R. Kass N18-5 1 IEEE06/San Diego Cables and Spliced SIMM/GRIN Fibers and Radiation Hardness of PIN/VCSEL Arrays W. Fernando, K.K. Gan, A. Law, H.P. Kagan, R.D. Kass, S. Smith The Ohio State University M.R.M. Lebbai, P.L. Skubic University of Oklahoma Richard Kass The Ohio State University OUTLINE Introduction-ATLAS/Pixel Detector/SuperLHC Bandwidth of micro twisted-pair cables Bandwidth of fusion spliced SIMM- GRIN fibers Radiation hardness of PIN/VCSEL
Transcript
R. Kass N18-5 1IEEE06/San Diego
Bandwidth of Micro Twisted-Pair Cables and Spliced SIMM/GRIN Fibers and
Radiation Hardness of PIN/VCSEL Arrays
W. Fernando, K.K. Gan, A. Law, H.P. Kagan, R.D. Kass, S. SmithThe Ohio State University
M.R.M. Lebbai, P.L. SkubicUniversity of Oklahoma
Richard KassThe Ohio State University
OUTLINEIntroduction-ATLAS/Pixel Detector/SuperLHCBandwidth of micro twisted-pair cablesBandwidth of fusion spliced SIMM-GRIN fibersRadiation hardness of PIN/VCSEL arraysSummary
R. Kass N18-5 2IEEE06/San Diego
The Current ATLAS Pixel Detector
A pixel module contains:1 sensor (2x6cm) ~40000 pixels
16 front end (FE) chips 2x8 array
Flex-hybrid1 module control chip (MCC)There are ~1700 modules ~108 channels
~1.85m
Pixel Detector:ATLAS’s Inner most charged particle tracker Measures (x,y,z) to ~30 mPixel detector is based on silicon Pixel size 50m by 400 m ~100 million
pixelsRadiation hardness is an issue must last ~ 10 years
ATLAS is a detector at CERN designed to study 14 TeV pp collisions Detector upgrade planned for Super-LHC in 2015
R. Kass N18-5 3IEEE06/San Diego
Present Pixel Opto-link ArchitectureCurrent optical link of pixel detector transmits signals at 80 Mb/sOpto-link separated from FE modules by ~1m
transmit control & data signals (LVDS) to/from modules on micro twisted pairs
Use PIN/VCSEL arrays
Use 8 m of rad-hard/low-bandwidth SIMM fiber fusionspliced to 70 m rad-tolerant/medium-bandwidth GRIN fiber Simplify opto-board and FE module production Sensitive optical components see lower radiation level than modules PIN/VCSEL arrays allow use of robust ribbon fiber
A Bandwidth of ~ 640 Mb/s is neededCan micro twisted pair transmit at this speed?Can fusion spliced SIMM/GRIN fiber transmit at this speed?
Radiation Hardness of opto-board components Can PIN/VCSEL arrays survive SLHC radiation dosage?
~150m
optoboard
~1m
R. Kass N18-5 5IEEE06/San Diego
Bandwidth of Micro Twisted Pairs
Bandwidth measurements made with LeCroy Wavemaster 8600A digital scope (6 GHz input bandwidth, and 7.5GHz differential probe)Eye diagrams made using pseudo-random data (650Mb/s, 1 Gb/s)Eye masks adapted from Gigabit Ethernet Spec. (IEEE std. 802.3)
Bandwidth of 3 micro twisted-pair wires were compared.Wire used is MWS Wire Industries Twistite
10 turns per inch , with 100Ω termination. 5 turns per inch, with 75Ω termination.
R. Kass N18-5 6IEEE06/San Diego
Bandwidth of Micro Twisted Pairs
Bandwidth of 3 micro twisted-pair wires were compared: 38 AWG/100 m, 2 turns/cm (current pixel cable) 36 AWG/127 m, 2 turns/cm 36 AWG/127 m, 4 turns/cm
0
200
400
600
800
1000
50 70 90 110 130 150
Length (cm)
Ris
e T
ime
(20%
- 8
0%)
(ps)
AWG 38, 5 TPIAWG 36, 5 TPIAWG 36, 10 TPI
The Current pixel cable is the best!
