Parameter optimization measuring nonlinear Kerr coefficient using self-aligned interferometer

The setup has been theoretically analyzed based on self-aligned interferometer, which consists of Mach-Zehnder (M-Z) interferometers used to measure optical fibers Kerr coefficient. The setup is insensitive to environmental perturbations. However, the phase shift isn't completely induced by self-phase modulation (SPM) of tested fibers, and there are some other phase shifts created by the fibers of the system. Since the pulses intensities are different between a forward pass and a return pass, and there is excessive phase shift, it is impossible to measure the optical fibers Kerr coefficient accurately. In the setup, a new parameter A which expresses the error of nonlinear phase shift is defined, the system parameter has been analyzed and optimized to obtain the minimum Δ.