Few-pumped flat Raman fiber amplifier for parallel distributed FBG-based sensor system

Multi-pump technique is frequently adopted to improve the flatness of Raman fiber amplifier (RFA), but brings the issues in terms of cost and algorithm complexity. In this article, we limit the number of pumps and the few-pumped RFA is proposed and investigated by optimizing the power and wavelengths. We further define three new factors to evaluate the improvement ratio of gain and flatness and determine the advisable number of pumps. By using the designed RFA, an experiment of distributed fiber Bragg grating-based sensor system is developed, and the flatness of less than ±0.44 dB is obtained with the gain of about 3 dB in the range of 1510–1570 nm.