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Re: transcievers/amplifiers for 150 km fiber run
- From: Francois Menard
- Date: Sun Oct 12 08:39:12 2008
or you buy some boxes from BTI Photonics that specialize into taking
GigE around the world...
François D. Ménard
On 11-Oct-08, at 12:25 PM, Lamar Owen wrote:
On Friday 10 October 2008 14:50:11 Fletcher Kittredge wrote:
We are looking to light a two strand fiber link of about 95 miles (or
150km). It would be worth a lot to us not to have repeaters. We
hoping for Gigabit Ethernet. Sonet is possible but a less
solution. Are there options for this sort of distance? The longest
current link we have is about 65 miles. I understand the
characteristics of the fiber will effect distance of transmission.
EDFA's can extend your power budget a few dB. Chromatic dispersion
still be an issue, though.
Used units that had previous homes in CATV supertrunk applications
well, at least for GigE; up to 120mW is easily possible (I have a
(18.1dBm) EDFA's that came as part of a donation). You hit the
input of the
EDFA with your ZX (1550nm) transceiver's transmit on each end, and
at the lit fiber or even a reflection of the lit fiber (IOW, wear
safety goggles). And don't even think about looping the EDFA output
around without many dB of attenuation.
At this power level you will have to use angle polish connectors at
output (the green SC/SPC or FC/APC ones) or you can burn out the
with the reflections.
You also will need to notify your carrier's tech department of the
with which you're lighting that fiber, as even several km down fiber
EDFA is in Class IIIB laser territory.
A bare Cisco ZX GBIC or SFP is rated to light 70km of ordinary
fiber, and up to 100km of either premium (low-loss) or dispersion-
(which is also low-loss) singlemode fiber. The rated output is
between 0 and
+5dBm (1 and 3.2 mW) for the ZX laser. The link budget is 23dB for
standard ZX optics. With a high-gain EDFA outputting 13 more dBm of
(20 times the power) you can get a link budget for loss of 36dB;
increase your range 40km, on ordinary fiber.
So, in a nutshell, you'd take the TX from a ZX SFP or GBIC, a few
of jumper to an EDFA, and light the fiber (with APC connectors only)
EDFA output. You do this at both ends.