The longest transmission distance of single mode fiber

Transmission distance of single-mode fiber: 64 channels of 40G Ethernet can be transmitted over a distance of 2,840 miles on a single-mode fiber optic cable. A single-mode fiber is mainly composed of a core, a cladding and a coating; the core is made of a highly transparent material; the refractive index of the cladding is slightly smaller than the core, resulting in an optical waveguide effect that makes most of the The electromagnetic field is bound in the fiber core and transmitted; the role of the coating layer is to protect the fiber from water vapor erosion and mechanical abrasion, while increasing the flexibility of the fiber. Outside the coating layer, a plastic jacket is often added.

What is the difference between single mode fiber and multimode fiber?

Differences in refractive index: Single-mode fibers often use a step-index profile. Multimode fibers can use either a step index distribution or a graded index distribution; therefore, silica fibers can generally also use multimode step index fibers, multimode graded index fibers, and single mode step index fibers three.

Different transmission modes: single-mode fiber can only transmit one mode for a given operating wavelength, and multi-mode fiber can transmit several modes. The propagation of electromagnetic waves such as light in optical fibers belongs to the medium circular waveguide. When the light is totally reflected at the interface of the medium, the electromagnetic wave is confined in the medium, which is called guided wave or guided mode. For a given guided wave and operating wavelength, there are multiple incident situations that satisfy the condition of total reflection, which are called different modes of the guided wave. According to the transmission mode, it is divided into multi-mode fiber and single-mode fiber.

The difference in transmission distance: The transmission distance and transmission bandwidth of single-mode fiber are obvious due to multi-mode fiber. If the transmission distance is greater than 5 kilometers, single-mode fiber is the best choice for transmitting large-bandwidth data signals in terms of applications; if the transmission distance is only a few kilometers, multi-mode is the best choice, because the LED transmitter/receiver requires more than single-mode lasers. Much cheaper.

Different wavelengths of optical fiber transmission: the core diameter of single-mode fiber is very small, and it can only transmit in a single mode at a given operating wavelength, and the transmission frequency is wide and the transmission capacity is large. Multimode fiber is a fiber that can transmit in multiple modes simultaneously at a given operating wavelength. Compared with single-mode fiber, the transmission performance of multi-mode fiber is poor.