New dispersion-compensated Raman-amplifier cascade with a single-pump parametric amplifier for dense wavelength-division multiplexing

Abstract

In this work a dispersion-compensated Raman amplifier has been cascaded with a single-pump parametric amplifier to build a dense wavelengthdivision multiplexed (DWDM) system. This hybrid system demonstrates a flat gain in the L-band. Our hybrid has been evaluated for a 25 GHz 96-channel system at 40 Gbps in the band spreading from 189 to 191.375 THz. The results demonstrate the gain larger than 16.9 dB and the gain ripple less than 5.82 dB, with no gainflattening technique used. The novelty of our design lies in combining dispersion compensation with signal amplification in a long-length Raman-amplifier fibre followed by a short-length parametric amplifier implemented on a separate highly nonlinear fibre. For the data rate 10 Gbps, the achievable gain ripple is as low as 1.9 dB, without any gain-compensation technique. The optical signal-to-noise ratio larger than 18 dB and the flat gain confirm that our Raman fibre-optic parametric amplifier can be used as a tunable and broad-gain amplifier for the future long-haul DWDM systems. The results obtained for our system have been compared with those of the L-band optical amplifiers developed recently. The comparison testifies that our amplifier is the best of all existing analogues.

Optical solitons and conservation laws associated with Kudryashov�s sextic power-law nonlinearity of refractive index

“…Kerr nonlinearity represents the most common form of self-phase modulation, when the refractive index is proportional to the intensity of light. In more general 'non-Kerr' cases, it is proportional to some function of the intensity [1][2][3][4][5]. In other words, the refractive index in the case of Kerr nonlinearity is a constant multiple of the intensity, while in a non-Kerr situation, the response of optical medium sometimes depends on the intensity raised to a positive power or, more generally, it is a sum of two terms, each of which being proportional to the intensity raised to some positive power.…”

Raman Assisted Fiber Optical Parametric Amplifier for S-Band Multichannel Transmission System

“…In practical implementations, the usable bandwidth for long reach transmission is limited by the gain bandwidth of applied amplification technology. In the case of widely used erbium-doped fiber amplifier (EDFA), the gain bandwidth covers only C (1530-1565 nm) and partly L (1565-1625 nm) bands (5)(6)(7)(8)(9)(10). To overcome this limitation, multiple amplification technologies can be used in parallel to form multiband amplifiers and transmission systems [4][5][6][7][8][9].…”

“…A very promising approach for mitigating FRA and FOPA drawbacks is hybrid amplification methods that have been extensively studied for various applications [5,8,31,[41][42][43][44][45][46][47][48][49]. This combination is the Raman assisted FOPA (RA-FOPA) amplifier.…”

“…RA-FOPA amplifiers have been studied for various purposes. Firstly the basic idea has been tested and described in several publications where the principles and benefits of this combination were analyzed [5,8,31,[41][42][43][44][45]47,48]. In these publications, the focus is on the combined amplifier gain spectra as well as the efficiency of different pumping schemes and noise figures.…”