities(Nos.2013-Ia-038 and 2013-Ia-006)
文摘The mode theory is the main way to study the propagation characteristics of light in fiber so far,but it is not suitable for analysis of light in duct.By using ray-tracing method,the rotary propagation characteristics of light in multimode-single mode-multimode(MSM) fiber structures are analyzed in this paper.Firstly,the light ray in fiber can propagate around an inscribed circle,and the central axis of this fiber is the propagation axis.Secondly,the radius of the inscribed circle is decided by both incident angle and incident position,and its variation is between 0 and RM,where RM is the radius of the multimode fiber.Lastly,the bigger the ratio of core and cladding diameter is,the higher the propagation efficiency is.
基金supported by the National Natural Science Foundation of China (No.40904018)the Key Laboratory Foundation of the Ministry of Education of China (No.201001)the Doctoral Innovation Foundation of Naval University of Engineering (No.BSJJ2011008)
文摘An effective and flexible rotation and compensation scheme is designed to improve the accuracy of rotating inertial navigation system （RINS）. The accuracy of single-axial R1NS is limited by the errors on the rotating axis. A novel inertial measurement unit （IMU） scheme with error compensation for the rotating axis of fiber optic gyros （FOG） RINS is presented. In the scheme, two couples of inertial sensors with similar error characteristics are mounted oppositely on the rotating axes to compensate the sensors error. Without any change for the rotation cycle, this scheme improves the system＇s precision and reliability, and also offers the redundancy for the system. The results of 36 h navigation simulation prove that the accuracy of the system is improved notably compared with normal strapdown INS, besides the heading accuracy is increased by 3 times compared with single-axial RINS, and the position accuracy is improved by 1 order of magnitude.
基金supported by the National Natural Science Foundation of China(Nos.61177088,61275051,61227012,61475096,61422507 and 61520106014)the Science and Technology Commission of Shanghai Municipality of China(Nos.14511105602,14DZ1201403 and 15220721500)
文摘The influence of the linear birefringence on magneto-optical property measurement for optical fibers is investigated theoretically and experimentally. The evolution of polarization in fibers is simulated by the Jones matrix. To verify this theoretical model, a magneto-optical system is built to measure the input azimuth, output azimuth and ellipticity. The Faraday rotation of spun fibers with different pitches is measured. The Verdet constant increases, while the linear birefringence decreases as the pitch becomes smaller. For spun fibers with 1 mm pitch, the Verdet constant can be enhanced by about 20.7% at 660 nm, compared with that of the unspun fiber. The results indicate that smaller linear birefringence can provide more accurate Faraday rotation measurement.
