Large-mode-area multicore Yb-doped fiber for an efficient high power 976 nm laser

• Main Authors: Li, Huizi, Zang, Jichao, Raghuraman, Sidharthan, Chen, Shaoxiang, Goel, Charu, Xia, Nan, Ishaaya, Amiel A., Yoo, Seongwoo
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Electrical and electronic engineering; Optical Constants; Optics
• Online Access: https://hdl.handle.net/10356/162471
• Institution: Nanyang Technological University

We present an efficient 976 nm laser generation from an ytterbium (Yb)-doped step-index multicore fiber (MCF) with six cores placed in a ring shape. Each of the six cores has a large-mode-area (LMA) and a low numerical aperture (NA), which makes the MCF equipped with the features of a large core-to-cladding area ratio and differential bending loss for wavelength and mode selection. Hence, the Yb-doped MCF benefits 976 nm laser generation by simultaneously suppressing unwanted 1030 nm emission and higher-order modes (HOMs). A 976 nm laser is obtained in a short piece (88 cm) of the Yb MCF, with a good slope efficiency of 46% with respect to launched pump power and the maximum output power of 25 W (pump power limited). A mode area of 1432 µm2 at the 976 nm is expected for the fundamental in-phase mode.