Analysis of the internal optical losses of the vertical-cavity surface-emitting laser of the spectral range of 1.55 $\mu$m formed by a plate sintering technique

The results of a study of internal optical losses and current injection efficiency in vertical-emitting lasers of a spectral range of 1.55 $\mu$m obtained by sintering plates of high-q Bragg reflectors and the active region on the basis of thin strained InGaAs/InAlGaAs quantum wells have been presented. It has been shown that the proposed design of the laser provides a record low level of internal optical losses (less than 6.5 cm$^{-1}$) and high efficiency of current injection (more than 90%) at room temperature, which allows the realization of submilliampere threshold currents. As the temperature rises to 85$^{\circ}$C, the current injection efficiency drops to 70% due to the thermal emission of charge carriers from the active region, accompanied by an increase in internal optical losses to 9.1 cm$^{-1}$ because of an increase in absorption on free carriers and/or intersubband absorption in the valence band.