Single-Frequency 336 W Spliceless All-Fiber Amplifier Based on a Chirally-Coupled-Core Fiber for the Next Generation of Gravitational Wave Detectors

• Published in: Journal of lightwave technology 2022-04, Vol.40 (7), p.2136-2143
• Main Authors: Hochheim, Sven, Brockmuller, Eike, Wessels, Peter, Koponen, Joona, Lowder, Tyson, Novotny, Steffen, Willke, Benno, Neumann, Jorg, Kracht, Dietmar
• Format: Article
• Language: English
• Subjects: Amplifiers; Chirally-coupled-core fiber; Fibers; gravitational wave detector; Gravitational waves; High power lasers; Isolators; Laser beams; Laser modes; Optical components; Optical polarization; Optical pumping; Polyesters; Power generation; Pump lasers; signal and pump combiner
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2021.3133814

Specialty fibers such as chirally-coupled-core fibers show a high potential for further power scaling of single-frequency fiber amplifiers. For the first time, we demonstrate a spliceless all-fiber amplifier, where all optical components are directly integrated in a single Yb^{3+}-doped 3C-fiber. Such a spliceless laser design enables a compact and robust architecture using specialty fibers, while maintaining excellent beam properties. At an output power of 336 W operating at 1064 nm, a fundamental mode content of 90.4% at a polarization extinction ratio above 13 dB was measured without any impact of transverse mode instabilities or other parasitic effects. This work emphasizes the field of applications of 3C-fibers in high-power laser systems.