| 摘要 |
PROBLEM TO BE SOLVED: To provide the optical fiber which has a larger photodetection angle, can transmit much light, is easy to handle, and has a small leak of light from the flank and no decrease in optical transmission performance with time. SOLUTION: A transparent core 1 which is circularly and elliptically sectioned and flexible is arranged in a flexible tube 2 which has its internal diameter larger than the external diameter of the core 1. An air layer 3 is interposed between the outer periphery of the core 1 and the inner periphery of the tube 2 and both the ends of the core 1 and tube 2 are caulked with sleeves 4. Thus, an optical fiber can be formed which has as a clad the air layer between the core 1 and tube 2. The core 1 and tube 2 are both flexible and freely bent. Further, both the ends of the core 1 and tube 2 are fixed by caulking and united to suppress the contacting between the core 1 and tube 2 when they are bent to a very small extent. |
