All-Optical Tuning of Light in WSe₂-Coated Microfiber

The tungsten diselenide (WSe₂) has attracted considerable interest owing to their versatile applications, such as p-n junctions, transistors, fiber lasers, spintronics, and conversion of solar energy into electricity. We demonstrate all-optical tuning of light in WSe₂-coated microfiber (MF) using WSe₂'s broad absorption bandwidth and thermo-optic effect. The transmitted optical power (TOP) can be tuned using external incidence pump lasers (405, 532, and 660 nm). The sensitivity under 405-nm pump light excitation is 0.30 dB/mW. A rise/fall time of ~ 15.3/16.9 ms is achieved under 532-nm pump light excitation. Theoretical simulations are performed to investigate the tuning mechanism of TOP. The advantages of this device are easy fabrication, all-optical control, high sensitivity, and fast response. The proposed all-optical tunable device has potential applications in all-optical circuitry, all-optical modulator, and multi-dimensionally tunable optical devices, etc.