Skin solitons.

Recently, the concept of skin effect has gained considerable attention in the context of non-Hermitian photonics. The experimental realization of Hatano-Nelson systems in optical coupled cavities has provided the opportunity to consider the effect of optical nonlinearity. In this work, we probe the interplay between Kerr nonlinearity and non-Hermiticity in a Hatano-Nelson lattice. In particular, we examine the relation between self-focusing and the skin effect under single-channel excitation. Moreover, we numerically identify skin soliton solutions, which exhibit power threshold and spatial asymmetry.