Wavelength of light source for optical cable communication

Optical fibers primarily use infrared light with standard wavelengths of 850 nm, 1300 nm, and 1550 nm for efficient data transmission.Standard WavelengthsOptical fibers transmit light in the near-infrared region, which is beyond the visible spectrum. The most commonly used wavelengths are 850 nm, 1300 nm, and 1550 nm for glass fibers, while plastic optical fibers often use 650 nm or 850 nm for short-range applications . These wavelengths are chosen because they minimize signal attenuation, which is caused by absorption and scattering within the fiber .Why Infrared Light?Infrared light is preferred because:Lower scattering: Rayleigh scattering decreases with longer wavelengths, reducing signal loss .Reduced absorption: Glass fibers have minimal absorption at 1300 nm and 1550 nm, allowing long-distance transmission .Compatibility with lasers and LEDs: Light sources and detectors are optimized for these wavelengths .Wavelength BandsOptical communication also uses specific wavelength bands for multiplexing and long-distance transmission:O-band: ~1260–1360 nmE-band: ~1360–1460 nmS-band: ~1460–1530 nmC-band: ~1530–1565 nmL-band: ~1565–1625 nmU-band: ~1625–1675 nm These bands are standardized to optimize attenuation and dispersion characteristics for different network applications .Wavelength Division Multiplexing (WDM)Modern fiber networks use WDM to transmit multiple data streams simultaneously on different wavelengths. There are two main types:Coarse WDM (CWDM): Uses fewer, widely spaced wavelengths for short-range networks.Dense WDM (DWDM): Uses many closely spaced wavelengths (up to 88 or more) for high-capacity, long-distance networks .SummaryIn optical cables, infrared light at 850 nm, 1300 nm, and 1550 nm is standard due to low attenuation and compatibility with fiber materials. Advanced networks leverage WDM to maximize data throughput by using multiple wavelengths simultaneously, with each wavelength acting as a separate data channel .