2-Gbit/s signal amplification at lambda =1.53 mu m in an erbium-doped single-mode fiber amplifier

Abstract

The gain, saturation power, and noise of an erbium-doped single-mode traveling-wave fiber amplifier operating at a wavelength lambda =1.53 mu m are characterized. In continuous-wave (CW) measurements amplification at 2 Gbit/s was demonstrated with up to 17-dB gain for 1*10/sup -9/ bit error rate at 1.531 mu m and a 3-dB full bandwidth of 14 nm. From the determination of the fiber-amplifier's output signal-to-noise ratio versus input signal power during data transmission, it was concluded that, with signal levels used here, signal-spontaneous beat noise limited the receiver sensitivity improvement. With the fiber amplifier acting as an optical preamplifier of the receiver, the best sensitivity was -30 dBm, obtained after installing a polarizer at the fiber amplifier output to reject half of the applied spontaneous emission power. This sensitivity was 6 dB better than without the fiber amplifier, proving that the fiber amplifier can be used as a preamplifier.