controlled separation experimental...

iNEMI Confidential

for member organization use only

Controlled Separation

Experimental Results

iNEMI F2F Meeting

Mar 5, 2012

1 iNEMI Confidential


Outline

•Objectives

•Description

•Results

•Summary



Experiment Objectives

•Verify ability of multiple wavelength probe,

using existing test equipment, to measure the

mated connector separation gap

•Controlled separation to map RL and IL as

function of gap for multiple wavelengths over

initial several μm



Experiment Description

•Test Procedure

•Parameters

•Equipment

•Setup at TE Connectivity



Test Execution

• Pre-test

– Adjust gap using manual stages

– Power reading and magnifying glass as feedback for

“contact”

• Test

– LV program separates ferrules, collects and stores RL/IL data

– Monitor real-time displays for data quality

• Post-process

– Run post-process program to recall stored data and create

data graphs with theoretical overlay



Parameters

•Range of motion was 2.5 μm and 4 μm

•Step size of 20 and 50 nm

•RL only measured

– Problems with IL data

• Appeared to be single wavelength (1310)

– Speed up measurement



Equipment

•OptoTest 930; Return & Insertion Loss

– λ±30nm, RL ±1 dB

•PI Piezo Stage Model P-752.21C

– 0-30 μm range, 0.2 nm resolution

– Open Loop control via NI DIO board

•Manual XYZ; ~500 nm resolution

•Custom fixture to hold ferrules

•Custom LabVIEW code to control motion and

read OptoTest RL/IL meter



Fixture Details

• Two bare ferrule SC

connectors held as shown at

right (Alignment sleeve NOT

used)

Piezo stage

Programmed Moves

Manual XYZ stage

Coarse Align



Setup at TE Connectivity

Shane uses

magnifying glass

to verify nominal

contact



Results



Results Summary

•Two RL data sets collected

•RL minimum was limited at 10-11 dB by

instrument

•Data was not limited by instrument’s max RL

of 80dB



Full Contact Test Results

• Measured RL > 65 dB

• Matched theory after iterative adjustments

– Gap offset, RL offset, Actual wavelengths

• Tight match in critical 50-200 nm region

• Departure from theory below 50 nm was likley due to

connector XY misalignment once full contact was

made (fixture issue)



Data for all λ’s; 20 nm Step



Data and Theory for all λ’s

Ideal is solid line

Data is symbol only



λ:1310,1490 nm; 50 nm Step

Ideal is solid line

Data is symbol only



λ:1550,1625 nm; 50 nm Step

Ideal is solid line

Data is symbol only



Method for Determining Corrections

• Found X offset (nominal) that aligned all peaks

• Varying offsets by λ/2 of 1310 nm had one or

more λ’s with gross misalignment

• Both manual and later automatic LMS error

optimization of match between data and theory

used to fine tune X offset

• RL offset was applied to nominally minimize

error in 50-200 nm separation range



Offset & λ Optimization

•Initially used manual process, then developed automatic optimization based on minimizing overall match error

•Peak location rather than magnitude of RL error might be better error measurement

•If possible eliminate RL offset, λ and position errors by change of instrument or additional measurements



Return Loss from 0-200nm

Uncorrected

Corrected

• Order of

wavelengths in

RL value is same

with or without

correction

• Correction

required to

improve match

is at most 0.5

dB, well within

the ±1 dB

accuracy spec

λ (nm) 1310 1550 1490 1625

Offset (dB) 0.15 -0.5 0.15 -0.5

RL offsets applied to minimize error

Ideal is solid line

Data is symbol only



RL Error from 0-200nm

Uncorrected RL Offsets Corrected RL Offsets


for member organization use only 2

0

• Actual wavelengths used for final theoretical

calculations:

• Variation from nominal were well within ±30nm

spec for the OptoTest 930

Estimated Wavelengths

Actual Wavelengths Delta Wavelengths

Nominal Step 50

nm Step 20 nm Zero Offset

Step 50 nm

Step 20 nm Zero Offset

1310 1310 1302 0 3

1550 1548 1539 -2 0

1490 1478 1465 -12 -18

1625 1618 1605 -7 -5



1

Data Adjustments

•Measured data position was adjusted by a

fixed, positive offset

•Wavelengths used for calculated RL adjusted

to optimize peak matches

•RL offset for each pair of wavelengths

selected after other adjustments made in

order to line data up in 50-200 nm region



2

Ambiguity Regions

• The ideal curves unambiguously resolve position over the range of interest for the four wavelengths used

• Meter’s inability to measure RL below 10 dB produces gap regions were 2,3 or all of the wavelengths are clipped

• Ambiguity holes are 100-400 nm wide

• More study required to develop gap mapping which includes this effect



3

Experiment Improvements

• Use more accurate (in RL and λ) instrument

– Different meter or in-situ calibration methods

• Drive the existing piezo stage to get initial contact,

along with load cell

• Improve fixture to hold ferrules more accurately,

eliminate concerns about XY slippage on contact



4

Summary

• Controlled separation experiment was

successfully conducted

• Demonstrated that multiple wavelength

interrogation technique may be used to probe

the separation distance in a mated connector

• Ability to measure low values of return loss,

greater wavelength accuracy and reduced RL

offsets required to accurately measure

contaminated connector in-situ gap



5

Experiment Participants

• Doug Wilson, Brian Bystrek of PVI Systems

• Dave Fisher and Shane Nipple of TE Connectivity

• Brian developed the LV code and integrated the

hardware

• Shane and Brian operated the equipment, ensuring high

quality data collection

iNEMI Confidential


www.inemi.org Email contacts:

Bill Bader [email protected]

Bob Pfahl [email protected]

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