How to choose single-mode and multi-mode optical fibers? What are the differences between single-mode optical fibers and multi-mode optical fibers? Many friends have mentioned related issues for a long time.

In the field of optical fiber data transmission, the term “mode” is used to describe the way light signals propagate within the glass core of an optical fiber—that is, a mode is the path that light travels.

Thus, with single-mode fiber, light travels along one path;

In multimode fiber, however, light travels in multiple paths.

single-mode fiber and multimode fiber

The difference between single-mode fiber and multi-mode fiber

1. Appearance

The sheath of the mode fiber jumper is generally yellow, while the multimode is generally orange or the so-called water green (that is, the color between blue and green); in terms of core diameter, the multimode is generally slightly thicker Some.

2. Transmission distance

The transmission distance of single-mode fiber is not less than 5km, and is generally used for long-distance communication; multimode fiber can only reach about 2km, and is suitable for short-distance communication in buildings or campuses.

3. Light source

Because the LED light source is relatively dispersed and can generate multiple modes of light, it is mostly used in multi-mode fiber; while the laser light source is close to a single mode, so it is usually used in single-mode fiber.

4. Bandwidth

Single-mode fiber has a higher bandwidth than multimode fiber. The dispersion of single-mode fiber is small, so it can transmit light over a long distance with a wide frequency band. Because multimode fiber will produce complex problems such as interference and interference, it is not as good as single-mode fiber in terms of bandwidth and capacity.

5. Use cost

Multimode fiber allows multiple light modes to pass through, so multimode fiber is more expensive than single-mode. However, single-mode fiber uses a solid-state laser diode as a light source, which is far more expensive than multimode fiber light source equipment, so the cost of using single-mode fiber is much higher than that of multimode fiber.

6. Loss

The Telecommunications Industry Alliance (TIA) and the Electronics Industry Alliance (EIA) jointly developed the EIA/TIA standard, which specifies the performance and transmission requirements of optical cables and connectors, and is now widely accepted and used in the optical fiber industry. The EIA/TIA standard specifies that the maximum attenuation is one of the most important parameters in fiber loss measurement. In fact, the maximum attenuation is the attenuation coefficient of the optical cable in dB/km.

The difference between single-mode fiber and multi-mode fiber is introduced here. No matter which fiber jumper we choose, we must make the correct choice according to the specific usage scenario, and don’t consider it unilaterally.