Removing Thermal Gain–Cavity Detuning Effect Based on Supergain Quantum Well–Wire Hybrid Nanostructures for Single-Frequency Laser Diodes

Abstract

It is well-known that thermal detuning between the gain peak and the cavity mode always occurs and leads to considerable gain loss in single-frequency laser diodes. For this issue, scientists have not found an effective solution so far. In this article, we propose an approach to addressing this problem effectively. It is associated with a fundamental change of the quantum structure to acquire a supergain spectrum (i.e., both wide and uniform gain distribution) by means of the self-assembled quantum well−wire hybrid nanostructure. With the supergain spectrum, the cavity mode can constantly obtain the max gain over a wide temperature range with a very small gain fluctuation of <4 cm −1 . The simulation of an InGaAs vertical-cavity surface-emitting laser (VCSEL) model shows that the effective gain that the cavity mode can obtain is increased by >202% and the threshold pump power is reduced by >38.9% accordingly when the device temperature is higher than 360 K, in comparison to the performance of a pure quantum well. Therefore, this demonstrates great superiority for removing the gain−cavity detuning effect and improving the high-temperature performance of single-frequency laser diodes.