The effect of a defective mode layer of GaAs semiconductor material of one-dimensional nonlinear photonic crystal, which is a function of intensity as well as the wavelength, is numerically simulated using transfer matrix method. It is observed that the transmission efficiency of this defective layer increases with an increase in the wavelength of the material. At the first transmission window (820 to 910 nm), the transmittance is low, but at the second (1260 to 1360 nm) and third transmission windows (1530 to 1565 nm), it approaches 100%. At the first transmission window, the efficiency of the material approaches 100% with an increase in the intensity up to 140  GW  /  cm². We have designed a tunable 8-channel dense wavelength division multiplexer for both (first and third) transmission windows and compared the quality factor and efficiency of the structure and found that the transmission efficiency of the defective layer of the third transmission window is better than first transmission window. We observed that the channel spacing for first and third transmission windows are 0.72 and 1.17 nm, respectively, which correspond to the International Telecommunication Union grid systems.