Actively Q switched ring Tm doped fiber laser with free space structure

We report a cladding-pumped actively Q-switched ring Tm-doped fiber laser (TDFL). This laser is Q-switched by a free space acousto-optic modulator. A pulse energy up to 150 μJ with a pulse width of 207 ns at a repetition rate of 100 Hz is achieved for a cavity optical length of 6.68 m. The pulse amp