Pulsed laser source with adjustable grating compressor

A laser source for producing a pulsed laser beam comprising a plurality of ultrashort optical pulses having a variable repetition rate, said laser source comprising:

• a fiber oscillator that outputs optical pulses having an optical pulse width;
• a pulse stretcher disposed to receive said optical pulses, said pulse stretcher having dispersion that increases said optical pulse width yielding stretched optical pulses;
• a fiber amplifier disposed to receive said stretched optical pulses, said fiber optical amplifier having gain so as to amplify said stretched optical pulses, wherein said fiber amplifier subjects said pulses to a level of self-phase modulation that affects the optical pulse width of said amplified pulses as a function of pulse repetition rate;
• an automatically adjustable grating compressor comprising at least one translatable bulk optical element, said compressor having dispersion that reduces the optical pulse width of said amplified pulses, said dispersion of said grating compressor being adjustable, said grating compressor automatically adjusting said dispersion for different repetition rates;
• and
• a feedback system that includes an optical detector that senses said optical pulse width of said amplified pulses or said repetition rate and a controller that adjusts said grating compressor based on said sensed optical pulse width or said sensed repetition rate.