Hi, everybody!
Today I will explain “How to choose the single-mode fiber?”.
There are different types of single-mode fiber. It depends on the length of the link, the wavelength of transmitters, data rate, and CWDM or DWDM. Now I will explain the most commonly used single-mode fibers.
Figure 1. Multimode and single-mode fibers
(http://www.fiberopticshare.com/single-mode-fiber-vs-multimode-fiber-choose-2.html)
Singlemode fibers are mainly used for outdoor installation, from a few meters to a few hundred kilometers. It has unlimited bandwidth and offers "unlimited possibilities". Singlemode fibers use FB or DFB laser diodes.
Next single-mode fibers are most widely used:
G.652 fiber is the most popular fiber and the oldest design. It was designed for applications at 1310nm, where is zero dispersion. This fiber we can use for short links on 1550nm or in systems employing dispersion compensation. There are G.652A, G.652B, G.652C, and G.652D. Today for ODN, in feeder and distribution segments, we use G.652D single-mode fibers.
G.653 fibers are used for long links with optical amplifier – EDFA (Erbium-Doped Fiber Amplifier).
G.654 fibers are used in systems with high optical power levels, for work in the range 1550-1600nm.
G.655 fiber is used in systems with high optical power levels, WDM, and long links (like transoceanic cables). This is NZ-DSF (Non-Zero Dispersion Shifted) fiber. We can use them in systems where dispersion is a problem, such as long links.
G.656 fibers are designed for local access and long systems with CWDM and DWDM at 1460nm to 1625nm.
Figure 2. Bending radius (in mm) for standards of optical fibers G.652 and G.657
(https://www.itu.int/dms_pub/itu-t/oth/0b/04/T0B040000542C01PDFE.pdf)
G.657 fiber is a new type of single-mode fiber. These fibers are designed to minimize the sensitivity of the fiber to bend or stress loss. There are G.657A1, G.657A2, G.657B2, and G.657B3. These fibers are very popular in PON FTTH. Usually, patch cords use G.657A1, tight buffer cables for installation in the building use G.657A2, indoor drop optical cable use G.657A2 or G.657B2, etc. Standard G.657A is compatible with G.652, but G.657B is not compatible with G.652. If we splice fibers G.652 and G.657B, we will have a big loss.
Thank you!
