A precise process for machining arrayed optical fiber ends to have tapered corners and slightly convex planes for use as the bare optical fiber connectors have been developed. The taper shapes are determined by the length L of the fiber from holder to the fiber ends, the height h of the holder, and number of revolutions. The underlying principle is that the machining amount is proportional to the product of the load and the work traveling length. The curvature radius (8 to 18 mm) of the slightly convex fiber end plane can be controlled by adjusting the polishing load. The polished plane with the silica abrasive lapping film has high optical return loss (55 to 60 dB).
