Gain and Threshold Improvements of 1300 nm Lasers based on InGaAs/InAlGaAs Superlattice Active Regions

TL;DR

This paper presents an experimental analysis of InGaAs/InAlGaAs superlattice active regions in 1300 nm lasers, demonstrating improved performance metrics such as low internal loss, high efficiency, and enhanced temperature stability.

Contribution

It introduces specific superlattice designs that enhance laser performance at 1300 nm, including temperature stability and efficiency improvements.

Findings

Low internal loss (~6 cm^{-1}) observed.

High internal efficiency of 53% achieved.

Improved characteristic temperatures T_0 and T_1 up to 76 K and 100 K.

Abstract

A detailed experimental analysis of the impact of active region design on the performance of 1300 nm lasers based on InGaAs/InAlGaAs superlattices is presented. Three different types of superlattice active regions and waveguide layer compositions were grown. Using a superlattice allows to downshift the energy position of the miniband, as compared to thin InGaAs quantum wells, having the same composition, being beneficial for high-temperature operation. Very low internal loss (~6$cm^{-1}$), low transparency current density of ~500$ A/cm^2$, together with 46$ cm^{-1}$ modal gain and 53 % internal efficiency were observed for broad-area lasers with an active region based on a highly strained $In_{0.74}Ga_{0.26}As/In_{0.53}Al_{0.25}Ga_{0.22}As$ superlattice. Characteristic temperatures $T_0$ and $T_1$ were improved up to 76 K and 100 K, respectively. These data suggest that such superlattices have also the potential to much improve VCSEL properties at this wavelength.