Sub-MHz Linewidth GaAs/AlGaAs GRIN-SCH-SQW DFB Laser Diodes with First-Order Gratings Fabricated by Electron Beam Lithography

Abstract
Narrow-linewidth GaAs/AlGaAs GRIN-SCH-SQW DFB laser diodes with first-order gratings are reported. The first-order gratings and the GRIN-SCH-SQW structures were fabricated using electron beam lithography and MOVPE. The narrowest linewidth achieved is 730 kHz for a 1 mm cavity length. We also report on problems with gratings fabricated by electron beam lithography.