Patent ID: 7787506

Claim:
A pulsed, gain switched fiber laser comprising: a resonant cavity; a thulium doped gain fiber located within the cavity, said thulium doped gain fiber having an emission band which overlaps with an absorption band; and a radiation pump source with the output thereof directed into the cavity to pump the thulium doped gain fiber, with the wavelength of the pump source being resonant with the lasing wavelength so that the relaxation from the pump energy level to the lasing energy level is essentially instantaneous and wherein the wavelength, intensity and duration of the pump pulses are selected so that the excitation population generated in the gain fiber by the pump pulses is depleted to a level below the lasing threshold in a time duration less than the relaxation oscillation period of the fiber laser in manner to generate one and only one output laser pulse for each pump pulse and wherein said output laser pulses are stable in amplitude and time.