基于多模光纤或多芯光纤的无透镜超细光纤内窥成像技术近些年获得了快速发展，有望成为下一代的极微创、高分辨率内窥显微镜。通过对相干入射光场的时空调控，该技术可克服多模光纤中模式色散或多芯光纤中相位畸变的影响，在无需光纤末端透镜或扫描器件的情况下实现高分辨率的聚焦、成像及相关应用。此外，在无透镜光纤内窥成像或图像传输等场景下，通过构建物理或深度学习模型，从光纤输出测量中也能实现物体信息重建。对相干光纤无透镜成像技术的发展进行综述，首先说明无透镜光纤成像的基础原理，并从主动波前调控和被动目标重建这两类角度阐述无透镜光纤成像方法，接着介绍一些先进光纤成像模态和技术，列举光纤成像相关应用，最后分析该领域所面临的挑战，总结并展望其进一步发展方向和应用前景。

Lensless ultrathin fiber-optic endomicroscopic imaging technology based on multimode fiber or multicore fiber has made great progress in recent years, and it is expected to produce the next-generation ultra-minimal high-resolution endoscope. By spatiotemporally controlling the coherent incident light field, the influence of mode dispersion in multimode fibers or phase distortion in multicore fibers can be overcome. High-resolution focusing, imaging, and related applications can be achieved through optical fibers without using lens or scanning device at the distal end. In addition, in scenarios of lensless fiber-optic endoscopic imaging or image transmission, object information reconstruction can be achieved from the output measurements by building a physical or deep learning model. This article reviews the development of coherent optical fiber lensless imaging technology. First, it depicts the basic working principles of lensless optical fiber imaging and the imaging methods from the two perspectives of active wavefront control and passive object reconstruction. Then it introduces some advanced optical fiber imaging modalities and technologies and lists fiber imaging related applications, with discussions of general challenges encountered in this field. Finally, a brief summary is made with envision of the development roadmaps.