Lab‐on‐Fiber Based on Optimized Gallium Selenide for Femtosecond Mode‐Locked Lasers and Fiber‐Compatible Photodetectors

Abstract

Although the physicochemical properties of gallium selenide (GaSe) have been widely investigated, the property and application exploration of GaSe-coupled fiber devices are still in its infancy. There are obvious challenges, namely, selecting from multiple GaSe phases and effectively coupling to the unique fiber structure. Herein, lab-on-fiber (LOF) based on optimized GaSe is proposed to be used for robust femtosecond pulse generation and fiber-compatible photodetection. First, based on density functional theory (DFT) calculations, ε-GaSe is selected as a preferable model material for its suitable band structures, low work function, and high damage threshold. Benefiting from the fiber-compatible ε-GaSe combined with micro?nano processing, stable femtosecond soliton pulse (≈303?fs, 16.67?MHz, 51.64?dB) output and multiwavelength (520, 808, and 1550?nm) detection are realized in LOF. These results pave the way for optics research of polyphase semiconductors and design of integrated all-fiber devices.