Spectral filtering for time isolation of intensive picosecond optical pulses from a Q-switched laser diode

A significant wavelength separation is found between the shot-pulsed mode and stationary lasing in the emission band of a Q-switched single-heterostructure laser. This feature allowed a 35 ps/100 W single optical pulse to be achieved by means of band-pass optical filtering. An attendant long-duration optical response, attributed to optical transitions with at least one localized tail state involved, is suppressed by a factor of 104 as compared with the peak power of the single picosecond pulse. A complicated time-resolved spectrum is interpreted in terms of a qualitative model involving saturable absorption and carrier heating.