20-nm consecutive discrete tuning range semiconductor laser with 125 GHz channel spacing based on slotted surface grating fabricated by standard lithography

Abstract

A widely tunable semiconductor laser based on slotted surface grating is presented. This regrowth-free tunable semiconductor laser is fabricated by contact i-line lithography rather than electron beam lithography. The fabrication process of this tunable laser is similar to Fabry-Pèrot lasers, which can simplify the fabrication. The tunable semiconductor laser achieves a 20-nm consecutive discrete tuning range with a 125 GHz channel spacing at 25 °C, which is, to the best of our knowledge, the highest consecutive discrete tuning range in such a channel spacing for this kind of four-section tunable semiconductor laser fabricated without electron beam lithography. This tunable semiconductor laser can be widely used in the applications such as wavelength-division-multiplexing systems and optical routing systems.