Two-pump Fiber Optical Parametric Amplifier Research Articles

Gain-saturated two-pump fiber optical parametric amplifiers in the presence of dispersion fluctuation and fourth-order dispersion coefficient

The saturated gain performance of the two-pump fiber optical parametric amplifier (2-P FOPA) in the presence of random dispersion fluctuation as well as fourth-order dispersion coefficient are investigated. The gain spectra of the 2-P FOPA is simulated by solving the coupled equations numerically, considering the dispersion fluctuations along the fiber as a stochastic process with a given standard deviation and correlation length. The gain performance of 2-P FOPA is analysed with the variation of correlation length, standard deviation and fourth-order dispersion coefficient, respectively. It shows that, the gain saturation curves of 2-P FOPA exhibit obvious differences in the presence of dispersion fluctuations and fourth-order dispersion coefficients. The peak gain reduces with the increase of the standard deviation and the reduction is higher in case of shorter correlation lengths, also the variations of 2-P FOPA saturation powers are affected by the standard deviation and correlation length significantly. In addition, the performance of the 2-P FOPA varies greatly while considering the fourth-order dispersion coefficient, where the peak gain remains the same, but the 3 dB bandwidth is wider with considering the fourth-order dispersion coefficient. The numerical analysis is meaningful for the research of 2-P FOPA saturated gain performance, which having attracted great research interests in the optical fiber communication systems.

Influence of chirped pump shape on the two-pump fiber optical parametric amplification

The gain performance of two-pump fiber optical parametric amplifier (FOPA) pumped by different kinds of chirped pump pulses is investigated numerically. It shows that the gain performances of FOPA are evidently influenced by the shapes of chirped pump pulses. The highest and broadest gain spectrum is obtained with the 10th-order super-Gaussian pulse in case of identical energy and full width at half-maximum of the pump pulses. Finally, the signal gain is also affected by the poor symmetry of pump pulse, which leads to a low gain performance.

Impact of Random Dispersion Fluctuations on Two-Pump Fiber Optical Parametric Amplifier Performances

The impact of random dispersion fluctuations on two-pump (2-P) fiber optical parametric amplifier (FOPA) performance in terms of parametric gain, 3-dB amplification bandwidth and saturation power is numerically investigated. The four-coupled amplitude equations which represent the parametric process in optical fiber are solved using the Runge-Kutta method. Based on the results, it was observed that the random dispersion fluctuations reduced the parametric gain, increased the saturation power and had no significant effect on 3-dB amplification bandwidth. The resulted behaviors are mainly due to the changes of phase-matching condition in optical fiber. All in all, the random dispersion fluctuations are potentially limited the 2-P FOPA performances.

Two-pump fiber optical parametric amplifiers: Beyond the 6-wave model

Abstract Two-pump (2-P) fiber optical parametric amplifiers (FOPAs) are a versatile class of FOPAs which can exhibit wide and flat gain spectra in arbitrary wavelength regions, when compared with one-pump (1-P) FOPAs. The 4-wave and the 6-wave models are commonly used to simulate 2-P FOPAs by considering four and six interacting waves, respectively. Although the 6-wave model provides more accurate results than the 4-wave model, it does not take into account higher-order four-wave mixing products (HFPs) especially when the FOPA saturates. The main goal of this paper is to accurately model the 2-P FOPA in which HFPs beyond six interacting waves are included. To this end, the nonlinear Schrodinger equation (NLSE) is solved using the split-step Fourier method and the results are compared with those of previous models such as the 4-wave and 6-wave models as well as an existing analytical solution. The results, which are compared with available experimental data, show that for high input signal levels where the FOPA operates in saturation, the 6-wave model fails to provide accurate simulation results and deviates from results obtained by the NLSE. Therefore, NLSE-based modeling, which includes arbitrary interacting waves beyond the 6-wave model is important for applications in the saturation regime such as signal processing, noise suppression and regeneration.

Flat and ultra-broadband two-pump fiber optical parametric amplifiers based on photonic crystal fibers

A two-pump fiber optical parametric amplifier (FOPA) based on the photonic crystal fiber (PCF) in the telecommunication region is investigated numerically. The fiber loss and pump depletion are considered. The influences of the fiber length, input signal power, input pump power, and the center pump wavelength on the gain bandwidth, flatness, and peak gain are discussed. The 6-wave model-based analysis of two-pump FOPA is also achieved and compared with that based on the 4-wave model; furthermore, the gain properties of the FOPA based on the 6-wave model are optimized and investigated. The comparison results show that the PCF-based two-pump FOPA achieves flatter and wider gain spectra with less fiber length and input pump power compared to the two-pump FOPA based on the normal highly nonlinear fiber, where the obtained results show the great potential of the FOPA for the optical communication system.