2 T/cm2 T/cm4 T/cm
0
200
400
600
800
1000
50 70 90 110 130 150
Length (cm)
Fal
l T
ime
(20%
- 8
0%)
(ps)
AWG 38, 5 TPI
AWG 36, 5 TPI
AWG 36, 10 TPI
R. Kass N18-5 7IEEE06/San Diego
Micro Twisted Pair Eye Diagrams 140 cm pixel cable 60 cm pixel cable
Transmission at 650 Mb/s is adequate
650 Mb/s
1.3Gb/s
Transmission at 1.3 Gb/s may be acceptable
R. Kass N18-5 8IEEE06/San Diego
Bandwidth of Fusion Spliced Fiber
GRIN: Graded Index multi mode optical fiberGRIN fibers are rad-tolerant with medium bandwidth
SIMM: Single Index MultiMode optical fiberSIMM fibers are rad-hard but lower bandwidth
Present system designed to work at 80Mb/s but will it work at1Gb/s ?
splices made using Fujikura fusion splicer
Bandwidth Test Setup for existing Pixel Architecture
R. Kass N18-5 9IEEE06/San Diego
Bandwidth of Fusion Spliced Fiber
8 + 80 m spliced SIMM/GRIN fiber1 m GRIN fiber
Transmission up to 2 Gb/s looks adequate
2 Gb/s
R. Kass N18-5 10IEEE06/San Diego
Radiation Level at SuperLHCOptical link of current pixel detector is mounted on patch panel:
much reduced radiation level compared to collision point:SI (PIN) @ SLHC:
2.5 x 1015 1-MeV neq/cm2
4.3 x 1015 p/cm2 or 114 Mrad for 24 GeV protons GaAs (VCSEL) @ SLHC:
14 x 1015 1-MeV neq/cm2
2.7 x 1015 p/cm2 or 71 Mrad for 24 GeV protons
R. Kass N18-5 11IEEE06/San Diego
SLHC Issues for PIN/VCSELPIN:What is responsivity after irradiation?What is rise/fall time after irradiation?VCSEL: Driver chip will most likely be fabricated with 0.13 m process
operating voltage is 1.2 Vthick oxide option can operate at 2.5 VVCSEL requirement: < 2.3 V to produce 10 mA or more
some VCSELs require > 2.3 V to operate at 10 mA or more
What is rise/fall time after irradiation?
What is optical power after irradiation?
What current is needed for annealing? We irradiated 4 different kinds of VCSELs: Optowell Advanced Optical Components (AOC) ULM Photonics (5Gb/s and 10Gb/s versions)
R. Kass N18-5 12IEEE06/San Diego
Real Time Monitoring in T7 Beam TestReal time testing of opto-board system using loop-back setup
dataDORIC
clockPIN
VDCVCSEL
Opto-board
VDCVCSEL
bi-phase marked optical signal
decoded data
decoded clock
Signal routed back to opto-baord via test board
attached to 80-pin connector & test board
Bit error test setupat CERN’sT-7 beamline24 GeV protons
Compare transmitted and decoded data
measure minimum PIN current for no bit errors
Measure optical power
In control room
25m optical
fiber cable
In beam
Two VCSEL arraysfrom same vendor per opto-board
R. Kass N18-5 13IEEE06/San Diego
Results: PIN Responsivity
Responsivity of PINs decrease by ~50% after SLHC dosage
0
1
2
3
4
5
6
7
