What effect does water have on the glass core of an optical fiber?

Water has a detrimental effect on the glass core of an optical fiber because it causes the fiber to absorb moisture, which can lead to the scattering of light within the core. This scattering decreases the clarity and strength of the signal transmitted through the fiber, making it less effective for data transmission. When water infiltrates the optical fiber, it disrupts the precise core structure, resulting in scattering and absorption losses.

In contrast, the other options do not accurately represent the impact of water on optical fibers. For instance, water does not enhance signal strength; rather, it hampers performance. Cooling is generally not a benefit brought by water, as optical fibers are designed to operate efficiently within a specific temperature range without the need for external cooling. Lastly, to say that water has no significant effect ignores the well-documented challenges that moisture presents to optical fiber integrity and performance.