The optical beam steering device is essential for LiDARs and non-mechanical ones have been developed extensively. We have studied the one based on a Si photonic crystal waveguide (PCW) that guides slow light. In LiDARs, the beam hits a distant object. Then, reflected light is scattered hemispherically and a part of it is returned and received by the PCW. In this process, a long PCW aperture is expected to increase the reception intensity. However, since the PCW has a propagation loss of the order of 10 dB/cm, the reception intensity is not increased by simply lengthening the PCW. In this study, in order to suppress the total loss of the PCW, we proposed and fabricated a serial array of PCWs, in which light is received by multiple and short PCWs and then summed by using Si wire waveguide and coupler. We first estimate the transmission and reception characteristics of the PCW array. The effective aperture radiating light is lengthened by dividing the PCW, so the beam divergence becomes small and the reception intensity is improved. Also, we measured the transmission characteristics of the PCW array. We obtained a 0.046° beam divergence by controlling the phase between the PCWs. In the beam steering by the wavelength scanning or heating, we confirmed that the phase matching angular step appears stepwise. If we use the angular step as a resolution point, we can obtain the beam steering without the phase control.