Petar,
Let me answer in two ways…
(1) We agreed that such specificity was
not appropriate in the CFI but that doesn’t mean it isn’t
appropriate in the Objectives for a particular PAR.
(2) I don’t happen to think that we
want or need an OM1 or OM2 solution, I was just responding to Mike B’s
query.
-Roger
From: Petar
Pepeljugoski [mailto:petarp@xxxxxxxxxx]
Sent: Thursday, September 28, 2006
5:25 PM
To:
STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [HSSG] Regarding LW
& SW VCSELs
Roger,
But
we decided in preparation of the CFI that we do not want any OM1 or OM2.
OM2
was at some version of the CFI slides and we dropped it.
Regards,
Petar Pepeljugoski
IBM Research
P.O.Box 218
(mail)
1101 Kitchawan Road,
Rte. 134 (shipping)
Yorktown Heights, NY 10598
e-mail: petarp@xxxxxxxxxx
phone: (914)-945-3761
fax: (914)-945-4134
|
Roger Merel
<roger@xxxxxxxxxxx>
09/28/2006 06:08 PM
|
Please
respond to
Roger Merel <roger@xxxxxxxxxxx>
|
|
|
To
|
STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
|
|
cc
|
|
|
Subject
|
Re: [HSSG] Regarding LW & SW VCSELs
|
|
My
thinking was that ...
Since we are talking about two new ribbon cables
between boxes in a datacenter using these VCSEL arrays, it doesn't really
matter if the legacy cable plant is pairs of OM2 or OM1; however, OM3 is indeed
the dominant MM media deployed in datacenters as of now.
Now if there is a requirement / SG objective for
HS-Ethernet over a single pair of legacy OM2/OM1, that changes things
entirely... but I haven't heard anyone considering / proposing this.
-----Original Message-----
From: Mike Bennett [mailto:mjbennett@xxxxxxx]
Sent: Thursday, September 28, 2006 4:58 PM
To: Roger Merel
Cc: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [HSSG] Regarding LW & SW VCSELs
Roger,
What you say regarding OM3 is true, however, I
don't think OM3 is
dominant in the installed base. Perhaps that
doesn't matter if it is
approaching dominance by the time we finish, but I
haven't seen any data
to suggest it will be. Does anyone have such data
that they're willing
to share with the study group?
Mike
Roger Merel wrote:
> Wenbin raises an important point. Going
with LW VCSELs on MMF would likely be a disadvantage as the OM3 is only
optimized for 850nm and thus modal dispersion limited reach would be shorter
for a LW VCSEL (to ~75m) vs a SW VCSEL (up to 300m or so).
>
>
> -----Original Message-----
> From: Wenbin Jiang [mailto:Wenbin.Jiang@xxxxxxxx]
> Sent: Thursday, September 28, 2006 3:26 PM
> To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: Re: [HSSG] Regarding presentation
"Implementation Considerations" by Roger Merel
>
> Frank,
>
> With the right volume, the cost difference
between a LW VCSEL chip and a directly modulated DFB laser chip is up for
debate. However, an optical isolator is normally needed for the DFB laser, but
not for the LW VCSEL.
>
> In the 2nd case, 850nm VCSEL parallel link
should match well with the data center reaches of <100m. The advantage of
going to LW VCSEL is not obvious for this application if on MMF.
>
> Wenbin
>
>
> -----Original Message-----
> From: Frank Chang [mailto:ychang@xxxxxxxxxxx]
> Sent: Thursday, September 28, 2006 12:35 PM
> To: Wenbin Jiang;
STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: RE: [HSSG] Regarding presentation
"Implementation Considerations" by Roger Merel
>
> Wenbin;
>
> I'm acually interested in both, but more for
the 2nd case. What is your opinion regarding LW VCSEL parallel link against a
DFB based CWDM link for datcenter reaches of <100m?
>
> Frank
>
> -----Original Message-----
> From: Wenbin Jiang
[mailto:Wenbin.Jiang@xxxxxxxx]
> Sent: Wednesday, September 27, 2006 6:40 PM
> To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: Re: [HSSG] Regarding presentation
"Implementation
> Considerations" by Roger Merel
>
> Frank,
>
> Do you mean to compare a LW VCSEL with a DFB
for WDM or to compare a LW VCSEL parallel link with a DFB based WDM link? In
the 2nd case, it is a matter of what the break-even distance is between the two
links.
