Operation Mode Characterization of a Chirped in AS/LNP Quantum-Dash Laser

In this paper, we analyze the lasing characteristics of a chirped InP based InAs quantum dash in a well multi stacked laser structure under different current operation modes. These modes are different short pulsed modes of different duty cycles (0.2, 0.5, 1, 2, 3, and 4%) and continuous wave mode. The investigation is carried out by obtaining the output light power against injection current principle characteristics and then shedding light over the involved physics of carrier transitions and distribution within the active medium. Thereafter, the corresponding emission spectra are obtained while the effects of operation under these modes are compared. The results show that the junction temperature of the laser diode is sensitive to the operation mode due to the excess influx of carriers when the duration of pumping the current into the laser diode is increased, thereby affecting the distribution of carriers across the inhomogeneous quantum dash active region. This change in the non-uniform distribution of carriers, together with junction temperature, resulted in a narrow and red-shifted lasing emission in continuous wave mode compared to pulsed mode. These results will help in achieving high wall plug efficiency devices by proper optimization of quantum dash active region.