Cascade vertical cavity surface emitting laser arrays

Summary form only given. One simple approach to achieve cascade laser diodes is to lithographically series connect individual devices. We report the first lithographic cascade VCSEL arrays which exhibit > 100% differential quantum efficiency. We present measurements of the light output into a broad area detector versus injection current into the cascade VCSEL arrays. The output power increases approximately linearly with the number of array elements, and arrays with 4 or more VCSELs exhibit > 100% differential quantum efficiency. These initial results indicate that lithographic cascade VCSEL arrays show promise for low cost optical links.