Passive Q-switching generation from an erbium-doped fiber laser using a Brewster fiber grating

We generate a passively nanosecond Q-switching by inserting a Brewster fiber grating which induces the nonlinear polarization rotation (NPR) effect. In our experiment, Q-switched pulses with pulse width of 502 ns, repetition rate of 207.5 kHz, output power of 12.7 mW and single pulse energy of 61.2 nJ are achieved under the pump power of 450 mW.