Stable in Phase Mode Operation in Coherent VCSEL Array With an Integrated Phase Shifter
Implant defined coherent vertical cavity surface emitting laser (VCSEL) arrays with an integrated phase shifter that can convert the out of phase mode into the in phase mode were demonstrated. The measured angular full width at half maximum (FWHM) from a <inline formula> <tex math notation="LaTeX"{9} \times {9} /tex math>/inline formula> coherent VCSEL array in the far field lobes is only 0.82deg. The intensity of the central lobe is about 2.9 times than that of surrounding sidelobes, showing excellent beam quality. The FWHM of the spectrum of a <inline formula> <tex math notation="LaTeX"{9} \times {9} /tex math>/inline formula> array is only 0.02 nm, showing a single mode operation. It provides a potential method to fabricate larger in phase coherent VCSEL arrays. A remaining challenge is enhancing output power via solving the heat problem.
IEEE Transactions on Electron Devices