Modulational Instability and Parametric Amplification Induced by Loss Dispersion in Optical Fibers

Abstract

We show that modulational instability may arise even in the normal group-velocity dispersion regime of an optical fiber when the fiber loss (gain) varies depending on the wavelength. A simple analytical expression for the instability gain is obtained, which reveals that the odd-order terms of the loss dispersion are responsible for this phenomenon. The instability gain is measured experimentally in an optical-parametric-amplification configuration. Large parametric gain is induced in a non-phase-matched regime as we apply narrow band loss at the idler wavelength.

Modulation instabilities in asymmetric nonlinear fiber coupler

“…Many nonlinear systems exhibit modulation instability (MI), when weak perturbations imposed on the continuous waves (CWs) grow exponentially, as a result of the interplay between dispersive and nonlinear effects [1][2][3]. In the context of optical fibers, MI exists in the anomalous dispersion regime and manifests itself as the breakup of CWs into a train of short pluses [1].…”

“…With additional physics, MI also occurs in the normal dispersion regime, e.g. by the cross phase modulation effects [4], in the presence of even higher-order dispersion [5], and loss dispersion [3]. For temporal pulse propagation in a single-mode optical fiber, governed by the nonlinear Schrödinger equation, the relevant factors are cubic (Kerr) nonlinearity and group velocity dispersion (GVD).…”

Modulation instabilities in two-core fiber coupler

“…Many nonlinear systems exhibit modulation instability (MI), when weak perturbations imposed on the continuous waves (CWs) grow exponentially, as a result of the interplay between dispersive and nonlinear effects [1][2][3]. In the context of optical fibers, MI exists in the anomalous dispersion regime and manifests itself as the breakup of CWs into a train of short pluses [1].…”

“…With additional physics, MI also occurs in the normal dispersion regime, e.g. by the cross phase modulation effects [4], in the presence of even higherorder dispersion [5], and loss dispersion [3]. For temporal pulse propagation in a single-mode optical fiber, governed by the nonlinear Schrödinger equation, the relevant factors are cubic (Kerr) nonlinearity and group velocity dispersion (GVD).…”

Modulational instability in metamaterials with saturable nonlinearity and higher-order dispersion

“…Although in the normal GVD regime, MI may be possible. It is limited to some special cases, such as in the presence of higher even-order linear dispersions [13][14][15][16] or loss dispersion [17], in the case of copropagation of two or more optical fields in the optical fiber [18], or in a ring cavity configuration [19].…”