Double-clad fiber coupler for endoscopy

We present a double-clad fiber coupler (DCFC) for use in endoscopy to reduce speckle contrast, increase signal collection and depth of field. The DCFC is made by fusing and tapering two all silica double-clad fiber (DCF) and allows achromatic transmission of >95% of core illumination (1265nm - 1325nm) as well as collection of >42% of inner cladding diffuse light. Its potential for endoscopy is demonstrated in a spectrally encoded imaging setup which shows speckle reduction by a factor 5, increased signal collection by a factor 9 and enhanced depth of field by 1.8 times. Separation by the DCFC of single-and multi-mode signals allows combining low-speckle reflectance images (25.5 fps) with interferometrically measured depth profiles (post-processed) for of small three-dimensional (3D) features through an all-fiber low loss instrument. (C) 2010 Optical Society of America

我们提出一种用于内窥镜检查的双包层光纤耦合器（DCFC），以降低散斑对比度，增加信号采集量和景深。该双包层光纤耦合器是通过将两根全石英双包层光纤（DCF）熔接并拉锥制成的，它能使超过95%的芯层照明光（1265nm - 1325nm）实现消色差传输，并且能收集超过42%的内包层漫射光。其在内窥镜检查中的潜力在一个光谱编码成像装置中得到了验证，该装置显示散斑降低了5倍，信号采集量增加了9倍，景深提高了1.8倍。双包层光纤耦合器对单模和多模信号的分离使得能够通过一种全光纤低损耗仪器将低散斑反射图像（25.5帧/秒）与干涉测量得到的深度剖面（后处理）相结合，用于小型三维（3D）特征的成像。（C）2010美国光学学会