Investigation of Bi-Directionally, Dual-Wavelength Pumped Extended L-Band EDFAs

We present numerical and experimental analysis of bi-directionally, dual-wavelength pumped extended L-band erbium-doped fiber amplifiers (EDFAs) that use a standard 1480 nm laser diode as the forward pump source and a high-power C-band light source as the backward pump source. When using a ~1535 nm backward pump, efficient amplification can be obtained over the extended L-band with no penalty to the noise figure. Experimentally, a bi-directionally pumped L-band EDFA achieves a wideband 20 dB-gain, covering 1570-1619 nm, with a noise figure lower than 5.6 dB. With either 1530.7 nm or 1537.8 nm as the backward pump wavelength, and 1480 nm as the forward pump wavelength, the power conversion efficiency is 40% higher compared to a configuration using 1480 nm pumping for both directions. To our best knowledge, it is the first time that C-band light has been used as the backward pump source for extended bandwidth of L-band EDFAs operating beyond 1610 nm.