Gain improvement in L-band double-pass EDFA with incorporated CFBG

We report a gain improvement of L-band double-pass erbium-doped fiber amplifier (EDFA) by incorporating chirped fiber Bragg grating (CFBG). CFBG has been used to compensate the effect of single mode fiber (SMF) dispersion, reflect the amplified signal back into the gain medium for double pass amplification and block the residual 1480 nm pump power and the recycled forward amplified spontaneous emission. A practical comparative is conducted to compare the performance of the double-pass EDFA formed by CFBG and an optical mirror. The input signal is connected to lengths of transmission fiber before it enters the amplifier. The gain improved to about 9 dB and the maximum gain obtained from the experiment is 51.5 dB with noise figure of about 4 dB.