Novel technique for measuring the residual stress and the strain-optic coefficient profile of an optical fiber

Summary form only given. A HeNe laser is used for the light source with random polarization. A rotating diffuser is used for reducing the unwanted diffraction effects result from high spatial coherence of the source light. The light is scattered and collected by lens. The state of polarization of the weakly focused light is modified by the linear birefringence device, which includes a rotating polarizer and a quarter wave plate. The light is focused by condenser and is polarized by an analyzer through the optical fiber immersed in index matching liquid. The magnified image of the optical fiber is detected by a CCD camera through 20X objective lens and is scanned as a line data by a monochrome frame-grabber. By using this technique we measured the residual stress and the strain-optic coefficient profiles of an Er-Ge-Al doped fiber.