[EFM] AW: [EFM-P2P] RE: Single wavelength, single fibre PMD for P2P

[Thomas.Murphy@xxxxxxxxxxxx]

In the analysis of the temperature response of a VCSEL (and DFB) I 
as refering to intensity variations and not shifts in wavelength.
The grating structure of both implies a larger sensitivity in
output power to temperature shift.

Tom



-----Ursprüngliche Nachricht-----
Von: Mike Dudek [mailto:mdudek@xxxxxxxxxxxx]
Gesendet am: Freitag, 15. Februar 2002 19:35
An: Hans Mickelsson (ERA)
Cc: 'Thomas.Murphy@infineon.com'; stds-802-3-efm@ieee.org;
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Betreff: Re: [EFM-P2P] RE: Single wavelength, single fibre PMD for P2P

VCSEL change in wavelength as a function of temperature is similar/slightly better than the quoted number for the DFB.

"Hans Mickelsson (ERA)" wrote:

> Tom,
>
> Good work, see below for some comments.
>
> "Fewest variations of PMD to track in field". I agree that it will be less PMDs to track however if this is a real problem is not clear. Assume that you decide to use a certain lamda for downstream then it it ijust to follow this approach in all your switches and the problem will be non-existing.
>
> Can you explain "Use of inexpensive TOSA a bit further"?
>
> "Temperature performance". An un-cooled DFB (0.01 nm/K) is less temp dependent than a FP (0.03 nm/K). Can anyone give some figures for a VCSEL?
>
> "Leverage of 1310 nm....", True, but you raise an interesting question here. The use of parallel optics will be very difficult with any single fiber solution.
>
> Some othe options to consider are;
>
> The need for angled polished connectors for controlling refelctions in the network. Not necessary for dual but probably necessary for single.
>
> Will the be any difference between the two options in an up-grade scenario to higher bit-rates?
>
>         Brgds//HANS MICKELSSON
>
> > -----Original Message-----
> > From: Thomas.Murphy@xxxxxxxxxxxx [mailto:Thomas.Murphy@xxxxxxxxxxxx]
> > Sent: den 14 februari 2002 17:25
> > To: stds-802-3-efm@ieee.org; stds-802-3-efm-p2p@majordomo.ieee.org;
> > bob.barret@xxxxxxxxxxxxxxxxxx; david@xxxxxxxxxxxxxx;
> > doravv@xxxxxxxxxx;
> > FEffenberger@xxxxxxxxxxxxxxxxx; hans.mickelsson@xxxxxxxxxxxxxxx;
> > jradcliffe@xxxxxxxxxxxxxxxxxxxx; jstiscia@xxxxxxxxxx;
> > mark.sankey@xxxxxxxxx; meir@xxxxxxxx; Thomas.Murphy@xxxxxxxxxxxx;
> > n.kleiner@xxxxxxxxxxxx; PengL@xxxxxxxxxxx; raanan@xxxxxxxxxxxxxxx;
> > rbrand@xxxxxxxxxxxxxxxxxx; sasaki144@xxxxxxx;
> > schelto.vandoorn@xxxxxxxxx; Tonyshouse@xxxxxxx; wdiab@xxxxxxxxx
> > Cc: Vipul_Bhatt@xxxxxxxx
> > Subject: Single wavelength, single fibre PMD for P2P
> >
> >
> > Hello All,
> >
> > First off I apologise for a blanket bomb approach with
> > sending out this e-mail but
> > I have my reasons, as will become clear below.
> >
> > As most of you will know, I am currently co-ordinating the development
> > of a single fibre, single wavelength PMD proposal for P2P links.
> > During a recent discussion of this work, it became clear that
> > a number of people
> > were unaware of what was happening or still unclear of some
> > of the technical issues involved. Several questions arose
> > which had already been answered in the course of dedicated
> > telephone conferences and
> > some new issues were also raised.
> >
> > Of course this discussion is very good for the quality of the
> > standard. However,
> > in the interest of progress and completion of a baseline
> > proposal for March, it
> > is essential that people allay any concerns they may have in
> > the interim and go
> > into the meeting feeling ready to make an informed decision.
> >
> > I would therefore ask people who have an opinion (or concern)
> > in this direction
> > to speak up, raise the issues and avoid further surprises in St Louis.
> >
> > Arising from the aforementioned discussions was the idea that
> > a 2 wavelength
> > PMD may be an alternative approach. In order to facilitate
> > comparison of the
> > two ideas, a matrix was proposed which I have included here
> > in a somewhat modified
> > form. I divided the table into Today and Future, the former
> > represent current laser sources (FP and DFB)
> > and the later assuming the use of VCSELs, be that at 1310,
> > 1490 or 1550 nm. I dislike the 1-10
> > approach of comparing as this is too subjective, rather a
> > binary 0 or 1 representing the better solution
> > for a particular criteria. In some cases there are no
> > differences and both receive 0. The 'points'
> > are added and a comparison may be made.  NOTE, this will not
> > be the basis of the decision, rather an aid
> > to objective comparison. I have included comments behind each
> > issue cells detailing my evaluation.
> >
> > So, speak up, play with the table, add issues if necessary,
> > send it back to me,
> > get on the telephone conferences.
> >
> > Best regards and looking forward to further progress.
> >
> > Tom and the P2P group
> >
> >  <<Comparison matrix for 1 and 2 wavelength PMDs.xls>>
> >