1. The difference between adapters
Fiber optic adapters (also called fiber optic couplers or mating sets) are designed to connect two fiber optic cables together. Fiber optic adapters are designed for multi-mode or single-mode cables and have a variety of characteristics that help distinguish them. When looking at the adapter, there are several options and styles that can help determine which one is appropriate. There are some substantial differences. Different colors help distinguish fiber optic cable types, connector types, and hybrid adapters. Adapters are available in different versions, which can connect a single fiber together (simplex), two fibers together (duplex), and sometimes four fibers can be connected together (four fibers). In the optical fiber, all adapters play a vital role, it helps the transmission of optical signals around the world.
2. Align the casing material
One major difference between single-mode and multi-mode adapters is the material used for the sleeve that connects the two male connectors together. Zirconia sleeves are usually used for single mode, and phosphor bronze sleeves for multi-mode. Recently, zirconia has even been used in multi-mode applications. This is important because tolerances play a vital role in matching fiber optic connectors, especially those with small core sizes. Since single-mode connectors have a smaller core size, usually 9um, the alignment tolerance of the two cores must be very tight. This is achieved by using zirconia sleeves with very tight tolerances. For multi-mode connectors with larger core sizes, they are usually 50um or 62.5um; in single-mode applications, the tolerance level can play a greater role. Another difference that explains this is the type of light source used on the network. Single-mode optical fiber uses a laser light source, and traditional multi-mode optical cables use LED lights to transmit signals. Furthermore, OM3 and OM4 are laser-optimized fibers, and they use vertical-cavity surface-emitting lasers (VCSELs) as a laser source.
3. Color recognition
The color helps determine what type of fiber optic cable you have, but it can also help to look at the adapter. The color can not only help you identify whether it is single-mode or multi-mode, but it can also help you distinguish the type of polishing on the connector or coupler end face. This mainly applies to single-mode connectors.
The core sizes of 50-micron multimode fibers vary as well as their bandwidth capacities. Beige adapters are often used for 62.5um fibers since beige fibers are associated with beige fibers. When handling 50um fiber, you must pay attention to all the details.
50um fiber comes either in the OM2, OM3, OM4, or OM5 types. Let’s start with OM2, because this one may be difficult to understand because it has the same orange coat as the 62.5 fiber. OM2 usually uses black adapters, but beige is also used. This is why it is the safest, always look at the printed mark on the fiber optic cable shell to know which fiber optic cable you have. OM3 and OM4 can also be confusing because they both use water, so you have to read the jacket to be sure. However, OM4 does have another color in use-magenta. Magenta is not an industry-standard color, but it can help you distinguish the types of fiber optic cables.
For single mode, it is slightly easier because only two color adapters are usually used. The blue color means you have a single-mode connector, but it also lets you know that it is a UPC (super physical contact) polished connector or slightly rounded edges. There is also a green adapter, which indicates that it is an APC (Angle Physical Contact) polished connector. In APC polishing, this connector has an 8-degree angle, which helps to reduce the back reflection of the connector. Applications such as FTTx use these fiber optic connectors, which require very low back reflections to achieve long-distance signals.
