We propose an arrayed-waveguide grating that shows uniform loss properties over the entire range of wavelength channels by combining two light waves with adjacent diffraction orders at its output. We applied this configuration to an arrayed-waveguide grating with 32 channels and a 50 GHz spacing and were able to reduce the deviations in loss to less than 1.0 and 1.8 dB over one and three free spectral ranges, respectively.