Applications of FFT and digital filtering in reconstruction of refractive index profile of surface channel waveguides from near-field intensity pattern

Hery Susanto Djie; Henri P. Uranus; M Muljono; John E. Batubara

doi:10.1117/12.370365

12 November 1999 Applications of FFT and digital filtering in reconstruction of refractive index profile of surface channel waveguides from near-field intensity pattern

Hery Susanto Djie, Henri P. Uranus, M Muljono, John E. Batubara

Author Affiliations +

Proceedings Volume 3896, Design, Fabrication, and Characterization of Photonic Devices; (1999) https://doi.org/10.1117/12.370365
Event: International Symposium on Photonics and Applications, 1999, Singapore, Singapore

Abstract

Refractive index profile of surface channel waveguides can be determined by analyzing the near-field intensity pattern. A mathematical model, the inverse Helmholtz equation, is derived in order to use these data to reconstruct the refractive index profile under consideration. In this work, the measured near-field intensities are preprocessed by means of gamma correction, background noise subtraction, Fast Fourier Transform, and low pass finite impulse response (FIR) digital filter. Several types of FIR windows are chosen. The results are used to reconstruct the refractive index profile of the waveguide. The results show that the application of low pass FIR digital filter by using Hamming window reduces noises better than other windows. The application of this method in determination of refractive index profile of annealed proton exchange LiNbO₃ channel waveguides is demonstrated.

Citation Download Citation

Hery Susanto Djie, Henri P. Uranus, M Muljono, and John E. Batubara "Applications of FFT and digital filtering in reconstruction of refractive index profile of surface channel waveguides from near-field intensity pattern", Proc. SPIE 3896, Design, Fabrication, and Characterization of Photonic Devices, (12 November 1999); https://doi.org/10.1117/12.370365

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available