GaAs microlens arrays grown by shadow masked MOVPE

This paper describes the fabrication of high quality GaAs microlenses and microlens arrays using shadow masked metalorganic vapor phase epitaxial (MOVPE) growth (SMMG). Microlenses with apertures as small as 30 µm were fabricated and focal lengths down to 40 µm were measured. The smaller lenses closely fit the theoretical behavior of ideal spherical lenses while larger lenses (focal length >80 µm) showed a more complex physical shape and could not be modeled as spherical. This deviation from a spherical shape is expected from simulation of SMMG. The full width at half maximum of the beam waist was <2 µm for all sizes of microlens indicating that these lenses are compatible with coupling to single mode fibers.