>
> Wenbin
>
> -----Original Message-----
> From: Frank Chang [mailto:ychang@xxxxxxxxxxx]
> Sent: Wednesday, September 27, 2006 5:41 PM
> To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: Re: [HSSG] Regarding presentation
"Implementation Considerations" by Roger Merel
>
> Jack et al.;
>
> The fibers.org article made a comment that
"A VCSEL solution is approximately five to 10 times cheaper than a WDM
solution", I guess it points to multiple 850nm VCSELs or array (if with
monitoring??). I amnot sure this statement still hold true for long wavelength
(1310nm or even 1550nm) VCSELs. Because of the disruptive nature in recipe or
process, the LW VCSEL may have cost structure totally different from its 850nm
counterpart. While LW VCSEL singlet could also be different from its array,
just like the article indicate its monitoring in an array still chalenging. My
question is can someone comment if LW VCSEL array can be potentially built cheaper
than a CWDM or WDM solution which is well available today?
>
> Thanks
> Frank
>
> -----Original Message-----
> From: Jack Jewell
[mailto:Jack.Jewell@xxxxxxxxxxxxx]
> Sent: Wednesday, September 27, 2006 7:16 AM
> To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: Re: [HSSG] Regarding presentation
"Implementation
> Considerations" by Roger Merel
>
> Marek,
> At OFC 2006, Picolight demonstrated a 1310nm
VCSEL operating at 10.3Gbps in an SFP+ module and transmitting over 20km of SMF
(10GBASE-LR with an extra 10km of fiber). This week at the European Conference
on Optical Communications, AMCC is demonstrating a 10.3Gbps link over 300m of
62.5um fiber (exceeding the 10GBASE-LRM spec). It uses a similar Picolight SFP+
module with a 1310nm VCSEL and a linear receiver. AMCC's EDC chip compensates
for the limited fiber modal bandwidth.
>
http://www.lightreading.com/document.asp?doc_id=104440&WT.svl=wire1_6
> There have been other 10G demonstrations
involving 1310nm and 1550nm VCSELs by various companies.
> Regards,
> Jack
>
> -----Original Message-----
> From: Hajduczenia, Marek
[mailto:marek.hajduczenia@xxxxxxxxxxx]
> Sent: Wednesday, September 27, 2006 12:51 AM
> To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: Re: [HSSG] Regarding presentation
"Implementation Considerations" by Roger Merel
>
> Dear Jack,
> I think that clarifies the situation to the
point beyond any doubt.
> My questions were still though not answered -
is there any valid demonstration of long-wave VCSELs (1310nm, 1550nm) operating
at data rate >= 3G that You might be aware of ?
> Thanks for the answer
>
> Marek Hajduczenia (141238)
> (PhD Student - COM RD1)
> SIEMENS SA - IC
> Rua Irmãos Siemens, 1
> Ed. 1, Piso 1
> Alfragide
> 2720-093 Amadora
> Portugal
> * Marek.Hajduczenia@xxxxxxxxxxx
> *+351.21.416.7472 *+351.21.424.2082
>
> -----Original Message-----
> From: Jack Jewell
[mailto:Jack.Jewell@xxxxxxxxxxxxx]
> Sent: terça-feira, 26 de Setembro de 2006
23:55
> To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: Re: [HSSG] Regarding presentation
"Implementation Considerations" by Roger Merel
>
> Roger,
>
> My comments regarding the fibers.org article
were not in any way meant to slight the researchers whose work was reported, or
their work, or to disagree with any of Jack's (Cunningham's) quotes. I
know Jack Cunningham from way back and respect him greatly. The work they
report only adds to the technological feasibility of 12x10G VCSEL arrays.
I apologize for any possible misunderstanding.
>
> My discussion regarding the status of 12x3G
and the technical feasibility of 12x10G VCSEL arrays mostly comprises
defensable facts, followed by a reasonably-stated opinion. "Well on
the way" indicates that key capabilities have been demonstrated, in this
case: 10G VCSEL speed, significant commercial volume at 1x10G and 12x3G,
reliability at 1x10G and 12x3G, and operation at 12x10G. Of course
challenges remain, but not so fundamental as those already demonstrated.
