Intensity noise in mode-locked external cavity laser

Effect of spontaneous and carrier noise on mode-locked HSPS utilizing linearly chirped fiber Bragg grating is investigated by using coupled mode-equations. It is found that transform-limited pulses are generated over a wide tuning range without noise and with low noise level. However, mode-locking is difficult to achieve for large value of spontaneous coupling factor and some value of rf and dc currents because of increasing noise. High noise introduce noise peak in the relative intensity noise (RIN) spectrum making transform-limited pulses unobtainable. Hence, proper mode-locking range that transform-limited pulses are generated reduces.