What is the effect of increasing the core diameter in multimode fibers?

Increasing the core diameter in multimode fibers leads to increased modal dispersion. Modal dispersion occurs because light travels through multiple paths or modes within the fiber. When the core diameter increases, more modes can propagate, and these modes can travel at different speeds and along different paths. As a result, the light pulses become spread out over time as they traverse the fiber. This phenomenon can ultimately limit the distance and bandwidth of the signal being transmitted, making it crucial for installers to consider the core diameter when designing or selecting multimode fiber optic cables.

In contrast, while a larger core diameter may allow for easier coupling of light, it does not inherently reduce signal loss or improve bandwidth; these factors are more closely related to fiber design and material properties. The numerical aperture, which describes the light-gathering capability of the fiber, is not reduced by increasing the core diameter; rather, it could remain the same or potentially increase, depending on the overall design of the fiber.