Major Differences between Single and Multi Mode Fiber Cables

According to the transmission mode, fiber cables can be divided into single-mode cables and multi-mode cables.

Single-mode fiber optic cable (SMF)
1. The single-mode cable can only transmit tone mode; therefore there is no mode dispersion.

2. The single-mode cable use solid laser as its light source, while the multi-mode cable use the Light Emitting Diode (LED). Single-mode cable doesn’t have the mode dispersion, thus the fiber core is thinner. The cable has broader transmission bandwidth, larger capacity and longer transmission distance, however, it need laser source so the cost is higher.

3. Single-mode cable has thin fiber core, and the light can be emitted directly to the center. It’s recommended to be used in the long distance. 

4. In addition, the single-mode cable has lower signal loss. For instance, in the distance of 3000 feet, the signal loss of muti-mode cable may up to 50%, while the single-mode is only 6.25%.

5. The single-mode cable may be the best choice for fast and long-distant transmission. The recent tests show that, the single-mode cable can transmit the 40G Ethernet to 2,840 miles distance with 64 channels.

Multi-mode fiber optic cable (MMF)
1. Multi-mode cable can transmit multiple modes of wave. The multi-mode cable has larger mode dispersion, so the capacity is lower. The fiber core is thicker, usually is 50um, the numerical aperture is about 0.2. Dispersing module technology limited the bandwidth and distance of multi-mode cable. Therefore, the multi-mode cable has low transmission speed and distance, but the low is low, generally use in building or the adjacent locations.

2. Multi-mode cable transmits signals with multiple channels, it’s recommended to use in short distance within one mile.

3. The effective distance between transmitter and receiver is about five miles. The transmission distance is also influenced by types and quality of transmitter and receiver. Tests show that the bandwidth of multi-mode cable is about 4000Mb / s.

In daily application, the distance is the most common factor need to consider when deciding taking what kind of fiber cables. When the distance is only several miles, it’s better to use multi-mode, for the LED device is more economical than laser. When is distance is over five miles, the better choice will be single-mode cable. The other factor is the bandwidth, if want to transmit the signal with large data, single-mode is definitely the best choice.