臺灣博碩士論文加值系統

光學同調斷層掃描技術是非常受到矚目的方法, 用來建造3D生醫影像, 頻域(FD-OCT)技術相較於其他技術而言, 可提供優越的訊雜比以及快速的訊號擷取。
本論文的目的是研究於一標準OCT架構中最常使用麥克森架構，關鍵元件—光纖耦合器的非對稱波長相依特性，會對系統訊號的量測造成何種影響，並且也針對FD-OCT架構進行研究討論.

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.

Abstract………………………………………………………………….I
Acknowledgement……………………………………………………...II
Table of Contents……………………………………………………...III
List of Tables……………………………………………………………V
List of Figures………………………………………………………….VI
Chapter 1 Introduction………………………………………………1
1.1 Overview……………………………………………………………………..1
1.2 Motivation……………………………………………………………………4
1.3 Organization of the thesis…………………………………………………...5
Chapter 2 Determination of characteristics of optical couplers…...6
2.1 Optical couplers……………………………………………………………...6
2.1.1 Fused-fiber couplers………………………………………………….7
2.2 Wavelength dependency characteristics of couplers……………………..10
2.2.1 Experimental results and analyses…………………………………12
2.3 Polarization dependent loss (PDL) characteristics of couplers…………18
2.3.1 Experimental results and analyses…………………………………19
2.4 Summary……………………………………………………………………21
Chapter 3 Principles of Optical Coherence Tomography………..22
3.1 OCT system concept………………………………………………………..22
3.1.1 Time-Domain Optical Coherence Tomography…………………..25
3.1.2 Frequency-Domain Optical Coherence Tomography……………26
3.2 Key components of OCT system…………………………………………..28
3.2.1 Light source………………………………………………………....28
3.2.2 Interferometer……………………………………………………....30
3.3 OCT Resolution…………………………………………………………….31
3.3.1 Axial and transverse resolutions of OCT………………………….31
3.3.2 Comparison of OCT with other imaging modalities……………..33
3.4 Summary…………………………………………………………………....35
Chapter 4 System design and performance analyses……………..36
4.1 System structure…………………………………………………………....36
4.2 Components characteristics of the FD-OCT system……………………..39
4.2.1 SLD source…………………………………………………………..39
4.2.2 Optical couplers……………………………………………………..40
4.2.3 Broadband fiber mirror…………………………………………….41
4.2.4 Mirror Sample………………………………………………………44
4.3 Experimental results and analyses………………………………………...45
4.4 Simulation results of FD-OCT system and analyses……………………..55
4.5 Summary……………………………………………………………………63
Chapter 5 Conclusions and future works………………………….64
5.1 Conclusions…………………………………………………………………64
5.2 Future works………………………………………………………………..65
References………………………………………………………………67
Publications…………………………………………………………….74

[1] K. H. Liao, T. C. Luo, C. C. Yang and C. W. Lin, Fiber-optics based Optical Coherence Tomography for Biomedical Application, Journal of Medical and Biological Engineering, Vol. 23 (1), pp. 7-12 (2003).
[2] J. G. Fujimoto, M. E. Brezinski, G. J. Tearney, S. A. Boppart, B. E. Bouma, M. R. Hee, J. F. Southern and E. A. Swanson, Optical biopsy and imaging using optical coherence tomography, Nature Med., Vol. 1, pp. 970-972 (1995).
[3] S. Y. Ryu, H. Y. Choi, J. Na, E. Choi, G. H. Yang and B. H. Lee, Optical coherence tomography implemented by photonic crystal fiber, Optical and Quantum Electronics, Vol. 37, pp. 1191-1198 (2005).
[4] S. C. Sekhar, H. Nazkani, T. Blu and M. Unser, A new technique for high-resolution frequency domain optical coherence tomography, IEEE ICASSP Conf, pp. 425-428, 2007.
[5] S. A. Boppart, Optical Coherence Tomography with Applications in Cancer Imaging, Chapter 8 of Biophotonics by L. Pavesi and P. M. Fauchet, pp. 127-150 (2008).
[6] L. V. Wang and H. I. Wu, Biomedical Optics- Principles and Imaging, John Wiley and Sons Inc., pp. 181-205 (2007).
[7] M. E. Brezinski and J. G. Fujimoto, Optical Coherence Tomography: High-Resolution Imaging in Nontransparent Tissue, IEEE Journal of Quantum Electronics, Vol. 5 (4), pp. 1185-1192 (1999).
[8] M. E. Brezinski, Optical Coherence Tomography, Academic, New York, 2007.
[9] http://obel.ee.uwa.edu.au/research/oct/intro/
[10] R. Huber, K. Taira, M. Wojtkowski, T. H. Ko and J. G. Fujimoto, High speed frequency swept light source for Fourier domain OCT at 20 kHz A-scan rate, Photonics West – Bios 2005, Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine IX (BO114).

