Investigation of bidirectional-pump, power-equalized Raman fiber amplifier with 24 dB gain

In this paper, we demonstrate two configurations (A and B) distributed Raman fiber amplifier (RFA) with near flatten bandwidth of 40 nm in the 1530-1570 nm region. The wavelengths of Raman pumps are 1445 nm and 1470 nm. The dual-pumped Raman amplifier includes two optical isolators, and two 1550/14xx nm WDM couplers. Inside RFA there are dispersion compensation fiber (DCF) fiber integrated single-mode fiber (SMF). The chromatic dispersion of DCF and SMF are -85 and +17 ps/nm-km, respectively, while the attenuation of them are 0.43 and 0.19 dB/km, respectively. For the measurement of polarization dependent gain, the maximum gain of 24 dB is achieved with gain variation of 3.5 dB for configuration A. For gain equalization issue, the gain variation among the 1530-1570 nm is decreased from 8.3 dB to 2.4 dB when appropriately adjust the individual pump power for configuration B. One 10 Gb/s modulated signal is used to confirm the bit error rate performance of RFA. Small power penalty of 0.7 dB is observed.