Aspect ratio based nonlinear effects in spot size dependent propagation characteristics of trapezoidal index single mode fiber

We investigate the nonlinear propagation characteristics of single mode trapezoidal index fibers involving the exact numerical linear and nonlinear spot sizes and their relative change with respect to aspect ratio. From comparison of normalized spot sizes in absence and presence of Kerr nonlinearity, it is seen that nonlinear effect is more pronounced in lower values of normalized frequency for each aspect ratio. Further, for near cut-off propagation, the triangular index fiber excels in performance in respect of percentage change of spot sizes and fractional core power.