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.

We demonstrated a 9-aperture transmit and single aperture receive FSO system transmitting 35-WDM 400 Gb/s DP-PS-16-QAM signals over 220 m. By splitting the WDM signals into 9 groups, eye-safe transmit power density was enabled.

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We demonstrate the athermal operation and the wavelength tuning of 850 nm GaAs-based vertical cavity surface emitting lasers with a thermally actuated cantilever structure. The thermal actuation of a top distributed Bragg reflector mirror enables us to compensate the temperature drift of lasing wavelengths. The temperature dependence of lasing wavelengths could be controlled from −0.011 nm/K to −0.18 nm/K by changing the cantilever length. In addition, a T-shape membrane structure was introduced for efficient electro-thermal tuning. A small temperature dependence of −0.011 nm/K and wavelength tuning of 4 nm were obtained.