The correct answer is: A. Low in single mode and considerable in multimode fiber.
Intermodal dispersion is a type of pulse broadening that occurs in multimode optical fibers. It is caused by the different paths that light takes through the fiber, as light rays can travel in multiple modes (or paths) down the fiber. The different paths have different lengths, so the light waves arrive at the receiver at different times, causing the pulse to spread out.
Intermodal dispersion is a major limitation in multimode fibers, and it is one of the reasons why single-mode fibers are preferred for long-distance communications. In single-mode fibers, light travels in a single mode, so there is no intermodal dispersion.
Here is a brief explanation of each option:
- Option A: Low in single mode and considerable in multimode fiber. This is the correct answer, as explained above.
- Option B: Low in both single mode and multimode fiber. This is not correct, as intermodal dispersion is only a significant issue in multimode fibers.
- Option C: High in both single mode and multimode fiber. This is not correct, as intermodal dispersion is only a significant issue in multimode fibers.
- Option D: High in single mode and low in multimode fiber. This is not correct, as intermodal dispersion is only a significant issue in multimode fibers.