On-demand rapid switching for fiber transverse mode based on a photonic lantern

We propose a new approach to achieve on-demand rapid switching for fiber transverse mode, by utilizing a mode control laser system based on photonic lantern. The phase conjugate hologram of the transverse mode is loaded onto the liquid crystal spatial light modulator (LC-SLM) to provide an evaluation function for the stochastic parallel gradient descent (SPGD) algorithm of the mode-switching laser system. This system can achieve fundamental mode (FM) and high-order modes (HOMs) with high-purity, mode superimposition and mode-switching according to different practical application requirements. The LP₀₁, LP₁₁ and orbital angular momentum (OAM) with a mode purity greater than 90% are obtained, and the superimposed output of LP₀₁ and LP₁₁ mode is realized. The output can be switched between modes in less than 5 ms. It holds great potential for applications in mode division multiplexing (MDM), industrial materials processing, and high-power fiber lasers.