Developing improved communication models for expanding wireless communication capacity in spatial dimensions is an important research goal. However, there are two main theoretical concerns with the construction of orthogonal channels in spatial dimensions: one is ill-conditioned problem, and the other is sparseness. Addressing these two issues, we propose a new communication model for spatial-dimension expansion. Considering the acousto-optic effect, a laser is used to expand the spatial dimension; a sparse array layout is designed by an optimization algorithm; and the optimal distribution is determined by a clustering algorithm to complete the model layout design. Through the simulation calculation model example, it can be obtained that its condition number is 25. After cluster analysis, only 4 laser receivers can replace the original 88 unit antennas to form a receiving array. This model plays an important role in improving wireless communication capacity, provides a new concept for building underwater lightweight long-distance and high-capacity integrated communication systems, and contributes basic research for the theoretical development of future wireless communication models.