Record Gain of 18-dB for Broadband Single-Model Cr-Doped Crystalline Core Fiber by Small Core Diameter

We demonstrate record gain of 18-dB broadband single-mode Cr-doped crystalline core fiber employing small core diameter. The gain-per-unit-length is 90 dB/m, which is higher than currently achieved Er and Bi-doped fibers of 0.6 - 3 dB/m.