Wideband Unrepeatered Transmission Using Doped Tellurite-Fiber Amplifiers

This work evaluates the use of wideband erbium-doped tellurite-fiber amplifiers (EDTFAs) for unrepeatered links. We demonstrate the transmission of a 40.5 Tb/s signal composed of 290 polarization-multiplexed 16-ary quadrature amplitude modulated channels spread across a continuous 60 nm band over a distance of 312 km. The transmission band is centered at the lowest loss wavelength of the link, 1575.7 nm, partially spanning the C and L bands. The unrepeatered system uses exclusively EDTFAs for wideband signal generation, transmission and receiver preamplification. Furthermore wideband distributed bidirectional Raman amplification is used to partially compensate the link losses. We evaluate the dependence of the optical signal-to-noise ratio, Q-factor and throughput on the launch power. The highest throughput is achieved at the maximum launch power of 18 dBm and, to date, is the highest throughput for unrepeatered systems over 300 km.