What defines the maximum critical angle in fiber optics?

The maximum critical angle in fiber optics is defined by the angle that, when surpassed, light will not reflect within the core of the fiber optic cable and will instead be lost in the cladding. This phenomenon occurs because light is guided through the fiber by total internal reflection, which relies on the relationship between the refractive indices of the core and cladding. When light exits the core at an angle greater than the critical angle, it fails to meet the conditions necessary for total internal reflection and thus cannot be guided through the fiber. Instead, it refracts into the cladding and is lost.

Understanding this concept is crucial for effective design and operation of fiber optic communication systems, as maintaining light within the core ensures efficient data transmission. This angle is determined by the material properties of the fiber, particularly the refractive indices involved.