On Thu, Oct 31, 2013 at 5:53 PM, Jimmy Hess <mysi...@gmail.com> wrote:
> On Thu, Oct 31, 2013 at 7:24 PM, Matthew Petach <mpet...@netflight.com>wrote: > >> On Thu, Oct 31, 2013 at 7:02 AM, Ray Soucy <r...@maine.edu> wrote: >> > Was the unplanned L3 DF maintenance that took place on Tuesday a frantic >> > removal of taps? :-) >> > No need for intrusive techniques such as direct taps: >> >> http://ieeexplore.ieee.org/xpl/articleDetails.jsp?reload=true&arnumber=1494884 >> > > For shame.... you've sent in a link to some article behind a paywall, > with some insane download fee. > Which is an equivalent of hand-waving. > > They must be hiding their content, for fear that flaws be pointed out. > Oy...OK, let me find a document that spells it out a bit more clearly for you. > > > "Of all the techniques, the bent fiber tap is the most easily deployed with >> minimal risk of damage or detection. The paper quantifies the bend loss >> required to >> tap a signal propagating in a single mode fiber" >> > > There will be some wavelengths of light, that may be on the cable, that > bending won't get a useful signal from. > > Bending the cable sufficiently to break the total internal reflection > property, and allow light to leak -- will generate power losses in the > cable, that can be identified on an OTDR. > This patent covers a technique developed to do non-intrusive optical tapping with a 0.5" microbend, with only 0.5dB signal loss: http://www.google.com/patents/CA2576969C Most people aren't going to be able to tell a 0.5dB loss from a microbend tap from a splice job. Matt > > > >> Matt >> > -- > -JH >
