Optoelectronic devices with tunable optical mode and carrier distribution in the waveguides

Abstract

Solid-state optical devices () enable tuning of an electrically tunable depletion region () to reduce and block lateral (in-junction) carrier spreading. This capability reduces the negative effects of gain-guiding in the junction plane and reduces an astigmatism of an emitted light beam. The tunable depletion region is created by forming a highly resistive Schottky contact () or metal-insulator-semiconductor (MIS) structure () next to a waveguide (optical mode propagation) and current injection region (), where lateral spread due to diffusion is expected. The depletion region area is tuned by applying a bias to the highly resistive Schottky contact or the MIS contact structure. Such contacts or similar lossy structures reduce in-junction plane gain-guiding also when unbiased by creating additional optical loss for the mode, thus reducing the effective carrier density participating in light generation, thereby reducing astigmatism.