Mike Buzzetti proposes an optical fiber polisher which is a link-type mechanism with double flats in 1999. Buzzetti’s optical fiber polisher produce 8-shaped grinding traces to polish the end face of optical fiber connector. The purpose of this paper is to design the optimal polishing traces of single-plate optical fiber polisher to avoid the patent of Buzzetti’s mechanism. First, a link-type single-plate optical fiber polisher, which is consist 7 links and 8 joints, is proposed. Then, analyze the polishing trace, velocity, and acceleration of Buzzetti’s mechanism and new mechanism. Finally, we take the curvature scope percentage (sp) and the velocity deviation percentage (Vdp) as the objective functions, and use global search to achieve optimized design so that the double- crank single-plate optical fiber polisher will produce the optimum polishing trace which is like the digit “8”. The results of this paper are: (1) The velocity deviation percentage of double-crank single-flat optical fiber polisher (Vdp= 61.8241%) is lower then the original mechanism (Vdp= 76.8652%). And, (2) The maximum acceleration of double-crank single-flat optical fiber polisher (amax = 1231 cm/s2) is lower then the original mechanism (amax= 2323.0 cm/sec2). The result indicates that the polishing effect of the double-crank single-flat optical fiber polisher is better then original mechanism.