Experimental demonstration of modulation instability in an optical fiber with a periodic dispersion landscape

Abstract

We report the experimental demonstration of a modulation instability (MI) process assisted by a periodic dispersion modulation in an optical fiber. We observe the spontaneous growth of more than 10 pairs of MI sidebands spanning over more than 10 THz thanks to a quasi-phase-matched process.

Far-detuned cascaded intermodal four-wave mixing in a multimode fiber

“…The longitudinal spatial intensity oscillations of a multimode beam give rise to GPI and multiple sidebands that can be generated far away from the pump (shifts larger than 100 THz) [11,12]. This self-induced phase-matching mechanism is analogous to quasi-phase matched wave (QPM) generation in periodic amplified transmission systems or dispersion-managed fibers [13][14][15]. For a few-mode fiber (FMF) instead, the number of intermodal, nonlinear coupling terms is much smaller: the frequencies of parametrically generated waves can be obtained from the phase-matching conditions of IMFWM processes.…”

Gain sideband splitting in dispersion oscillating fibers

“…(4) (see dashed vertical lines). The possibility of observing QPM-induced MI in such a situation, where a large set of spectral lines is generated, was experimentally confirmed in the work of Droques et al [5]. However, for an increasing level of dispersion amplitude oscillations (e.g., D amp = 1.7 ps/km/nm, case (b) of Fig.…”

“…Nevertheless, we checked that these effects do not have a noticeable influence on the MI spectral dynamics that we are going to describe. MI induced by the longitudinal variations of chromatic dispersion has been theoretically investigated before in a wide range of configurations, ranging from sinusoidal profiles with a spatial period of a few tens of meters [5,9], up to dispersion-managed systems with periods of several kilometers [6,[12][13][14]. We consider in this contribution the specific case of DOF whose parameters are inspired by the previous numerical works which were carried out in the context of the transmission of high-speed telecommunication signals in dense dispersion managed links [15].…”

“…Indeed, thanks to the periodic dispersion landscape, which leads to quasi-phase-matching (QPM) of the nonlinear four-wave mixing (FWM) process, MI sidebands can be observed even in the regime of normal average GVD of a dispersion-oscillating optical fiber (DOF) [6][7][8]. Recent experimental works have confirmed the QPM-induced MI process in the normal GVD regime of microstructured DOF around 1 lm [5], as well as of non-microstructured highly nonlinear DOF at telecom wavelengths [9,10].…”

“…In nonlinear fiber optics, such a process has been demonstrated in fibers with anomalous, constant group velocity dispersion (GVD) [1], as well as in normal GVD fibers by enabling the fulfillment of the nonlinear phase-matching condition through either fourth order dispersion [2], birefringence or a multimodal structure [3,4]. More recently, a renewed experimental and theoretical interest in MI studies has been stimulated by the availability of fibers presenting a longitudinal and periodic modulation of their dispersion properties [5]. Indeed, thanks to the periodic dispersion landscape, which leads to quasi-phase-matching (QPM) of the nonlinear four-wave mixing (FWM) process, MI sidebands can be observed even in the regime of normal average GVD of a dispersion-oscillating optical fiber (DOF) [6][7][8].…”