Recent advancements in femtosecond laser inscribed waveguides in germanate glass for ∼ 2.1 µm laser applications

Abstract

The realization and integration of high-power and high-speed microscale functionalities on a single chip have been made possible through the revolutionizing field of Photonics. This next generation monolithic technology emphasizes on efficient and cost-effective fabrication of the miniaturized photonic devices with high degree of accuracy. For such monolithic devices small cavity, single frequency laser sources (waveguide lasers) are of immense importance. Multiple techniques have been utilized for the inscription of waveguides in the laser gain media. Femtosecond laser direct writing (FLDW) is an emerging technique for rapid inscription of highly symmetrical and high-quality 3D guiding structures in substrates with low propagation loss. In this article, we present a review on the latest developments around femtosecond laser inscribed waveguides in an emerging germanate glass (in contrast to the commercially available and exotic transparent media) for short to mid-IR laser applications.