50 nm continuously tunable MEMS VCSEL devices with surface micromachining operating at 1.95 micron emission wavelength

An investigation of micro-electro-mechanical-system vertical-cavity surface-emitting lasers at 1.95 ?m emission wavelength grown on InP is presented. The top sided distributed Bragg reflector has been substituted by a dielectric SiOx/SiNy membrane. Its deflection causes a continuous change of emission wavelength due to cavity tuning. The membrane actuation can be achieved in two different ways: by electrostatic attraction and electrothermal expansion. The recently developed surface-micro-machining technique allows both tuning mechanisms on one and the same device. The maximum achieved continuous tuning range is 50 nm with side-mode-suppression-ratios beyond 50 dB over the entire tuning range. Peak optical output powers of 1.0 to 1.8 mW with threshold current densities of 2.2 kA cm-2 will be presented.