Group velocity manipulation using cross gain modulation in erbium-doped fibers with co-direction structure

We experimentally demonstrated tunable delays using mutrally modulated cross-gain modulation (MM XGM) in erbium-doped fiber (EDF) with a new co-direction structure. The group velocity of the signal light can be controlled by the saturating light at an arbitrary wavelength in the EDF gain bandwidth. We have observed slow light propagation with a group velocity as low as 146.4 m/s, which means a 88.8 ms delay, and an advancement of 11.2 ms after a 13 m EDF at the same time. This provides a greater enhancement on the delay or advancement compared to the previous experiment. Furthermore, we confirmed the influence on delay or advancement by varying the pump power, the input power of the saturate light. Also, we discussed the influence of recovery time, the modulation depth of the saturating light and the modulation frequency on the modulation gain. This attractive approach could be one of the suitable solutions for real applications.