Analysis of Energy Transfer among Stokes Components in Raman Fiber Lasers

This work presents a methodology to estimate the pumping power required for the first Stokes to reach its maximum stored energy level, before it generates the next Stokes. These estimates are achieved by experimentally measuring the critical power and the relationship between the pumping power (PP0) and the small signal of the stimulated Raman spread (PF0). For our study we used 1 km of 1060-XP fiber, experimentally obtaining Pcr = 6.693 W, PF0/PP0 = 6.759x10−6. With these experimental data, the pump power required for the first Stokes to reach its maximum stored energy level was 13.39 W, and the stored energy in the first Stokes was 9.88 W. It is important to note that the Raman threshold ln(PP0/PF0) = 11.9 is smaller than the initially reported ∼16.