Boosting dispersive wave emission via spectral phase shaping in nonlinear optical fibers

Abstract

Dispersive waves (DWs) radiation in optical fibers allow to excite frequencies in spectral regions that are otherwise difficult to access. However, the resonant emission is weak and phase matching inhibits its shaping, making it ineffective in many applications. Here, we numerically investigated that DWs generated from high-energy pulses propagating in nonlinear optical fibers can be controlled through spectral phase modulation. Using tunable asymmetric and oscillatory temporal pulse shapes obtained by cubic and quadratic spectral phase modulation, we excite a multiple emission process that strongly enhances the energy and peaks of DWs. Successive collisions between the shed soliton and multiple secondary peaks of the asymmetric pulse give the mechanism to stimulate various resonant frequencies. The whole process can be precisely controlled by simply adjusting the spectral phase modulation structure without the need to change the fiber length. This radiation is either reduced or enhanced by the Raman effect depending on whether the third-order dispersion is positive or negative. Our results provide a novel strategy to manipulate DWs emission and particularly to boost the DWs energy in optical fibers that may be relevant in the development of novel electromagnetic sources for broadband supercontinuum and on-chip frequency-comb generation.