Yield and reliability are sure to be concerns for any multi-laser
approach, especially if very high performance is required.
>
> You'll be hard-pressed to get any VCSEL
vendors (or any other vendors!) to divulge the technical details of their
recipes. Instead I'll address concerns about array reliability and yield
in a general and nonproprietary way. Unless VCSELs are explicitly
mentioned, these properties apply to ANY array of lasers, e.g. DFBs, FPs or
VCSELs. WEAROUT RELIABILITY: The wearout lifetime of a 12x array is
usually NOT 12x shorter than that of a singlet. It is only about 2x
shorter in VCSEL experiments reported by both Infineon and AOC. The fact
that array wearout lifetime is shorter at all (for any array) is only due to
variation among the elements. If all elements aged identically, the
wearout lifetime for a 12x array would be identical to that of a singlet.
Better uniformity results in better array lifetimes. NON-WEAROUT
RELIABILITY: Worst-possible-case early-failure rate is 12x higher for a 12x
array compared to a singlet. But again, the array penalty is often
lessened by t!
he!
> nature of the root cause. For
example, ESD is one culprit for early, non-wearout, failure. If an ESD
event kills a laser array for a multi-laser product (parallel or WDM), the
effect is the same as if it kills a singlet in a serial product: it kills one
module. In this case there is no "array penalty," assuming the
array is equally susceptible to ESD as the singlet. VCSEL early-failure
rates are already extremely low. [Any numbers here would lead down a rathole of
definitions, conditions, exclusions, qualifications, etc.] YIELD: Array
yield behaves similarly to wearout reliability. The better the
uniformity, the closer the array yield approaches the singlet yield.
>
> Since nearly all concepts discussed at HSSG
involve multiple-laser sources of one kind or another, I hope the above is
generally useful.
>
> Regards,
> Jack
>
> -----Original Message-----
> From: Roger Merel [mailto:roger@xxxxxxxxxxx]
> Sent: Tuesday, September 26, 2006 9:05 AM
> To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: Re: [HSSG] Regarding presentation
"Implementation Considerations" by Roger Merel
>
> John (goes by "Jack") Cunningham is
well versed in VCSELs. The article is rather short and doesn't say very much.
They are specifically working on approaches for higher speed VCSELs.
So I'm sure the "experimental" is in the higher speeds.
>
> Jack Jewell below would suggest that single
VCSEL products at 10G + arrays products at 2.5/3.125G, and a demonstration with
IBM in 2003 are together proof that 12x arrays at 10G not challenging... but by
doing so in such a way specifically raises the exact red flags we are all
concerned about... both yield and reliability for VCSELs scale inversely with
direct modulation speed (tied in part to current density)... such that unless
there is some new design and new material incorporated (rather than just
improved manufacturing process control), one would have to be suspect that (10x
or) 12x10G VCSEL arrays are and will continue to be "challenging".
>
> With that all said, I am NOT suggesting that
a 10x or 12x VCSELs should be precluded from a possible HS-Ethernet PMD.
HS-Ethernet is going to be challenging all-around. The VCSEL array
solutions are a viable avenue for some of the shorter distance applications.
>
> It would be beneficial if Jack or other VCSEL
vendors would explain what has changed in the technical basis of VCSELs to
ameliorate the yield and reliability concerns especially tied to modulation
rate and current density. This could provide the SG with comfort for
moving from Demos to Standards for (10x or) 12x 10G VCSELs.
>
> -Roger
>
> -----Original Message-----
> From: Jack Jewell
[mailto:Jack.Jewell@xxxxxxxxxxxxx]
> Sent: Tuesday, September 26, 2006 7:19 AM
> To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: Re: [HSSG] Regarding presentation
"Implementation Considerations" by Roger Merel
>
> The tone of the fibers.org article
misleadingly suggests that the implementation of VCSEL arrays is "still at
rather experimental stage." Suffice it to say that there are well
over 100,000 12-channel parallel VCSEL-array link products operating in the
field at present. Significant volumes began several years ago and keep
rising. Manufacturers and users of these parallel optical interconnections
are represented at 802.3 and the present HSSG. There is no need to
discuss the technological details of monitoring (the subject of the fibers.org
article) here; it is handled by various means. The parallel optical
interconnect products have undergone rigorous qualification by customers with
the highest standards of quality and reliability. VCSEL-array based
parallel links are real, and this email is surely traveling through some of
them.
