Which type of ray travels through an optical fiber without passing through its axis?

The type of ray that travels through an optical fiber without passing through its axis is known as skew rays. Skew rays are light rays that enter the fiber at oblique angles and do not intersect the central axis of the fiber, allowing them to travel along a helical path as they propagate through the core of the optical fiber. This characteristic distinguishes skew rays from meridional rays, which do pass through the axis and reflect back and forth within the fiber's core.

By forming a helical path, skew rays contribute to the total internal reflection and help maintain the signal as it travels through the optical fiber. Understanding the different types of rays in this context is essential for grasping the principles of optical fiber communication, as it influences how light behaves when transmitted through these fibers, which is critical for applications in telecommunications and networking.