Investigation of two-pump fiber optical parametric amplifiers for a broadband and flat gain with a low pump-to-signal noise transfer

Two-pump fiber optical parametric amplifiers (2-P FOPAs) are investigated to obtain a broadband and flat gain simultaneously with a low pump-to-signal noise transfer. The analysis is performed based on the six-wave model to find the optimum pump wavelength separation and also the fiber length to simultaneously maximize the gain and minimize the noise transfer from the pump to the signal. The results of this paper show the potential of 2-P FOPAs for application in fiber optical communication systems; for example, wavelength division multiplexing (WDM).

Modelling of noise suppression in gain-saturated fiber optical parametric amplifiers

Noise properties of both one-pump (1-P) and two-pump (2-P) fiber optical parametric amplifiers (FOPAs) are theoretically investigated and particularly the unique feature of FOPAs for the noise suppression in the gain-saturated regime is modeled. For the 1-P FOPAs, the simulation results are compared with the available experimental data and a very good agreement is obtained. Also, for the 2-P FOPA where no experimental work has been reported regarding their noise properties in the saturation regime, the noise behavior of the amplified signal is simulated for the first time. It is shown that for a specific power in the deep saturation regime, the signal noise is suppressed; and with further increase of the signal power when the gain saturation reaches its new cycle, a periodic behavior of noise suppression is observed originating from the phase-matching condition. The existence of a negative feedback mechanism which is responsible to the suppression of the excess noise in the first cycle of the gain saturation is confirmed both for 1-P and 2-P FOPAs. Generally, it is shown that the noise suppression can be observed for several specific powers at which the slope of the output signal power versus the input one is zero. The results of this paper may have some applications in signal processing, e.g., cleaning noisy signals.

Amplification of ultra-short optical pulses in a two-pump fiber optical parametric chirped pulse amplifier

We demonstrate with realistic numerical simulations that fiber optical parametric chirped pulse amplification is able to amplify ultra-short optical pulses. Such amplifiers driven by two-pump waves can amplify pulse bandwidth twice as large as the one of a single pump configuration. We show that pulses as short as 50 fs can be directly amplified. In addition, we take benefit from the saturation regime to achieve spectral broadening which makes possible to reduce pulse duration down to 15 fs.

Erratum: Analysis of crosstalk between 10 Gb/s × 64 channels in two-pump fiber optical parametric amplifier

Originally published Microwave Opt Technol Lett 55:926–929, 2013. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1703, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27668 (Original article DOI 10.1002/mop.27408)

Analysis of crosstalk between 10 Gb/s x 64 channels in two-pump fiber optical parametric amplifier

We present a numerical study of 64 signals amplified by a two-pump fiber optical parametric amplifier. The amplifier was alternatively simulated with two fibers with different values of nonlinear coefficient but the same length. The gain remained constant in both cases. The performance of the amplifier is improved when it is designed with the fiber of lower nonlinear coefficient. Also, it was observed that the performance of the amplifier is strongly dependent on channel separation. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:926–929, 2013; View this article online at wileyonlinelibrary.com. DOI: 10.1002/mop.27408

Continuous-Wave Parametric Amplifier With 6.9-ExaHz Gain-Bandwidth Product

A continuous-wave two-pump fiber-optic parametric amplifier with a record small-signal gain-bandwidth product of 6.9 EHz is reported. The amplifier was used to achieve errorless amplification of a 10.7-Gb/s nonreturn-to-zero differential-phase-shift-keyed signal. The receiver performance limit was defined by pump depletion, with the maximal gain limit set by the gain saturation of amplified quantum noise. The record performance was achieved using a bandwidth-efficient pump dithering technique.

Bandwidth-efficient phase modulation techniques for Stimulated Brillouin Scattering suppression in fiber optic parametric amplifiers

Two novel bandwidth efficient pump-dithering Stimulated Brillouin Scattering (SBS) suppression techniques are introduced. The techniques employ a frequency-hopped chirp and an RF noise source to impart phase modulation on the pumps of a two pump Fiber Optical Parametric Amplifier (FOPA). The effectiveness of the introduced techniques is confirmed by measurements of the SBS threshold increase and the associated improvements relative to the current state of the art. Additionally, the effect on the idler signal integrity is presented as measured following amplification from a two pump FOPA employing both techniques. The measured 0.8 dB penalty with pumps dithered by an RF noise source, after accruing 160 ps/nm of dispersion with 38 dB conversion gain in a two-pump FOPA is the lowest reported to date.

