Multimode’s primary attraction is the lower cost of the LED transmitters, as opposed to the high cost of the lasers used in singlemode fiber.

Recent developments have shown that multimode fiber can be used with laser transmitters to successfully transmit 10 Gigabit Ethernet more than 300 meters. It is expected that more 50 micron core multimode fiber will be installed in the future, as the smaller core will carry signals further than the 62.5 size, just as a garden hose will spray water further when it is pinched at the end.

When planning an installation where new fiber will be installed, the system designer should first consider whether multimode fiber will function. Multimode is easier to work with, more forgiving of minor installation errors, and can be terminated and spliced using lower cost tools and equipment. Transmission and receiving equipment will also be lower cost than for singlemode.

Singlemode fiber has higher bandwidth and can go farther distances than multimode. However, the fusion splicers and Optical Time Domain Reflectometers (OTDR’s) that are used to splice singlemode and test the completed fiber links are very expensive to purchase. Singlemode is more sensitive to bend violations, and is generally more complex to install, splice, terminate, and test than multimode.

When utilizing pre-installed “dark” fiber strands, the contractor will have to use the fiber type that is available. If the pre-installed fiber link selected for use is a singlemode, the contractor can rent an OTDR tester to verify the link's quality.