DWDM on 250 Km dark fiber without re-amplification

Josh Galvez josh at zevlag.com
Tue Dec 27 19:08:37 UTC 2016


SmartOptics is one such vendor that I've used in the past that may be able
to do this.



On Tue, Dec 27, 2016 at 10:41 AM, Brian R <briansupport at hotmail.com> wrote:

> I have to agree with Brandon.  I have not worked with Ciena equipment
> directly but have work with carriers that use it.  I worked with Adtran on
> this kind of setup and like Brandon said they require a lot of information
> to build what is needed for each specific run (fiber type, quality, wave
> length optimization, number of splices, etc).  I've seen the tools Adtran
> uses to calculate exactly what equipment is required and it is pretty
> complex for distances even close to what you are talking about.
> Definitely check for a re-gen site(s), most likely the carrier has to
> re-gen their own runs down this fiber path (another thing to consider in
> the calculation matrix especially if you are not trying to re-gen your run).
> I have to give Baldur kudos for finding that I'm still amazed that
> Fiberstore is claiming that's possible without a lot of information.  I
> have worked with Fiberstore and they are a cooperative vendor and their
> products work for what we have used them for.
> My suggestion is to reach out to Fiberstore, Ciena, Adtran, and other
> vendors that people recommend with a detailed email of what you would like
> to accomplish and the information you can get.  Ask for a design engineer
> (I know Adtran has them and assume others do) to get the info you need and
> see what they can mock up for you.
> Brian
> ________________________________
> From: NANOG <nanog-bounces at nanog.org> on behalf of Brandon Martin <
> lists.nanog at monmotha.net>
> Sent: Sunday, December 25, 2016 12:41 AM
> To: nanog at nanog.org
> Subject: Re: DWDM on 250 Km dark fiber without re-amplification
> On 12/23/2016 07:14 PM, Jeremy wrote:
> > Hi all,
> >
> > First, i'm sorry for my english, i'm french and i don't have a good
> > level in this language. But i want some informations and i'm sure,
> > someone will be give the good anwser about my question.
> >
> > So, i'm regarding to rent a dual dark fiber in France, the estimated
> > distance is 225 Km, but i know there are a lot of optical switching on
> > the highway where it's fiber is installed (in theory, all 80 Km). So, i
> > used the bad scenario, in adding 25 Km on my need.
> >
> > I would like to buy a amplificator and multiplexer DWDM to add some
> > 10Gb/s waves on this dark fiber. I've see that the amplification is
> > better on 100 Gb/s synchronised ports, but we don't have enoug capacity
> > on our router to add 100 Gb/s interfaces.
> >
> > So, someone has installed this type of hardware on a dark fiber without
> > regeneration  on 250 Km of distance ?
> > If yes, with what kind of hardware ? If you are commercial for this
> > hardware, please contact me in private message.
> Look up Raman amplification.  The short of what this does is it pumps a
> ton of power into the near end of the fiber span and creates what looks
> somewhat like a typical color-blind amplifier somewhere several dozen km
> out on the span.  You'll also need to dump a ton of power into the span
> at the far end using an EDFA or similar.  Even with both of those, that
> distance is still going to push the raw optical power budget of even
> most state-of-the-art transceivers especially if the fiber is old or of
> low quality (high loss, high dispersion, etc.).
> The longest span I've ever gotten a vendor to commit to an engineered
> design for was about 140km, and of course they needed full
> characterization of the span before they'd do it.  At those distances,
> distance alone is no longer sufficient to throw together a design.
> It seems highly likely that there's at least one re-gen facility along
> that span.  I'd definitely see if there is one and if you can get some
> space in it.  That will knock you down into the 100-130km range on both
> sides of the re-gen, hopefully, which is perfectly doable.
> You are somewhat correct that 100Gb interfaces often handle longer
> distances better, but it's because they are often using coherent
> receivers and carrier-synchronous transmitters rather than raw power
> receivers and ASK pulsed transmitters.  There are vendors that sell
> coherent 10Gb transceivers, too, and they'll be cheaper than 100Gb
> solutions especially if you don't need the extra capacity anyway.  I'd
> definitely check them out for this type of application especially if you
> can't get any dispersion compensation in the middle since coherent
> optics are usually much more tolerant of chromatic dispersion.
> The big vendor I've worked with in the past on this sort of stuff is
> Ciena (and they're certainly a juggernaut in the industry) though I have
> no connection to them other than as a satisfied (if occasionally broke
> after a PO or out of breath after seeing a quotation) customer/integrator.
> --
> Brandon Martin

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