Frequency-modulated cavity-dumped Nd-doped fiber laser

A cw-pumped Nd-doped single-mode double-clad fiber laser coiled around a resonant piezoelectric ceramic ring and coupled to an empty external cavity with strong feedback is described. Intensity laser pulses with durations in the 1-2-micros range are observed as the pump power or the ring drive voltage is increased, yielding peak powers as much as 25 times greater than average powers. The effect is attributed to strong phase modulation of the fiber laser by the piezoelectric ring, which induces FM laser oscillation. The external cavity acts as a frequency-dependent reflector, thus effectively cavity dumping the fiber laser as the oscillation frequency is swept through the narrow transparent windows of the external cavity.