Tunable Er3+-doped fiber amplifiers covering S and C plus L bands over 1490-1610 nm based on discrete fundamental-mode cutoff filters

Abstract

We demonstrate thermo-optically tunable Er3+-doped fiber amplifiers covering S and C+L bands (1490-1610 nm) using fundamental-mode cutoff filters discretely located in a 17.5 m long standard Er3+-doped fiber. The material dispersion and waveguide structure of the tapered fibers are locally modified to produce high-cutoff-efficiency filters that make the unwanted amplified spontaneous emission highly attenuated at the longer wavelengths, and the optical gain is thus moved toward the shorter wavelengths. The maximal signal gains are measured to be 18.92, 37.18, and 15.19 dB with 980 mn pump power of 135 mW in the S, C, and L bands, respectively. (c) 2006 Optical Society of America.