Japanese Journal of Applied Physics
All-Optical Switch Derived from the Negative Nonlinear Absorption Effect in Erbium-Doped Fibers
Yoshinobu Maeda, Masatoshi Migitaka
Abstract
An all-optical switch which has a negative amplification of the optical signal was demonstrated in an erbium-doped fiber. The dependence of the negative nonlinear absorption effect on the modulation degree of the incident laser was investigated and we obtained the negative amplification degree of -3 for a fiber length of 6 m at room temperature. It has been confirmed that the mechanism of the effect can be explained by calculating the rate equations based on an analytical model for a five-level system of the Er3+ ion. It is suggested that the effect was due to stimulated emission from the 4 S 3/2 level to the 4 I 13/2 level.