Fiber Optic Cables
Tags
singlemode multimode fiber optic
Differences Between Multimode and Singlemode Fiber Cables

Differences Between Multimode and Singlemode Fiber Cables

Multimode and singlemode fiber optic cables are two types of optical fiber cables used for transmitting data over long and short distances. Here’s a breakdown of the key differences:

1. Core Diameter

  • Multimode Fiber (MMF) has a larger core diameter, typically ranging from 50 to 62.5 micrometers (µm), which allows multiple modes of light to propagate simultaneously. The older style (OM1 and OM2) multimode fiber is usually orange in color; whereas modern multimode is Agua (OM3/OM4) or Violet (OM5) in color. For the LC Connectors, the multimode tend to be either beige or aqua as well.
  • Singlemode Fiber (SMF) has a much smaller core diameter (though the same outside diameter of about 2mm), around 8 to 10 µm, which allows only a single mode of light to propagate. This eliminates modal dispersion, leading to better signal quality over longer distances. Singlemode is not as forgiving as multimode, which means the connectors needs to be very clean (i.e. no dust or fingerprints)

2. Mode of Transmission

  • MMF supports multiple paths (modes) of light, resulting in different paths of light rays that can cause signal distortion over long distances due to modal dispersion.
  • SMF supports a single light path (mode), virtually eliminating modal dispersion and allowing for cleaner signal transmission over longer distances.

3. Bandwidth

  • MMF provides high bandwidth at short distances. Its bandwidth is limited by modal dispersion.
  • SMF offers a higher bandwidth capacity because it supports higher transmission rates over much longer distances without the limitations imposed by modal dispersion.

4. Distance

  • MMF is suitable for shorter distances, typically up to 550 meters (for OM4/OM5) for data communications and about 2 kilometers for telecommunication applications.
  • SMF is designed for long-distance communication (typically measured in miles), capable of transmitting signals over tens of kilometers without significant loss of signal quality, and with the use of repeaters or amplifiers, distances can extend to hundreds or even thousands of kilometers.

5. Applications

  • MMF is often used for short-distance communications, such as within buildings or on campus environments, including data centers and local area networks (LANs).
  • SMF is used for long-haul communications, broadband networks, and high-speed data transmission applications, including long-distance telecommunication networks and cable television networks.

6. Cost

  • MMF cables and associated optics are generally less expensive than SMF, making them a cost-effective solution for short-distance applications.
  • SMF cables and the required optics are more expensive due to the precision needed for singlemode transmission, but they are more cost-effective for long-distance applications because of the lower signal attenuation and higher bandwidth capabilities.

7. Light Source

  • MMF can use LEDs or lasers as light sources.
  • SMF typically requires more expensive laser technology to generate the single light mode that can travel through the smaller core.

In summary, the choice between multimode and singlemode fiber depends on the specific requirements of the application, including distance, bandwidth, and budget constraints. Multimode fiber is preferred for shorter distances with high bandwidth needs, while singlemode fiber is chosen for long-distance, high-speed transmissions.