Coherent transverse coupling in 2×2 arrays of defect cavities in photonic crystal (PhC) vertical cavity surface emitting lasers (VCSELs) is reported. Modification of the effective index and optical loss by design of the photonic crystal hole pattern results in evanescent coupling between the multiple defect cavities of a PhC VCSEL. Fabrication processes for these devices are discussed. Far field measurements are utilized to demonstrate both the out-of-phase and in-phase results. Room temperature continuous wave operating characteristics for the devices are provided, and a quantitative description of the coherently coupled operation is presented. The resulting agreement between the simulated and observed far fields is shown.
Photonic crystal confinement in vertical cavity surface-emitting lasers (VCSELs) is a robust and reliable technology for achieving operation in the fundamental lateral mode and is potentially applicable to a variety of materials systems and operating wavelengths. We demonstrate photonic crystal VCSELs operating in a single transverse mode with over 30 dB side mode suppression and over 1 mW of output power. These lasers have been subjected to a post-process technique to introduce the etched holes making up the photonic crystals that surround a centralized defect in which lasing occurs. We also show that coupling between adjacent defects in a photonic lattice is possible, further increasing the power available in the devices.