Mode-locked laser stabilizing method and apparatus

A mode-locked laser stabilized apparatus comprising:

• a mode-locked laser comprising:
• optical modulating means for modulating an input optical signal based on a specific frequency;
• optical amplifying means for amplifying the modulated optical signal output from the optical modulating means;
• and
• optical branching means for outputting an optical signal from a mode-locked laser cavity;
• optical path length changing means for changing the optical path length of the mode-locked laser cavity;
• optical splitting means for splitting the laser output;
• converting means for converting an optical signal in the split laser output into an electrical signal;
• extracting means for extracting at least one component from among a relaxation oscillation frequency and harmonic components thereof from the electrical signal for use as an error signal in feedback control of the optical path length changing means;
• and
• electrical signal processing means for receiving the error signal and for outputting a signal to control the optical path length changing means to reduce the error signal below a predetermined value.