Role of Wavelength Division Multiplexing in Optical Communication

Optical communication, also known as optical telecommunication, is a method of long-distance communication in which light is used to carry data. Wavelength Division Multiplexing (WDM) is used for fast data transmission. WDM (wave-length division multiplexing) is a fiber-optic communications device that uses different wavelengths (or colors) of laser light to multiplex a range of optical carrier signals into a single optical fiber. This technique, also known as wavelength-division duplexing, allows bidirectional communication over a single strand of cable. WDM describes an optical carrier that is traditionally specified by wavelength, while frequency-division multiplexing describes a radio carrier that is typically defined by frequency. This is strictly conventional since wavelength and frequency convey the same information. The frequency (in Hertz, which is cycles per second) multiplied by wavelength determines the carrier wave's velocity (the physical duration of one cycle). The lower case letter c is used to represent the speed of light in a vacuum. In glass fiber, it moves at a much slower pace, about 0.7 times c. The data rate, which should ideally be at the carrier level, is always a fraction of the carrier frequency in practical devices. Normal WDM, Coarse WDM, and Dense WDM are the three wavelength patterns used in WDM systems. The data transmission speed increases as a result of the WDM concept.