Wavelength Tunable Actively Q-Switched Fiber Laser

Abstract

In this letter, we present the design and implementation of a wavelength tunable Q-switching fiber laser based on two-cascaded tunable filters; overlapping on transmission spectrum of both filters allows keeping the cavity losses at low level, while losing the overlapping condition increases the losses in the cavity. Following these two conditions, one tunable filter is used to select the wavelength emission of the laser; and the other tunable filter is used to actively switch on-off the overlapping condition along the range of tuning. Implementing this switching principle, pulses of light within 30 nanometers of tuning range are easily generated. Despite this range is limited by the Erbium-Ytterbium co-doped fiber implemented as the laser amplifier, the technique can be implemented at different wavelengths and ranges of emission using different doped fibers. Also, experimental characterization of the wavelength tunable pulsing laser is presented, pulsing emission at different wavelengths, time duration of pulses and average optical power as a function of wavelength, and time duration and peak power of pulses as a function of the switching rate.