Slow and fast light via two-wave mixing in ytterbium-doped fiber at 1064 nm

Experimental results on observation of slow and fast light propagation via two-wave mixing (TWM) in ytterbium doped fibers (YDF) at the wavelength 1064 nm are reported. For ≈10 mW of the incident cw laser power the effective population dynamic gratings with sub-ms formation time τg and dominating phase (refractive index) components are formed in YDF by two counter-propagating coherent waves. The TWM at the recorded not shifted phase gratings is characterized by absence of any energy exchange between two interacting counter-propagating waves if they have the same frequency. For the no-degenerated TWM (i.e. that with the frequency off-set ΔΩ between the interacting waves) the maximal energy exchange is observed when ΔΩ is approximately equal to τg−1 and changes its sign with the inversion of ΔΩ. In the reported experiments an effective slow and fast light propagation with maximal fractional delay of about 0.04 for 3.5 ms pulses was observed for these two maxima located at the frequency off-set ≈±200 Hz.