对目前正成为研究热点的光纤延迟线(FDL)进行了原理和结构特点的分析，总结了光纤延迟线的分类，对光纤延迟线的3个重要应用领域作了详细的跟踪研究。在光纤传感与光学测量领域，分析了激光器线宽测试系统、晶体双折射参数测量系统、光相干层析成像(OCT)测量系统及光相关光谱术(OCS)测量系统，指出了光纤延迟线在这些系统中的主要作用及参数设置；在光纤通信领域，从原理和系统结构上重点分析了高速脉冲串发生器、光缓存器及光编/解码器，指出了目前存在的问题；在微波光子学领域，详细分析了多频光振荡器、微波光纤延迟线、光A/D转换器及光信号相关处理器。指出了关于光纤延迟线技术的最新研究方向主要是提高延时精度、实现连续可调、减小插入损耗和提高工程可靠性。解决这些问题是光纤延迟线实用化的关键所在。

The principle and configuration characteristics of fiber delay lines (FDL) are analyzed, which are becoming research hotspots. Categories of fiber delay lines are concluded and three important application fields of fiber delay lines are tailed after particularly. At first, in fiber sensing and optical measurement field, the paper analyzes laser line-width measurement system, crystalloid birefringence measurement system, optical coherence tomography (OCT) measurement system and optical correlation spectroscopy (OCS) measurement system. The primary function and parameter setting of fiber delay lines in these systems are pointed out. Secondly, it analyzes the principles and system configurations of high-speed pulse code generator, hybrid optical buffer and optical encoder /decoder in optical communication field, including some essential problems. Thirdly, in detail, it analyzes multi-tone photonic oscillator, microwave fiber delay line, optical A/D converter and optical signal correlation processor in microwave photonics field. At last the paper proposes that the research directions of fiber delay lines are improving delay time precision, realizing delay time regulation continuously, reducing insert loss and improving engineering reliability. Overcoming these problems is the key for wide application of fiber delay lines.