A group at Corning Incorporated (Corning, NY) has demonstrated ultralong-haul fiber-optic transmission spanning more than 10,000 km in two different experiments—both of which involve 112 Gbit/s non-return-to-zero polarization-multiplexed quadrature phase-shift keying (NRZ-PM-QPSK) signals; 40 channels; all-Raman amplification; and ultralow-loss, large-effective-area optical fibers. The first transmission consisted of 100 km spans and a fiber with an effective area of 112 microns square, and achieved a reach length of 10,228 km. The second transmission experiment had 75 km spans and a fiber with an effective area of 134 microns square, and attained a reach length of 13,288 km.
The fiber employed for the first experiment was the company’s commercially available Vascade EX 2000 fiber, which has an average attenuation of 0.163 dB/km. For the second experiment, Corning created a new prototype version of the Vascade fiber; while no attenuation-per-length data was given, the 75.5 km spans each had an average loss, including connectors, of 12.86 dB. The receiver contained a tunable optical filter, a polarization- and phase-diverse digital coherent receiver, analog-to-digital converters (ADCs), and a computer to process the sampled waveforms using standard algorithms. The system is intended for transoceanic use. Contact John Downie at [email protected].
