Generation of optical pulses from long wavelength semiconductor lasers using Q-switching technique

We report on production of high energy picosecond pulses from a two-contact tapered InGaAlAs/InP diode laser using a passive Q-switching technique. Single peak pulses with high pulse energies up to 500 pJ and durations of typically hundreds of picoseconds are obtained from the device by applying reverse bias voltages in the range of 0 V to -18 V to the absorber section of the device. It is also demonstrated that more symmetrical Q-switched pulses are obtained by reducing the duration of electrical pulses applied to the gain section of the laser.