Dense Wavelength Division Multiplexing (DWDM) is a technology used in fiber optic communication that allows multiple signals to be transmitted simultaneously over a single optical fiber. It achieves this by using different wavelengths, or colors, of laser light to carry separate data streams. This increases the capacity of the fiber, enabling more data to be sent over long distances without degradation. DWDM is widely used in telecommunications networks to enhance bandwidth and improve efficiency. By combining various wavelengths, service providers can optimize their infrastructure, reduce costs, and meet the growing demand for high-speed internet and data services.