Razali, Naqiuddin, and Noor Azura Awang. “The Impact of Fiber Length on the Gain and Efficiency of Erbium Doped Amplifier”. Enhanced Knowledge in Sciences and Technology, vol. 5, no. 1, Aug. 2025, pp. 116-24, https://penerbit.uthm.edu.my/periodicals/index.php/ekst/article/view/18676.