航天器任务具有任务复杂、高风险、高成本、高可靠性、长周期等特点,为了适应未来更加复杂的航天器任务研制需要,在航天器设计与研制中引入了基于模型的系统工程(model-based system engineering,MBSE)方法。提出了基于模型的航天器研...航天器任务具有任务复杂、高风险、高成本、高可靠性、长周期等特点,为了适应未来更加复杂的航天器任务研制需要,在航天器设计与研制中引入了基于模型的系统工程(model-based system engineering,MBSE)方法。提出了基于模型的航天器研制流程和适应航天器研制过程需要的6类模型体系,分别为需求模型、功能模型、工艺模型、架构模型、产品模型以及验证模型。以月球水资源探测为假想任务背景,给出了MBSE建模过程及其模型,充分体现了MBSE方法在航天器设计及其集成仿真验证方面的优势。展开更多
For achieving the greatest sensitivity,numerical simulation is proposed to optimize the parameters of light force accelerometer(LFA).Firstly,the basic principle of the LFA is analyzed,and the mathematical model is est...For achieving the greatest sensitivity,numerical simulation is proposed to optimize the parameters of light force accelerometer(LFA).Firstly,the basic principle of the LFA is analyzed,and the mathematical model is established to describe the axial and radial optical trapping forces on microspheres in the fundamental mode Gaussian laser beam.Secondly,the axial and radial optical trapping forces applied on Mie spheres are simulated to obtain the optimal parameters of open-loop LFA.Results show that the sensitivity can reach 103μm/g.Finally,the LFA system is proposed based on the closed-loop scheme with dual beams.This can provide reference for the design and fabrication of LFA in future.展开更多
Polarization fluctuation induced noise and backscattering-induced noise are the dominant noises in resonant fiber optic gyroscopes. This Letter proposes a new method to suppress the carrier and backscattering induced ...Polarization fluctuation induced noise and backscattering-induced noise are the dominant noises in resonant fiber optic gyroscopes. This Letter proposes a new method to suppress the carrier and backscattering induced noise by the sideband locking technique. Besides choosing an optimized modulation depth and different clockwise and counterclockwise modulation frequencies, the sideband is locked to the cavity resonance. With the proper modulation frequency, the carrier frequency component locates at a position far away from the resonant frequency, and then it is suppressed by the cavity itself, which can be taken as a bandpass filter. The amplitude of the carrier frequency can be suppressed by 20–25 d B additionally by the cavity and the total intensity suppression ratio can reach 115.74 d B. The backscattering induced noise can be eliminated for the adoption of different frequencies. The method can realize a stable and high suppression ratio without high requirements for parameter accuracy or device performance.展开更多
A novel hybrid air-core photonic band-gap fiber(PBF) ring resonator with twin 90° polarization-axis rotated splices is proposed and demonstrated. Frist, we measure the temperature dependent birefringence coeffici...A novel hybrid air-core photonic band-gap fiber(PBF) ring resonator with twin 90° polarization-axis rotated splices is proposed and demonstrated. Frist, we measure the temperature dependent birefringence coefficient of air-core PBF and Panda fiber. Experimental results show that the relative temperature dependent birefringence coefficient of air-core PBF is 1.42×10^(-8)/℃, which is typically ~16 times less than that of Panda fiber. Then, we extract the geometry profile of air-core PBF from scanning electron microscope(SEM) images. Numerical modal is built to distinguish the fast axis and slow axis in the fiber. By precisely setting the length difference in air-core PBF and Panda fiber between two 90° polarization-axis rotated splicing points, the hybrid air-core PBF ring resonator is constructed, and the finesse of the resonator is 8.4. Environmental birefringence variation induced by temperature change can be well compensated, and experimental results show an 18-fold reduction in thermal sensitivity, compared with resonator with twin 0° polarization-axis rotated splices.展开更多
文摘航天器任务具有任务复杂、高风险、高成本、高可靠性、长周期等特点,为了适应未来更加复杂的航天器任务研制需要,在航天器设计与研制中引入了基于模型的系统工程(model-based system engineering,MBSE)方法。提出了基于模型的航天器研制流程和适应航天器研制过程需要的6类模型体系,分别为需求模型、功能模型、工艺模型、架构模型、产品模型以及验证模型。以月球水资源探测为假想任务背景,给出了MBSE建模过程及其模型,充分体现了MBSE方法在航天器设计及其集成仿真验证方面的优势。
文摘For achieving the greatest sensitivity,numerical simulation is proposed to optimize the parameters of light force accelerometer(LFA).Firstly,the basic principle of the LFA is analyzed,and the mathematical model is established to describe the axial and radial optical trapping forces on microspheres in the fundamental mode Gaussian laser beam.Secondly,the axial and radial optical trapping forces applied on Mie spheres are simulated to obtain the optimal parameters of open-loop LFA.Results show that the sensitivity can reach 103μm/g.Finally,the LFA system is proposed based on the closed-loop scheme with dual beams.This can provide reference for the design and fabrication of LFA in future.
文摘Polarization fluctuation induced noise and backscattering-induced noise are the dominant noises in resonant fiber optic gyroscopes. This Letter proposes a new method to suppress the carrier and backscattering induced noise by the sideband locking technique. Besides choosing an optimized modulation depth and different clockwise and counterclockwise modulation frequencies, the sideband is locked to the cavity resonance. With the proper modulation frequency, the carrier frequency component locates at a position far away from the resonant frequency, and then it is suppressed by the cavity itself, which can be taken as a bandpass filter. The amplitude of the carrier frequency can be suppressed by 20–25 d B additionally by the cavity and the total intensity suppression ratio can reach 115.74 d B. The backscattering induced noise can be eliminated for the adoption of different frequencies. The method can realize a stable and high suppression ratio without high requirements for parameter accuracy or device performance.
基金supported by the National Natural Science Foundation of China(No.61473022)
文摘A novel hybrid air-core photonic band-gap fiber(PBF) ring resonator with twin 90° polarization-axis rotated splices is proposed and demonstrated. Frist, we measure the temperature dependent birefringence coefficient of air-core PBF and Panda fiber. Experimental results show that the relative temperature dependent birefringence coefficient of air-core PBF is 1.42×10^(-8)/℃, which is typically ~16 times less than that of Panda fiber. Then, we extract the geometry profile of air-core PBF from scanning electron microscope(SEM) images. Numerical modal is built to distinguish the fast axis and slow axis in the fiber. By precisely setting the length difference in air-core PBF and Panda fiber between two 90° polarization-axis rotated splicing points, the hybrid air-core PBF ring resonator is constructed, and the finesse of the resonator is 8.4. Environmental birefringence variation induced by temperature change can be well compensated, and experimental results show an 18-fold reduction in thermal sensitivity, compared with resonator with twin 0° polarization-axis rotated splices.
