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RE: PMD discussion




With regards to open fiber control:

Blaze has developed and shipped an eight channel CWDM transceiver with Open
Fiber Control that links up in less than 150 milliseconds.

In an Albuquerque presentation we discussed two methods of implementation.
http://grouper.ieee.org/groups/802/3/ae/public/mar00/herrity_1_0300.pdf

We are currently working with multiple transceiver vendors who plan to
design and manufacture the 850CWDM transceiver including open fiber control.

Best regards,

Ken Herrity

-----Original Message-----
From: owner-stds-802-3-hssg@ieee.org
[mailto:owner-stds-802-3-hssg@ieee.org]On Behalf Of Lemoff, Brian
Sent: Tuesday, May 30, 2000 9:38 AM
To: 'Seto, Koichiro'; stds-802-3-hssg@ieee.org
Subject: RE: PMD discussion



Dear Seto,

Yes, we did spend several years working on 850-nm WWDM, and demonstrated
4x2.5 Gb/s about 2 years ago in our lab.  As with the long wavelength WWDM
vs. Serial debate, I believe that 850nm-WWDM will be cheaper in the short
term than 850-nm serial.  The VCSEL and electronics technology for 2.5-Gb/s
are already mature and very low-cost. Also, the 4-1 electronic MUX will not
be needed in the WWDM approach.

With the current FDA eye-safety requirements, it will be nearly impossible
to make an 850-nm WWDM module which meets Class I eye safety, without using
open fiber control.  The expectation is that the FDA will soon raise the
limit quite substantially, opening up the possibility of Class I safe 850-nm
WWDM modules.

By the way, WWDM and CWDM are exactly the same thing.  I know its convenient
to use WWDM for 1300 nm and CWDM for 850 nm, but this is completely
arbitrary.  I personally always refer to the approach simply as WDM.

Best Regards,

Brian Lemoff

> -----Original Message-----
> From: Seto, Koichiro [mailto:seto@sj.hitachi-cable.com]
> Sent: Monday, May 29, 2000 11:43 PM
> To: stds-802-3-hssg@ieee.org
> Subject: Re: PMD discussion
>
>
>
> [Date: 05/29/2000  From Seto]
>
> Dear Brian,
>
> Thanks for your clarification.  I look forward to your
> evaluation result in
> July.  I'm sure you are aware that I'm not at all against
> 1310nm-WWDM proposal.
>
> BTW, I assume your team has a lot of experience with
> 850nm-WWDM solution.  I
> believe you once had a 850nm-WWDM lab prototype (per Mr.
> Dolfi's presentation
> in 3/1999).  Would you provide your insight on the argument
> on 850nm-serial vs.
>  850nm-WWDM?  Do you think there would be a potential laser
> eye safety issue
> in 850nm-WWDM proposal as suggested by Jonathan?
>
> Seto
>
> >
> > Dear Seto,
> >
> > No offense taken.  There should be no problem going 10 km
> over single mode
> > fiber with the same module that is optimum for going 300 m
> over MMF.  I
> > expect that a full set of link results will be presented in
> July, to provide
> > the physical evidence you are looking for.  Until then,
> you'll have to trust
> > the link model.
> >
> >
> > As for relative cost, most people believe that WWDM will be
> cheaper than
> > serial in the short term and that in the long run, serial
> will be cheaper.
> > The debate seems to be over when the two will cross. Some
> believe it will be
> > as soon as 2 years from now, while others believe it will
> be 3 or 4 years
> > from now.  The 1.8x and 3.0x numbers you are referring to
> have no basis,
> > other than an unscientific survey among a very small sample
> (I believe the
> > number of survey respondents was 4) of serial PMD advocates.
> >
> > Since companies that are actually developing serial and
> WWDM products for
> > sale usually choose to keep their cost models to
> themselves, it will be
> > difficult to establish relative cost until products hit the
> market.  Even
> > then, selling price and cost are two different things!
> >
> > - Brian Lemoff
> >
> > -----Original Message-----
> > From: Seto, Koichiro [mailto:seto@sj.hitachi-cable.com]
> > Sent: Monday, May 29, 2000 7:25 AM
> > To: wthirion@jatotech.com; stds-802-3-hssg@ieee.org
> > Subject: Re: PMD discussion
> >
> >
> >
> > [Date: 05/29/2000  From Seto]
> >
> > Walter,
> >
> > My understanding is that the following set is also one of
> the top favorites:
> >
> > ________________optimized for	may be used for
> > 1310 nm WWDM	MMF upto 300m	SMF upto 10km
> > 1310 nm Serial	SMF upto 10km	MMF upto 86m
> > 1550 nm Serial	SMF upto 40km
> > ________________
> >
> >
> > I understand there are some risks that 850nm-WWDM solution
> may not satisfy
> > laser eye safety as Jonathan pointed out in the discussion
> on Thursday.
> > Also, I learned that there are some risks that 1310nm-WWDM
> may not be able
> > to achieve 10km at SMF if not impossible.  At least we have
> not seen any
> > data that would prove the feasibility of 1310nm-WWDM over
> 10km SMF.  It is
> > not to say that this can not be done, but I have not been
> convinced that the
> >  same 1310nm-WWDM optics at same cost factor will serve for
> both 300m MMF
> > and 10km SMF.  Also, some people pointed out that
> 1310nm-Serial can be built
> >  at cost factors of x1.8 to 850nm-Serial while 1310nm-WWDM
> is x3.  If we can
> >  achieve the same goal (SMF 10km), the cheaper is the better.
> >
> > I hope no one is offended by my not-so-educated opinion.  I
> would appreciate
> >  a healthy discussion.
> >
> > Seto
> >
> > >
> > > First of all, thanks to everybody that presented PMD
> proposals at the last
> > > meeting. I've sent my presentation to David Law, so it
> should be available
> > > on the web site in the next couple of days.
> > >
> > > In listening to the discussion after my presentation and
> then going around
> > > and talking to people, it feels to me like we're starting
> to converge. Not
> > > there, yet, but making progress.
> > >
> > > The equipment manufacturers made it pretty clear they
> would like to see no
> > > more than 3 PMDs in the standard. The PMD vendors have
> some concern that
> > > using only 3 PMDs may sub-optimize certain objectives,
> however, they could
> > > support the 3 PMD position if it is made clear which 3
> PMDs the equipment
> > > oems want.
> > >
> > > Based on an informal straw poll and anecdotal evidence,
> my opinion is the
> > > first choice would be the set:
> > > ________________
> > > 850 nm WWDM
> > > 1310 nm WWDM
> > > 1550 nm Serial
> > > ________________
> > >
> > > If that set isn't feasible, then the 2nd most popular choice is:
> > > ________________
> > > 850 nm WWDM
> > > 1310 nm Serial
> > > 1550 nm Serial
> > > ________________
> > >
> > > Thoughts, feedback?
> > >
> > > Walt
> > > ___________________
> > > Walter Thirion
> > > Chair, IEEE 802.3ae PMD Sub-Task Force
> > > 301 Congress Ave.
> > > Suite 2050
> > > Austin, Texas 78701
> > > Voice:	512-236-6951
> > > Fax:	512-236-6959
> > > wthirion@jatotech.com
> > > ___________________
> > >
> > >
> > >
>