PULSE BUILDUP DYNAMICS OF AN ACTIVELY MODE-LOCKED LASER-DIODE ARRAY IN THE EXTERNAL-CAVITY

Dynamic pulse evolution characteristics of an actively mode-locked las er diode array in the external cavity have been investigated, Numerica l calculations based on modified traveling-wave rate equations reprodu ce experimentally observed pulse and spectral width evolution and show that the buildup time is about 45 round-trips, We have also performed a theoretical analysis to understand which of the laser operating par ameters would affect the buildup dynamics, It is shown that either hig her de bias current or larger radiative recombination coefficient (whi ch is inversely proportional to the excited-state lifetime) will rende r the laser exhibiting shorter steady-state pulse width and faster evo lution to the steady state, Other parameters affecting the buildup, bu t to a lesser extent, include the radio-frequency (RF) modulation curr ent, spontaneous emission coefficient, and gain coefficient, The power reflectivities of the output mirror and the antireflection coated dio de facet, on the other hand, have little effect on the pulse width and buildup time for single pulse generation.