1. How do optical fibers transmit light?
The realization of communication by fiber optics It is based on the principle of total reflection of light.
When light propagates towards the center of the fiber, the refractive index n1 of the fiber core is greater than that of the cladding n2, and the core loss is less than that of the cladding, so the light will undergo total internal reflection and its light energy is transmitted mainly in the core. Due to successive total internal reflections, the light can be transmitted from one end to the other.
2. How are optical fibers classified?
Classified by transmission mode: single-mode fiber and multi-mode fiber.
Single-mode fiber has a small core diameter and can only transmit light waves in one mode.
Multimode fiber has a large core diameter and can transmit light waves in multiple modes.
You can also distinguish single-mode fiber from multi-mode fiber by the color of its appearance:
Most of the optical fibers Single-mode fibers have a yellow jacket and a blue connector, and the cable core is 9.0 μm. There are two core wavelengths for single-mode fiber: 1310 nm and 1550 nm. 1310 nm is generally used for short, medium, or long-distance transmission, and 1550 nm for long and ultra-long-distance transmission. The transmission distance depends on the transmission power of the optical module. The transmission distance of a 1310 nm single-mode port is 10 km, 30 km, 40 km, etc., and the transmission distance of a 1550 nm single-mode port is 40 km, 70 km, 100 km, etc.
Multimode optical fibers are mostly orange/gray jacketed with black/beige connectors, and the core diameters are 50.0 μm and 62.5 μm. The center wavelength of multimode fiber is typically 850 nm. The transmission distance of multimode optical fiber is relatively short, generally within 500 m.
Classification according to ITU-T international standards: G.651, G.652, G.653, G.654, G.655, G.656, G.657.
Post time: Feb-24-2023
