Erbium-Doped Fiber Amplifiers: Principles and Applications

Mode-locked laser pulse sources for wavelength division multiplexing

“…Such theoretical findings are in agreement with experimental efforts in WDM systems to enhance the inhomogeneous gain broadening for stabilizing lightwave systems. 19 For dual-frequency operation, the transition in mode-locking stability as a function of the parameter α is completely characterized by a center manifold reduction when the largest eigenvalue passes through zero. The center manifold reduction shows the fundamental bifurcation structure at the stability transition to be a supercritical pitchfork bifurcation.…”

“…However, it is known that in such a multi-frequency, broadband scenario, two gain effects are present: homogeneous gain broadening and inhomogeneous gain broadening. 19 Qualitatively, the homogeneous gain broadening effect amplifies all frequencies equally. Thus in a multi-frequency scenario, all frequency channels would act to saturate the erbium optical amplifier.…”

“…19 Thus given the absence of a comprehensive experimental study of the degree of homogeneous to inhomogeneous gain broadening, it is difficult to estimate the parameter α. However, provided there is only a small amount of inhomogeneous gain broadening, it will be shown that the laser cavity can support stable multi-frequency operation.…”

“…This is in agreement with the effort to use enhanced inhomogeneous gain broadening for gain equilization in WDM systems. 19 As with WDM systems, the multifrequency mode-locking stability is greatly influenced by enhancing the inhomogenous gain broadening.…”

“…This is consistent with numerical simulations 11,12 and efforts to enhance inhomogeneous gain broadening in WDM system. 19 The fixed points P 2 = (η, 0) and P 3 = (0,η) represent single-channel operation. Due to the symmetry of (6), the linear stability analysis for P 2 is the same as for P 3 , thus allowing us to only consider P 2 .…”