A Steady-Gain C-band EDFA for Multi-Wavelength Fiber Optical Transport Networks

A steady-gain C-band Erbium-doped fiber amplifier (EDFA) is proposed to assist the transmission performance in multi-wavelength long-distance fiber optical transport networks. Different from the published gain-clamped EDFAs which utilize an in-line device to steady their performance in L-band, this proposal is focusing on the C-band and is employing an off-line feedback lightwave technique to clamp the gain variation. The effect of the off-line technique is theoretically studied and the outcomes are employed to optimize the proposed technique. simulation results show that when a saturated optical carrier and 14 individual tested optical carriers located from 1530 nm to 1565 nm are inserted in to the proposed EDFA, the maximum gain variation for the 14 normal optical carriers are efficiently reduced from 2 dB to 0.11 dB. Almost 20 times improvement in the gain stability is achieved to practically eliminate the accumulated power variation caused by the cascaded in-line EDFAs in a long distance fiber optical link. This achievement will greatly ensure the overall transmission performance and will significantly assist a system provider to estimate the power budget in each link.