Transcript INTERNSHIP REPORT

DEBASMIT DAS
ENROLLMENT NO. – 10115039
BATCH E3
DETAILS ABOUT MY INTERNSHIP
 TYPE – RESEARCH INTERNSHIP
 PLACE – ECOLE POLYTECHNIQUE DE MONTREAL
 FIELD – PHOTONICS
 GUIDE – DR. RAMAN KASHYAP
 LAB- ADVANCED PHOTONICS CONCEPTS
LABORATORY
 DURATION – 13TH MAY TO 19TH JULY, 2013
CONTENTS OF MY INTERNSHIP
 FABRICATION OF A 4-PORT OPTICAL FIBER
COUPLER
 EXPERIMENTAL AND THEORITICAL ANALYSIS OF
SURFACE PLASMON DEVICES (SPR) BASED ON
OPTICAL FIBER
FABRICATION OF A 4-PORT
OPTICAL FIBER COUPLER
 AIM OF THIS PROJECT IS TO BUILD A COUPLER
THAT CAN BE USED MULTIPURPOSELY FOR
DIFFERENT PROJECTS IN THE FUTURE.
 I APPLIED THE COUPLER TO OBTAIN THE
REFLECTION AND TRANSMISSION SPECTRUM OF
A TILTED FIBER BRAGG GRATING.
 DETAILS ON THESE IN THE COMING SLIDES……
FIBER OPTIC COUPLER
Coupler used to direct light into the Fiber Bragg Grating.
LC=Coupling Length ; LW = Waist Length ; LT = Taper length
P1-3 (Power in wave guide 1 to 3) = cos2(kz)
P2-4(Power in wave guide 2 to 4) = sin2(kz)
Plot of power P1-3 (red) P2-4 (green) with
distance along coupling length
FBG and tilted FBG
 Resonance condition for FBG
λB = 2nt
For tilted FBG the condition holds as
λB = 2nt cos (x) where x is the angle of tilt
But why is the tilted FBG?
Because my fiber is DCF (double clad fiber)
Schematic of the Coupler I am to
produce
Steps
 Etching of two DCF fibers around 15 cm length
 Twisting of the two fibers along the etched portion.
 Fixing the coupler to a platform to make it ready for
measurements
 Characterization of the coupler and observing the
spectrum of the tilted FBG
DCF before being etched
DCF after being etched
Characterization
 Excessive Loss = -10 log(P1+P2/Pin)
 CR = P2/P1+P2 x 100 % (Coupling Ratio)
 For 6 Twists –
Pin= 12.35dBm
P1=10.45 dBm
P2=-32.45 dBm
So excessive Loss = 1.5497 dB
CR=0.005688 %
Reflection and Transmission
Spectrum
SURFACE PLASMON RESONANCE
 AIM OF THIS PROJECT IS SIMULATION AND
ANALYSIS OF SPR ON A NOVEL H-SHAPED FIBER
 SIMULATION HAS BEEN DONE IN MATLAB
 PURPOSE OF SIMULATION IS TO ANALYSE AND
COMPARE WITH EXPERIMENTAL RESULTS
PHENOMENON OF SPR
k*ng *sinθ = k((ns2*εm)/( ns2 + εm ))^0.5
MOMENTUM TRANSFER CONDITION
APPLICATION
 As a biosensor or a chemical sensor
 As refractive index of sensing medium changes so will
the resonance wavelength
 So the resonance wavelength can plotted with
refractive index and this calibration is used to create
biosensor
 It can indirectly be used to measure concentration of
analyte which perturbs refractive index
 ADVANTAGE : Very high sensitve sensors ~ 3000
nm/RIU . Apt for the nano world.
The Special H-shaped fiber
Why H-shaped Fiber?
 Birefringent fiber with elliptical core
 Two orthogonal single modes with no interference in
visible region.
 Can be used to measure two quantities simultaneously
 But for now analysis is done for one axis that is the axis
along the cleavage….
N-Layer Model Parameters
 N=3 for our cases
 n1=core n2=metal n3=dielectric sensing medium
 Core diameter =10 nm Metal thickness (gold) =50 nm
and Dielectric thickness = 25 nm
0.9
0.8
Normalised Power
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.4
0.5
0.6
0.7
Wavelength (nm)
0.8
0.9
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SPECIAL THANKS TO MITACS FOR
FUNDING THE INTERNSHIP