Research on the effects of dual pumping on fast light propagation in an Er³⁺-doped optical fiber

Abstract

In this paper, we propose a general theory for the coherent population oscillation effect in an Er 3+ -doped optical fiber under dual-frequency laser pumping at room temperature. We aim at comparing the effect of dual pumping (1480 nm and 980 nm) with single pumping of 980 nm and single pumping of 1480 nm on time advancement. According to the numerical calculations, we analyze the relationships between relative modulation attenuation and modulation frequency, plus fractional advancement and modulation frequency under the dualfrequency pumping laser with co-propagation. Compared to single pumping, a greater change in the group refractive index can be found. The maximum time advancement of 0.24 ms under a dual-frequency pump laser with co-propagation is obtained. Moreover, we demonstrate the influence of the pump ratio M on time advancement with modulation frequencies of 40 Hz, 100 Hz and 200 Hz. The ability to control the group velocity of light could have an important application for photonics.