Wavelength-tunable Q-switched erbium-doped fiber laser based on a digital micromirror device

A wavelength-tunable Q-switched erbium-doped fiber laser based on a digital micromirror device (DMD) is experimentally demonstrated. The Q-switched pulses are generated by incorporating a saturable absorption device made of graphene oxide. Stable Q-switched pulses at 1.5 µm band are obtained at a low threshold of 20 mW, corresponding to the pulse width of 7.1 µs and the repetition rate of 43.3 kHz. The maximum output power and the maximum pulse energy of the Q-switched pulses are 260.1 µW and 3.97 nJ, respectively. By controlling the DMD, the center wavelength of the Q-switched pulses can be tuned from 1528.2 to 1559.3 nm, with a tuning range of about 31 nm. The fine tunable accuracy can reach 0.08 nm by precisely controlling the DMD. Combining the filtering characteristics of the DMD with the saturable absorption characteristics of nanomaterials, the Q-switched laser with tunable wavelength is realized, which, we believe, is reported for the first time and has broad application prospects.