Differences Between MMF and SMF Optic Cables

Single-mode fiber (SMF) and multi-mode fiber (MMF) transceivers differ in distinct ways. Knowing the subtle differences will help you make the best selection for your project. The differences are highlighted to help you determine which protocol is best for your optical fiber transceiver application.

MMF and SMF Optic CablesSingle Path Versus Multiple Paths
SMF uses laser light. The light usually follows a single path through the fiber. MMF takes multiple paths, which may result in a differential mode delay. Each type of fiber can be used for different applications. It’s best to know which application is best for your project. Otherwise, it will not operate at optimal levels.

Short Distances Versus Long Distances
SMF is used for long distance communication, and MMF is used for distances of 500m or less. Each type is equally as effective when chosen for the proper communication device. Check the ratings to determine which type is best for your application. The distances should be clearly marked.

Precision Termination Versus Not
An SMF transceiver will typically have a narrower core with a more precise termination than a connection with MMF. This type of core can be used in different applications even more so than the latter type of core. Some designers prefer the precision termination because it can fit into smaller spaces.

Low Cost Versus High Cost
MMF is typically a lower cost solution than SMF. Budgetary concerns may prompt designers to seek solutions with MMF fiber optic cables. The equipment that’s used for communications over MMF is usually less expensive than SMF also. The typical transmission speed and distance have limitations of 100 Mbit/s for distances up to 2 km.

Color Distinction
To distinguish between MMF and SMF cables, a color distinction is made. Typically, yellow is used for SMF cable color and orange or aqua is used for MMF cables. The angular physical connector is displayed in the color of green.

Other Primary Differences
MMF is typically characterized by having a larger core diameter. In most instances, it’s larger than the wavelength of light it supports. MMF has more capacity to gather light than SMF. A larger core size means that designers can create a lower cost electronic device and offer a lower price to the public. By using light-emitting diodes (LEDs) and vertical-cavity surface-emitting lasers (VCSELs), the costs can be driven down even more.

MMF bandwidth distance is even lower than SMF fibers, and thus, it can support more than one propogation mode. However, unlike single mode, it has modal dispersion limitations. The lasers used to drive SMF fibers will produce light of a single wavelength.

Differences Between SMF and MMF Optic Cables
There are some distinct differences between SMF and MMF optic cables that will make a difference in the types of applications for which they can be used. Most people will buy the devices without regard to the application, but this can be a mistake. Evaluate your project to determine which will be the best choice for SMF and MMF optic cables.

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