UNCLASSIFIEDUNCLASSIFIED
Modulator Evaluation and DemonstrationModulator Evaluation and Demonstration
Paul Ashley
US Army RDECOM/AMRDECUS Army RDECOM/AMRDEC
Redstone Arsenal, AL 35898
March 19, 2008March 19, 2008
UNCLASSIFIEDUNCLASSIFIED
Outline
Current status of the evaluation of packaged
modulators from Lumera Corporation.
Current status of the investigation of the effect
of thin buffer layers on poling.
Plans for transition opportunity modulator demo
for military/space applications.
UNCLASSIFIEDUNCLASSIFIED
Thermal Stability of LPD80
Thermal stability of the modulators were evaluated by monitoring the Vπ at the
storage temperature of 800C. (Data provided by Lumera Corpration)
Two-parameter KWW model and Jonscher model were used in predicting the
usable lifetime of the devices over 5 10 year periodusable lifetime of the devices over 5-10 year period.
The distribution width of
relaxation times (0 < β < 1)
Jonscher
Model
relaxation times (0 < β < 1)
KWW
Model
The average relaxation
time constant
• R. Kohlrausch, Ann. Phys. (Leipzig) 12, 393 (1847)
• G. Williams and D. C. Watts, Trans. Faraday Soc. 66, 80 (1970)
Jonscher model was preferred
because of the its consistency with causality
UNCLASSIFIEDUNCLASSIFIED
Thermal Stability of LPD80
Ignored Average of 5 data sets
Normalized (Vπ = 1.0 V at t=0)
1.5
Jonscher Model
Error bars represent
the standard deviation
Coefficient of determination
(r2 = 0.96)
1.1
1.3
V_
pi
V π
(V
)
τ = 606168 hrs
β = 0.22
( )
0 500 1000 1500 2000 2500
Ti (H )
0.9
1.4
1.6
_p
i(V
)Predictions were made up to
10 b t l ti th
Time (Hrs)
1.2
V_V π10 years by extrapolating the
fitted curve. In 5 yrs, Vπ = 1.56 ± 0.01 V
In 10 yrs, Vπ = 1.65 ± 0.02 V
With KWW model, 5 & 10 year predictions were
1 60 V d 1 70 V ti l
0 2 4 6 8 10
Time (Years)
1.01.60 V and 1.70 V respectively.
The differences in the predicted values of the
models become significant at t >> τ (~ 70 yrs).
UNCLASSIFIEDUNCLASSIFIED
Thermal Cycling
Linear ramp : 300C 800C 300C
Ramp rate : ~ 0 6 0C/minRamp rate : 0.6 C/min
Vπ, Modulation Depth, and Total Insertion Loss
were monitored in real time.
UNCLASSIFIEDUNCLASSIFIED
Thermal Cycling : Summary
Vπ(V) 3.2 Vπ(V) 3.3 Vπ(V) 3.2
300C 300C
850C
300C 300C
850C
3.2
TIL
(dB)
9.9
Mod
Depth 11 6
3 3
TIL
(dB)
9.3
Mod
Depth 11 2
3.2
TIL
(dB)
9.5
Mod
Depth 11 630 C 30 C
2 hrs
30 C 30 C
3 hrs
Depth
(dB)
11.6 Depth
(dB)
11.2 Depth
(dB)
11.6
UNCLASSIFIEDUNCLASSIFIED
Thermal Cycling : Vπ
755
60
75
)
4
5
) )
45
Te
m
p(
C
)
3
V_
pi
(V
)
pe
ra
tu
re
(0
C
)
V π
(V
ol
ts
)
30
T
2
V
Te
m
p
Initial modulation
depth ~ 11.2 dB
Final modulation
depth ~ 11.5 dB
0
15
0
1
Modulation depth varied during the thermal cycle.
Mechanical instability in the input fiber connector is suspected.
0
0 50 100 150 200
Time (min)
0
UNCLASSIFIEDUNCLASSIFIED
Thermal Cycling : TIL (2nd cycle)
7510 5
11.0
60
75
10.0
10.5
(d
B
)
45
Te
m
p(
C
)
9.5
TI
L
(d
B
)
er
at
ur
e
(0
C
)
er
tio
n
Lo
ss
(
30
T
9.0
T
Te
m
pe
To
ta
l I
ns
e
0
15
8 0
8.5
0
0 50 100 150 200
Time (min)
8.0
UNCLASSIFIEDUNCLASSIFIED
Thermal Cycling : TIL (1st cycle)
10
11.0
60
75
10.0
10.5
C
)
45
em
p(
C
)
9.5
TI
L
(d
B
)
pe
ra
tu
re
(0
C
n
Lo
ss
(d
B
)
30
T
9.0
T
Te
m
ta
l I
ns
er
tio
n
0
15
8 0
8.5T
ot
0
5 30 55 80 105 130 155
Time (min)
8.0
UNCLASSIFIEDUNCLASSIFIED
Photobleaching
0 035
0.040
AJ 416
n 0 025
0.030
0.035 AJ 416
AJ 309
AJ 404
LPD 80
AJ-CKL1
Photobleached time : 8 – 16 hrs
Δ
0.015
0.020
0.025
UV intensity : 7.9 mW cm-2 (@ 365 nm)
0.005
0.010
0.015
Time (hrs)
0 4 8 12 16
0.000
0.005
Time (hrs)
UNCLASSIFIEDUNCLASSIFIED
Preparation of Test Samples for the
Measurement of E-O Coefficients
Fabrication of buffer layers on ITO coated
glass substrates : Northwestern Univ.
