Eye protection in DWDM systems -- what threshold?
At what power level do DWDM systems become dangerous to work near (i.e. not staring into any optics, using light meters, etc)? I never see technicians on inside DWDM systems using eye protection, but I see power levels of amps going higher and higher. On a recent meter I saw almost .6mW... Any pointers to a document saying 1550nm becomes dangerous at xxxx dbM? Thanks in advance, DJ
There are erbium doped raman lasers with output of up to 10 watts continuous wave, they are (obviously) class 4 devices and are considered hazardous. 3r and 3b emitters shouldn't be directly exposed to the eye, and carry an appropriate warnings. the 10-80km stuff should all be 1 or 1m and does't merit the yellow triangle. Deepak Jain wrote:
At what power level do DWDM systems become dangerous to work near (i.e. not staring into any optics, using light meters, etc)? I never see technicians on inside DWDM systems using eye protection, but I see power levels of amps going higher and higher. On a recent meter I saw almost .6mW...
Any pointers to a document saying 1550nm becomes dangerous at xxxx dbM?
Thanks in advance,
DJ
Hi Deepak, Most modern DWDM transponders with 160km network side optics will be launching anywhere from -2dBm to +2dBm depending on how warm the laser is, assuming a +2 dBm launch you are looking at around 1.6mW - not something you want to be exposing your eyes too. If you've also deployed EDFA's in your optical topology potentially adding another +20 dBm or so, its a good idea to start documenting expected optical power levels at each point in your topology for times when splice work or other maintenance work needs to be performed. To be on the safe side, the best policy is to simply shut down any light contributing lasers on a given strand when performing any kind of maintenance on that strand (design your optical topology with redundancy in mind, so you can seamlessly take light off a given path if need be). Modern gear usually comes equipped with a feature called ALS (Auto Laser Shutdown), where if an LOS condition is detected the laser is automatically shutdown. If your gear supports this, enable it. It could potentially save an ignorant tech's eyesight :). Cheers, Kevin Hodle On Mon, Jun 8, 2009 at 11:42 PM, Deepak Jain<deepak@ai.net> wrote:
At what power level do DWDM systems become dangerous to work near (i.e. not staring into any optics, using light meters, etc)? I never see technicians on inside DWDM systems using eye protection, but I see power levels of amps going higher and higher. On a recent meter I saw almost .6mW...
Any pointers to a document saying 1550nm becomes dangerous at xxxx dbM?
Thanks in advance,
DJ
On Tue, 9 Jun 2009, Kevin Hodle wrote:
Hi Deepak,
Most modern DWDM transponders with 160km network side optics will be launching anywhere from -2dBm to +2dBm depending on how warm the laser is, assuming a +2 dBm launch you are looking at around 1.6mW -
It might be good to note that there are ZX GBICs (120km variants) that are launching at +2 to +5, so you don't really need a DWDM system to achieve these levels. Care not to expose eyes to this light should be taken whenever handling optics of any kind. -- Mikael Abrahamsson email: swmike@swm.pp.se
I forget who the vendor is now, but their shelves are sealed with a door which, when opened, turns off all the lasers on the shelf so you can work on it, yes, a simple provisioning operation causes an outage / protection switchover!! Dave. Deepak Jain wrote:
At what power level do DWDM systems become dangerous to work near (i.e. not staring into any optics, using light meters, etc)? I never see technicians on inside DWDM systems using eye protection, but I see power levels of amps going higher and higher. On a recent meter I saw almost .6mW...
Any pointers to a document saying 1550nm becomes dangerous at xxxx dbM?
Thanks in advance,
DJ
Reminds me of the old warning/attention sign over a termination rack... WARNING: Do not look into laser with remaining eye. Jeff
On Tue, Jun 09, 2009 at 12:43:09PM -0400, Jeff Kell wrote:
Reminds me of the old warning/attention sign over a termination rack...
WARNING: Do not look into laser with remaining eye.
The only problem with those funny signs is they scare remote hands techs into never looking at a fiber because they don't want to try and understand the difference between a SX GBIC and a class 3 ultra longhaul amp. -- Richard A Steenbergen <ras@e-gerbil.net> http://www.e-gerbil.net/ras GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)
On Jun 9, 2009, at 2:06 PM, Richard A Steenbergen wrote:
On Tue, Jun 09, 2009 at 12:43:09PM -0400, Jeff Kell wrote:
Reminds me of the old warning/attention sign over a termination rack...
WARNING: Do not look into laser with remaining eye.
The only problem with those funny signs is they scare remote hands techs into never looking at a fiber because they don't want to try and understand the difference between a SX GBIC and a class 3 ultra longhaul amp.
Honestly, that is probably better. Kinda like never pointing a gun at anyone, whether you think it is loaded or not. Put another way: I don't trust many H&E techs to know the difference between an SX GBIC and a Buck Rogers Laser Cannon. Besides, lots of lasers these days are infrared, so you can't see them anyway. (Hence the "last thing you never saw" comment.) -- TTFN, patrick
In a message written on Tue, Jun 09, 2009 at 01:06:42PM -0500, Richard A Steenbergen wrote:
The only problem with those funny signs is they scare remote hands techs into never looking at a fiber because they don't want to try and understand the difference between a SX GBIC and a class 3 ultra longhaul amp.
