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winterforge
Premium
join:2000-07-23
Seattle, WA
clubs: 
| reply to DaneJasper
Re: Woa, don't try this at home!
said by DaneJasper  :Regarding the photo - Shining laser in your eye, NOT a good idea. Don't try that at home! -Dane When most people think of safety in fiber optic installations, the first thing that comes to mind is eye damage from laser light in the fiber. They have an image of a laser burning holes in metal or perhaps burning off warts. While these images may be real for their applications, they have little relevance to most types of fiber optic communications. Eye safety is an issue, but usually not from light in the fiber. However, fiber optics installation is not without risks.
Eye Safety
Optical sources used in fiber optics, especially LEDs used in premises networks, are of much lower power levels than used for laser surgery or cutting materials. Even the output of OTDRs, WDM and fiber amplifier systems, which are much higher than LED systems, are still well below that used in laser surgery or machining.
The light that exits an optical fiber is also spreading out in a cone, so the farther away from the end of the fiber your eye is, the lower the amount of power your eye receives. If you are using a microscope, which can efficiently focus all the light into your eye, it should have infrared filters to reduce the danger of invisible infrared light.
The infrared light in fiber optic links is at a wavelength that cannot penetrate your eye easily because it's absorbed by the water in your eyeball. Light in the 1300-1550 nm range is unlikely to damage your retina, but might harm the cornea or lens.
A typical laser pointer, which has a beam that is collimated (not expanding), and is at visible wavelength (650 nm) where the eye is transparent, is probably more danger to the retina than a fiber optic link.
That being said, it's not a good idea to look into a fiber unless you know no source is being transmitted down it. Since the light is infrared, you can't see it, which means you cannot tell if there is light present by looking at it. You should always check the fiber with a power meter before examining it.
The real issue of eye safety is getting fiber scraps into the eye. As part of the termination and splicing process, you will be continually exposed to small scraps of bare fiber, cleaved off the ends of the fibers being terminated or spliced. These scraps are very dangerous. If they get into your eyes, they are very hard to flush out and will probably lead to a trip to the emergency room at the hospital. Whenever you are working with fiber, wear safety glasses!
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In my many years I have come to a conclusion that one useless man is a shame, two is a law firm, and three or more is a congress. - John Adams | |
DaneJasper
Sonic.Net
Premium,VIP
join:2001-08-20
Santa Rosa, CA
clubs:
| said by winterforge :A typical laser pointer, which has a beam that is collimated (not expanding), and is at visible wavelength (650 nm) where the eye is transparent, is probably more danger to the retina than a fiber optic link. All very good data. In this photo, the light is visible green light, apparently laser - obviously NOT what's used for data communications. I wonder if the model was told the risks? 
-Dane | |
Done_Posting
Shoot to kill
Premium
join:2003-08-22
Toledo, OH
 ·buckeye cable
| reply to winterforge
So, what you're saying is that it's safe for me to scope our OC-192 ring connections while they're still lit, and that I should avoid using protective eyewear at all costs? Cool! 
Seriously though, there's no longer a need to turn down circuits anymore with our the new scope we just got at work. It's this neat little USB unit that hooks right into your laptop, which gives you get a nice full screen (live) view of the fiber. The scope doesn't mind if the fiber is lit or not. It even has this sweet feature where it will analyze any contaminants it sees and then tell you their size and a best guess of what they are. Sure beats having to kill the circuit, use a light meter to confirm the fiber is dark, and then hold a bulky monocular-type scope up to your eye while trying to focus the darn thing!
Ah, technology.
- Tate
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Happiness is an OC-48 in your basement... | |
Gizmo_piper
join:2007-11-25 | reply to DaneJasper
lol..it was standard light from a LED, a very bright one, not a laser. | |
swhx7
Premium
join:2006-07-23
Elbonia | reply to winterforge
Thanks for an informative post!
It looks great for home networking, especially if it enables higher speed at low cost. | |
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