Wafer-level fabrication of distributed feedback laser diodes by utilizing UV nanoimprint lithography

Abstract

The authors have succeeded in employing nanoimprint lithography (NIL) to form diffraction gratings of distributed feedback laser diodes (DFB LDs) used in optical communication. We have fabricated more than 300 phase-shifted DFB LDs on a 2-in. InP substrate. The devices have indicated comparable characteristics including uniformity and reliability with those fabricated by conventional electron beam lithography. We have also demonstrated a novel concept of a mold containing various types of grating patterns in a field (VARI-mold). By utilizing the new mold, DFB LDs with various emission wavelengths are formed simultaneously on a wafer. It indicates that one VARI-mold is possible to be applied to various kinds of product, leading to the cost reduction of the molds and the total NIL process. The results of this study indicate that NIL is a promising candidate of the production technique for phase-shifted DFB LDs featuring low cost and high throughput.