Ultra Thin Optical Fiberscope Using Phase Conjugate Wave

近年来，光纤镜在医学诊断和无损检测中发挥了重要作用，其图像特性得到了显著改善。对物体的观测直接建立在光信息本身传输的基础上，因此对光场的观测是必不可少的。但是在传统的光纤镜中，图像分辨率受到光纤尺寸的限制，因为光纤束中的每一根光纤对应于这些系统中的一个图像像素。作为该纤维束的替代方案，还显示了一种通过使用具有透镜状折射率变化的纤维直接传输图像的方法，但在这种情况下只能使用直且相对较短的纤维。另一方面，利用相位共轭技术，研制并演示了一种仅用一根多模光纤就能实现物体视场重建的新型光纤镜。所需要的相位共轭波可以通过将光纤的输出…More场通过相位共轭器来产生；图像通过具有相同特性的单个光纤重新传输。因此，在这个系统中，必须提供一对具有相同特性的光纤。然而，两根具有相同特性的光纤很难制作，为了避免这一问题，本研究提出了将读写过程合并为一根光纤的时间共享方法。这个过程导致丢弃实时处理；大大降低了对光纤的要求，完全消除了外来光引起的噪声。用该方案对小物体进行了实际观测。为此目的，所需的照明源是通过将微透镜与第二根光纤组装在一起来实现的，这样就实现了一个紧凑而非常薄的光纤镜，其尺寸约为单个多模光纤直径的两倍。观察小物体的三维场的结果产生了系统的三维分辨率。此外，还讨论了纤维弯曲的影响。给出了对IC芯片的观察结果。少

Optical fiberscopes have played an important role in medical diagnosis and nondestructive measurements, and the image characteristics have recently been remarkably improved. The object is observed directly on the basis of transmission of the optical information itself, so it is essential for the observation of optical fields. But in conventional optical fiberscopest the image resolution is restricted by fiber size, because each fiber of the fiber bundle corresponds to an image Dixel in these systems. As an alternative to this fiber bundle, a method transmitting the image directly by using a fiber having a lenslike index variation has also been shown but in this case only straight and relatively short fiber can be used.On the other hand, by using phase conjugation a possible new fiberscope that achieves the reconstruction of the object's field with only a single multimode fiber is produced and demonstrated. The required phase conjugate wave can be generated by putting the fiber's output … More field through a Phase conjugator; the image is retransmitted through a single fiber with the same characteristics. Hence, in this system a pair of fibers with the same characteristics must be provided. However, it is difficult to fabricate two fibers with the same characteristics, and to avoid this problem in this research time sharing between read and write processing combined into a single fiber was proposed. This procedure leads to discarding real-time processing; the requirements on the fiber are greatly reduced and noise caused by extraneous light is eliminated completely.Demonstrations are shown of the actual observation of small objects using this scheme. For this purpose, the required source of illumination is made by assembling a microlens with a second fiber, thus a compact and very thin fiberscope having a size of about twice the diameter of a single multimode fiber is achieved. The results of observing a 3-D field of small objects yield the 3-D resolution of the system. In addition, the effects of fiber bending are also discussed. Results of observation of IC chips were shown. Less