Measurements of differential group delay and chromatic dispersion for LP01 and LP11 modes of few-mode fibers with depressed claddings

Abstract

The chromatic dispersion of the LP11 mode in a few-mode fiber with low differential group delay is evaluated experimentally. A differential group delay of less than 100 ps/km around 1550 nm can be evaluated with the modal interferometer method. The white-light interferometric method confirms that the LP11 mode is behind the LP01 mode in the 1300–1600 nm wavelength region. The difference between the chromatic dispersion values of the two modes is less than 0.5 ps/km/nm, which means that the optical pulse spreading characteristics of the LP11 mode are similar to those of the LP01 mode for fibers with depressed claddings.