Wavelength-Division Multiplexing (WDM) is an advanced optical technology that significantly enhances the capacity of communication networks. It achieves this by multiplexing, or combining, multiple optical carrier signals onto a single optical fiber. This is accomplished through the use of different wavelengths of laser light, with each wavelength representing a separate data channel. By utilizing various wavelengths, WDM allows for the simultaneous transmission of multiple data streams over the same fiber, effectively increasing the bandwidth and efficiency of the network.

WDM is particularly beneficial in telecommunications and data centers, where the demand for high-speed data transmission is continually growing. It enables service providers to expand their network capacity without the need for laying additional fiber, thus reducing infrastructure costs.

There are two main types of WDM: Coarse Wavelength-Division Multiplexing (CWDM) and Dense Wavelength-Division Multiplexing (DWDM). CWDM typically uses fewer channels with wider spacing between wavelengths, making it more cost-effective for shorter distances. In contrast, DWDM offers a higher number of channels with closer spacing, suitable for long-haul and high-capacity applications.

Overall, WDM is a crucial technology in modern optical communication systems, providing the flexibility and scalability needed to meet the ever-increasing demands for data transmission.