The effect of the number and position of AlInAs energy barrier layers on the output characteristics of high-power multimode AlGaInAs / InP lasers, spectral range 1400–1600 nm, has been studied. It was shown that the use of energy barriers allows increasing the laser maximum output power 1.5-2 times. It was found that the barrier layer should be installed at the waveguide-cladding heterojunction from the p-side in order to localize electrons in the waveguide layer.
The study was supported by the Russian Science Foundation, project No. 19-79-30072
The design of the AlGaAs/InGaAs/GaAs laser heterostructure with an ultra-narrow waveguide was developed and studies on the generation of high-power laser pulses with high beam quality were carried out. The heterostructure design included a 100-nm-thick waveguide and an InGaAs quantum well for a lasing at 1060 nm. For the studies the mesa-stripe geometry single-mode lasers with a 5.1-μm-width contact were fabricated. The mesa-stripe geometry parameters were optimized using a 2D-simulation of waveguide properties, taking into account the spatial distribution of temperature and gain. As a result, the divergence was of 18.5 and 5 degrees in the growth direction and parallel to the heterostructure layers, respectively. Studies of the light-current characteristics in the range of pulse durations of 5–1000 ns showed that the peak power of 1.75 W was limited by the catastrophic optical damage. The dynamics is associated with modes of high-quality factor that approach their threshold conditions at high pumping level. A spectral line of these modes is redshifted relative to a fundamental one.
The results of research and development of a pulse laser module are presented. The aim was to create and a compact pulse laser source with a peak power of more than 10 W for optical pulses of 10 ns - 10 μs duration, emitting in spectral range 900-1600 nm. Pulsed modules were based on MOCVD-grown edge-emitting multimode semiconductor lasers integrated with a pulse pumping board. It was shown that the laser output characteristics can be optimized via a series resistance in the laser pump circuit. The 1550 nm wavelength modules with free-space outputs showed power levels of 15 and 25 W, for 1 μs and 100 ns pulses respectively, at 25° C temperature with a regular pulse shape.
The results of designing, manufacturing and investigating characteristics of AlGaAs/InGaAs/GaAs lasers with ultranarrow waveguides are presented. Low threshold current density near 40 A/cm2 has been observed for the lasers with quantum wells. We have demonstrated the possibility of obtaining up to 5 W of output power in continuous mode and up to 40 W in pulsed mode, with a beam convergence (FWHM) of 17.8° It is demonstrated that such lasers can exhibit main characteristics similar to conventional laser heterostructures and allow a potential for further improvement and optimization.