Calculated voltage characteristics for tunnel junctions in double cavity long-wavelength surface emitting lasers

This work presents a breakdown of the voltage contributions from various parts of the structure. The device layout delimits several key contributors to the total voltage of the device: the voltage due to lateral spreading resistance of the two intracavity contacts, the voltage due to the series resistance of vertical transport through the p-cladding layer, the active region diode, and the tunnel junction (TJ). Since TJs in VCSELs based on the InP material system are still a maturing technology, we focus most of our effort on developing a thorough model for the tunnel junction in hopes of improving our TJ for future VCSEL devices.