MULTIWAVELENGTH DISTRIBUTED-BRAGG-REFLECTOR LASER ARRAY FABRICATED USING NEAR-FIELD HOLOGRAPHIC PRINTING WITH AN ELECTRON-BEAM GENERATED PHASE GRATING MASK

We describe near optimum near field holography grating masks patterned by e-beam lithography and a distributed Bragg reflector (DBR) multiwavelength laser array fabricated using near field printing with this mask. Grating pitches in the array ranged from 242.861 to 243.750 nm in 0.127 nm steps. Data on the pitch precision and pitch adjustment is presented. Use of a conventional UV source rather than laser illumination both greatly simplified the printing process and eliminated coherent artifacts from the printed gratings. Chemically etched InP test gratings are shown to be extremely ''clean'' in appearance and low in edge roughness. DBR laser arrays designed with 100 GHz frequency separation were processed using the mask described. The measured frequency separation was 99 GHz which could be further adjusted with a tuning section of the four-section laser design. Characterization of a similar grating mask containing 16 wavelengths with similar pitch increments is also described.