A simple reflection-type two-dimensional refractive index profile measurement technique for optical waveguides

✍ Scribed by Youngchun Youk; Dug Young Kim

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 292 KB
• Volume: 262
• Category: Article
• ISSN: 0030-4018
• DOI: 10.1016/j.optcom.2005.12.061

✦ Synopsis

We report a new configuration of a reflection-type confocal scanning optical microscope system for measuring the refractive index profile of an optical waveguide. Several improvements on the earlier design are proposed; a light emitting diode at 650 nm wavelength instead of a laser diode or He-Ne laser is used as a light source for better index precision, and a simple longitudinal linear scanning and a curve fitting techniques are adapted instead of a servo control for maintaining an optical confocal arrangement. We have obtained spatial resolution of 800 nm and an index precision of 2 • 10 À4 . To verify the system's capability, the refractive index profiles of a conventional multimode fiber and a home-made four-mode fiber were examined with our proposed measurement method.