The Effect of Bend Angle, Bend Radius, and Coating on the Percent Retention of Light in an Optical Fiber

One major flaw with optical fibers is that, when bent, there is a loss in the intensity of the light transmitted through them. The purpose of this research was to determine the magnitude of these losses and the factors that would affect the overall efficiency of the fibers. Optical fibers are valuable to the telecommunication industry as they transfer large amounts of data quickly and efficiently. They transfer information better than the traditional standard of copper, as light can travel faster in glass than electricity can travel in copper. Fiber optics work because of the phenomenon of total internal reflection: the property that allows light to be completely reflected back into the medium, in this case glass. To determine the magnitude of the bend losses, thin glass strands were coated with silicone, and then bent at different angles and along different radii. The glass rods attached to a laser via connectors, and the initial intensity of the light was measured before the strands were bent. Then, they were bent to the desired values and the intensity was measured again. Finally, the final intensity was divided by the initial intensity to determine the percent intensity that the fibers retained. The greatest efficiency was present in a fiber with two silicone coats that was bent along a 5 centimeter radius at a 45 angle; the lowest efficiency was in a single-coat fiber bent along a 4 centimeter radius at a 30 angle. It was concluded that the only significant factor was the coating. All other single and interaction effects were deemed insignificant.

Research Conducted By:

Jeremy Maurice
Warren Mott High School

Daniel Pisarski
Sterling Heights High School