114 km, repeaterless, 10 Gbit/s transmission at 1310 nm using an RZ data format

There is an increasing interest in 1310-nm optical amplification as more than 50 million km of standard single-mode fiber (SSMF) has been installed worldwide. Consistent developments in the field of 1310-nm optical amplification have resulted in high-gain (>30 dB) polarization-insensitive semiconductor optical amplifiers (SOAs) for optical pre-amplification and high saturation output power (14 dBm) SOA boosters. These devices were implemented in a repeaterless transmission system. Here a DFB laser diode operating at 1310 nm was gain switched at 10 GHz to produce return-to-zero (RZ) pulses of 30 ps at FWHM that were subsequently de-chirped and compressed to 18 ps at FWHM using 4.4 km of dispersion-shifted fiber. After boosting the 10-GHz pulse train up to 10 dBm, the pulse train was modulated with a 10 Gbit/s, 2³¹-1 pseudorandom bit sequence by the LiNbO₃ electro-optic modulator with an extinction ratio of 15 dB. Finally, the signal is boosted up to 12 dBm and launched into 114 km of SSMF (zero dispersion at 1309 nm) with a total attenuation of 42.9 dB. The signal at the output of the second booster did not show any pattern effects. A 400-mA bias current was applied to each of the two boosters. The boosters exhibited a fiber-to-fiber gain of 13.6 dB and 15.4 dB and a 3-dB saturation output power of 16 dBm and 13 dBm, respectively