The purpose of the present paper is to extend the concept of pattern photopolymerization-induced phase separation of a binary blend to a single-component system containing pure photoreactive monomers with a minute level of photoinitiators. The patterning formation process was simulated in the framework of Cahn-Hilliard equation coupled with the photoreaction kinetic equation. Unlike binary systems undergoing photopolymerization-induced phase separation driven by thermodynamic force, the mechanism of pattern formation in the single-component system is essentially a photoreaction-induced transport phenomenon. Of particular interest is the observation of polymer concentration profiles evolving from a sinusoidal wave to various truncated ones. On the basis of two-wave interference optics, the microchannel layers have been fabricated. Resultant morphology was characterized using optical and atomic force microscopes. A two-dimensional light scattering device was utilized to study the diffraction patterns from the fabricated microchannel layers. The observed concentration profiles were compared with the theoretical predictions, and good agreement was found.