The primary mirror is an important optical component of space camera. Its performance related to the optical image quality, and the weight directly affects the whole camera weight. The traditional design of primary mirror relies on much experience, lacking of precise theory, and many design parameters obtained by empirical formulas, thus the performance of the result is unstable. For this study, a primary mirror made of SiC with the diameter of 700mm was conceptual designed to get the optimized structure. Then sensitivity analysis was carried out to determine the optimum thickness of the back muscles. Finally, the optimum primary mirror fully satisfied the required was completed, with outstanding mechanical performance and light weight. A comparison between the optimum primary and traditional primary was performed and the results showed that the optimum primary has higher lightweight ratio increased by 5%, higher modal frequency increased by 81Hz.The maximum deformation under gravity reduced by 48nm, PV of the mirror surface reduced by 8.1nm and RMS reduced by 3.1nm. All the results indicated that the optimization method in the paper is reasonable and effective, which gives a reference to the primary mirror design in the future.
We experimentally demonstrate an all-optical approach for generating frequency-shift keying (FSK) radio-frequency (RF) signal based on nonlinear polarization rotation (NPR) in a highly nonlinear fiber (HNLF). A continuous wave probe beam is polarization-rotated by an optical amplitude-shift keying control beam via NPR in the HNLF. After removing the undesired control beam by a tunable optical filter, the polarization-rotated probe beam is converted to an intensity-modulated optical signal using a polarizer. By carefully adjusting the polarization controller before the polarizer and the optical power of the control beam, FSK RF signals are generated after photodetection.
The impact of the mirror self-weight or other structural stress may cause bad optical imaging quality. The
large-diameter primary mirror was optimized based on variable density topology optimization method and in the
condition of gravity to satisfy the design requirements. A new primary mirror has been designed, comparing which with
the traditional lightweight primary mirror in the method of finite element analysis, the results prove that the new primary
mirror is superior to the traditional model in the lightweight rate, surface accuracy and structural rigidity, so the paper
puts forward a new idea in the lightweight design.