Multipath Interference in Pulse-Pumped Fiber Raman Amplifiers: Analytical Approach

We present an analytical study of multipath interference (MPI) in pulse-pumped fiber Raman amplifiers (FRAs), caused by the internal reflections from the fiber facets and the effect of Rayleigh backscattering. For the first time, to the best of our knowledge, we derive a generalized expression for the MPI-induced noise on signal in counter-pumped FRAs. The obtained result takes into account four major sources of MPI, suggests their physically transparent classification, and enables us to predict the FRA's noise performance for an arbitrary modulated pump. Using the derived expression, we characterize the MPI-induced noise in a typical 80-km span of single-mode optical fiber. Specifically , we examine the noise enhancement in the pulse-pumped amplifier as compared to the amplifier operating in the continuous-wave regime, and analyze its dependence on the on-off gain and the pump-pulse duty cycle. We also estimate the impact of the MPI-induced noise transfer on the amplifier's performance, and discuss the optimal choice of pump modulation for different values of Q-penalty. The results of our study are important for the design optimization of FRAs with time-division-multiplexed pumping.

[1]  A. R. Grant.  Calculating the Raman pump distribution to achieve minimum gain ripple , 2002 .

[2]  S. Chernikov,et al.  Characterization of double Rayleigh scatter noise in Raman amplifiers , 2000, IEEE Photonics Technology Letters.

[3]  J.J. DeMarco,et al.  Rayleigh scattering limitations in distributed Raman pre-amplifiers , 1998, IEEE Photonics Technology Letters.

[4]  J. Bromage,et al.  Raman amplification for fiber communications systems , 2003, Journal of Lightwave Technology.

[5]  Robert J. Mears,et al.  Ultra-broadband high performance distributed Raman amplifier employing pump modulation , 2002, Optical Fiber Communication Conference and Exhibit.

[6]  Wei Zhang,et al.  An analytical expression of equivalent noise figure for distributed fiber Raman amplifiers with Rayleigh scattering , 2001 .

[7]  E. Desurvire,et al.  Theory and implementation of a Raman active fiber delay line , 1986 .

[8]  R.-J. Essiambre.  Effects of Raman noise and double Rayleigh backscattering on bidirectionally Raman-pumped systems at constant fibre nonlinearity , 2001, Proceedings 27th European Conference on Optical Communication (Cat. No.01TH8551).

[9]  J. Bromage,et al.  Raman amplification for fiber communication systems , 2003, OFC 2003 Optical Fiber Communications Conference, 2003..

[10]  V. Kalavally,et al.  Analytical Study of RIN Transfer in Pulse-Pumped Raman Amplifiers , 2009, Journal of Lightwave Technology.

[11]  Morten Nissov,et al.  Rayleigh crosstalk in long cascades of distributed unsaturated Raman amplifiers , 1999 .

[12]  M. Premaratne,et al.  Dispersion-Compensating Fiber Raman Amplifiers With Step, Parabolic, and Triangular Refractive Index Profiles , 2007, Journal of Lightwave Technology.

[13]  C. Fludger,et al.  Pump to signal RIN transfer in Raman fiber amplifiers , 2001 .

[14]  G. Bolognini,et al.  Double Rayleigh scattering noise in Raman amplifiers using pump time-division-multiplexing schemes , 2004, IEEE Photonics Technology Letters.

[15]  J. Bromage,et al.  Reflection-induced penalty in Raman amplified systems , 2002, IEEE Photonics Technology Letters.

[16]  M. Islam.  Raman amplifiers for telecommunications , 2002 .

[17]  Michael Vasilyev,et al.  Quantitative analysis of Rayleigh crosstalk in Raman amplifiers , 2003 .

[18]  S. Namiki,et al.  Ultrabroad-band Raman amplifiers pumped and gain-equalized by wavelength-division-multiplexed high-power laser diodes , 2001 .

[19]  Paola Parolari,et al.  Double Rayleigh scattering noise in lumped and distributed Raman amplifiers , 2003 .

[20]  P. Winzer,et al.  Time-division multiplexed Raman pump experiment using a tunable C-band laser , 2002, IEEE Photonics Technology Letters.

[21]  Effects of time‐division multiplexing of two‐pump wavelengths on a counter‐pumped Raman‐fiber amplifier , 2004 .

[22]  Alberto Bononi,et al.  Reduction of double Rayleigh scattering noise in distributed Raman amplifiers employing higher-order pumping. , 2009, Optics express.

[23]  Bit-Error-Rate Evaluation of the Distributed Raman Amplified Transmission Systems in the Presence of Double Rayleigh Backscattering Noise , 2007, IEEE Photonics Technology Letters.

[24]  S. Faralli,et al.  Impact of double Rayleigh scattering noise in distributed higher order Raman pumping schemes , 2003, IEEE Photonics Technology Letters.

[25]  L. Mollenauer,et al.  Time-division multiplexing of pump wavelengths to achieve ultrabroadband, flat, backward-pumped Raman gain. , 2002, Optics letters.

[26]  S. V. Chernikov,et al.  Enhancement of double Rayleigh scattering by pump intensity noise in fiber Raman amplifiers , 2002, Optical Fiber Communication Conference and Exhibit.

[27]  J. Radil,et al.  Large signal model of TDM-pumped Raman fiber amplifier , 2005, IEEE Photonics Technology Letters.

[28]  Michael V. Dashkov.  Investigation of noise performance in Raman amplifiers of various design , 2006, Optical Technologies for Telecommunications.

[29]  J. Bromage,et al.  Repetition rate requirements for time-division multiplexed Raman pumping , 2004, Journal of Lightwave Technology.

[30]  C. Fludger,et al.  Electrical measurements of multipath interference in distributed Raman amplifiers , 2001 .