to agree with Rich and Bob. I'm a user and I can tell you that I believe
the fewer the PMDs the better especially when you have more than one for the
same application space. I believe the set of PMDs we have now
meet the objectives we agreed upon back in the beginning of this process.
I don't think anyone can make a substantive claim that we have not served the
industry. In the beginning of this process, Howard Frazier said the way
we'll know if we've done our job correctly is check to see if our objectives
have been met. I think we will have done so by the time we're
Michael J. Bennett
Lawrence Berkeley National Lab
agree with Bob's response from a process perspective and would like to take
this opportunity to address the market issues which you raise.
IEEE P802.3ae draft standard currently provides multiple solutions for short
reach links. Depending on your definition of "short", either 850 nm VCSEL,
1310 nm VCSEL, 1310 nm DFB or 1310 nm CWDM solutions adequately cover all
customer distance and fiber type requirements with significant overlap. I'm
unaware of any significant change since this decision, but I have seen a huge
discounting of highly integrated 10G optical module solutions relative to the
timeframe of the decision. Looking into the future, vendors are already
addressing short reach links with more compact optical module solutions which
will adequately and economically meet customer requirements. I beg to differ
with you on your statement that: "Customers don't care how many PMDs". This is
not what I've heard from any system supplier at IEEE 802.3ae Task Force
Lastly, I don't perceive that anything is "broken"
with the current specification (of PMDs). This is usually the impetus for
change. In my view, the PMDs specified in IEEE P802.3ae adequately and
economically allow customers to deploy 10GbE equipment.
you believe that you have enough support for a Call for Interest for a 10GbE
1310 nm FP PMD, the call must be initiated through IEEE 802.3, not
Intel Communications Group
3101 Jay Street, Suite 110
Optical Strategic Marketing
Santa Clara, CA
95054 Santa Clara
Thanks for your quick response. If it is
a right thing to do, it never be too late. Imagine if majority of the
short reach link deployed in next few years are using FP lasers and it
is not covered by the standard, it will go down to the history book that the
committee did not do a good job of serving the industry. Since the
committee discussed and make the decision a long time ago, many things have
been changed. Many technologies promised to deliver low cost products have
not done it yet for variety of reasons. FP lasers has
been available and always be available to serve the industry.
There are concern of too many PMDs in the standard, the keys is how many PMD
are low cost and can deliver in volume. Customers don't care how many
PMDs, all they care is how they can get parts that can do the job, cheap and
reliable. I'd urge the committee should initiate a call for
interest for this topic. Thanks
Office: 626-969-0681 x121
1335 W. Foothill Blvd.
Azusa, CA 91702
----- Original Message -----
Sent: Thursday, March 28, 2002 4:58
Subject: RE: [802.3ae] Bad idea...not
including FP laser in PMD
It is too late to add major functionality
you describe to the 802.3ae project. As you point out, the committee
discussed the topic and made its decision a long time ago. The
P802.3ae draft has completed Working Group and is in the final stages of
Sponsor ballot. The addition you propose is outside the scope of the
current Sponsor recirculation ballot and therefore should not be
considered by the P802.3ae Task Force.
Evening Creek Drive
San Diego, CA 92128
I understand that this is an old topic, but I still strongly
believe that it is a bad idea not to include 1310 nm Fabry-Perot (FP)
lasers in the PMD. Let me
re-cap some of the advantages of FP lasers:
- Low cost comparing to DFB lasers: high yield single-growth
wafer process, less sensitive to back reflection that eliminates the
need for isolator in package.
(1.3 VCSEL yield/cost is not clear now, therefore it is hard to
- Edge emitting lasers (FP and DFB) are more mature technology
and have been deployed in market for many years. Both lasers are available
today through multiple vendors.
- FP laser can handle at least 0 to 2km (some test even indicate
7km is possible). And majority of the 10G Ethernet applications fall
into this range.
- Some companies are shipping transceiver/transponder products
using 1310 FP lasers today, but unfortunately they are being treated
as non-802.3ae standard products.
1310 PMD specification has a 30 dB SMSR spec that prohibits the use of
FP lasers. I believe that
it is to the best interest of our industry to standardize a PMD based on
1310 nm FP lasers. If there
is a way to start a new project or modify the current specifications to
include FP lasers, I'll love to lead an effort on it.