JPS5573011A - Mask forming method of optical fiber and face - Google Patents

Abstract

PURPOSE:To accurately measure effective incident light quantity without using any long-length optical fiber by forming a non-reflecting non-transparent shield mask on the end face excluding the required portion for the core part of the incident end face of the optical fiber. CONSTITUTION:A non-reflecting non-transparent photo resist film 11 is deposited on the incident end face of an optical fiber and the light of a light source 6 is focused and entered by way of a lens 7 or the like to the core part of its output end. After only the film 11 is exposed by its radiation light 8, this is developed. As a result, the film 11 of the incident end face remains on the end face other than the core part which substantially becomes an optical guide, thereby forming a non- reflecting and non-transparent shield mask 12. Hence, even if the incident light is radiated to the entire surrace of the optical fiber end face, it turns out that the required light signal enters the core end face only and that the effective light quantity incident from the light source is faithfully transmitted to the output end of the optical fiber. Thereby, the effective incident light quantity may be accurately measured without using any long-length optical fiber.