Mechanism of multisoliton formation and soliton energy quantization in passively mode-locked fiber lasers

TLDR

The study numerically investigates multiple‑soliton generation and energy quantization in a passively mode‑locked fiber ring laser, suggesting a similar mechanism may operate in other soliton fiber lasers. Numerical simulations of a passively mode‑locked fiber ring laser using nonlinear polarization rotation were performed to study multiple‑soliton generation and energy quantization. The simulations show that a peak‑power‑limiting effect in the cavity drives multiple‑soliton formation, suppresses pulse collapse, stabilizes the solitons, and naturally leads to energy quantization through gain competition.

Abstract

We report results of numerical simulations on multiple-soliton generation and soliton energy quantization in a soliton fiber ring laser passively mode locked by using the nonlinear polarization rotation technique. We found numerically that the formation of multiple solitons in the laser is caused by a peak-power-limiting effect of the laser cavity. It is also the same effect that suppresses the soliton pulse collapse, an intrinsic feature of solitons propagating in gain media, and makes the solitons stable in the laser. Furthermore, we show that the soliton energy quantization observed in the lasers is a natural consequence of the gain competition between the multiple solitons. Enlightened by the numerical result we speculate that multisoliton formation and soliton energy quantization observed in other types of soliton fiber lasers could have a similar mechanism.