Save your poor techs eyes, and make them more reliable all at the same time: http://search.newport.com/?sku=F-IRC2-F -- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/
Leo Bicknell wrote:
In a message written on Tue, Jun 09, 2009 at 01:06:42PM -0500, Richard A Steenbergen wrote:
The only problem with those funny signs is they scare remote hands techs into never looking at a fiber because they don't want to try and understand the difference between a SX GBIC and a class 3 ultra longhaul amp.
Save your poor techs eyes, and make them more reliable all at the same time:
This conversation has gone places I didn't expect. Leo, that card is pretty cool, but for a few hundred $$ more, you can get a light meter (if someone is smart enough to use the card...) Does anyone *use* any eye protection (other that not looking at the light, turning off the light etc) -- I mean like protective goggles, etc, when doing simple things like adding/removing patch cables from an SMF patch panel. I get that if you *know* the gear you are using has a Class 3 laser on it, you should be careful... but when you are patching it into a building's cable plant and some schmuck is patching the last leg in for you (or has pulled it accidentally, etc).. um, "don't look at it" is our community's BCP? DJ
On Tue, Jun 09, 2009 at 04:06:58PM -0400, Deepak Jain wrote:
This conversation has gone places I didn't expect. Leo, that card is pretty cool, but for a few hundred $$ more, you can get a light meter (if someone is smart enough to use the card...)
Now if only you could train people to use them... If I had a nickel for every time an Equinix tech has told me I'm sending them a +67dBm signal I'd be able to actually buy the laser to do that.
Does anyone *use* any eye protection (other that not looking at the light, turning off the light etc) -- I mean like protective goggles, etc, when doing simple things like adding/removing patch cables from an SMF patch panel.
I get that if you *know* the gear you are using has a Class 3 laser on it, you should be careful... but when you are patching it into a building's cable plant and some schmuck is patching the last leg in for you (or has pulled it accidentally, etc).. um, "don't look at it" is our community's BCP?
Come on, the closest thing to a dangerous laser you're going to find in most colos is the laser pointer built in to the vendor pen schwag you picked up at the last beer and gear. The class 3 lasers are few and far between, and copiously labeled when you do come across them. Spend 5 minutes teaching people what the laser classes and how how to read the label. -- Richard A Steenbergen <ras@e-gerbil.net> http://www.e-gerbil.net/ras GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)
On Tue, Jun 09, 2009 at 04:06:58PM -0400, Deepak Jain wrote:
This conversation has gone places I didn't expect. Leo, that card is pretty cool, but for a few hundred $$ more, you can get a light meter (if someone is smart enough to use the card...)
In a pinch the camera on a MacBook pro can be used to detect presence of IR light. Here's light from a 10Gbase-LR xenpak: http://www.majhost.com/gallery/kl/Macbook/macbook-laser-camera.jpg It's easier to see when previewing in real time than in the static picture but it does require careful aim. - Kevin
----- Original Message ----- From: "Kevin Loch" <kloch@kl.net> Cc: <nanog@nanog.org> Sent: Tuesday, June 09, 2009 12:17 PM Subject: Re: Eye protection in DWDM systems -- what threshold?
In a pinch the camera on a MacBook pro can be used to detect presence of IR light. Here's light from a 10Gbase-LR xenpak:
http://www.majhost.com/gallery/kl/Macbook/macbook-laser-camera.jpg
It's easier to see when previewing in real time than in the static picture but it does require careful aim.
- Kevin
Most 'cell phone' cameras also detect IR. Handy to verify that A/V equipment "Remotes" are working. --Michael
Deepak Jain wrote:
Does anyone *use* any eye protection (other that not looking at the light, turning off the light etc) -- I mean like protective goggles, etc, when doing simple things like adding/removing patch cables from an SMF patch panel.
There are osha requirements and ansi standards. ANSI Z136.1 - Safe Use of Lasers ANSI Z136.2 - Safe Use of Lasers in Optical Fiber Communication Systems Utilizing Laser Diode and LED Sources
I get that if you *know* the gear you are using has a Class 3 laser on it, you should be careful... but when you are patching it into a building's cable plant and some schmuck is patching the last leg in for you (or has pulled it accidentally, etc).. um, "don't look at it" is our community's BCP?
Actually that's pretty much the requirement for 3r, for 3b and 4 the requirements for eye protection and manual safety systems are much higher. All this high power stuff is rather rare (your cisco ons for example is a class 1 laser product), unless you terminate one end of a submarine system you'll likely never see a class 4 laser in this context. I tend to carry around extra dust protection boots in the tool bag to recover the exposed sc/st plugs that seem to accumulate in panels that people touch a lot, mostly, it protects the ends of the ferrules.
DJ
participants (12)
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David Freedman -
Deepak Jain -
Jeff Kell -
Joel Jaeggli -
Kevin Hodle -
Kevin Loch -
Leo Bicknell -
Michael Painter -
Mikael Abrahamsson -
Patrick W. Gilmore -
Richard A Steenbergen -
Robert E. Seastrom