Study of Optical Coupler Asymmetry Effects on Optical Coherence Tomography Measurements
| Autor: | Olivia Devi Haobijam, 歐莉文 |
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| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 Optical coherence tomography (OCT) is a popular method for creating real-time three-dimensional images of biological and non-biological specimens. This imaging modality uses the interference between light backscattered from a sample and light that has traversed a known reference path delay to determine the scattering profile over penetration depths up to several millimeters in biological tissues. Frequency-domain OCT (FD-OCT) is an implementation of OCT which provides advantages in signal-to-noise ratio along with faster signal acquisition than other OCT methods. In an OCT set-up, a fused-fiber optical coupler is one of the key components. Ideally the coupler should have a splitting ratio that is independent of wavelength. However all commercially available optical fiber couplers have some variations in transmission loss as a function of wavelength. This is because of configure variations in the common fabrication method for the fused-fiber coupler which involves twisting together, melting, and pulling two closely spaced single-mode or multi-mode fibers over a uniform length section. The goal of the thesis is to determine what effect any wavelength-dependent asymmetry in the operational characteristics of an optical coupler has on the OCT system performance. In this study a Frequency-domain OCT (FD-OCT) set-up, with a Michelson interferometer using a 2x2 optical fiber coupler, is used. By interchanging the orientations of the optical coupler arms in the FD-OCT set-up, a detailed experimental and simulated study was done to determine the effects of wavelength-dependent characteristics of optical couplers on the accuracy of OCT measurements. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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