[11] S. C. Sekhar, R. A. Leitgeb, M. L. Villiger, A. H. Bachmann, T. Blu and M. Unser, Non-iterative exact signal recovery in frequency domain optical coherence tomography, IEEE ISBI conf, pp. 808-811 (2007).
[12] G. E. Keiser, Optical Fiber Communications, McGraw-Hill, 2010.
[13] G. Rajan, Y. Semenova, G. Farrell, Q. Wang and P. Wang, Investigation of the influence of a 3dB coupler on ratiometric wavelength measurements, Proc. of SPIE, Vol. 7003(70031U), pp. 1-8 (2008).
[14] U. Sharma, N. M. Fried and J. U. Kang, All-Fiber Common-Path Optical Coherence Tomography: Sensitivity Optimization and System Analysis, IEEE J. Quantum Electronics, Vol. 11 (4), pp. 799-805 (2005).
[15] K. S. Lee, C. Koehler, E. G. Johnson and J. P. Rolland, Fourier domain optical coherence tomography with an 800μm diameter axicon lens for long-depth-range probing, Proc. of SPIE, Vol. 6079 (607919), pp. 1-8 (2006).
[16] A. F. Fercher, W. Drexler, C. K. Hitzenberger and T. Lasser, Optical coherence tomography-principles and applications, Reports on Progress in Physics, 66, pp. 239–303 (2003).
[17] A. H. Nejadmalayeri, Optical Coherence Tomography, December 14, 2001.
[18] P. E. Anderson, Introduction: Optical coherence tomography, Optics and Plasma Research Department, April 2004.