160-Gb/s optical time division multiplexing and multicasting in parametric amplifiers

We report the generation of an optical time division multiplexed single data channel at 160 Gb/s using a one-pump fiber-optic parametric amplifier, and its subsequent multicasting. A two-pump fiber optic parametric amplifier was used to perform all-optical multicasting of 160 Gb/s channel to four data streams. New processing scheme combined the increase in signal extinction ratio and low-impairment multicasting using continuous-wave parametric pumps. Selective conjugation of 160 Gb/s was demonstrated for the first time.

Investigation of gain ripple in two-pump fiber optical parametric amplifiers

By using the four-sideband theory, we analyze the gain spectrum in wideband two-pump fiber optical parametric amplifiers and predict gain ripples over the flat gain region. We derive an approximation of their pseudo-periods and discuss methods for reducing their amplitudes.

Gain bandwidth optimization in two-pump fiber optical parametric amplifiers under bounded zero-dispersion wavelength fluctuations

We study gain bandwidth optimization in a two-pump fiber optical parametric amplifier (2P-OPA) with bounded zero-dispersion wavelength (ZDW) uncertainty. Maximum-bandwidth 2P-OPAs are designed ensuring positive parametric gain, tunable gain spectrum, and robustness against ZDW fluctuations. By recognizing the polynomial nature of the phase mismatch, the design task is formulated as a nonconvex multivariate polynomial optimization problem, which is then solved through the latest convex programming techniques based on linear matrix inequality relaxations. The proposed framework exhibits superior computational efficiency and guarantees, up to modeling accuracy, globally optimal wavelength assignment. It provides an analytical ground to assist experimental tunings in practice, and allows visualization of tradeoff between gain bandwidth and spectrum quality against ZDW uncertainty.

Experimental studies of the WDM signal crosstalk in two-pump fiber optical parametric amplifiers

We showed that cross-gain modulation is dominant over another kind of common signal quality degradation, namely four-wave mixing, in a two-pump fiber optical parametric amplifier (OPA) WDM system. We also demonstrated experimentally that the signal quality degradation can be improved significantly by a two-orthogonal-pump OPA (2OP-OPA) over the conventional two-parallel-pump OPA (2PP-OPA).

Simultaneous all-optical inverted and noninverted wavelength conversion using a single-stage fiber-optical parametric amplifier

We have demonstrated, for the first time to our knowledge, simultaneous all-optical inverted and noninverted wavelength conversion by using a single-stage two-pump fiber-optical parametric amplifier with an extinction ratio between 7 and 14 dB over 24 nm.

Two-pump fiber optical parametric amplifiers using optimized photonic crystal fiber by genetic algorithm

In this paper, we investigate the gain spectra of fiber optical parametric amplifiers (FOPAs) consisting of dispersion-flattened fibers (DFFs) with different dispersion curves comparatively by means of the dispersion curve model of the DFFs. It is demonstrated that the broader gain spectrum of FOPAs can be achieved if the dispersion curve is lower and more flattened. Based on the preceding analyses, we propose to constitute FOPAs by using index-guiding photonic crystal fiber (PCF) with an anticipated ultra-flattened dispersion and ultra-low dispersion slope. The as-proposed PCF had different air-holes in the cladding rings. In total, four parameters of the PCF are optimized by using genetic algorithm.

Gain characteristics and optimization of dual-pump fiber optical parametric amplifier using two-section highly nonlinear fibers

In this paper the gain characteristics of two-pump fiber optical parametric amplifiers (FOPA) with two-section highly nonlinear fibers are analyzed numerically and the parameters of the fibers are optimized to reach broad and flat gain spectra using genetic algorithm. Different from the previous methods, here the space between two pump wavelengths and the parameter β 4 of the fibers are included as a pivotal factor in the optimization. The numerical simulation shows that using two-section practical high nonlinear fibers, the amplifier may reach 110 nm bandwidth covering 1495–1605 nm with 10.5 dB average gain and gain ripple of 0.17 dB, when the total pump power is 1 W.

The effect of phase mismatch on two-pump fiber optical parametrical amplifier

In the paper, the effect of phase mismatch on two-pump fiber optical parametric amplifier is investigate based on analytic solutions of parametric gain. The phase mismatch is mainly induced by the fiber losses, the fourth-order dispersion and zero-dispersion wavelength fluctuations. The fiber losses reduce the pump powers resulting in a fall of the parametric gain, and make the phase mismatch vary with propagation distance leading to an obvious gain ripple. When the fiber losses are taken into account, the fourth-order dispersion produces a deeper ripple on the parametric gain and deteriorates the gain flatness. Zero-dispersion wavelength fluctuations result in variations of gain spectrum, and the long-scale fluctuations are more devastating than the short-scale ones.