The large capacity ultra long haul(ULH) transmission is a very promising technology for future.This paper introduces the research and realization of 16010Gb/s actual 3040km optical fiber transmission system without electronic regeneration in C+L Band.This system uses the channel interval 50GHz

line rate 10.7Gb/s

adopting CSRZ (Carrier-Suppressed Return Zero) as the line code and super FEC(Forward Error Correction)

with OSNR(Optical Signal Niose Ratio) being larger than 15dB.Moreover

in the nationit first achieves successfully 10Gb/s signals in C+L band transmitted in an actual 3040km G.652 fiber line

and in the nationit first employs the C+L board band distributed Raman fiber amplifier on the ULH system

and the system runs error free for continuous 24 hours.These achieved practical significative experimental results offer the experimental foundations for studying the system perfor mances

parameters

characteristics and standards for ULH system applications.