Highly Uniform Fabrication of Diffraction Gratings for Distributed Feedback Laser Diodes by Nanoimprint Lithography

Abstract

We have used a nanoimprint technique to fabricate diffraction gratings of distributed feedback laser diodes (DFB LDs) used in optical communication. We have aimed to establish the fabrication process featuring the high reproducibility of the period and linewidth of grating corrugations, which leads to an increase in the production yield of DFB LDs. The combination of the reverse tone nanoimprint and optimized etching techniques has contributed to the improvement of the reproducibility. The variation in grating period has been less than 0.2 nm and the variation in linewidth has been less than 10 nm over the six wafers. The results of this study indicate that our fabrication process for the diffraction gratings utilizing the nanoimprint technique has a high potential for the fabrication of DFB LDs.