MEMS-tunable 1.55-μm VCSEL with extended tuning range incorporating a buried tunnel junction

We present an electrically pumped and micromechanically tunable InP-based vertical-cavity surface-emitting laser operating in the 1.55-μm wavelength range. The current confinement is achieved by a buried tunnel junction. The GaAs-based movable top mirror membrane is fabricated separately, assembled on top of the device, and can be actuated electrothermally. A single mode output power of about 1.7 mW and a tuning range of 28 nm was obtained. By the use of an antireflection coating at the semiconductor-air-interface, we were able to extend the tuning range up to 60 nm as expected from one-dimensional simulations.