Hello all,
I am thinking about using different POS interfaces on dark-fibers.
On one side, i already have POS-OC48-LR card (Cisco).
This card use 1550 nm wave length.
We would like to use a POS-OC48-SR (Cisco).
This card use 1310 nm wave length.
Are 1310 and 1550 optics comptatible ?
If yes, i guess that there is impact on the power Budget available. How-Much ?!
Some colleagues reported successful implementation with such config (Cisco
POS OC48 Cards)
It looks strange to me and i wonder if Juniper and Cisco POS OC48 would
also work corretly in such environnement ...
I guess that "official" answer from manufacturer would be : NO WAY 
Some carriers may already tested such config ? Any feedback ?
Thanks.
V
Hello all,
[ snip ]
Are 1310 and 1550 optics comptatible ?
Can humans see ultraviolet light? These are two different wavelengths.
The equipment is specifically designed and built to _not_ allow
interaction between different wavelengths.
One can run 1310 and 1550 on the same fiber with WDM, but 1310 and 1550
won't talk to each other.
Eddy
> Are 1310 and 1550 optics comptatible ?
Can humans see ultraviolet light? These are two different wavelengths.
The equipment is specifically designed and built to _not_ allow
interaction between different wavelengths.
One can run 1310 and 1550 on the same fiber with WDM, but 1310 and 1550
won't talk to each other.
As someone already pointed out, the receivers
are often wide enough to see both wavelengths.
(Cheaper to build that way.)
So it might work, depending on the loss and dispersion
characteristics of the specific fiber installation.
But I'd be surprised if Cisco would actually support
that configuration...
An WDM demultiplexer typically has a passive narrowband
optical filter in front of the receiver to allow
only the desired wavelength through.
Steve
The receivers are probably wide enough to see both wavelengths, but maybe
not. The 1550 transmitter might not be seen by the 1310 receiver,
depending on choices made by the manufacturer.
You might need to use different attenuators in the two directions. (You
are planning to use two fibers, right?)
You should do no harm by testing it, but check the transmit powers before
you do. Make sure that you add attenuators if one of the transmitters is
spec'd at a higher output power than the other.
I come from an optics background and did some optoelectronics. My gut
tells me it will probably work.
Steve Schaefer
Dashbit - The Leader In Internet Topology
www.dashbit.com www.traceloop.com
You can do that. The issue really is whether the receivers are going to
accept signals in the other band and you will find that they will.
You can also do el-cheapo CWDM (CoarseWDM) using inexpensive filters so you
can run a 1310 and a 1550 at one end to their respective pair-mates at the
opposite end
to get 2 seperate signals on the same fibers without full-blown and
expensive DWDM gear. One color could be POS and the other GIG-E, if that is
handier.
A filter to split 1310 from 1550 is inexpensive campared to ITU grid
spacing. Nothing labeled xWDM needed except perhaps the simple filters you
need at each end.
In a closer to each other color wise but still mismatched situation, if you
happen to be using cisco's 15454 family (Cerent) ITU grid OC-48 cards not
for their different colors, but for their much higher power than the plain
LR card, any two different colors cards you happen to have on hand will play
fine to each other - just don't put any filters inbetween.
Also note that some of cisco's published GBIC configurations include cross
band applications.