Q-switched tunable fiber laser with aluminum oxide saturable absorber and Sagnac loop mirror

A Q-switched erbium-doped fiber laser with tunable output wavelength was demonstrated by utilizing aluminum oxide saturable absorber in conjunction with Sagnac loop mirror (SLM) filter. As the SLM temperature was increased from 30 to 70 °C, the laser operation can be tuned from 1568 to 1556 nm. At 1568 nm operation, the laser pulse frequency can be raised from 13.66 to 26.25 kHz by increasing the pump power from the threshold of 53 to 87 mW. With the increase in temperature, it is found that the pump threshold for the Q-switching increased, while the laser operation shifted to a shorter wavelength.