A novel all-optical switch composed of cascaded Gaussian nonlinear directional couplers (NLDCs) and Exponential NLDCs is proposed. It is found by theoretical analysis and numerical simulation that the proposed switch possesses better switching characteristics since the proposed switch can suppress the sidelobes of the switching curves compared with conventional cascaded NLDCs and has steeper dynamic switching region where the power transmission increases from 0 to 1 than that of cascaded Gaussian NLDCs. The proposed switch is more suitable for all-optical switch than conventional cascaded NLDCs and cascaded Gaussian NLDCs. The parameters of cascaded couplers can also be adjusted to change the number of unit couplers to satisfy the certain requirements of the switching curve.