All-Optical Tuning of Micro-Resonator Overlaid With MoTe2 Nanosheets

Molybdenum telluride (MoTe
₂
) has attracted renewed interest owing to their versatile applications, such as transistors, logic circuits, photovoltaic cells, photodetectors, sensors, and lasers. We demonstrate an all-optically tunable microfiber knot resonator (MKR) overlaid with MoTe
₂
nanosheets. The optical transmitted power (OTP), resonance wavelength, and extinction ratio of the MoTe
₂
coated MKR can be tuned using external incidence pump lasers (405, 450, and 660 nm). MKR with MoTe
₂
nanosheets has strong absorption in the visible regime and enhanced light–matter interaction, resulting in enhanced tuning efficiency. Assisted by thermo-optic effect and photon generated carriers, the intensity and the wavelength of the MKR can be simultaneously tuned. The tuning efficiencies of the OTP, resonance wavelength, and extinction ratio of the MKR are up to 0.5 dB/mW, 7.52 pm/mW, and 0.16 dB/mW, respectively. The response time is measured to be ∼3 ms. Theoretical simulations are performed for the MKR with and without MoTe
₂
, which agree well with the experimental results. The advantages of this device are all-optical tuning, easy fabrication, all-fiber content, high tuning efficiency, and fast response. This all-optical tunable MKR can find applications in all-optical circuitry, all-optical modulator, multi-dimensionally tunable optical devices, etc.