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 ?
You have to have the same wavelength at both ends, otherwise it won't work.
If yes, i guess that there is impact on the power Budget available. How-Much ?!
LR tends to be 1550nm, because 1550nm has less signal loss over the same
length of fiber.
Simon
So I guess the right answer here is that everyone needs to learn how
to use attenuators propperly...
Unless I've severely forgotten most of my physics classes, no; attenuators
reduce a signal's strength so as to not overload the input stage of the
receiver, if the signal is that strong; or, as mentioned later, to simulate
a long-distance run over a short length of fiber.
1310nm and 1550nm wavelengths are entirely different frequencies
(not amplitudes) of light. The only way to convert is to use an active
repeater that has the one type of transceiver on one side, and the other
on the opposite side, or to use Acme Singularity Inc's black hole with
ST connectors in a nifty in-line package to slow down the light wave
enough (and speed it up in the other direction) that it shifts
wavelengths. ( }
)
-dalvenjah
On Thu, Jun 07, 2001 at 10:08:46AM -0700, Wayne Bouchard put this into my mailbox:
Attenuation has nothing to do with the reason the two cards won't work
together. Think of the cards as color blind. They can only see ONE
color. They ignore all other colors.
1550nm and 1310nm are different colors.
Attenuation has nothing to do with the reason the two cards won't work
together. Think of the cards as color blind. They can only see ONE
color. They ignore all other colors.
Have you actually tried this? I have personally gotten linkups between
1310 and 1550 GBICs. Just as someone said here before, the receivers are
very wide-band.
1550nm and 1310nm are different colors.
Yes, but if your receiver picks up photons in a range from (just guessing)
1200 to 1700nm light, it doesn't matter.
Receivers convert light into electricity when a photon bumps an electron
through the semiconductor band gap. There is a sharp cutoff at the low
energy side. (If the photon energy is less than the band gap energy, it
can't push the electron to the higher energy state.) The cutoff on the
high energy side is very broad.
Since shorter wavelengths means higher energy photons, the 1310 nm
transmitter will almost certainly work with the 1550 nm receiver. It is
possible that the 1310 nm receiver might not work with the 1550 nm
transmitter. This is because the efficiency of the reciever is best near
the band gap of the material. It is possible to choose the material and
do some other structural things (multiple quantum wells) to the
semiconductor to boost the sensitivity at the desired wavelenth.
The manufacturer may have elected to use a receiver that was optimized for
1300 nm. In that case, it may have no sensitivity to 1510 nm signal.
But it would still work for 800 nm.
BTW, the attenuators are only important for making sure you don't burn
out a receiver when you test the unsupported configuration.
-steve