Abstract: The study on high quality surface formation mechanism in lapping of optical fiber end-face has become an important topic about improving performances of optical fiber connectors. With diamond abrasive lapping-films whose grain sizes are from 0.5 mm to 6 mm used, the optical fiber end-face lapping experiments are processed on optical fiber connector lapping machine, whose style is KE-OFP-12. The experimental results show that there are three material removal modes during lapping optical fiber, namely, brittle fracture mode, semi-brittle & semi-ductile mode, and ductile mode. These modes are mainly controlled by abrasive grain size. Brittle-ductile transition’s critical point appears when the lapping-films whose abrasive grain size is 3 mm are used to lap optical fiber; and they are analyzed theoretically. The surface roughness from ductile lapping mode is much less than that from brittle fracture lapping mode, and the ductile lapping mode is an effective method that improves surface quality of fiber end-faces. The surface roughness Ra 5 nm can be obtained and there are not any scratches and cracks on the fiber end-face when fiber material is removed by ductile mode; it makes insertion loss and return loss of optical fiber connectors meet the requirements of high-speed and broad-brand optical fiber communication.

Key words: Material removal mode, Optical fiber lapping, Surface roughness, Surface topography