## 1 Introduction  
Various optical filters with complex target specifications can be applied to various state-of-art technologies, including the superconducting technology, green energy generation/storage technology, and the emerging 5G networks technology [1]. Optical filters consist of a complex multilayer thin film coating using tens or hundreds of layers made of two or more materials [2]. Among the special application fields using optical filters, taxiway lights helping aircraft to move safely and quickly on the ground must emit green light in accordance with international standards [3]. If the color classification of the lights installed on the runway is not clear, a serious aviation accident may occur. Therefore, it is mandatory to use the aviation lighting system emitting green light.  
To meet international standards, optical band pass filters with a high transmittance in the 530 nm wavelength band must be applied. In order to develop an optical band pass filter mounted on taxiway lights among aviation lighting devices, an optical thin film with a transmission performance of more than 95% in the 500-550 nm band was studied. The reliability of lighting devices exposed to the external environment all year round is very important for safety. Therefore, it is very important to select the most durable coating method and materials to produce optical band pass filters with excellent visibility.  
SiO\({}_{2}\) is well known as a low-refractive-index material in optical multilayer systems because of its wide region of transparency from UV to near-infrared wavelengths and superior environmental resistance [2; 4; 5; 6]. Nb\({}_{2}\)O\({}_{5}\) as a high-refractive-index material has been used instead of the more common TiO\({}_{2}\) because of some advantages such as dense microstructures and low optical absorption [7]. To improve its optical properties, Nb\({}_{2}\)O\({}_{5}\) has been selected as a high-refractive-index and low-loss material for optical waveguides, interference filters, and anti-reflection [8]. Nb\({}_{2}\)O\({}_{5}\) as a highly refractive material has been applied by using the plasma-assisted vapor deposition, ion-assisted electron beam evaporation and sputtering methods, etc. [9; 10].  
In this work, Nb\({}_{2}\)O\({}_{5}\) was selected as a high-refractive-index material and SiO\({}_{2}\) was selected as a low-refractive-index material. SiO\({}_{2}\)/Nb\({}_{2}\)O\({}_{5}\) multilayer thin films were designed using the software Essential Macleod (version 11.8.600) on the basis of characteristics such as refractive index, optical constant, and substrate. Nb\({}_{2}\)O\({}_{5}\) and SiO\({}_{2}\) were sputtered to obtain an excellent transmission performance. The structural characteristics of single-layer Nb\({}_{2}\)O\({}_{5}\) and SiO\({}_{2}\) thin films deposited by using a magnetron sputtering were analyzed using an X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). Surface and cross-sectional images were characterized by using scanning electron microscopy (SEM). The surface roughness of 60 layers of SiO\({}_{2}\)/Nb\({}_{2}\)O\({}_{5}\) multilayer thin films was evaluated by atomic force microscopy (AFM). The optical transmittance and reflectance of the SiO\({}_{2}\)/Nb\({}_{2}\)O\({}_{5}\) multilayer thin films was characterized by using a UV-VIS spectrophotometer. Hardness properties of the thin films were measured by using a nanoindenter equipped with a modified Berkovich indenter. The optical transmittance of 60 layers of the SiO\({}_{2}\)/Nb\({}_{2}\)O\({}_{5}\) multilayer thin films was compared with that of commercial products. Finally, the feasibility of the SiO\({}_{2}\)/Nb\({}_{2}\)O\({}_{5}\) multilayer thin films was evaluated for application to taxiway lights.