Nonlinear multimode interference-based dual-color mode-locked fiber laser
Kangjun Zhao, Yan Li, Xiaosheng Xiao, Changxi Yang
Abstract
We present a dual-color-soliton fiber laser at two different wavebands by nonlinear multimode interference. A saturable absorber (SA) with single-mode-multimode (MMF)-single-mode fiber structure is placed in the common branch shared by two sub-cavities. Saturable absorption effects can be simultaneously satisfied at 1.5 and 2 µm at a proper length of the MMF. Dual-color solitons can still remain, even by slightly tuning the length of the MMF. The periodical characteristic of this SA provides a flexible choice of MMF length, making it simple for simultaneous mode locking (SML) at two separate wavebands in practice. Our approach not only paves the way for SML at two or more wavebands by the MMF but also could lead to significant applications in pump-probe spectroscopy.