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Re: Optical Connectors


There is a very fine line between technical discussion and a marketing
pitch. Following yours <Please let me know if anything is amiss. Let's try
and maintain objectivity here> I feel obligated to reply to your note as it
misleads those that are not experts in this field.

First of all set of numbers associated with each connector you've presented
is very misleading. As you know there is a big difference between the mean
and the maximum insertion or reflection loss values or between multi mode
and singlemode fiber. Please be specific next time around.

Second, for your and other reflector subscribers information the VF-45
singlemode insertion loss mean value as published more than a year ago in a
technical report, available upon request, is 0.19 dB with back reflection of
negative 56 dB.

Third, the 4.9 fiber pitch of VF-45 reflects the active devices can size not
the ability of the VF-45 ferrule-less connector technology or active devices
to space the fibers and/or active devices at larger pitch or as close as 250
micrometers apart.

Forth, I don't know if you're referring to the cable or fiber so let me
elaborate on both. The duplex cables are manufactured in both so-called
zip-cord and round structures. While zip-cord is used typically for the
jumpers due to ease of termination and ability to recover failed termination
of the single ferrule connectors such ST, SC or LC the round is used in the
typical cabling environment. The VF-45 represents an innovative,
ferrule-less, plug and socket design in a RJ-45 format. The in-field
installable socket can be terminated onto any cable design while jumper is
provided as factory made product in a similar to UTP fashion.

If you're making references to fiber I advise you to check L.K. Baker, G.S.
Glaeseman, Corning's fiber reliability experts, paper titled "A mechanical
reliability study of bare fibers under stress" presented September '99 at
the IICIT conference. To make the long story short here are Corning's
conclusions for VF-45 wall socket:

" The results show that wall socket terminated with silica fiber have a very
low failure probability of 0.04% over 20 years. This corresponds to a 2.5
FIT (failures per billion hours), which means that over 20 years
approximately one wall socket would fail for every 1,000 installed.

and VF-45 plug:
"The results show that for the jumpers manufactured with either standard
silica glass or a high durability fiber with the proof test operation the
predicted failure rate falls to zero over the 20 years service life"

And one more thing in case you don't know. All this for one-seventh the cost
of the traditional ferrule-like connector design.


----- Original Message -----
From: <mittalr@xxxxxxxxxx>
To: Roy Bynum <rabynum@xxxxxxxxxxxxxx>
Cc: <stds-802-3-hssg@xxxxxxxx>
Sent: Thursday, July 27, 2000 7:17 PM
Subject: RE: Optical Connectors

> Roy, I do not believe your assesment is correct. I can give you name of at
> least 6 other BIG companies who are doing LC. That is more than you can
> count for MT-RJ, I'm sure.
> I think it will be instructive to give people a feel of the various pros
> cons of various small form factor devices. Please let me know if anything
> amiss. Lets try and mantain objectivity here.
> LC
> ---
> Fiber pitch: 6.25mm (simple and easy to manufacture)
> Insertion loss 0.1-0.15dbm
> Return loss: 50-60dbm
> Mu
> ---
> Very similar to LC
> Only difference is lack of latch which might be
> depending upon whom you talk to
> -----
> Fiber pitch: 0.75mm(difficult to manufacture)
> Insertion loss 0.15-0.2 dbm
> Return loss: ~40dbm
> VF (volition)
> ----
> Fiber pitch: 4.9mm(special cabling reqd.)
> Insertion loss 0.5dbm
> Return loss: ~20dbm
> Thanks
> Rohit
> ps: I agree with a lot of people on this reflector that it doesn't make
> sense to get into these discussions on and on. Everyone has their own
> favourite connector and the protocol is anyway independent of whether you
> use SC or LC or MT-RJ.
> _______________________________________________________
> Say Bye to Slow Internet!