Optimal Design of Optically Gain-Clamped L-band Erbium-Doped Fiber Amplifier by Fiber Bragg Grating Method

摘要

We theoretically investigated the optimal design of optically gain-clamped (GC) L-band (1570-1610 nm) erbium-doped fiber amplifier (EDFA), in order to control the EDFA gain to ensure that the gain does not vary markedly in the presence of the add/drop of optical channels. It used a single fiber Bragg grating (FBG) on the input or output end of the erbium-doped fiber (EDF) to inject a portion of the amplified spontaneous emission (ASE) back into the system. The FBG center wavelengths (λ_B) at either 1565 or 1610 nm for optically gain-clamped operation of such L-band GC-EDFAs were examined. In addition, the different FBG bandwidths (Δλ_B) for such L-band GC-EDFAs were compared. From the good gain-clamping capability point of view, the input-end FBG of 1565 nm center wavelength together with 4 nm bandwidth is the best choice for obtaining large gain-clamping dynamic ranges of good channel gain variation (ΔG) and fairly low noise figure characteristics.