We report a wavelength division demultiplexer (WDDM) using collinear surface‐normal input and output coupling. The reported device employs polymer‐based multiplexed waveguide holograms in conjunction with substrate guided waves. A two‐channel WDDM device operating at 700 and 738 nm with diffraction angles of 45° and 50° are demonstrated. The peak diffraction efficiencies of 80% and 77% are measured for these two channels. A crosstalk of −31 dB between the two channels is measured. Variations of the diffraction efficiencies and of the bandwidths as a function of film thickness and index modulation are further considered. A good agreement between theoretical analysis and experimental results is obtained. ©1995 American Institute of Physics.