https://www.sunet.se/blogg/long-read-cleanliness-is-a-virtue/
This is an excellent article regarding fiber cleaning and its importance. Please do share with other people in our business. I'm sure lack of proper fiber cleaning causes a lot of unneccessary outages and operational problems worldwide, partly because people aren't aware of its importance.
It is a good article. It is missing a few points:
If you are going to do the full efford of cleaning and then microscope each connector, you would also want to finish off by doing a OTDR scan of the link. This is your documentation for a clean link.
Always use optics that can monitor the signal level. The reality is that best practice, as described in the article, will not always be followed. In most case you will be good anyway as long your optics report back a signal strength with a good margin. Have your automated monitoring system watch over those signal levels.
Slightly dirty connectors will often give a sufficient link quality anyway if you have plenty of power budget to spare. We use many 1G single mode BIDI optics which cost about 10 USD each for 20 km modules and most of the links are only 1-5 km. The customer end of those links are probably all half dirty, but nobody cares as long we get a strong signal back with power budget to spare.
Regards,
Baldur
This is a very comprehensive article, and worth handing out to techs. I have one comment on Balder’s OTDR suggestion, and one on the article’s microscope instructions.
Although it certainly can’t hurt to run an OTDR test (except for extended downtime), I fear hauling out the extra gear will prompt many techs to put off fiber cleaning. In my experience, just doing the cleaning solves 99.9% of the problem. Anything that an OTDR would pick up would likely severely impact performance, while dirty connector will just increase the error rate.
Also, the article didn’t mention eye safety when using a fiber microscope. The example showed a USB digital video microscope, but many maintainer kits in the field have much cheaper direct-view optical microscopes. Viewing an energized fiber with a direct-view microscope can cause major eye damage. I recommend all fiber kits throw out their optical scopes and substitute a USB or WiFI scope (some of these can be used with a cell phone or tablet).
-mel
Cool that this article got posted here (im not the author, but im the dude in the pictures).
One reason we didn't bring up OTDR in the article is that OTDR-test only works on certain occasions. If you have problems with a circuit and decide to take it down to clean it up and inspect patches and ODFs you need to also disconnect the other side if you feel doing a OTDR-test. Launching light from a OTDR-instrument where you have a regular transceiver on the other side gives a potential risk
of destroying it. Also if running the OTDR towards a TX will also skew up the results since there is already light in the fibre.
We have however (both me and j�rgen) done a few articles where we go through OTDR-stuff.
https://www.sunet.se/blogg/sites-and-fibers-being-delivered/
https://www.sunet.se/blogg/first-test-on-real-fiber/
https://www.sunet.se/blogg/full-speed-ahead/
https://www.sunet.se/blogg/otdr-grundlaggande-om/ (use google translate on that one, i can get it translated if its of interest)