The time delay of several rays of light entering a fiber, exiting that fiber at different times, is known as _____.

The correct answer is pulse dispersion, which refers specifically to the broadening of light pulses as they travel through a fiber optic cable. This phenomenon occurs when different modes or paths of light take varying amounts of time to travel through the fiber, leading to a delay between the arrival of different rays of light. As a result, the shape of the original pulse can become distorted over long distances, adversely affecting the quality of the signal being transmitted.

While terms like mode dispersion might sound relevant, they refer to the specific types of dispersion related to different light paths rather than the overall time delay of light pulses. Signal lag is not a commonly used term in this context and does not specifically describe the distortions in light signals due to pulse propagation. Phase shift deals with the change in the phase of a wave but does not capture the concept of the delay in the arrival of light rays that leads to pulse dispersion. Understanding pulse dispersion is crucial in applications involving long-distance fiber optic communication, as it highlights the importance of managing and minimizing signal distortion for effective data transmission.