A vertical-cavity surface-emitting laser for the 1.55-$\mu$m spectral range with tunnel junction based on $n^{++}$-InGaAs/$p^{++}$-InGaAs/$p^{++}$-InAlGaAs layers

The design of the $n^{++}$-InGaAs/$p^{++}$-InGaAs/$p^{++}$-InAlGaAs tunnel junction (TJ) for 1.55 $\mu$m range vertical-cavity surface-emitting lasers (VCSELs), developed by wafer fusion technique of InAlGaAsP/InP optical cavity with AlGaAs/GaAs distributed Bragg reflectors is proposed and realized. The presence of oxidation-resistant InGaAs layers allows the use of molecular-beam epitaxy at all stages of the heterostructure fabrication, including for regrowth of the TJ surface relief. In the case of using the $n^{++}$-InGaAs/$p^{++}$-InGaAs/$p^{++}$-InAlGaAs TJ, a noticeable increase in the internal optical losses compared to the $n^{++}/p^{++}$-InAlGaAs TJ design was not obtained. The increase in internal optical loss in lasers can be avoided due to Burshtein–Moss effect in $n^{++}$-InGaAs layers and thickness minimization of $p^{++}$-InGaAs layer. As a result, the characteristics of fabricated lasers are comparable with characteristics of VCSELs with $n^{++}/p^{++}$-InAlGaAs TJ with a similar level of mirror losses.