Generation and dynamics of dual-wavelength solitons in ultrafast fiber lasers

Abstract

We present a comprehensive investigation of dual-wavelength soliton dynamics in an erbium-doped fiber laser incorporating lead selenide quantum dots (PbSe QDs) as a saturable absorber. Stable dual-wavelength operation at 1529 nm and 1557 nm is demonstrated, exhibiting distinct spectral and temporal characteristics. Reversible transitions between dual- and single-wavelength states are achieved by tuning the intracavity polarization controller. Numerical simulations, in excellent agreement with experimental results, reveal that dual-wavelength generation arises from the interplay of the erbium gain profile, birefringence-induced spectral filtering, and the nonlinear absorption of PbSe QDs. Additionally, soliton interactions exhibit elastic collisions with a 562 Hz repetition-rate difference, confirming independent propagation dynamics. These findings establish PbSe QDs as a promising nonlinear medium for multi-wavelength fiber lasers, with potential applications in dual-comb spectroscopy and wavelength-division multiplexing networks.