Fabrication of first-order gratings for 1.5 μm DFB lasers by high-voltage electron-beam lithography

First-order gratings for 1.5 μm-wavelength distributed-feedback lasers have been fabricated reproducibly in InGaAsP by a combination of electron-beam lithography and wet-chemical etching. A high-voltage electron beam (60 kV) of small diameter (50 nm) is employed in the exposure step.