Seeded intermodal four-wave mixing in a highly multimode fiber
We experimentally and theoretically investigate the process of seeded intermodal four-wave mixing in a graded-index multimode fiber, pumped in the normal dispersion regime. By using a fiber with a 100-μm core diameter, we generate a parametric sideband in the C-band (1530-1565 nm), hence allowing the use of an erbium-based laser to seed the mixing process. To limit nonlinear coupling between the pump and the seed to low-order fiber modes, the waist diameter of the pump beam is properly adjusted. We observe that the superimposed seed stimulates the generation of new spectral sidebands.