The influence of medical fiber bending on laser spot distribution of out terminals

In order to investigate the relationship between the bending radius and spot size and uniformity, and to determine the minimum bending radius of medical fiber. A medical fiber spot acquisition test device was built and the output spots of medical fibers with different core diameters were tested. A thulium 1940 nm laser was used as the laser source and a CCD was used to capture the spot output of the medical fiber at different bend radii. The uniformity of the output spot and the change in the spot size of the medical fiber under different bending radius conditions were recorded and analyzed. The test results show that as the bending radius increases, the spot uniformity becomes better and the spot size becomes larger, and when the bending radius reaches 150 times the diameter of the fiber core, the spot size and uniformity change drastically. It was found that the larger the core diameter, the greater the change in spot after bending. The test results provide a reference basis for the setting of the minimum bending radius of medical fibers.