Characterization of single-mode laser and tunable laser array based on etched high order surface gratings

Abstract

Wavelength tunable single-mode semiconductor lasers play an essential role in modern optical communication systems. They are also rapidly replacing fixed-wavelength light sources in dense wavelength-division-multiplexing (DWDM) systems, which will significantly reduce the system size and cost. The optical communication industry demands light sources with relatively small volume, low inventory cost and high manufacturing yield process. Therefore, laser diodes along with high power, stable operation and narrow linewidth should have simple fabrication process and high yield. Up to now conventional distributed feedback (DFB) and distributed Bragg reflector (DBR) lasers achieved great success in terms of stable operation, high power and wide tuning range. However, these lasers require complex fabrication steps and high resolution processing by using e-beam lithography which is time consuming and an expensive process. Previously it was demonstrated that single-mode operation can be achieved in Fabry-Perot lasers by introducing reflective defects (slots) at particular locations along the cavity. But in these lasers it is extremely hard to integrate them with other photonic components in one chip due to cleavage of both facets. This work presents cost effective and integrable a new single-mode laser design. These lasers based on etched high order gratings (slots) on one side of the laser cavity to provide enough reflection for lasing to occur. Therefore, no regrowth is needed. This work describes the slotted single-mode laser platform from design to fabrication to experimental characterization.