>
> The present links typically operate at a lane
rate (channel rate) of 2.7-3.3Gbps. Customer-driven initiatives are already
underway to increase the lane rate to 10Gbps. IBM (with Picolight) demonstrated
a 12x10Gbps link operating over 300m of MMF at OFC 2003. It used
"SNAP-12" modules, i.e. the same modules used today. Since then,
10Gbps VCSEL technology has matured significantly, driven by 10GBASE-SR sales.
>
> Parallel optical links using VCSEL arrays,
detector arrays, and MM parallel fibers are well on the way to showing
"technically feasible" at speeds up to 120Gbps.
>
> Jack
>
> -----Original Message-----
> From: Hajduczenia, Marek
[mailto:marek.hajduczenia@xxxxxxxxxxx]
> Sent: Tuesday, September 26, 2006 2:36 AM
> To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: [HSSG] Regarding presentation "Implementation
Considerations" by Roger Merel
>
> Dear all,
> If I recall it correctly, Roger expressed his
concerns for the wavelength selection plan on slide number 8 of his
presentation and pointed out that most likely the VCSEL arrays with 10 or more
integrated sources can be technologically challenging. I would only like to
point out that perhaps we should investigate his proposal to use integrated
VCSEL arrays operating at 10+ Gbit/s -> here is why:
http://fibers.org/articles/news/8/8/10. The arrays seems to be still at rather
experimental stage though this is not the first piece of evidence that such
devices can be achieved and may be a much cheaper solution than standard WDM
systems ...
> Looking forward to receiving any feedback ...
> Best wishes
>
> Marek Hajduczenia
> (COM RD1)
> SIEMENS SA - IC
> Rua Irmãos Siemens, 1
> Ed. 1, Piso 1
> Alfragide
> 2720-093 Amadora
> Portugal
> * Marek.Hajduczenia@xxxxxxxxxxx
> *+351.21.416.7472 *+351.21.424.2082
>
> -----Original Message-----
> From: Andy Moorwood
[mailto:amoorwood@xxxxxxxxxxxxxxxxxxx]
> Sent: segunda-feira, 25 de Setembro de 2006
18:36
> To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
> Subject: [HSSG] Reach Ad Hoc, call for
participation and conference call announce ment
>
> Dear HSSG Members,
> thank you to those who have already replied
with their intent to join this activity, let me echo John's request for
participation. I want to schedule a conference call for Thursday October
5th at 11 am to 12:30 Pacific with the following objectives:
> 1. Identify what media and reach information
is already available to the group for the nominated applications: "HPCC, Data Center,
Metro, others"
> 2. Identify what media reach questions are of
particular interest to the group. For example, the 10 gigabit LR specification
has a link budget capable of supporting a reach of 10km in many installations.
Are end users actually using this budget? considerably less ? or they could use
more ?
> 3. Define a schedule for future conference
calls To facilitate data sharing/viewing at the meeting we need to use
some kind of collaborative environment in addition to voice conferencing.
Extreme uses "Conference
Place" by Intercall and I will host this kick
off meeting (If other members care to donate resources for future meetings this
would be appreciated). Live data sharing does however impose some
restrictions in that a member needs to be invited to the meeting place.
> Consequently I need a minimum of 24 hours
notice prior to the meeting if a member intends to participate.
> If a member wants to present at the
meeting I need a minimum of 48 hours notice and the slides (PDF or PPT)
format Any requests not meeting these timelines will be supported on a best
efforts basis. If it is possible to support audio only participation on a
"drop in basis" I will forward this to the reflector just prior to
the meeting.
> Thanks for your support !
> Andy
>
--
Michael J. Bennett
Sr. Network Engineer
LBLnet Services Group
Lawrence Berkeley
Laboratory
Tel. 510.486.7913