On-chip tunable microdisk laser fabricated on Er³⁺-doped lithium niobate on insulator

We demonstrate a C-band wavelength-tunable microlaser with an Er³⁺-doped high quality (∼1.8×10⁶) lithium niobate microdisk resonator. With a 976 nm continuous-wave pump laser, lasing action can be observed at a pump power threshold lower than 400 µW at room temperature. Furthermore, the microdisk laser wavelength can be tuned by varying the pump laser power, showing a tuning efficiency of ∼-17.03pm/mW at low pump power below 13 mW, and 10.58 pm/mW at high pump power above 13 mW.