The difference between single-mode optical cable and multi-mode optical cable

Transmission over single-mode fiber optic cable

Single-mode optical cables actually use an intermediate core for transmission, called an optical fiber. That is, the single-mode optical cable is composed of optical fiber + outer sheath + intermediate medium. In fiber optic communications, a single-mode fiber (SMF) is a fiber that directly transmits optical signals in the transverse mode. Single-mode fiber runs at a data rate of 100M/s or 1 G/s, and the transmission distance can reach at least 5 kilometers.

Single-mode optical fiber: the central glass core is very thin (core diameter is generally 9 or 10 μm), and only one mode of optical fiber can be transmitted. Therefore, its intermodal dispersion is very small, suitable for long-distance communication, but there are still material dispersion and waveguide dispersion, so single-mode fiber has higher requirements on the spectral width and stability of the light source, that is, the spectral width should be narrow and the stability better.

Transmission of multimode fiber optic cable

Multimode fiber optic cables are mainly used for short-distance fiber optic communications, such as within buildings or campuses. The typical transmission speed is 100M/s, the transmission distance can reach 2km, 1G/s can reach 1000m, and 10G/s can reach 550m. There are two types of indices: graded index and step index.

Multimode Fiber: An optical fiber that transmits multiple modes at a given operating wavelength. According to the distribution of its refractive index, it can be divided into sudden type and gradual type. Since there are hundreds of modes transmitted in multimode fiber, the propagation constant and group velocity of each mode are different, so the bandwidth of the fiber is narrow, the dispersion is large, and the loss is also large. It is only suitable for short-to-medium distance and small-capacity optical fiber communication systems. .

What is the difference between single-mode optical cable and multi-mode optical cable?

Model: GYFTY and GYFTZY are generally multi-mode; GYXTW and GYTS are generally single-mode.

Color: Indoor multi-mode optical cable is orange, indoor single-mode optical cable is yellow.

Mark: MM is multi-mode, SM is single-mode.

Transmission mode: distinguished by the transmission mode of light in the optical fiber.