Suppressing 1.06-μm spontaneous emission of neodymium ions using a novel tellurite all-solid photonic bandgap fiber

In order to take advantage of the 1.3-mu m emission of neodymium (Nd3+) ions for many practical applications, we propose a tellurite all-solid photonic bandgap fiber (ASPBGF) to filter out the competing emission at 1.06 mu m which is most prominent in the emission spectrum of Nd3+ ion. A novel Nd3+-doped tellurite ASPBGF is fabricated by using our developed tellurite glasses which have high compatibility of thermal properties and their refractive index difference is 0.096 at 1320 nm. The fiber is designed with 4 layers of high-index rods to have low confinement loss. The measured transmission spectrum of a 2.2-cm-long section of the fabricated fiber exhibits high transmission bands near 0.75 and 1.33 mu m (about -20 dB and -19 dB) and a low transmission band in the vicinity of 1.06 mu m which is about -27 dB. By using our fabricated Nd3+-doped tellurite ASPBGF, it is demonstrated for the first time that the 1.06-mu m emission peak due to the F-4(3/2) -> I-4(11/2) transition of Nd3+ ions is greatly suppressed about 12 times as compared to that obtained by using a bulk samples with the same doping concentration. (C) 2018 Elsevier B.V. All rights reserved.