Variational principle for the Kaup-Newell system

Document Type : Research Paper


1 College of Economics and Management, Shanghai University of Political Science and Law, Qingpu Area, Shanghai, China.

2 School of Mathematics and Information Science, Henan Polytechnic University, Jiaozuo, China.

3 National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou, China.


The Kaup-Newell system describes the pulse propagation in optical fibers. This paper applies the semi-inverse method to construct the system’s variational formulations, two trial-variational formulations with an unknown function are established, and a detailed derivation is given to determine the unknown function. Finally, the Kaup-Newell system with two variables is converted to a partial differential equation with only one variable.


Main Subjects

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Volume 54, Issue 3
September 2023
Pages 405-409
  • Receive Date: 10 September 2023
  • Accept Date: 10 September 2023