How does WDM enhance optical network capacity?

Wavelength Division Multiplexing (WDM) enhances optical network capacity by allowing multiple wavelengths to carry data simultaneously on a single optical fiber. Each wavelength acts as an independent channel that can transmit information concurrently with others, effectively multiplying the amount of data that can be sent over that single fiber. This technique capitalizes on the fiber's bandwidth potential by utilizing different colors of light (wavelengths) to separate the various data streams, increasing the total capacity without requiring additional physical fibers.

In contrast, larger cables or a reduction in the number of fibers does not inherently increase the data transmission capabilities. While increasing the speed of a single wavelength might improve the performance of that specific channel, it does not contribute to the overall capacity as significantly as using multiple wavelengths in parallel does.