Research of the Spectral Characteristics of Apodized Fiber Bragg Gratings Maksat Kalimoldayev, Aliya Kalizhanova, Waldemar Wójcik, Gulzhan Kashaganova, Saltanat Amirgaliyeva, Azhibek Dasibekov, Ainur Kozbakova and Zhalau Aitkulov ITM Web Conf., 24 (2019) 01015 Published online: 01 February 2019 DOI: 10.1051/itmconf/20192401015