1.58-μm broad-band erbium-doped tellurite fiber amplifier

This paper describes the development of a 1.58-μm broad-band and gain-flattened erbium-doped tellurite fiber amplifier (EDTFA). First, we compare the spectroscopic properties of various glasses including the stimulated emission cross sections of the Er³⁺⁴ I₁₃2/ ⁴I₁₅2/ transition and the signal excited-state absorption (ESA) cross sections of the Er³⁺⁴ I₁₃2/ - ⁴I₉2/ transition. We detail the amplification characteristics of a 1.58-μm-band EDTFA designed for wavelength-division-multiplexing applications by comparing it with a 1.58-μm-band erbium-doped silica fiber amplifier. Furthermore, we describe the 1.58-μm-band gain-flattened EDTFA we developed using a fiber-Bragg-grating-type gain equalizer. We achieved a gain of 25.3 dB and a noise figure of less than 6 dB with a slight gain excursion of 0.6 dB over a wide wavelength range of 1561-1611 nm. The total output power of the EDTFA module was 20.4 dBm and its power conversion efficiency reached 32.8%.