Design methodology for multi-pumped discrete Raman amplifiers: case-study employing photonic crystal fibers

Abstract

This paper proposes a new design methodology for discrete multi-pumped Raman amplifier. In a multi-objective optimization scenario, in a first step the whole solution-space is inspected by a CW analytical formulation. Then, the most promising solutions are fully investigated by a rigorous numerical treatment and the Raman amplification performance is thus determined by the combination of analytical and numerical approaches. As an application of our methodology we designed an photonic crystal fiber Raman amplifier configuration which provides low ripple, high gain, clear eye opening and a low power penalty. The amplifier configuration also enables to fully compensate the dispersion introduced by a 70-km singlemode fiber in a 10 Gbit/s system. We have successfully obtained a configuration with 8.5 dB average gain over the C-band and 0.71 dB ripple with almost zero eye-penalty using only two pump lasers with relatively low pump power.

Study and Optimization of Raman Amplifiers in Tellurite-Based Optical Fibers for Wide-Band Telecommunication Systems

“…For the optimization process the pump wavelengths were allowed to vary from 1360 to 1500 nm and their initial powers from 600 to 800 mW each in order to assure that we are proposing a low-cost system. The 2-pump system was optimized using an exhaustive search technique based on the one used in [16], which utilizes a very fast simplified analytic model [17] to simulate multi-pump systems allowing the generation of hundred thousands of different configurations within minutes. This fast technique allowed us to generate all possible combinations varying each pump wavelength by 2 nm and each pump power by 20 mW within the chosen range, which gives a total of 609961 different cases.…”

Fast optimization of multipump Raman amplifiers based on a simplified wavelength and power budget heuristic

“…5,18,19 It is based on the continuous-wave propagation of the pump and signals described by the nonlinear Schrodinger equations, 1 and it includes pump-to-pump, signal-to-signal, and signal-to-pump interactions, wavelengthdependent effects, such as effective area variation and individual loss coefficients, pump depletion, amplified spontaneous emission, and Rayleigh backscattering. 5,18,19 It is based on the continuous-wave propagation of the pump and signals described by the nonlinear Schrodinger equations, 1 and it includes pump-to-pump, signal-to-signal, and signal-to-pump interactions, wavelengthdependent effects, such as effective area variation and individual loss coefficients, pump depletion, amplified spontaneous emission, and Rayleigh backscattering.…”

“…1 However, in wavelength division multiplexing (WDM) telecommunication systems, it is important not only to have high gains, but also the gain should be made as flat as possible over the entire amplification window, so that different channels do not receive an uneven amount of power. To solve this problem, a number of approaches have already been proposed based on simulated annealing, 4 exhaustive search, 5 neural networks, 6 ant colony optimization, 7 swarm optimization, 8 but mainly genetic algorithms (GAs) or hybrid GAs (Refs. 2 This capability of shaping the gain profile over a very broad amplification band (>100 nm) by properly setting the arrangement of pump lasers is what makes Raman amplifiers unique tools in the design of telecommunication systems.…”

“…To overcome this issue and effectively reduce time consumption, the use of a simplified analytical 5,12 or semianalytical 9 solution has been proposed for the calculation of the Raman gain profile. Moreover, previous reports of optimizations of multipump Raman amplifiers based on analytical calculation of the Raman gain profile 5,9,12 still present issues concerning the time consumption due to the use of slow optimization heuristics needing a huge number of iterations to achieve the desired result. Moreover, previous reports of optimizations of multipump Raman amplifiers based on analytical calculation of the Raman gain profile 5,9,12 still present issues concerning the time consumption due to the use of slow optimization heuristics needing a huge number of iterations to achieve the desired result.…”

Performance analysis of multi-pump Raman+EDFA hybrid amplifiers for WDM systems

“…An optimization technique to Raman+EDFA hybrid amplifiers for WDM applications is applied in this work [9]. It uses an analytical approximated model to determine the spectral shaping of the Raman gain stage avoiding the time-consuming process of spectral profile optimization [11]- [12]. The optimization has been carried out on a hybrid Raman+EDFA amplifier configuration, using dispersion compensating fiber with multiple pump lasers in the Raman amplification stage.…”