Graphdiyne-Based All-Optical Modulator for an Actively Q-Switched Fiber Laser

Over the past decade, Q-switched fiber lasers have drawn extensive attention in nonlinear frequency conversion, industrial material processing, bioscience, spectroscopy, etc., due to their cost-effectiveness, robustness, and compactness. However, the widely employed passive Q-switching easily suffers from the degradation of saturable absorbers under intracavity pulse irradiation and the inaccurate modification of the repetition rate, leading to a large barrier for their practical applications. To this end, an all-optical modulator (AOM) is rationally designed based on the superior photothermal conversion of two-dimensional (2D) graphdiyne (GDY) in this work for an actively Q-switched fiber laser. The developed AOM based on a Michelson interferometer composed of few-layer 2D GDY nanosheets exhibits tunable output parameters (e.g., intensity and phase modulation), high stability, and easy synchronization due to the high photothermal effect of 2D GDY and is successfully applied into all-optical signal processing with reliable transmission of ASCII codes (“N”, “T”, and “U”). Additionally, an actively Q-switched laser is also constructed by the 2D GDY-based AOM, which demonstrates that the developed active AOM processes all-optically tunable output parameters, precise synchronization, and environmental robustness. It is expected that this prototypical active 2D GDY-based AOM with multiple features (superior photothermal conversion, satisfactory energy consumption, and large modulation depth) can provide fundamental guidance on designs of advanced all-optical information processing and all-optical communication networks.