Japanese Journal of Applied Physics
Optical Switch-Off Effect Using Excited State Absorption of Erbium-Doped Fibers
Yoshinobu Maeda, Masatoshi Migitaka
Abstract
Optical switch-off in which the constant signal light is suddenly decreased at 1.4 and 25.0 W/cm2 was demonstrated with an erbium-doped fiber using a single-wavelength control light. Discontinuous phenomena of optical switch-off have hysteresis and occur at a minimum or inflection point in the transmission curve. Negative intensity dependence, which causes the transmission to decrease as the laser intensity is increased, was observed at 787 nm, but not at 808 nm. Numerical analyses were carried out using a four-level double-absorption model. As a result, it was found that these phenomena take place because the absorption cross section from 4I13/2 to 2H11/2 is larger than that from 4I15/2 to 4I9/2.