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We present a multimode longitudinal pumping scheme for integrated rare-earth-doped waveguide amplifiers which allows an efficient use of low cost multimode pump sources. The scheme is based on evanescent pump light coupling from a multimode low loss waveguide to a single mode active core. Multimode pump light is gradually coupled to the active waveguide, which is single mode at the signal wavelengths, providing population inversion along the whole amplifier length and overcoming the main limitation of conventional single mode pump butt-coupling in case of strongly absorbing active materials. We propose this pumping scheme at 477 nm for Si-nanocluster sensitized Erbium doped waveguide amplifiers, in which conventional butt-coupling is inefficient due to the strong pump absorption by the Si- nanoclusters , and top pumping by LED arrays is limited by the low pump intensity values achievable within the active region. The coupling between the multimode waveguide and the active core has been numerically studied for slab waveguide structures using a 2-D split-step finite element method. [ABSTRACT FROM PUBLISHER]

We compare standard fiber Raman laser and new high-power- and low relative-intensity-noise (RIN)-copumping technologies for long-span unrepeated wavelength-division-multiplexing (WDM) transmission systems. We show that, by using enhanced forward-error-correction techniques and by optimizing the transmission-system parameters in terms of signal power per channel, dispersion map, and copropagating on- off Raman gain, both copumping technologies allow successful transmission of 8 10-Gb/s WDM channels over more than 70 dB of standard single-mode fiber. However, transmission experiments point out that only the newly proposed high-power and low-RIN lasers can guarantee realistic system margins and can potentially provide further span-reach enhancement when used in optimized higher order copumping configurations. [ABSTRACT FROM PUBLISHER]

Benefits provided by higher order bidirectional Raman pumping schemes in 10-Gb/s unrepeated wavelength-division-multiplexing transmission systems are experimentally quantified in terms of BER performances at 10 Gb/s. By keeping under control double-Rayleigh-scattering-noise-induced transmission penalties, which can degrade system performance at very high ON-OFF Raman gain, as well as nonlinear propagation effects such as Brillouin scattering, self- and cross-phase modulations, four-wave-mixing, and Raman-induced crosstalks, we show a total unrepeated system reach enhancement up to 3.5 dB with respect to first-order bidirectional pumping. As confirmed by theory, the maximum reach enhancement is mainly limited by pump-to-signal relative intensity noise transfer induced by higher order copumping. [ABSTRACT FROM PUBLISHER]

We present a longitudinal multimode pumping scheme which allows Yb-sensitized Er-doped silica waveguide amplifiers to be effectively pumped by high-power and low-cost broad-area lasers. The proposed configuration is based on evanescent pump light coupling from a multimode low-loss waveguide to a Er-Yb codoped active core. Theoretical predictions, based on propagation and population-rate equations for the coupled Er-Yb system, show that longitudinal multimode pumping by high-power broad-area lasers at around 980 nm can provide up to 4-dB gain per centimeter, suggesting possible integration of low-cost amplifiers with important applications in wavelength-division-multiplexing metro and access optical networks. [ABSTRACT FROM PUBLISHER]

We propose a novel high-power (up to 1.9 W) and low relative intensity noise (RIN) laser structure for effective first- and higher order distributed Raman copumping. RIN characterization and bit-error-rate measurements at 10 Gb/s point out RIN-penalty free transmission up to 25 dB of on-off copropagating Raman gain. This new copumping technology can provide sensible span reach enhancement in long-span unrepeated WDM transmission systems in a simple and effective way [ABSTRACT FROM PUBLISHER]

We discuss penalties induced by pump intensity noise transfer and parametric nonlinear interactions in counterpumped distributed Raman amplifiers based on nonzero dispersion shifted fibers. An effective suppression of penalties induced by parametric nonlinear interaction is experimentally demonstrated by a new Raman pump module, based on cascaded fiber Raman lasers. [ABSTRACT FROM PUBLISHER]