A shared modulator applies radial stress to the polarization-dependent fiber chains to induce birefringence and simultaneously Q-switch two or more fiber lasers. Multiple temporally overlapping pulsed beams can be generated with pulses <100 ns and even <30 ns with repetition rates from 50 Hz up to 650 KHz. A pair of Q-switched fiber lasers at slightly different wavelengths being well suited to provide a low-frequency light source through difference frequency generation (DFG) by nonlinear optical materials.