Optical Fiber Communications (Principles and Applications) || WDM Concepts and Components

摘要： Wavelength division multiplexing (WDM) is the second major fiber–optic revolution in the field of telecommunications. WDM is a technology which combines many different segments of wavelength range, called different independent optical channels, into the same optical fiber. The best feature of an optical fiber is that it has a wide spectral region which ranges from 1260 nm to 1675 nm. The light source used in high-capacity optical fiber communication systems emits a narrow wavelength band of less than 1 nm, thus enabling simultaneous transmission of many optical channels using the same optical fiber. WDM allows a huge increase in capacity of an optical fiber as compared to point-to-point link that carries only a single optical channel. Another big advantage of WDM is that different transmission formats can be supported by various optical channels. It means that without the need of common signal format, any data rate can be transmitted simultaneously and independently using the common optical fiber.