High Speed Data Transmission and Processing
Wajahat Ali
Marie Curie PhD Fellow Scoula Superiore’ Sant’Anna
Objective: Design of Optical wireless communication (OWC) System for high bandwidth data transfer in relation
to HEP or Astrophysics.
Optical Wireless Transmission System For CMS
Tracker
Optical
wireless
transmission system is
proposed to connect
the
silicon
strip
modules through Gb
connection.
OWC results in :
• Radial connectivity
in order to have
faster
event
selection and lower
latency.
• To reduce the
material
budget
inside the detector
system.
•
•
CFS-2 (-8.9dBm)
CFS-5 (-7.7dBm)
CFS-11 (-0.9dBm)
CFS-18 (2.8 dBm)
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0
-1.1 -1 -0.9-0.8-0.7-0.6-0.5-0.4-0.3-0.2-0.1 0 0.10.20.30.40.50.60.70.80.9 1 1.1
Y axix displacement (mm)
Conclusion
Preliminary tasks in order to design the OWC link between
Silicon strips sensor are performed. 1550 nm wavelength
will be used for transmitter source. Experimental Tolerance
study and simulation will be used to design OWC system
with required tolerance and transmitter power limitation.
Moreover study of radiation hardness of optical
components and optics are required .
Norm Exp (0.6 dBm) CFS-11
Norm Simul (-2.8 dBm) CFS-11
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-1.1 -1 -0.9-0.8-0.7-0.6-0.5-0.4-0.3-0.2-0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1
Displacement (mm)
Experiment
Simulations
Beam
Width(m
Max Displacement
Max Displacement
m)
(mm)(3dB Point)(Verticle) (mm)(3dB Point)(Verticle)
Collimator
CFS-2
CFS-5
CFS-11
CFS-18
0.38
0.87
2.1
3.5
0.25
0.25
0.55
0.9
0.2
0.25
0.65
0.8
Sensitivity Improvement by Increasing Ball Lens
Diameter
• Simulations of transmission
system using VCSEL of 1mW
output power and distance
of 10 cm have been
performed.
• Improvement in Sensitivity
is observed as the diameter
of ball lens is increased at
the receiver.
• Similar results were obtain
when Quartz , fused Silica,
Sapphire lens (Exhibits good
radiation hard Properties)
are used instead of BK7.
Lens type
Refractive Index
BK7
1.5
Quartz
1.536
Fused Silica
1.44
Sapphire
1.74711
Sensitivity (dBm) BK7
Sensitivity (dBm) quartz
0
-2
Sensitivity (dBm)
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Calibration of Simulator (TracePro)
• Simulations
were
performed to calibrate
the simulator software
(TracePro)
comparing
results
with
data
acquired
in
the
experimental activity for
tolerance study.
• It was found that
simulated
tolerance
values approximate well
the experimental data
Power Penalty (dB)@ 1e-9(BER)
•
Experimental activity of
Free space Optics (FSO)
propagation
was
performed to study system
tolerance
due
to
misalignment.
Collimators of different
beam diameter (0.38mm,
0.87mm, 2.1mm, 3.5mm)
and Photodiodes with and
without focusing lens (Flat
Window or Ball Lens) were
used to study tolerance
limits.
It was analysed that
collimator (0.38 0.87mm)
can provide alignment
tolerance of ± 0.25mm
approximately with input
power less than 1mW.
It was a group activity
performed in INFN labs. The
experimental setup was
made to compare the effect
of 1060nm with 1550nm
laser on silicon sensor strip
1550nm laser does not
produce any trace in the
acquired signal.
Power Penalty(dB)
System Tolerance Study
•
Wavelength Selection
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-10
-12
-14
-16
0
2
4
6
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Ball Lens Diameter (mm)
This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grand agreement n!
! 317446
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