[19] R. Splinter and B. A. Hooper, An introduction to biomedical optics, Taylor & Francis Group, 2007.
[20] C. Ding, P. Bu, X. Wang and O. Sasaki, A new spectral calibration method for Fourier domain optical coherence tomography, Optik 121, pp. 965-970 (2010).
[21] Y. Hung, G. Brambilla, and D. J. Richardson, Broadband single-mode micro-fiber coupler for OCT, Optical Fiber Communication Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper OThK3.
[22] Q. Wang, G. Farrell, T. Freir, G. Rajan and P. Wang, Low-cost wavelength measurement based on a macrobending single-mode fiber, Optics Letters, Vol. 31 (12), pp. 1785-1787 (2006).
[23] D. B. Mortimore, Wavelength flattened fused couplers, Electronics Letters, Vol. 21(17), pp. 742-743 (1985).
[24] T. L. Wu and H. J. Ou, Rigorous Analysis of Polarization-Dependence Loss (PDL) for Equilateral 3x3 Fused Fiber Couplers, IEEE Photonics Technology Letters, Vol. 16 (1), pp. 165-167 (2004).
[25] Xingde Li, S. Martin, C. Pitris, R. Ghanta, D. L. Stamper, M. Harman, J. G. Fujimoto and M. E. Brezinski, High-resolution optical coherence tomographic imaging of osteoarthritic cartilage during open knee surgery, Arthritis Res Ther, 7, pp. R318-R323 (2005).
[26] A. Ozcan, M. J. F. Digonnet and G. S. Kino, Frequency-domain optical coherence tomography based on minimum-phase functions, Proc. of SPIE, Vol. 6079 (607912), pp. 1-11 (2006).
[27] A. Ozcan, O. T. Inan, N. I. Maluf, G. T. A. Kovacs, M. J. F. Digonnet and G. S. Kino, Alternative data processing for frequency-domain optical coherence tomography, in Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference and Photonic Applications Systems Technologies, Technical Digest (CD) (Optical Society of America, 2006), paper CMZ3.
[28] I. Hartl, X. D. Li, C. Chudoba, R. K. Ghanta, T. H. Ko, J. G. Fujimoto, J. K. Ranka and R. S. Windeler, Ultrahigh-resolution optical coherence tomography using continuum generation in an air-silica microstructure optical fiber, Optics Letters, Vol. 26 (9), pp.608-610 (2001).
[29] W. H. Knox, N. M. Pearson, K. D. Li and C. A. Hirlimannt, Interferometric measurements of femtosecond group delay in optical components, Optics Letters, Vol. 13 (7), pp. 574-576 (1988).
[30] D. J. Kane, R. Trebino, Single-shot measurement of the intensity and phase of an arbitrary ultrashort pulse by using frequency-resolved optical gating, Optics Letters, Vol. 18 (10), pp. 823-825 (1993).
[31] B. Choi, T. E. Milner, J. Kim, J. N. Goodman, G. Vargas, G. Aguilar, J. S. Nelson, Use of optical coherence tomography to monitor biological tissue freezing during cryosurgery, Journal of Biomedical Optics, Vol. 9 (2), pp. 282–286 (2004).
[32] B. F. Kennedy, S. Loitsch, R. A. McLaughlin, L. Scolaro, P. Rigby and D. D. Sampsona, Fibrin phantom for use in optical coherence tomography, Journal of Biomedical Optics, Vol. 15 (3), pp. 1-3 (2010).
[33] J. F. de Boer, S. M. Srinivas, B. H. Park, T. Pham, Z. Chen, T. E. Milner, and J. S. Nelson, Polarization Effects in Optical Coherence Tomography of Various Biological Tissues, IEEE J. Quantum Electronics, Vol. 5 (4), pp. 1200-1204 (1999).
[34] B. Povazay, B. Hermann, A. Unterhuber, H. Sattmann, B. Hofer, F. Zeiler. J. Morgan, A. C. Pirson, C. Glittenberg, S, Binder and W. Drexler, Spatially Encoded Frequency Domain Optical Coherence Tomography System for Volumetric In-Vivo Imaging at 1050 nm.
[35] R. N. Graf, W. J. Brown, and A. Wax, Parallel frequency-domain optical coherence tomography scatter-mode imaging of the hamster cheek pouch using a thermal light source, Optics Letters, Vol. 33 (12), pp. 1285-1287 (2008).
[36] S. C. Sekhar, R. A. Leitgeb, A. H. Bachmann and M. Unser, Logarithmic transformation technique for exact signal recovery in frequency-domain optical-coherence tomography, SPIE-OSA, Vol. 6627 (662714), pp. 1-6 (2007).
[37] A. G. Podoleanu, G. M. Dobre, D. J. Webb and D. A. Jackson, Fiberised Set-up for retinal imaging of the living eye using low coherence interferometry, Biomedical Applications of Photonics (Digest No. 1997/124).

[38] C. Kasseck, K. Lehmann, N. C. Gerhardt, M. Hofmann, Spectroscopic Fourier domain optical coherence tomography, SPIE-OSA, Vol. 6627 (66271I), pp. 1-9 (2007).

[39] B. Grajciar, M. Pircher, A. F. Fercher, R. A. Leitgeb, Parallel Fourier domain optical coherence tomography for in vivo measurement of the human eye, Optics Express, Vol. 13 (4), pp. 1131-1137 (2005).

[40] L. Wei, M. Xiaohong and Z. Huafeng, A Fiber Based Interferometer with Discrete Tunable Laser for Fourier Domain Optical Coherence Tomography, IEEE, 2006.

