“Transmission Spectrum Shifting By Varying Ambient Refractive Index in LPFG”. Al-Rafidain Engineering Journal (AREJ) 20, no. 2 (April 1, 2012): 131–139. Accessed September 12, 2026. https://rengj.uomosul.edu.iq/index.php/rengj/article/view/30708.