Hello, everyone!
Today, I want to continue to explain a new topic – ODN engineering and maintenance. Now, I will continue to explain ODN engineering.
Today's topic is optical instruments. There are a large number of instruments used in optical systems, and especially those that specialize in PON systems. In general, all optical instruments can be divided into two groups as shown in the following figure.
I will now briefly explain three instruments, namely OPM, light source and OTDR. I have written about them many times, and we can see them in the following pictures.
OPM is short for Optical Power Meter. It is an instrument for measuring optical power. It allows the measurement of one optical signal at a time. On the instrument, we can choose the wavelength (for MM it is 650, 850 and 1300 nm, and for SM it is 1310, 1490, 1550, 1650 nm) and the unit of measurement dB (most often because it is a logarithmic display) or mW. Can be used with or without reference cable (approx. 1 or 2 m, 0 dB) depending on the IL measurement method.
LS or Light Source is a light source used in conjunction with OPM to test IL on an optical link. There are different LS. They are always used with a reference optical cable (about 1 or 2 m, 0 dB). Calibration is also performed with the reference optical cable, and after that, disassembly of the cable is not allowed. Depending on the type of optical fiber, there are different sources and wavelengths.
OTDR is short for Optical Time Detect Reflectometer. One of the most important instruments for testing and measuring in all optical networks. With the help of OTDR, the length and attenuation of the optical fiber, the attenuation and reflections of all events on the optical route, the location of optical fiber interruptions, etc. can be measured. There are different OTDRs, some can measure optical splitters, test live optical fibers, etc. They are always used with a reference cable that is about 100 m due to the dead zone. By the way, with modern OTDRs, the dead zone is up to 1 m. For better results, you need to adjust the OTDR parameters that I talked about in one of the previous articles.
This is the end of this article. I will continue to explain this topic in the next article >> ODN Engineering and Maintenance (26).
Thank you!
Reference:
HCIA-Access, ver. 2.5, Huawei Access Certification Training
