Tuning Characteristics of Monolithic MEMS VCSELs With Oxide Anti-Reflection Layer

We demonstrate a micromachined tunable vertical-cavity surface-emitting laser with a monolithically formed anti-reflection (AR) layer for highly efficient electro-thermal wavelength tuning. The AR layer is formed by the lateral oxidation of an aluminum-rich AlGaAs layer and no extra process is needed. We fabricated a micromachined GaAs vertical-cavity surface-emitting laser and measured its wavelength tuning characteristic. The measurement result shows that the oxide layer functions as an AR layer for linear and efficient tuning characteristics. A large negative temperature dependence of wavelength from -0.24 to -2.0 nm/K was demonstrated using a thermally actuated cantilever for efficient electro-thermal wavelength tuning. An electro-thermal tuning efficiency of -2.3 to -4.8 nm/mW was obtained.