We demonstrate a low-repetition-rate all-fiber allnormal-dispersion Yb-doped mode-locked fiber laser. Stable mode-locking is achieved by nonlinear polarization rotation and its spectral-filtering effect. Nanosecond pulses with steep edges spectrum at repetition rate 217.4 kHz are achieved. Our preliminary experiment shows that it is a promising seed for all-fiber amplifier system.

By using the symmetry properties of the reversible planar maps, instead of the Melnikov analysis, we improve the homoclinic orbit approach without assuming small perturbations to prove rigorously the existence of bright and dark soliton solutions of the discrete nonlinear Schrödinger equations with various nonlinearities in one-dimensional lattices. Our approach is valid both for small and large coupling constants. The latter case is inaccessible to the anti-integrability method.

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Lithium-sulfur (Li-S) batteries are competitive for the next-generation energy storage applications. However, soluble polysulfides cause severe shuttle effect and electrolyte abuse. Solid-solid and quasi-solid conversions are effective to address the...