We present a phase mask inscription technique with two beam interferometry using a lateral non-homogeneous beam splitter to create gratings with non-homogeneous periods, so-called chirped fiber Bragg gratings. Inscription experiments with deep ultraviolet excimer and femtosecond laser sources reveal how this inscription method depends on the coherence properties of the inscription laser. Non-homogeneous beam splitters are shown to provide a method to generate chirped fiber Bragg gratings with great wavelength versatility, even with the ultraviolet femtosecond laser.