As we all know, if an optical fiber is designed with the right material and properly bent, light can be transmitted along the fiber with very little attenuation.
Figure 1 shows the interaction of radiation F with a conical structure. The cone is a hollow mass with an internal reflector layer or a homogeneous mass of transparent material. Due to the non-ideal incident angle of radiation F (as shown in figure 1), radiation F will be easily reflected back or transferred out of the cone.
In the case of the above cone is a system of multiple optical fibers (figure 2). Optical fibers are arranged as a multi-branch tree: Start by an optical fiber at the bottom, then it is gradually branched at the upper rows and the top row will have the most fibers. Optical fibers have one narrow end below and the other larger end above. The optical fibers are separated by a vacuum layer so that total internal reflection can occur optimally. It can be noticed that radiation F will be easily transmitted along the fiber inside the cone.
We find that with the same incident angle and interaction position, radiation F in the two figures will have two different directions. It can be seen that a system of multiple optical fibers will have a much larger acceptance angle.
The key is to find the right material for the fiber and bend the fibers properly (without bending too strongly) so that radiation F is not refracted out of the fiber during transmission.
Extending from radiation F, can we use the above multiple optical fibers system to optimize solar energy harvesting (similar to Winston cones or Fresnel lenses but with higher efficiency)?