Dynamical characterization of monolithic MOPAs emitting at 1.5 μm

Eye-safety requirements in important applications like LIDAR or Free Space Optical Communications make specifically interesting the generation of high power, short optical pulses at 1.5 μm. Moreover, high repetition rates allow reducing the error and/or the measurement time in applications involving pulsed time-of-flight measurements, as range finders, 3D scanners or traffic velocity controls. The Master Oscillator Power Amplifier (MOPA) architecture is an interesting source for these applications since large changes in output power can be obtained at GHz rates with a relatively small modulation of the current in the Master Oscillator (MO). We have recently demonstrated short optical pulses (100 ps) with high peak power (2.7 W) by gain switching the MO of a monolithically integrated 1.5 μm MOPA. Although in an integrated MOPA the laser and the amplifier are ideally independent devices, compound cavity effects due to the residual reflectance at the different interfaces are often observed, leading to modal instabilities such as self-pulsations.