• ETRI Journal
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• v.24 no.2
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• pp.81-96
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• 2002

This paper describes our design of a hybrid amplifier composed of a distributed Raman amplifier and erbium-doped fiber amplifiers for C- and L-bands. We characterize the distributed Raman amplifier by numerical simulation based on the experimentally measured Raman gain coefficient of an ordinary single mode fiber transmission line. In single channel amplification, the crosstalk caused by double Rayleigh scattering was independent of signal input power and simply given as a function of the Raman gain. The double Rayleigh scattering induced power penalty was less than 0.1 dB after 1000 km if the on-off Raman gain was below 21 dB. For multiple channel amplification, using commercially available pump laser diodes and fiber components, we determined and optimized the conditions of three-wavelength Raman pumping for an amplification bandwidth of 32 nm for C-band and 34 nm for L-band. After analyzing the conventional erbium-doped fiber amplifier analysis in C-band, we estimated the performance of the hybrid amplifier for long haul optical transmission. Compared with erbium-doped fiber amplifiers, the optical signal-to-noise ratio was calculated to be higher by more than 3 dB in the optical link using the designed hybrid amplifier.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6B
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• pp.568-574
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• 2009

320km optical transmission link for 128 channel DWDM (dense wavelength-division-multiplexing) signals is simulated and fabricated. An optical fiber amplifier for the link is composed of a distributed Raman amplifier and dual C/L-band EDFAs which are optimized for the performances of an optical amplifier obtained from the simulation. Gain and NF of the optimized EDFAs are above 19dB and below 7.5dB, respectively. The resultant OSNRs (optical signal to noise ratios) of the link are average 25dB on each band.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.66-67
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• 2002

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.712-718
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• 2004

We report 1.6 Tb/s (160${\times}$10 Gb/s) WDM transmission over 2,000 km of single mode fiber using distributed hybrid(distributed Raman amplifier＋Erbium-doped fiber amplifier) optical amplifiers. After transmission over 2,000 km of single mode fiber, average optical signal to noise ratios of C/L-band were 20.5 dB, 21.9 dB, respectively. The minimum Q-factors of each band were 14.65 dB (BER=5.8e-8) in C-band, 13.75 dB (BER=5.0e-7) in L-band without forward error correction. We performed 1.6 Tb/s error-free transmission over 2,000 km of single mode fiber using Reed-Solomon (255, 239) forward error correction code.