High performance gratings for DFB-lasers fabricated by direct-write e-beam lithography

摘要

The fabrication of high performance gratings for distributed feedback (DFB) lasers by direct-write (DW) electron-beam lithography (EBL) is presented. This paper starts with a short introduction of the grating theory and various types of gratings commonly used in DFB lasers, laying out resolution requirements and other fabrication challenges. The development and optimization process of the adopted EBL technology is then disclosed to address these challenges. In the end, the state-of-the-art laser performance is demonstrated, validating the technology and also paving ways for more advanced applications in the modern optical networks. We concentrate on grating fabrication technology of DFB lasers for telecommunication applications as the technology has been continuously developed at Fraunhofer Heinrich Hertz Institute (HHI) for more than two decades.