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Lateral offsets for multimode fiber (MMF)
connectors part 1 Al Brunsting Rick
Pimpinella Panduit Corporation 17301 Ridgeland
Avenue Tinley Park, IL 60477 Voice
708-532-1800/888-506-5400 Fax [phone] www.pa
nduit.com
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Background
Simulations for connector lateral offsets are
required to specify maximum connector insertion
loss. A worst-case MMF lateral offset of 7.0?m
is currently being used. Based on a large
comprehensive set of ferrule measurements and
fiber specifications, we calculated connector
lateral offsets using probability density
functions (PDF). From this study it can be
assumed that at least 95 of the lateral offsets
in the field are less than or equal to 6.0?m.
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Simulation theory
Vectors for lateral offsets of a MMF connector
(not to scale).
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Simulation theory (cont.)
Resultant vector, S, is the sum of its 3
component vectors
S S1 S2 S3
S simulated lateral offset for one of the two
connectors in a MMF connection. Component
offsets and connector rotations are accommodated
in this simulation. x and y components of S
Sx S1 S2cos?2 S3cos?3 Sy S2sin?2
S3sin?3
From Slide 2 x-y coordinate system chosen so that
?1 0.
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Simulation theory (cont.)
?2 ?3 independently take on 6 values of 0?,
60?, 120?, 180?, 240?, 300?. Mean and
standard deviation (SD) for each of S1, S2,
S3 come from Panduit measurements and MMF
spec. (TIA/EIA-492AAAA-A, January 1998, Table 1).
There are 5 indep. variables (?2, ?3, S1, S2,
S3). For each simulation there are 66555
4500 resultant vectors, (S). Each S will have
a statistical wt. Distribution of Ss
associated wts. give final lateral offset PDF for
one connector. Multiply offsets by SQRT(2) to
simulate two connectors (one connection).
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Simulation theory (cont.)

• SD for S2 has 3 RMS components
• Measured ferrule ID SD.
• Specified MMF cladding diameter OD.
• Secondary effects specified cladding
  non-circularity alignment sleeve (est. from
  Panduit measurements). All taken to be 0.50mm.

Each magnitude (S1, S2, S3) has 5 values
(Sa, Sb, Sc, Sd, Se) (mean 2SD, mean SD,
mean, mean SD, mean 2SD). Correspond. stat.
wts. (wi) (0.135, 0.607, 1.000, 0.607, 0.135).
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An example
Consider Supplier 2 1 case of 4500 simulated
cases Angles ?2 120?, ?3 240? S1
0.14?m (mean 2SD), w1 0.135 S2 0.59?m
(mean 2SD), w2 0.135 S3 1.00?m, w3
0.607 (mean SD) Results Total stat. Wt.
0.1350.1350.607 0.011 From Slide 4 Sx
-0.655, Sy -0.355, S 0.745?m.
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Values for S1, S2, S3
Note (S1, S2, S3) depends on (ferrule
only, ferrule MMF, MMF only). Sa ? 0.
Tolerances for MMF are assumed to be at ?3SD.
Some measurements, dimensions, and tolerances
must be divided by 2 to convert from diameter to
radius.
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Panduit measurements.
(Eccent., OD, ID) are (eccentricity, outside
diameter, inside diameter)?m N no. of ferrules
measured. The three middle columns give mean ?
SD. 3050 ferrules were measured.
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Lateral offset PDF. Simulation giving the
relative probability that the connection has a
give lateral offset, S.
Cumulative frequency is more useful for
conclusions.