Microfiber closed-loop laser and preparation method thereof

The invention discloses a microfiber closed-loop laser and a preparation method thereof. The preparation method comprises the following steps of: outputting single pulses to converge at a point through a ZnSe lens by using a CO2 pulse laser under the modulation of an arbitrary waveform generator; bending a doped microfiber until the head is overlapped with the end, and setting the overlapping point as the focus of the lens; fusing and welding the microfiber by using single pulse laser to form a closed-loop resonant cavity; and tangentially combining the closed-loop cavity with a biconical microfiber at the cone waist to form the microfiber closed-loop laser. The method for fusing and welding the microfiber by the single pulses of the CO2 laser has the characteristics that: the device is simple, the cost is low, the process is controllable, the microfiber fusing and welding loss is low, and the like. The laser has the characteristics that: the laser is simple to prepare and easy to integrate, along with miniaturization, firm structure, stable output characteristics and the like. The maximum power output obtained by the conventional erbium-ytterbium co-doped single longitudinal mode microfiber closed-loop laser at the working waveband of 1.5 mu m is 2.3 mu W, and the threshold power is only 2.4 mW.