nanog mailing list archives
Re: Eye protection in DWDM systems -- what threshold?
From: Kevin Hodle <kevin.hodle () gmail com>
Date: Tue, 9 Jun 2009 01:16:53 -0500
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
Current thread:
- Eye protection in DWDM systems -- what threshold? Deepak Jain (Jun 08)
- Re: Eye protection in DWDM systems -- what threshold? Joel Jaeggli (Jun 08)
- Re: Eye protection in DWDM systems -- what threshold? Kevin Hodle (Jun 08)
- Re: Eye protection in DWDM systems -- what threshold? Mikael Abrahamsson (Jun 08)
- Re: Eye protection in DWDM systems -- what threshold? David Freedman (Jun 09)
- Re: Eye protection in DWDM systems -- what threshold? Robert E. Seastrom (Jun 09)
- Re: Eye protection in DWDM systems -- what threshold? Jeff Kell (Jun 09)
- Re: Eye protection in DWDM systems -- what threshold? Patrick W. Gilmore (Jun 09)
- Re: Eye protection in DWDM systems -- what threshold? Richard A Steenbergen (Jun 09)
- Re: Eye protection in DWDM systems -- what threshold? Patrick W. Gilmore (Jun 09)
- Re: Eye protection in DWDM systems -- what threshold? Leo Bicknell (Jun 09)
- Re: Eye protection in DWDM systems -- what threshold? Deepak Jain (Jun 09)
- Re: Eye protection in DWDM systems -- what threshold? Richard A Steenbergen (Jun 09)
- Re: Eye protection in DWDM systems -- what threshold? Jeff Kell (Jun 09)