Difficult to have a clear idea for SFP

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Bonjour,

Is an SFP can convert a value of a wavelength (at the client sink
side) in another value of a wavelength (at the long distance network
source side)?

Would you have please an example?

If this conversion is possible, does the client signal need to pass by
the electrical domain, or do we stay at the optical level without
going to the electrical domain?

Thanks for your words about that.
Best regards,
Michelot

Re: Difficult to have a clear idea for SFP
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Hello Michelot,

I will now try to explain what transceivers are and how do they work.

Transceiver is a contraction of two words "transmitter" and
"receiver". Lets talk about the optical receiver first. Signal is
received by a photodetector which gives a small amout of current to
the output.Current then is amplified and is converted to voltage which
should be amplified further by LA (limiting amplifier) which is known
as main amplifier. The resulting signal which is several 100mV is put
into a clock and data recovery circuit, extraxting the clock signal
and re-timing the data signal. In high speed receiver, demultiplexer
(DMUX) converts a fast speed data stream to (n)paralel slow speed data
stream that can be further processed by digital logic block (DLB). DLB
decodes the bits, performs error checks, synchronizes to another clock
domain, etc.

The same happens with the transmitter but in reverse order.


Ergyn Sadiku

Re: Difficult to have a clear idea for SFP
Bonsoir Ergyn,

Thanks for the time you spent in this interresting description.

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Reading another time my question, I realized that it was not really
clear (as almost all questions...). In fact we have SFP for many
different applications.

What you describe could be e.g. what we call 3R regeneration, with the
functions: reamplification, reshaping, resynchronization.

I saw also that we used SFP to transmit Ethernet frames on TDM circuit
networks (E1 at the SFP network side). And in this application, the
description you give seems natural (thanks for reminding it).

What I had in my brain was a WDM SFP. For example, you receive at the
client side a 1310 nm wavelength of an Ethernet signal. To insert the
wavelength in a CWDM multiplexing group, you choose an SFP that
convert it in a 1491 nm value.

To make this conversion, I suppose we have 2 solutions:
- either to go through the electrical domain, as you well described
it,
- either to stand only in the optical domain, using a kind of mirror
(I don't know if it is a good word).

Thanks for your opinion,
best regards,
Michelot

Re: Difficult to have a clear idea for SFP
Bonjour,

Thanks to Omnicron support, I have the perfect reply to my question.
The conversion is not done by going through the electrical domain.

"The conversion of wavelengths is done in the optical domain.  Using
our
iConverter xFF module, you can provide a 1310nm interface to the
client
and convert it to 1491nm for transport on the network side.  The only
requirement is both interfaces must be the same speed".

http://www.omnitron-systems.com/downloads/datasheets/8699DS-C.pdf

Thanks to you, this channel and Omnicron support.
Best regards,
Michelot

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