The group refractive-index difference of cladding modes excited by a long-period fiber grating is characterized by use of the technique of optical low-coherence reflectometry, with a precision of <10<sup>-4</sup> . Very good agreement between theoretical and experimental results is demonstrated.
© 1999 Optical Society of America
(030.4070) Coherence and statistical optics : Modes
(050.2770) Diffraction and gratings : Gratings
(060.2270) Fiber optics and optical communications : Fiber characterization
(120.1840) Instrumentation, measurement, and metrology : Densitometers, reflectometers
(290.3030) Scattering : Index measurements
D. Varelas, A. Iocco, H. G. Limberger, R. P. Salathé, S. A. Vasiliev, E. M. Dianov, O. I. Medvedkov, and V. N. Protopopov, "Optical low-coherence reflectometry characterization of cladding modes excited by long-period fiber gratings," Opt. Lett. 24, 1106-1108 (1999)