When laser pulses propagate in an inhomogeneous nonlinear medium, we theoretically investigate the evolution of laser pulses by analytically solving the (3 + 1)-dimensional generalized nonlinear Schrodinger equation with variable coefficients and optical lattice. A series of chirped-free and chirped analytic solutions, such as soliton solutions are found and intensities evolution of these analytic solutions are studied in detail. In the absence of optical lattice, we find that the intensities evolution of chirped-free and chirped analytic solutions vary regularly when the diffraction coefficie...