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Post-irradPre-irrad
Co
un
t
Responsivity (uA/uW)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
1 6 11 16 21 26
Channel Number
PIN
Re
sp
on
siv
ity
(A
/W)
Pre IrradPost Irrad
Responsivity (A/W)
Cou
nt
channel number
Res
pons
ivit
y (
A/
W)
PINS are manufactured by TRUELIGHT
R. Kass N18-5 14IEEE06/San Diego
VCSEL LIV Characteristics
ULM requires higher voltage to operate
All arrays have very good optical power
Pre-irradiation OSU V0010 (Advanced Optical Components HFE8012-101)
Opto-Board 3151 Left VCSEL
0
500
1000
1500
2000
2500
3000
3500
0 2 4 6 8 10 12
Current (mA)
Po
we
r (μ
W)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Vo
lta
ge
(V
)
AOC
current (mA)
po
wer
(W
)
Vo
ltag
e (V
)
OSU V006 (ULM 10 Gb/s ULM850-10-TN-N0112U)Opto-Board 2150 Left VCSEL
0
500
1000
1500
2000
2500
3000
0 2 4 6 8 10 12
Current (mA)
Po
we
r (μ
W)
0
0.5
1
1.5
2
2.5
Vo
lta
ge
(V
)
ULM 10Gb/s
current (mA)
po
wer
(W
)
Vo
ltag
e (V
)
OSU V0012 (Optowell AM85-1N112)Opto-Board 3152 Left VCSEL
0
500
1000
1500
2000
2500
3000
3500
0 2 4 6 8 10 12
Current (mA)
Po
wer
(μ
W)
0
0.5
1
1.5
2
2.5
Vo
ltag
e (V
)
Optowell
current (mA)
po
wer
(W
)
Vo
ltag
e (V
)
OSU V005 (ULM 5 Gb/s ULM850-05-TN-B0112U)Opto-Board 2151 Left VCSEL
0
500
1000
1500
2000
2500
3000
3500
0 2 4 6 8 10 12
Current (mA)
Po
we
r (μ
W)
0
0.5
1
1.5
2
2.5
Vo
lta
ge
(V
)
ULM 5Gb/s
current (mA)
po
wer
(W
)
Vo
ltag
e (V
)
R. Kass N18-5 15IEEE06/San Diego
Optowell
71 MRad
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0 100 200 300 400
Time (Hours)
Da
ta O
pti
ca
l P
ow
er
(mW
)
0
20
40
60
80
100
120
Do
se
(M
rad
s)
Ch 1
Ch 2
Ch 3
Ch 4
Ch 5
Ch 6
Ch 7
Dose
VCSEL Power vs Dosage
Optowell survives to SLHC dosage
Other VCSELs might survive with more annealing or slower irradiation
SLHC
AOC
71 MRad
0.0
0.3
0.6
0.9
1.2
1.5
1.8
0 100 200 300 400
Time (Hours)
Da
ta O
pti
ca
l P
ow
er
(mW
)
0
20
40
60
80
100
120
Do
se
(M
rad
s)
Ch 1
Ch 2
Ch 3
Ch 4
Ch 5
Ch 6
Ch 7
Dose
AOC
ULM 5G
71 MRad
0.0
0.4
0.8
1.2
1.6
2.0
2.4
2.8
0 100 200 300 400
Time (Hours)
Da
ta O
pti
ca
l P
ow
er
(mW
)
0
20
40
60
80
100
120
Do
se (
Mra
ds
)
Ch 1
Ch 2
Ch 3
Ch 4
Ch 5
Ch 6
Ch 7
Dose
ULM 10G
71 MRad
0.0
0.3
0.6
0.9
1.2
1.5
0 100 200 300 400
Time (Hours)
Da
ta O
pti
ca
l P
ow
er
(mW
)
0
20
40
60
80
100
120
Do
se
(M
rad
s)
Ch 1
Ch 2
Ch 3
Ch 4
Ch 5
Ch 6
Ch 7
Dose
R. Kass N18-5 16IEEE06/San Diego
Summary
Micro twisted-pair cable of current ATLAS pixel detectorcan be used for transmission up to 1 Gb/s
Fusion spliced SIMM/GRIN fiber can transmit up to 2 Gb/s
PIN responsivity decreases by 50% after SLHC dosage
Optowell VCSEL survives SLHC dosage
Current opto-link architecture satisfies SLHC requirements
