Four-photon mixing and high-speed WDM systems

Quantum key distribution and 1 Gbps data encryption over a single fibre

“…The generation efficiency depends on the phase-matching condition, as well as on the relative polarization and propagation direction of the involved field frequency components. Phase matching is particularly easy to fulfil around the zero dispersion wavelength, where generated sidebands can corrupt even classical communication [10]. In section 3, we present a channel configuration that prevents efficient FWM generation in the quantum channel passband in standard single-mode fibres, dispersion shifted fibres and nonzero dispersion shifted fibres.…”

A Novel Multiclad Single Mode Optical Fibers for Broadband Optical Networks

“…In order to increase the information carrying capacity, latest high speed communication system is based on the dense wavelength division multiplexing/demultiplexing (DWDM) [16,17]. In such systems, nonlinear effects like four wave mixing (FWM), which arise due to simultaneous transmission at many closely spaced wavelengths and high optical gain from EDFA, imposes serious limitations on the use of a DSF with zero dispersion wavelength at 1550 nm [18,19]. To overcome this difficulty, the nonzero dispersion shifted fibers having small dispersion in the range ~ 2−4 ps/km/nm over the entire gain window of EDFA have been proposed [20,21].…”

Generalised dispersive phase and its effect on four wave mixing in fibers

“…It is often indicated that, in the case of fibers, the FWM efficiency at any wavelength is degraded due to the chromatic dispersion of the fiber at that wavelength [7]. Hence, the use of dispersion shifted fiber (DSF) and choice of the signal wavelengths close to or at the zero dispersion wavelength are suggested as the best options to achieve phase matching and hence higher FWM efficiencies.…”

“…FWM in single mode fibers was first reported by Hill et al [1]. Since it can significantly influence the multi channel transmission systems, this phenomenon has been studied extensively in different types of fibers [2][3][4][5][6][7][8]. FWM leads to signal deterioration and cross talk in dense wavelength division multiplexed (DWDM) systems [9][10][11], and many methods are being used to reduce the deleterious effect of FWM in communication [12][13][14].…”