通过理论计算确立了多功能介质金属结构空芯光纤的结构参量,优化了液相镀膜法的有关条件,明确了具体制作参量。制作了以聚碳酸酯毛细管为基管的,高柔韧性的,可同时低损耗传输红外目标波长激光和可见导航光红外的空芯光纤。对光纤传输性能进行了测试。在2.94 μm波长的Er∶YAG和0.63 μm波长的红色半导体激光器的直线损耗分别为0.4 dB/m和3 dB/m。组装在医疗内窥镜中的柔性空芯光纤,在先端以0.9 cm半径135°角弯曲时,对Er∶YAG激光仍有近70%的传输效率;绿色导航光在内窥镜中的的损耗值为11 dB,绿色指示点在内窥镜的视窗中清晰可见。结果表明此种光纤在内窥镜的激光传输方面有重要的应用价值。

Low-loss and flexible hollow optical fibers were fabricated based on the polycarbonate capillary. Silver and cyclic olefin polymer films were innerly coated to enhance the reflectance at objective wavelengths. By optimizing the liquid-phase coating parameters, polymer layer obtained optimum thickness for simultaneous transmission for Er∶YAG and visible pilot beams. Polycarbonate capillary based hollow fibers are flexible and safe, which makes it possible to deliver infrared laser power in endoscopic application. The transmission losses are 0.4 dB/m and 3 dB/m for the 2.94 μm Er∶YAG laser and red visible laser, respectively. The transmittance of Er∶YAG laser light is about 70% and loss of visible pilot beam is 11 dB when the fiber was sharply bent with a bending radius as small as 0.9 centimeter and bending angle at 135°. Experimental results show that cyclic olefin polymer coated silver hollow polycarbonate fiber are suitable for the delivery of endoscopic laser and visible pilot beam.