Record Gain of 18-dB for Broadband Single-Model Cr-Doped Crystalline Core Fiber by Small Core Diameter. - Kai-Chieh Chang; Chia-Ling Tsai; Wei-Chih Cheng; Zon; Chun-Nien Liu; Tien-Tsorng Shih; Sheng-Lung Huang; Charles W. Tu; Wood-Hi Cheng (OFC, 2023)