Polarization-independent liquid-crystal (LC) phase modulators can significantly improve the efficiency and reduce the complexity of optical systems. However, achieving good polarization independence for LC phase modulators with a simple structure is difficult. A light-controlled azimuth angle (LCAA) process based on the optical rotatory effect of cholesteric liquid crystals (CLC) was developed for fabricating single-layer, multi-microdomain, orthogonally twisted (MMOT) structures. The developed LC phase modulator with a single-layer MMOT structure may have a low polarization dependence with a large phase depth. This device shows good potential for applications in optical communications, wearable devices, and displays.