In order to solve the engineering problems that exposed during the RB-SiC fabrication and shorten the processing cycle of aspheric

the RB-SiC mirror preparation

surface modification and aspheric processing techniques were analyzed. First

according the special modification characteristic of the RB-SiC mirror

the researchers chose a new material that its thermal expansion coefficient was matched very well to the RB-SiC thermal expansion coefficient. Then the modification and fabrication technology of RB-SiC were improved based on the actual situation of the aspheric processing in order to improve the reliability of the processing and shorten its processing cycle. Finally

the improved technology and methods were verified by the experiment. And the experimental results indicate that the modified RB-SiC mirror is in a good condition and RMS of the mirror surface modified before and after changed was only 0.017λ（λ=623.8nm）

13% rate of change and the aspheric processing time decreased 1 month or 2 months. The new technology ensured that adequate margin of the 10μm modified layer thickness in the subsequent processing and made the modified layer to be ground leakage difficultly. The security of the processing was improved and the processing cycle of aspheric was shortening in the engineering practice. The new technology can been applied to other SiC mirror preparation and processing of aspheric very well.