Wavelength Tunable Q-Switched Fiber Laser Using Variable Attenuator Based on Tapered Fiber

We demonstrate a wavelength tunable, Q-switched Er-doped fiber laser using a mixture of gold nanorods and nanospheres as a saturable absorber. The laser has a very low Q-switched threshold pump power of 22 mW, and at a pump power of 47.86 mW, a pulse with a maximum pulse energy of 36.01 nJ, repetition rate of 37.50 kHz, and pulse width of 2.74 μs was obtained. In addition, by using a tapered fiber as a variable attenuator (ATT), the central wavelength of the laser could be tuned continuously from 1560.97 to 1554.74 nm. The experimental results further verify that a tapered fiber ATT possesses potential advantages for applications in stable, wavelength tunable, all-fiber laser systems.