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: 708-532-1811
www.panduit.com
December 13, 2004
Panduit Corp.
Slide 1 of 12
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.
December 13, 2004
Panduit Corp.
Slide 2 of 12
Simulation theory
Vectors for lateral offsets of a MMF connector (not to scale).
ferrule OD
y
Center line of the
fiber core, c3
fiber OD
ferrule ID
fiber core
Center line of
the fiber OD, c2
Center line of the
ferrule ID, c1
y
x
fiber OD
ferrule ID
fiber core
S2
S3
c2
x & y axes are located on the
orthogonal center lines of the
ferrule OD.
S1
c1 & x
y

S3
S2
Fiber
radius, r2
Ferrule inside
radius, r1
December 13, 2004
c3
Panduit Corp.
S

S1

Slide 3 of 12
x
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| + |S2|cos2 + |S3|cos3
Sy = |S2|sin2 + |S3|sin3
From Slide 2 x-y coordinate system chosen so that 1 = 0.
December 13, 2004
Panduit Corp.
Slide 4 of 12
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/EIA492AAAA-A, January 1998, Table 1).
There are 5 indep. variables (2, 3, |S1|, |S2|, & |S3|). For each
simulation there are 6*6*5*5*5 = 4500 resultant vectors, (S).
Each S will have a statistical wt. Distribution of S‘s &
associated wts. give final lateral offset PDF for one connector.
Multiply offsets by SQRT(2) to simulate two connectors (one
connection).
December 13, 2004
Panduit Corp.
Slide 5 of 12
Simulation theory (cont.)
SD for |S2| has 3 RMS components:
1. Measured ferrule ID SD.
2. Specified MMF cladding diameter OD.
3. Secondary effects: specified cladding non-circularity &
alignment sleeve (est. from Panduit measurements). All
taken to be 0.50m.
Each magnitude (|S1|, |S2|, |S3|) has 5 values (Sa, Sb, Sc, Sd, Se)
= (mean – 2*SD, mean – SD, mean, mean + SD, mean + 2*SD).
Correspond. stat. wts. (wi) = (0.135, 0.607, 1.000, 0.607, 0.135).
December 13, 2004
Panduit Corp.
Slide 6 of 12
An example
Consider Supplier 2 & 1 case of 4500 simulated cases:
Angles: 2 = 120, 3 = 240
|S1| = 0.14m (mean – 2*SD), w1 = 0.135
|S2| = 0.59m (mean – 2*SD), w2 = 0.135
|S3| = 1.00m, w3 = 0.607 (mean + SD)
Results: Total stat. Wt. = 0.135*0.135*0.607 = 0.011
From Slide 4: Sx = -0.655, Sy = -0.355, |S| = 0.745m.
December 13, 2004
Panduit Corp.
Slide 7 of 12
Values for |S1|, |S2|, & |S3|
Sa
Sb
Sc
Sd
Se
Supplier 1
|S1|
|S2|
0.23
0.02
0.74
0.63
1.25
1.24
1.76
1.85
2.27
2.46
Supplier 2
|S1|
|S2|
0.14
0.59
0.60
1.20
1.06
1.81
1.52
2.42
1.98
3.03
Supplier 3
|S1|
|S2|
0.10
0.00
0.90
0.57
1.70
1.14
2.50
1.75
3.30
2.36
Supplier 4
|S1|
|S2|
0.00
0.00
0.79
0.39
1.57
0.77
2.81
2.01
4.05
3.25
Note: (|S1|, |S2|, |S3|) depends on (ferrule only, ferrule & MMF,
MMF only). Sa  0. Tolerances for MMF are assumed to be at
3*SD. Some measurements, dimensions, and tolerances must
be divided by 2 to convert from diameter to radius.
December 13, 2004
Panduit Corp.
Slide 8 of 12
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.
Source
Supplier 1
Supplier 2
Supplier 3
Supplier 4
Eccent.
0.72  0.38
0.53  0.43
0.23  0.12
1.02  0.60
December 13, 2004
OD
2498.81  0.34
2498.90  0.17
2498.53  0.44
2498.37  1.08
Panduit Corp.
ID
N
127.47  0.18 500
128.62  0.26 328
127.27  0.25 1225
126.54  0.42 997
Slide 9 of 12
Lateral offset PDF.
Simulation giving the relative probability that the connection has a
give lateral offset, |S|.
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
relative frequency
PDF for |S|. Supplier 2.
|S|, m
Cumulative frequency is more useful for conclusions.
December 13, 2004
Panduit Corp.
Slide 10 of 12