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Re: [10GMMF] Task 2 and 4 slides for Dec15th - OM3 fibre measurements




Joerg,
I agree that it is possible to find fibers that cause problems with any given launch.  But we should review the present evidence. Throughout the several new launch condition examinations of the .aq task force, the nominal 20 um offset launch condition continues to be one of the optimal launches for OM1 fiber.  What has not yet been well examined by .aq is the launch condition for OM2 fibers.  It may turn out that once we model OM2, the present offset launch patch cord spec for 50 um fibers (nominal 13 um offset) can be better optimized for EDC receivers.   Until we complete that part of the modeling, it is premature to assume that the present OM2 launch condition is the best one to choose, and even further astray to apply its present inner EF limit to OM1 when it has already been shown to be sub-optimal by about 0.7 dB.  

Regards,
Paul Kolesar
SYSTIMAX« SOLUTIONS
1300 East Lookout Drive
Richardson, TX 75082
Phone:  972.792.3155
Fax:      972.792.3111
eMail:   pkolesar@systimax.com



"Joerg-R. Kropp" <Joerg.Kropp@INFINEON.COM>
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Re: [10GMMF] Task 2 and 4 slides for Dec15th - OM3 fibre measurements





Paul,
thanks for having a close look to the launch conditions and the discussion of the presented results.
In the last months task groups discussed several results on different fibers with the various deviations from the ideal profile. If you are looking for bad behaving fibers you will find samples with deviations on all radial sections of the core. Our "kink fiber" (I gave some presentations on it) behaves badly just within the range of the current offset patchcord but is very good for all other launches. Our "benchmark fiber" behaves badly for nearly all radial launches instead of pure central launch. Agilent presented results of a fiber which behaves badly in the center launch situation but is well suited for offset launch. Beside this examples there are hundrets of fibers which will behave well, but we focused (offcause) in the last months on the critical examples in order to understand better all the fiber issues.
The allover result of all the examinations for me is that most of the (old) fibers (OM1 and OM2 ) will work better with offset launch than with central launch because of the central dip deviations (and because of the OFL selection criterion which weights strongest the larger radius areas). For these fibers we need to avoid the launch in the central region. Since the central defects are similar for OM1 and OM2 fibers we should use the same spec for both and we should keep it at 6Ám for EFL <30%. The spec for the large radii must be adjusted to the different fiber diameters of OM1 and OM2.
The center launch spec for the OM3 fibers seems to me to be very usefull for the OM1/OM2 fibers with deviations at larger radii because many of them will behave very good with center launch (because the OFL bandwidth has to exceed the bandwidth spec and if there is a outer defect there has to be a very good center area).
 
Regards
Joerg

Infineon Technologies Fiber Optics GmbH
MOD CE

Dr. Joerg-R. Kropp

Senior Staff Expert

Wernerwerkdamm 16

D-13629 Berlin / Germany

Phone -49-30-85400-4918

Fax     -49-30-85400-4900

Mail     joerg.kropp@infineon.com


 
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Re: [10GMMF] Task 2 and 4 slides for Dec15th - OM3 fibre measurements


Joerg,

thanks for the confirmation and clarification.  


Regarding the EF at 30%, if the radial limit is a small as 6 um, then singlemode launches offset by as little as 8 um would be allowed.  Launches in this range have been shown by John Ewen this week to produce the largest PIE-D in OM1 fibers, with values about 0.7 dB higher than those for 20 um offset launches.   So a spec this loose seems considerably sub-optimal.


Regards,
Paul Kolesar
SYSTIMAX« SOLUTIONS
1300 East Lookout Drive
Richardson, TX 75082
Phone:  972.792.3155
Fax:      972.792.3111
eMail:   pkolesar@systimax.com



"Joerg-R. Kropp" <Joerg.Kropp@INFINEON.COM>
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Re: [10GMMF] Task 2 and 4 slides for Dec15th - OM3 fibre measurements







Paul,

you are correct! The Bandwidth diagram is scaled for a length of 300m of a 1300nm transmission. It is just the bandwidth which results from the pulse forms over the 300m length (large diagram on each slide). In addition to that bandwidth dependence on the offset radius of the launch I included the calculated OFL bandwidth of the fiber by a straight line in order to give some additional information.

 

A statement to the EFD values:

I agree that the lower borders for OM1 and OM2 offset launch should be adjusted to the same value in order to get no difference between both, my favorite for that is < 30% for EFD at 6Ám.
The reason of the definition of the center border is to avoid to large power in the central region because of the possible dip in the center of the fiber. Since this dip is in general of the same size for OM1 and OM2 fibers it makes no sense to define different values for the EFD borders in that area.

 

Joerg

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Re: [10GMMF] Task 2 and 4 slides for Dec15th - OM3 fibre measurements



Joerg,

I believe I've answered my first question.  The OFL line is the raw OFL BW at 1300 nm not normalized to GHz-km, simply GHz.  The value is 0.5GHz-km/0.3km = 1.67GHz.  Correct?


Paul


Paul Kolesar <PKOLESAR@SYSTIMAX.COM>
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Re: [10GMMF] Task 2 and 4 slides for Dec15th - OM3 fibre measurements










Joerg,

In your and Stefano's contribution to Task2/4  this week you provide bandwidth plots on the right side of three slides showing the trend with offset.  I have two questions:

1. In each of these there is a horizontal line at about 1.6 GHz-km that appears to be labeled OFL.  Is this the OFL BW at 850 nm?  

2. The horizontal axis is labeled "radius of launch (um)".  This can be interpeted in two ways.  Is it the encircled flux radius at perhaps 86% level, or (more likely) the offset radius of the launch?


Thanks in advance for the clarifications.


Paul Kolesar

"Joerg-R. Kropp" <Joerg.Kropp@INFINEON.COM>
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Jonathan and all,

please find enclosed further simulations about the OM3 transmission and our proposal based on that simulations.

I hope it will be possible to discuss that today.
I have to cut the presentation into two because of the 100k limit.


Joerg-R. Kropp

 

Infineon Technologies Fiber Optics GmbH
MOD CE

Dr. Joerg-R. Kropp

Senior Staff Expert

Wernerwerkdamm 16

D-13629 Berlin / Germany

Phone -49-30-85400-4918

Fax     -49-30-85400-4900

Mail     joerg.kropp@infineon.com



[attachment "OM3 Fiber EFD PIED1.pdf" deleted by Paul F Kolesar/CommScope]