What Are the Differences between Multimode Fiber and Single-mode Fiber?

With the increasing demand for high bandwidth and high speed in networks, optical fibers are widely used as a transmission medium in network cabling. The common types of optical fibers are multimode fiber (MMF) and single-mode fiber (SMF).

Multimode fiber is a common type of fiber operating at 850 nm/1300 nm. This type of fiber has the advantages of high bandwidth and low cost. It is suitable for short distance transmission. Multimode fibers can have hundreds of transmission modes, while single-mode fibers have a single transmission mode. In addition to the differences in transmission modes, there are the following differences between multimode and single-mode fibers.

1. Core diameter

The cladding diameter of multimode fiber is the same as that of single-mode fiber, both are 125μm. However, the core diameter of multimode fiber is much larger than that of single-mode fiber. The core diameter of single-mode fiber is generally 9μm, while the core diameter of multimode fiber is generally 50μm/62.5μm.

2. Transmission distance.

Single-mode fibers have a long transmission distance. So, they are suitable for long distance applications. However, multimode fibers have a shorter transmission distance and are suitable for short distances. In addition, OM3/OM4/OM5 multimode fibers can support high data rates.

3. Light source

Multimode fibers usually use LED (light emitting diode) or VCSEL (vertical cavity surface emitting laser) as light sources, because LED light sources can produce many light modes and the light is more scattered. On the other hand, single-mode fibers usually use lasers or laser diodes as light sources, because laser light sources can produce a single mode of light with high brightness and high power.

4. Chromatic Dispersion

The lower the dispersion of the fiber, the wider its bandwidth. Single-mode fibers have almost no dispersion, so the bandwidth of single-mode fibers is greater than that of multimode fibers.

5. Cost

As mentioned above, single-mode fibers use a laser or laser diode as the light source, while multimode fibers use an LED or VCSEL as the light source. The price of lasers is higher than that of LEDs, so single-mode fiber is more expensive than multimode fiber.

This information is provided by ZMS Cable Group, a professional manufacturer of various cables and related accessories. If you have any questions, please contact us.