Q-Switch All-Fiber Laser Pulsed by High Order Modes

In this letter, we demonstrate an all-fiber Q-switch laser in erbium-doped fiber using an intracavity loss modulator that controls the power transmitted by a cladding mode. The cladding mode is coupled by a pair of concatenated long period gratings; pulsed regime is achieved by dynamic attenuation of the power transmitted by the cladding mode, and attenuation is caused by lateral compression with a piezoelectric transducer. The pulse sequence can be controlled from a single shot up to repetition rates of 2 kHz. The laser performance is analyzed as a function of the pump power and emission frequency; pulses having a peak power of 4 W and a duration of ~80 ns can be generated with an absorbed pump of 100 mW.