Lasing characteristics of highly bend compensated large mode area ytterbium doped modified hybrid multi trench fiber

Abstract In this article, lasing characteristics of a newly designed ytterbium-doped modified hybrid multi trench fiber (YDMHMTF) has been numerically investigated for strongly pumped conditions. The designed YDMHMTF is maintained single-mode condition with an effective mode area of 1300 μ m 2 at the wavelength of 1064 nm for the compact bending radius of 7.5 cm. The radius of doped region is varied up to a maximum core size of ~19 µm through numerical simulations to achieve maximum conversion efficiency for the straight and bending cases. The effective signal overlap factor is ensured by introducing a high-index arc in the inner trench of fiber along with a maximum doped core region. A 1.5 m length of highly bend LMA YDMHMTF shows slope efficiency of 74% and conversion efficiency of 75% when pumped with a laser source of 975 nm. Further, the high slope efficiency of 81% and conversion efficiency of 80% are achieved with aid of a 2 m length YDMHMTF for the straight and practical bending conditions. Therefore, the proposed YDMHMTF can be utilized to develop an efficient compact laser system suitable for industrial lasing applications. Moreover, the fabrication feasibility of our proposed YDMHMTF becomes easier than the photonic crystal fiber and Bragg fiber based designs.