E-PSCF, third-order Raman pumps, remotely-pumped amplifier, NRZ-DPSK transmitter and receiver are used to realize a record 485 km long unrepeatered transmission of 4 WDM channels at 43 Gb/s.

An error-free transmission experiment in bidirectional unrepeatered configuration over 436 km is reported. Particular attention has been paid to Rayleigh backscattering and distributed Raman amplification, enabling us to cover 77 dB span loss.

We demonstrate the relationship between coating temperature and fiber lifetime when high power is launched in lightly bent fibers. Coating temperature at the bend can thus be used as a relevant indicator for fiber reliability

Unrepeatered transmission of 12 channels at 10 Gbit/s over a record distance of 500 km is demonstrated taking advantage of ultra-large effective area fibre combined with a novel remote amplification scheme.

Raman amplification is a key technology for unrepeatered transmissions as it allows to widely increase both span length and optical bandwidth in a very simple manner. We review in this paper recent record demonstrations and installed systems where Raman amplification fulfills its role as a mean to reach very long repeaterless distances and to expand into new spectral areas. (C)2002 Optical Society of America.