Athermal 850 nm Vertical Cavity Surface Emitting Lasers with Thermally Actuated Cantilever Structure

We demonstrate the first athermal and tunable operation of 850 nm vertical cavity surface emitting lasers (VCSELs) using a thermally actuated cantilever for compensating the temperature dependence of lasing wavelengths. A novel micromachined air-gap cavity with an anti-reflection Al x O y layer which can be formed by a wet-oxidation process is proposed and fabricated. The temperature dependence is as low as 0.002 nm/K, which is 40 times smaller than that of conventional VCSELs. In addition, the fine wavelength tuning of 0.8 nm is also realized with changing injection current.