Core (AJ-CKL1 in APC) provided by Univ. of Washington
Fabrication of polymer layer and gold electrodes :Fabrication of polymer layer and gold electrodes :
AMRDEC, Redstone Arsenal
Poling and removal of gold :
by AMRDEC, Redstone Arsenal
E-O measurements : Laboratory for Physical ScienceE O measurements : Laboratory for Physical Science
Sample
Buffer
Thickness Sample
(nm)
ITO/Polymer 0
ITO/SiO2/Polymer 50
6 mm
diameter
ITO/SiO2/Polymer 280
ITO/TiO2/Polymer 50
ITO/TiO2/Polymer 250
ITO/In2O3/Polymer 50
ITO/In2O3/Polymer 250
UNCLASSIFIEDUNCLASSIFIED
Poling Parameters using
AJ-CKL1 E-O Polymer
Polarity: negative on top electrode
Voltage: 70V/μm (based on thickness of core material only)
Voltage is turned on at the temperature of 25ºCVoltage is turned on at the temperature of 25 C
Temperature: ramp at 10ºC/min from 25ºC to 135ºC
Dwell time at 135ºC: 30 sec
Cool down from 135ºC to 25ºC within about 5-6 min.
Voltage is turned off at the temperature of 25ºC
UNCLASSIFIEDUNCLASSIFIED
Poling Process for AJ-CKL1/APC
without buffer layer
Polymer thickness = 2.3 μm
UNCLASSIFIEDUNCLASSIFIED
AJ-CKL1 Low Temperature
Current Peak
α γ
Double Current Peak in single layer poling
Typically indicates a low temperature dipole alignment peak (α) followed yp y p p g p ( )
by a higher temperature conduction peak (γ)
These peaks are generally coincident in materials previously evaluated
α
γ
Double Current Peak in buffer layer poling
Plot shows a much smaller peak for the 50 nm TiO2 buffer layerp 2 y
No discernable peaks in thicker TiO2 or either of the SiO2 samples
Indicates boundary charge layer is damping the signal
• Need to investigate boundary charge effect on dipole relaxation
UNCLASSIFIEDUNCLASSIFIED
Poling Process for AJ-CKL1/APC
With SiO2 Buffer Layer
Buffer : 50 nm SiO2
Polymer : AJ-CKL1 in APC
Buffer : 280 nm SiO2
Polymer : AJ-CKL1 in APC Polymer : AJ CKL1 in APC
Polymer thicknes = 2.4 μm
Poling Voltage = 167V
y
Polymer thicknes = 2.4 μm
Poling Voltage = 167V
UNCLASSIFIEDUNCLASSIFIED
Poling Process for AJ-CKL1/APC
With TiO2 Buffer Layer
Buffer : 50 nm TiO2
Polymer : AJ-CKL1 in APC
Buffer : 250 nm TiO2
Polymer : AJ-CKL1 in APC Polymer : AJ CKL1 in APC
Polymer thicknes = 2.4 μm
Poling voltage = 167V
y
Polymer thicknes = 2.4 μm
Poling voltage = 167V
UNCLASSIFIEDUNCLASSIFIED
Experimental Results
r33 (pm/V) at 1310nm
S l Thi k ( ) #1 #2 #3 #4 AVGSample Thickness (nm) #1 #2 #3 #4 AVG
NB1 No Buffer-1 0 N/A 74.0 N/A 67.0 70.5
NB2 No Buffer-1 0 55.0 55.0 55.0 N/A 55.0
SI280H SiO2 280 40 0 42 2 46 6 40 0 42.2SI280H SiO2 280 40.0 42.2 46.6 40.0 42.2
SI50H SiO2 50 39.3 44.0 34.6 38.1 39.0
TI250H TiO2 250 N/A 85.0 N/A 82.0 83.5
TI50H TiO2 50 84.0 78.9 82.1 N/A 81.7
60 0
70.0
80.0
90.0
20.0
30.0
40.0
50.0
60.0
r3
3
(p
m
/V
)
0.0
10.0
20.0
NB1 NB2 SI280H SI50H TI250H TI50H Measured by Laboratory
for Physical Science
UNCLASSIFIEDUNCLASSIFIED
Preparation of Test Samples for
Conductivity Measurements
Sample
Buffer
Thickness
(nm)
Fabrication of buffer layers on ITO/Au coated
glass substrates : by Northwestern Univ.
Core (AJ-CKL1 in APC) provided by Univ. of Washington
ITO/Polymer 0
Au/Polymer 0
ITO/SiO2 50
Fabrication of polymer layer and gold electrodes :
by AMRDEC, Redstone Arsenal
Conductivity measurements : by NAVAIR, China Lake
ITO/SiO2 280
ITO/TiO2 50
ITO/TiO2 250
ITO/In2O3 50
ITO/In2O3 250
Au/SiO2 50
Au/SiO2 280
Au/TiO2 50
Au/TiO2 250
3- 4 mm
diameter
Au/In2O3 50
Au/In2O3 250
