Integration of microdiffractive lens with continuous relief with vertical-cavity surface-emitting lasers using focused ion beam direct milling

A novel one-step integration of bottom-emitting vertical-cavity surface-emitting laser (VCSEL) (operation wavelength of 980 nm) with microdiffractive lens by means of focused ion beam (FIB) technology is described. A diffractive lens with continuous relief, diameter of 140 μm, and six annulus was designed and fabricated using FIB direct milling on the backside of VCSEL with GaAs substrate for beam collimation. The divergence angle (half angle) of the VCSEL was reduced from 12/spl deg/ before integration of the VCSEL/diffractive optical elements (DOEs) to 0.6/spl deg/ after FIB integration, allowing for an interconnect length of /spl sim/4 mm. It was proven by device testing that there is little influence upon the VCSEL performance after FIB processing.