1. DEBASMIT DAS ENROLLMENT NO. – 10115039 BATCH E3

2. DETAILS ABOUT MY INTERNSHIP TYPE – RESEARCH INTERNSHIP PLACE – ECOLE POLYTECHNIQUE DE MONTREAL FIELD – PHOTONICS GUIDE – DR. RAMAN KASHYAP LAB- ADVANCED PHOTONICS CONCEPTS LABORATORY DURATION – 13 TH MAY TO 19 TH JULY, 2013

3. 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

4. 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……

5. FIBER OPTIC COUPLER Coupler used to direct light into the Fiber Bragg Grating. L C =Coupling Length ; L W = Waist Length ; L T = Taper length

6. Plot of power P 1-3 (red) P 2-4 (green) with distance along coupling length P 1-3 (Power in wave guide 1 to 3) = cos 2 (kz) P 2-4 (Power in wave guide 2 to 4) = sin 2 (kz)

7. FBG and tilted FBG Resonance condition for FBG λ B = 2nt For tilted FBG the condition holds as λ B = 2nt cos (x) where x is the angle of tilt But why is the tilted FBG? Because my fiber is DCF (double clad fiber)

8. Schematic of the Coupler I am to produce

9. 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

10. DCF before being etchedDCF after being etched

11. Characterization Excessive Loss = -10 log(P1+P2/Pin) CR = P2/P1+P2 x 100 % (Coupling Ratio) For 6 Twists – P in = 12.35dBm P 1 =10.45 dBm P 2 =-32.45 dBm So excessive Loss = 1.5497 dB CR=0.005688 %

12. Reflection and Transmission Spectrum

13. 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

14. PHENOMENON OF SPR k*n g *sinθ = k((n s 2 *ε m )/( n s 2 + ε m ))^0.5 MOMENTUM TRANSFER CONDITION

15. 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.

16. The Special H-shaped fiber

17. 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….

18. 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

20. SPECIAL THANKS TO MITACS FOR FUNDING THE INTERNSHIP