Efficient method of calculation of Raman soliton self-frequency shift in nonlinear optical media

We present a method to evaluate Raman soliton self-frequency shift of soliton light pulses solution for higher-order nonlinear Schrödinger equation with non-Kerr nonlinearity which propagate in high-bit-rate optical systems. We show that the conventional technique, known as collective coordinates theory, becomes inappropriate and leads to a qualitatively and unpredictable dynamics of collective coordinates. We resolve this changeableness by reformulating the conventional technique during which we add two appropriate pulse parameters called the simulated Raman scattering specific coordinates. We point out the use of these coordinates by applying them to a correct calculation of soliton self-frequency shift (SSFS) and temporal shift when cubic-quintic effects effectively act. This method of calculation of soliton self-frequency shift could be an interesting physical tool to those working on propagation of nonlinear pulses in optical media where the investigations of simulated Raman scattering with associated phenomena are required.