Silica-based highly nonlinear fibers with a high SBS threshold

Results on suppression of stimulated Brillouin scattering in highly nonlinear fibers with germanium-doped core as well as aluminum-doped core based on spooling the fiber with a linear strain gradient is presented

Interaction of pulses in nonlinear Schroedinger model

The interaction of two rectangular pulses in nonlinear Schroedinger model is studied by solving the appropriate Zakharov-Shabat system. It is shown that two real pulses may result in appearance of moving solitons. Different limiting cases, such as a single pulse with a phase jump, a single chirped pulse, in-phase and out-of-phase pulses, and pulses with frequency separation, are analyzed. The thresholds of creation of new solitons and multi-soliton states are found.Comment: 9 pages, 7 figures. Accepted to Phys. Rev. E, 200

Fiber optical parametric amplifiers in optical communication systems

The prospects for using fiber optical parametric amplifiers (OPAs) in optical communication systems are reviewed. Phase-insensitive amplifiers (PIAs) and phase-sensitive amplifiers (PSAs) are considered. Low-penalty amplification at/or near 1 Tb/s has been achieved, for both wavelength- and time-division multiplexed formats. High-quality mid-span spectral inversion has been demonstrated at 0.64 Tb/s, avoiding electronic dispersion compensation. All-optical amplitude regeneration of amplitude-modulated signals has been performed, while PSAs have been used to demonstrate phase regeneration of phase-modulated signals. A PSA with 1.1-dB noise figure has been demonstrated, and preliminary wavelength-division multiplexing experiments have been performed with PSAs. 512 Gb/s have been transmitted over 6,000 km by periodic phase conjugation. Simulations indicate that PIAs could reach data rate x reach products in excess of 14,000 Tb/s × km in realistic wavelength-division multiplexed long-haul networks. Technical challenges remaining to be addressed in order for fiber OPAs to become useful for long-haul communication networks are discussed

Raman-induced asymmetric pump noise transfer in fiber-optical parametric amplifiers

In this letter, a theoretical model accounting for the asymmetric transfer of pump noise in the gain spectrum of a single-pump fiber parametric amplifier due to the Raman effect is presented. The model is satisfactorily verified by the experiments. The experiments demonstrate that the pump electrical signal-to-noise ratio remains unchanged in contrast to the optical signal-to-noise ratio which decreases along the fiber. © 2006 IEEE

Ultralow noise, broadband phase-sensitive optical amplifiers, and their applications

Frequency nondegenerate phase-sensitive amplifiers (PSAs) have the potential to realize broadband and noiseless amplification. However, the rigorous requirement of phase-and wavelength-locking of the input waves has significantly hampered their progress. In this paper, we review recent research on this type of optical amplifier. This work is based on a copier-PSA scheme, which consists of a parametric phase-insensitive copier followed by one or more PSAs. Broadband gain and noise performance of a fiber-based nondegenerate PSA has been characterized, both theoretically and experimentally. A record-low 1.1 dB noise figure was measured at >26 dB gain, and a clear phase dependent gain was observed. Moreover, potential applications including phase noise squeezing and ultralow noise, multichannel and modulation-format-transparent linear amplification with up to 6dB link noise figure advantage over conventional EDFA-amplified links have been experimentally demonstrated. The prospects and practical challenges of this intriguing amplification technology are also discussed. © 2011 IEEE