Polarization-Stable Wavelength-Tunable Single-Mode Vertical-Cavity Surface-Emitting Lasers with a Monolithic High-Refractive-Index-Contrast Grating Top Coupling Mirror

Vertical cavity surface emitting lasers (VCSELs) are high performance quality and low cost light sources in many optoelectronic components. Polarization stable single mode (SM) emission over a large spectral bandwidth at high ambient temperatures is an important prerequisite for many applications such as microscale atomic clocks, gas sensing, optical coherence tomography, and optical interconnects. At the same time, it is important to maintain a simple and robust VCSEL device design concept. A hybrid monolithic high index contrast grating (MHCG) distributed Bragg reflector (DBR) VCSEL design showing mono-linearly polarized, true single mode (SM) emission over a thermally tuned wavelength range >9 nm and excellent performance at ambient temperatures up to 80 °C is reported. Spectral tuning is achieved solely by intrinsic heating induced by the injection current, offering a low power budget and robust tuning mechanism compared to other wavelength-swept devices, while achieving about double the tuning range of standard single-mode VCSELs. The devices are fabricated by conventional nanoprocessing techniques, and the device architecture exhibits the robustness of standard VCSELs with a simple monolithic one-mesa structure.