Re: POS OC48 interfaces using different wave length

[Steve Schaefer <schaefer () simone dashbit com>]

On Thu, 7 Jun 2001, Steve Feldman wrote:

> > > 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

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