Development of thermally stable glass from SiO 2 -Bi 2 O 3 -PbO-ZnO-BaO oxide system suitable for all-solid photonic crystal fibers Jaroslaw Cimek a, b , Ryszard Ste˛ pie  n a , Mariusz Klimczak a , Izabela Zalewska a , Ryszard Buczy  nski a, b, * a Institute of Electronic Materials Technology, W olczy nska 133, 01-919, Warsaw, Poland b Faculty of Physics, University of Warsaw, Pasteura 7, 02-093 Warsaw, Poland article info Article history: Received 28 May 2017 Received in revised form 14 July 2017 Accepted 18 August 2017 Keywords: Multicomponent glass Glass synthesis Hydroxyl groups Absorption coefficient Photonic crystal fiber abstract The series of SiO 2 -Bi 2 O 3 -PbO-ZnO-BaO and SiO 2 -TiO 2 -Bi 2 O 3 -PbO-Na 2 O glasses were synthetized to obtain non-crystallizing materials, dedicated to fabrication of photonic crystal fibers. During composition development, the thermal properties were investigated according to the change of chemical composi- tion. The glasses contain high concentrations of heavy metal oxides for high refractive index, large nonlinear refractive index and spectrally broad transmission window from 0.5 to 4.5 mm. Their thermal properties are optimized to enable drawing of all-solid glass photonic crystal fibers in tandem with previously designed highly nonlinear glass PBG81 based on SiO 2 -Ga 2 O 3 -Bi 2 O 3 -PbO-CdO system. This creates novel dual glass combinations for PCF fibers. We have also investigated influence of melting conditions on the final thermal and optical properties, including absorption from water contamination at around 2.8 mm. © 2017 Published by Elsevier B.V. 1. Introduction Multicomponent silicate glasses have been among the key ma- terials in optoelectronics and photonic systems for over the two past decades, both in free-space, bulk optical components and in fiber optics [1e3]. In particular, they are used for drawing of optical fibers dedicated to nonlinear optics applications and for their extended infrared transmission compared to silica fibers [4]. Versatility of multicomponent glasses in designing of properties allows fabrication of all-solid PCFs where air holes are replaced with another glass. This approach opens up an additional degree of freedom in engineering of modal and dispersion properties of the PCF [5,6]. To the day all-solid glass PCFs have been fabricated from various glasses including silica [7] and multicomponent glasses, such as phosphate [8], tellurite [9], chalcogenide [10,11] or silicate glasses [12]. Phosphate glasses are desirable for lasing applications due to low refractive index and low attenuation, combined with the ability to incorporate high concentration of rare earth ion dopants [13,14]. While tellurite and chalcogenide glasses are favorable for nonlinear and mid-infrared applications [15e19], tellurite glasses can be also used for lasing applications [20]. The potential of silicate glasses to attain various thermal and optical properties makes them ideal for all-solid glass PCFs, both for lasing [21,22] and for nonlinear optics [23]. The capability to incorporate into the silicate glass matrix various oxides enables great variety of combinations to obtain specific relationship of optical and thermal properties. As for fabrication of all-solid glass optical fiber microstructures, it is essential to match thermal expansion coefficients and tempera- tures of processing in the two materials. This can be achieved by chemical composition designing [24]. Compared to other systems based on boron, germanium and tellurium, silicate glasses offer the best to obtain non-crystallizing optical materials, which can be processed many times without change of the internal structure and allowing fabrication of complex fiber structures. Proper design of composition and properties of materials enables also a combination of glasses from different oxide systems in one microstructured fiber lattice. For example, borosilicate glass can be combined within a single fiber with lead-silicate [24], and tellurite with germanate [25] or with phosphate glasses [26]. This presents progress since the first reports on all-solid glass fibers made from germanium doped fused silica and lead-silicate glasses [5,27]. Nowadays glasses are designed to obtain target properties like nonlinearity, refractive * Corresponding author. Institute of Electronic Materials Technology, W olczy nska 133, 01-919, Warsaw, Poland. E-mail address: rbuczyns@igf.fuw.edu.pl (R. Buczy nski). Contents lists available at ScienceDirect Optical Materials journal homepage: www.elsevier.com/locate/optmat http://dx.doi.org/10.1016/j.optmat.2017.08.028 0925-3467/© 2017 Published by Elsevier B.V. Optical Materials 73 (2017) 277e283