Abstract

We characterise the linear and nonlinear noise of dual stage broadband discrete Raman amplifiers (DRAs) based on conventional Raman gain fibres. Also, we propose an optimised dual stage DRA setup that lowers the impact of nonlinear noise (generated in the amplifier) on the performance of a transmission link (with 100-km amplifier spacing). We numerically analyse the design of a backward pumped cascaded dual stage 100-nm DRA with high gain (∼20 dB) and high saturated output power (>23 dBm). We show that the noise figure (NF) of the dual stage DRA is mainly dominated by the first stage irrespective of the type of gain fibre chosen in the second stage, and we also demonstrate that optimising the length and the type of Raman gain fibre can have significant impact on the size of inter/intrasignal nonlinearities generated. Here, we report a theoretical model to calculate the nonlinear noise power generated in transmission spans with dual stage DRAs considering piecewise signal power evolution through the Raman gain fibres. The predicted signal-to-noise ratio (SNR) performances are calculated from the combined contributions from NF and nonlinear product power obtained using the proposed analytical model for transmission systems deployed with 100-km transmission span compensated by different dual stage DRAs. Finally, an optimised IDF 6 km–SMF 10 km dual stage configuration has been identified using the theoretical model, which allows maximum SNR of 14.6 dB at 1000 km for 1 THz Nyquist wavelength division multiplexed signal and maximum transmission reach of 3400 km at optimum launch power assuming 8.5 dB HD-FEC limit of the Nyquist PM-QPSK signal.

Low transmission penalty dual-stage broadband discrete Raman amplifier

Lukasz Krzczanowicz, Md Asif Iqbal, Ian Phillips, Mingming Tan, Pavel Skvortcov, Paul Harper, and Wladek Forysiak
Opt. Express 26(6) 7091-7097 (2018)

Performance evaluation of discrete Raman amplifiers in coherent transmission systems

Pratim Hazarika, Mingming Tan, Md Asif Iqbal, Ian Phillips, Paul Harper, Jeffery S. Stone, Ming Jun Li, and Wladek Forysiak
Opt. Express 30(24) 43053-43061 (2022)

E-, S-, C- and L-band coherent transmission with a multistage discrete Raman amplifier

Pratim Hazarika, Mingming Tan, Aleksandr Donodin, Shabnam Noor, Ian Phillips, Paul Harper, Jeffery S. Stone, Ming Jun Li, and Wladek Forysiak
Opt. Express 30(24) 43118-43126 (2022)

Noise and transmission performance improvement of broadband distributed Raman amplifier using bidirectional Raman pumping with dual order co-pumps

M. A. Iqbal, M. Tan, L. Krzczanowicz, A. E. El-Taher, W. Forysiak, J. D. Ania-Castañón, and P. Harper
Opt. Express 25(22) 27533-27542 (2017)

Ultra-wideband discrete Raman amplifier optimization for single-span S-C-L-band coherent transmission systems

Pratim Hazarika, Mingming Tan, Aleksandr Donodin, Mohammad Patel, Ian Phillips, Paul Harper, and Wladek Forysiak
Opt. Lett. 47(24) 6472-6475 (2022)