Types and differences of SM optical fibers

Hello everyone!

There are a number of different SM fiber optic standards. In today’s article, I will explain the G.652, G.653, G.654, and G.655 standards. Let’s familiarize ourselves with these standards!

The following table shows the standards with a basic description that I will write about today.

There are different standards that are used, such as ITU-T, IEC, and TIA. The largest number of countries in the world use ITU-T standards. With these standards, ITU-T defines the geometry of optical fibers and the performance of transmission of optical signals for SM and MM optical fibers.

ITU-T G.652

This standard applies to SM optical fibers. It is one of the oldest standards, but it is still widely used. The optical fibers are optimized to work in the range around 1310 nm, but the amount of water is also reduced to enable work in the range around 1400 nm.

There are four subcategories: G.652.A, G.652.B, G.652.C, and G.652.D. Today, the G.652.D standard is widely represented. in FTTH systems, the feeder and distribution segments use this standard. They match well with the G.657 standards used for the drop segment.

The most important features of these G.652 substandards are:

G.652A :
Atten </= 0.5 / 0.4 at 1310 / 1550nm
Macrobend </= 0.5 dB at 1550nm
PMD </= 0.5 ps/sqrt(km)

G.652B :
Atten </= 0.4 / 0.35 /0.4 at 1310 / 1550 / 1625nm
Macrobend </= 0.5 dB at 1625nm
PMD </= 0.2 ps/sqrt(km)

G.652C :
Atten </= 0.4 from 1310 to 1625nm, </= 0.3 at 1550nm, and
at 1383nm, it must be </= that specified at 1310nm, after hydrogen aging.
Macrobend </= 0.5 dB at 1625nm
PMD </= 0.5 ps/sqrt(km)

G.652D (covers all above):
Atten </= 0.4 from 1310 to 1625nm, </= 0.3 at 1550nm, and
at 1383nm, it must be </= that specified at 1310nm, after hydrogen aging.
Macrobend </= 0.5 dB at 1625nm
PMD </= 0.2 ps/sqrt(km)

ITU-T G.653

This standard describes dispersion-shifted SM optical fiber. The optical fiber is designed to operate in the 1550 nm range (lowest attenuation). This standard is most often used for the realization of very long optical routes – transport networks. Attenuation is around 0.2 to 0.25 dB/km, and in addition, optical amplifiers – EDFAs – work in this range.

ITU-T G.654

The G.654 standard is a standard for SM optical fibers. In the range of around 1300 nm, SM optical fibers have zero-dispersion. Around 1550 nm has minimal attenuation. Optical fibers are designed for optimal operation in the range from 1500 to 1600 nm. Therefore, like optical fibers of the previous standard, they are used for transmissions over very long distances.

ITU-T G.655

This standard, like previous standards, applies to SM optical fibers. This is single-mode NZ-DSF (Non Zero Dispersion-shifted Fiber). With these SM optical fibers, the dispersion that caused problems in WDM (Wavelength Division Multiplexing) systems is suppressed. These optical fibers are optimized for operation in WDM systems, over very long distances. One of the applications of all types of SM optical fibers is in transoceanic optical cables.

This is the end of this article. I hope you learned something new!

Thank you!