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) multiwa velength laser array fabricated using near field printing with this ma sk. 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 pr esented. Use of a conventional UV source rather than laser illuminatio n both greatly simplified the printing process and eliminated coherent artifacts from the printed gratings. Chemically etched InP test grati ngs 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 separ ation was 99 GHz which could be further adjusted with a tuning section of the four-section laser design. Characterization of a similar grati ng mask containing 16 wavelengths with similar pitch increments is als o described.