多阶光存储是一种在不改变原有光路和机械系统的情况下，利用先进的信号处理与调制编码技术，显著提高存储容量和数据传输率的新型技术。综述了多阶光存储的发展历史及研究现状，并针对多阶光存储的两种类型(信号多阶和介质多阶)，列举了几种典型的多阶光存储方案。从本质上分析了信号多阶技术和介质多阶技术的不同，展望了其发展方向。

Using advanced signal processing and modulation coding techniques,multilevel optical storage can further increase the disc capacity and data transfer rate without changing the optical pick-up head and mechanical system of the disc drives. The history and the state-of-the-art of multilevel optical storage are summarized. Several typical multilevel schemes are presented for two kinds of multilevel optical storage,which are signaling multilevel and material multilevel respectively. An essential distinction between signaling multilevel and material multilevel is illustrated. The development trends of multilevel optical storage are discussed and analyzed.