Abstract

The market for high capacity unrepeatered transmission systems has been growing steadily for several years. Wavelength division multiplexing with large channel numbers and high channel bit rates is a prerequisite for cost-effective future solutions for island hopping and festoon applications. Remotely pumped amplifiers are particularly attractive, since they can provide improved OSNR performance by adding signal gain in the transmission fiber. Different approaches have been investigated for improving 40 Gb/s line rate system performance: utilization of large effective area fibers, distributed Raman amplification, remote Erbium-doped fiber amplifiers (EDFAs) in the C-band, use of separate fibers for remotely pumped EDFAs, polarization interleaving, and use of bandwidth limited signals.^1–4 Presently the record capacity for systems with transmission distances >200 km is 2.56 Tb/s (64 × 40 Gb/s over 230 km, ¹ and the highest 40 Gb/s unrepeatered transmission distance is 306 km.² Here we report on a new pump scheme which allows for the first time high capacity transmission in the C and L band over unrepeatered distances > 200 km.

© 2002 Optical Society of America