Concept and numerical simulations of a widely tunable GaAs‐based sampled‐grating diode laser emitting at 976 nm

Abstract

Tunable diode lasers are essential components in various optical systems. The authors present a concept and simulations of a four-section, widely tunable GaAs-based sampled-grating (SG) distributed-Bragg reflector (DBR) laser emitting at 976 nm. This work includes the design approach of the SG reflectors and the simulation of the behaviour of the modes in the active cavity during the wavelength tuning process. Parameters such as the lasing wavelength, threshold current and the gain of the lasing and of the adjacent side modes during the tuning are presented. The numerical results presented suggest a tunability of at least 17 nm, with a threshold current change of only 2.5 mA and single-mode operation over the entire tuning range, without the need of simultaneous adjustments of the phase section. Finally, the authors present early experimental results of a developed GaAs-based vertical structure, providing a high coupling coefficient of $\kappa = 240 \, \hbox{c}\hbox{m}^{ - 1}$κ=240 cm-1, thus suitable for implementation of an SG-DBR laser design.