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Proceedings Paper

New method of surface characterization with a single-mode fiber to thin film coupler
Author(s): Alok Kumar Das; Amar K. Ganguly; Anawar Hussain; Shila Ghosh; Bharat P. Choudhury
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Paper Abstract

The evanescent field coupling characteristics between a single-mode half coupler and a thin-film planar waveguide (PWG) placed on the substrate is discussed. The throughput fiber power T changes with the variation of the effetive thickness of the film. Experiments for different thicknesses of the PWGs are carried out. The . thickness of the spacer deposited on the substrate or the roughness of the substrate with fixed spacer, controls the effective thickness of the PWG. Thus, T measures the roughness quality of the substrate and also the thickness of the spacer. The substrate was fused silica for the standard telecommunication fiber as half coupler. However, coupling fiber was also used in the case of germania-silica substrate for matching the propagation constants fo the fiber and the substrate. The variation of T with the change of refractive index of PWG and also the substrate are also shown. Theoretical analysis was carried out and a good agreement is observed with the experimental results.

Paper Details

Date Published: 4 November 1996
PDF: 6 pages
Proc. SPIE 2862, Flatness, Roughness, and Discrete Defect Characterization for Computer Disks, Wafers, and Flat Panel Displays, (4 November 1996); doi: 10.1117/12.256202
Show Author Affiliations
Alok Kumar Das, Jadavpur Univ. (India)
Amar K. Ganguly, Jadavpur Univ. (India)
Anawar Hussain, Jadavpur Univ. (India)
Shila Ghosh, Jadavpur Univ. (India)
Bharat P. Choudhury, Jadavpur Univ. (India)


Published in SPIE Proceedings Vol. 2862:
Flatness, Roughness, and Discrete Defect Characterization for Computer Disks, Wafers, and Flat Panel Displays
John C. Stover, Editor(s)

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