Study of temperature effects on loss mechanisms in laser diodes with electron stopper layer

Abstract

The importance of the electron loss from the separate confinement layer (SCL) to the p-cladding in 1.5 µm lasers is analysed comparing two structures. One is a regular structure with strained InGaAsP quantum wells and a 1.15 µm emitting InGaAsP SCL and the second one incorporates an additional In 0.81 Ga 0.19 P electron stopper layer (about 50 meV high) at the interface between the p-cladding and the SCL. The results are analysed using comprehensive simulation software. It is shown that the current leakage at the SCL p-cladding interface is not the dominant loss phenomenon at room temperature. Instead, the inhomogeneity of the carrier injection over the QWs is identified as being mainly responsible for the non-unit internal quantum efficiency. The inhomogeneity increases above threshold with the current injection and produces increasing carrier recombination losses. However, at higher temperature (above 60 • C) the additional In 0.81 Ga 0.19 P electron stopper layer is efficient to decrease the electron leakage from the SCL to the p-cladding. It is also shown that besides the beneficial effect of improving the internal quantum efficiency at high temperature the electron stopper layer also slightly increases the threshold current by increasing the carrier density and the absorption loss in the SCL. Finally, our measurements show that above a critical temperature (97 • C in this case) the SCL absorption loss increases dramatically.

Temperature effects on the characterization of new quantum dot dual mode lasers for terahertz generation

“…Where the threshold current is defined by (6), quantum efficiency by (7), and the temperature dependence is included inside to the threshold current as well as in the quantum efficiency. Equation (8) shows that the output optical power of the laser will decrease when the temperature increases.…”

“…In this work, we will study and model the temperature effects on the threshold current density of AlGaAs/GaAs/InGaAs quantum dot diode lasers and its validation with experimental results. The characteristic temperature of QD laser T 0 shows to fall off profoundly with increasing temperature, and where threshold current density is controlled by radiative recombination in the optical confinement layer instead of radiative recombination in QD [7]. Therefore, by controlling the temperature of this new QD laser, we can obtain compact tunable sources in order to get dual mode lasers for mmW and THz generation.…”

Design optimization of InGaAsP–InGaAlAs 1.55 µm strain-compensated MQW lasers for direct modulation applications

“…more wells cannot be added to increase the optical confinement factor, if the hole confinement energy is too large. Auger recombination and electron leakage at high optical power has been shown to be the main carrier loss mechanism in 1550 nm lasers [6][7][8][9]. By aiming for a uniform carrier density in all the wells, the total material gain can be maximized and the non-radiative carrier losses minimized, which is essential to reduce the threshold current and the threshold carrier density in the wells.…”