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RE: Optical Connectors


SC is one the best designed connector out there.  Any connector with similar
design will also have good property, examples are MU and LC.  In the 10 Gig
space insertion loss and return loss are more critical than in the building
wiring.  As guideline we need to use more strengthen selection 
criteria such:

o. Insertion loss mean + 3 sigma of 0.5 dB instead of 0.75-1.0 dB
o. Return loss max of -35 dB instead of -20 (GBE MM) or -26 (GBE SM)
o. Availability of OC-48/OC-192/FC-2X transceiver.

The best selection criteria would be whoever offers a royalty free licence.
The down side would be you may not get any jumbo shrimp in the next meeting
and Howard won't get the extra head count he is counting on.

Don't even bother include cost criteria, because every one is the
lowest cost! 


Ali Ghiasi
Sun Microsystems

> From: Mick Seaman <mick@xxxxxxxxxxx>
> To: "'HSSG_reflector (E-mail)'" <stds-802-3-hssg@xxxxxxxx>
> Subject: RE: Optical Connectors
> Date: Wed, 19 Jul 2000 09:44:25 -0700
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> For what it is worth a number of our suppliers and our own technical
> resources are supporting/advocating the use of LC. It seems to mate better
> than MTRJ (less loss/more reliability of achieving low coupling loss on all
> insertion conditions) and has been easy to handle. So from one part of the
> (MAN) market, I would support this.
> More broadly, I liked Howard Frazier's previous email on the subject
> (connector skirmishes - wars being too grand a designation).
> Mick
> -----Original Message-----
> From: owner-stds-802-3-hssg@xxxxxxxx
> [mailto:owner-stds-802-3-hssg@xxxxxxxx]On Behalf Of Roy Bynum
> Sent: Tuesday, July 18, 2000 11:09 AM
> To: Jonathan Thatcher; HSSG_reflector (E-mail)
> Subject: Re: Optical Connectors
> Jonathan,
> In spite of what Lucent wants, the LC connector does not have the market 
> support that MTRJ does.  MTRJ also has a smaller form factor than does 
> LC.  I don't like and am specifying the non-use of LC on transmission gear 
> because of the fragile "lock" tab that is on the connector.
> Thank you,
> Roy Bynum
> At 08:48 AM 7/18/00 -0700, Jonathan Thatcher wrote:
> >I have opened this thread to continue the discussion on optical 
> >connectors. So far (what has come into my reader), we have the following 
> >comments:
> >
> >-----------------------
> >"Bill Wiedemann: Regarding 850CWDM we are planning to make first 
> >implementations with duplex SC moving to LC with small form factors. Our 
> >expectation is that small form factor with LC could be available a year 
> >from today. "
> >-----------------------
> >"Jim Tatum: I would assume that 802.3ae would do the same as 802.3z, and 
> >NOT specify conectors. "
> >-----------------------
> >"Ed Chang: There are so many different form factors, and connectors, which 
> >even the GbE and Fibre Channel market can not get consensus."
> >-----------------------
> >
> >If we review the 802.3 Ethernet specification, we see that we have 
> >identified connectors for each variant (I don't remember an exception). 
> >For example:
> >7.6.2 AUI Configuration cable
> > Optical for repeaters
> >...
> >38.11.3 MDI = Duplex SC for GigE Optics
> >39.5.1 MDI = Style 1 (DB9) and Style 2 for GigE Cu
> >
> >While I remember no rules that require us to do so, it seems obvious that 
> >there exists a precedent which should guide our decision.
> >
> >In 802.3z, we specifically took a vote to avoid connector discussions 
> >("connector wars")**. We could do the same in 802.3ae. If we did, I would 
> >argue that we would, effectively, be retaining the duplex SC optical 
> >connector specified in clause 38.
> >
> >My PERSONAL preference would be to specify the LC connector. Rationale:
> >1. There seems to be an overall inclination to move in that direction.
> >2. It sets the stage for some kind of "Small Form Factor" 10 Gig
> transceiver.
> >3. I don't think that it would negatively impact the cost of the 
> >transceiver in the 2002 (standard completion time frame).
> >
> >As CHAIR, I don't want to use up any cycles on this. If there isn't 
> >sufficient consensus to agree on an alternative to the SC, we should just 
> >adopt the SC and move on.
> >
> >jonathan
> >
> >** In reality, this was bumped up to 802.3 because neither I (sub-chair 
> >for PMD) nor Howard (802.3z chair) wanted to use precious committee time 
> >for the discussion.
> >
> >Jonathan Thatcher,
> >Chair, IEEE 802.3ae (10 Gigabit Ethernet)
> >Principal Engineer, World Wide Packets
> >PO BOX 141719, Suite B; 12720 E. Nora, Spokane, WA 99214
> >509-242-9000 X228; Fax 509-242-9001; jonathan@xxxxxxxxxxxxxxxxxxxx
> >