UC Berkeley

Vertical-cavity surface-emitting lasers (VCSELs) are key optical components used in optical communication, datacom, and many other applications. Recently, as 3D sensing technology has become more popular, VCSEL arrays have attracted more attention. As a result, VCSELs with more advanced and improved performance are needed to satisfy the increasing trend. This is very hard to achieve by traditional VCSELs alone. Therefore, it creates an opportunity for VCSELs to integrate with other optical elements.

Grating is such a traditional optical element but with many unique properties. It has been studied by researchers for a long time. There are many reasons why grating is an ideal candidate for such integration. Besides its various optical properties, its fabrication is usually very simple as well. Therefore, this thesis will focus on different ways that gratings can be integrated with VCSELs to bring novel and unique properties.

First, we will introduce a design toolbox we developed to model such grating structures. With this toolbox, we will demonstrate a novel wavelength tunable VCSEL design. By replacing the traditional VCSEL top mirror by high-contrast grating (HCG) and changing the cavity design, the laser tuning range can be greatly extended. Second, we will discuss a more compact HCG VCSEL architecture by incorporating a low-index oxide spacer. By carefully optimizing HCG design, the highest efficiency HCG VCSEL has been demonstrated. Finally, we will introduce a two-step growth method to fabricate a new grating aperture VCSEL. By replacing the traditional oxide aperture by a grating, large-aperture, single-mode laser can be achieved. In addition, polarization selective emission is also possible. With these three examples, we hope to show the capability of integrating grating structures to VCSELs and pave the road for future VCSEL design.