The fabrication process of Arrayed Waveguide Grating (AWG) for the Coarse Wavelength Division Multiplexing (CWDM) by the casting method using the micro die is proposed, and the optical characteristics are evaluated for the fabricated device. In the 1^st report, the fabrication process of AWG by the casting method was proposed. To fabricate the micro die, the electro-plating method after fabricating the mother shape using SU-8 was used. In this paper, the improved process of filling the core material to the core channel of the formed under clad using the spin-coater is examined. The condition of filling the core material is decided by optimizing the condition of the spin coating. The AWG is realized by the proposed method, and then the optical characteristics are evaluated. As the result, the wavelength demultiplexing are successfully confirmed.