[41] A. Wax, C. Yang and J. A. Izatt, Fourier-domain low-coherence interferometry for light-scattering spectroscopy, Optics Letters, Vol. 28 (14), pp. 1230-1232 (2003).

[42] L. Genzel and J. Kuhl, A new version of a Michelson interferometer for fourier transform infrared spectroscopy, Infrared Physics, Vol. 18, pp. 113-120 (1978).

[43] Z. Hu, M. Zhao, J. A. Izatt and A. M. Rollins, Enhancement of FDOCT Imaging Range by Sub-Pixel Spectral Shifting, OSA/CLEO conf, paper CFA7, 2005.

[44] A. Ozcan, M. J. F. Digonnet and G. S. Kino, Non-destructive characterization tools using spectral interferometry and minimum-phase functions, UC Berkeley Optoelectronics Seminar Series, November 18, 2005.

[45] J. M. Lerner, Imaging Spectrometer Fundamentals for Researchers in the Biosciences – A Tutorial, International Society for Analytical Cytology, Cytometry Part A 69A, pp. 712-734 (2006).

[46] R. Michaely, Supercontinuum generation by Photonics Crystal Fibers, PO14 Photonics Crystals 2007.
[47] A. R. Harvey and D. W. Fletcher-Holmes, Birefringent Fourier-transform imaging spectrometer, Optics Express, Vol. 12 (22), pp. 5368-5374 (2004).
[48] K. Yu, N. Park, D. Le and O. Solgaard, Micromirror-based scan range enhancement in Fourier-domain optical coherence tomography, IEEE, pp. 42-43 (2006).
[49] R. Leitgeb, C. K. Hitzenberger and A. F. Fercher, Performance of fourier domain vs. time domain optical coherence tomography, Optics Express, Vol. 11 (8), pp. 889-894 (2003).
[50] Y. Garini, I. T. Young and G. McNamara, Spectral Imaging: Principles and Applications, International Society for Analytical Cytology Cytometry Part A 69A, pp. 735-747 (2006).
[51] A. B. Vakhtin, D. J. Kane, W. R. Wood and K. A. Peterson, Common-path interferometer for frequency-domain optical coherence tomography, Applied Optics, Vol. 42 (34), pp. 6953-6958 (2003).
[52] M. Y. Jeon, J. Zhang and Z. Chen, Characterization of Fourier domain mode-locked wavelength swept laser for optical coherence tomography imaging, Optics Letters, Vol. 16 (6), pp. 3727-3737 (2008).
[53] R. A. Leitgeb, C. K. Hitzenberger and A. F. Fercher, Phase-shifting algorithm to achieve high-speed long-depth-range probing by frequency-domain optical coherence tomography, Optics Letters, Vol. 28 (22), pp. 2201-2203 (2003).
[54] B. Hofer, B. Povazay, B. Hermann, A. Unterhuber, G. Matz, F. Hlawatsch and W. Drexler, Signal post processing in frequency domain OCT and OCM using filter bank approach.
[55] K. Suzuki, V. Sharma, J. G. Fujimoto and E. P. Ippen, Characterization of symmetric [3 x 3] directional couplers fabricated by direct writing with a femtosecond laser oscillator, Optics Express, Vol. 14 (6), pp. 2335-2343 (2006).
[56] R. Huber, M. Wojtkowski, K. Taira, and J. G. Fujimoto, Amplified, frequency swept lasers for frequency domain reflectometry and OCT imaging: design and scaling principles, Optics Express, Vol. 13 (9), pp. 3513-3528 (2005).
[57] Maciej Wojtkowski, High-speed optical coherence tomography: basics and applications, Applied Optics, Vol. 49 (16), pp. D30-D61 (2010).
[58] U. Morgner, W. Drexler, F.X. Kartner, X. D. Li, C. Pitris, E. P. Ippen and J. G. Fujimoto, Spectroscopic optical coherence tomography, Optics Letters, Vol. 25 (2), pp. 111-113 (2000).
[59] V. Jaedicke, C. Kasseck, N. C. Gerhardt, H. Welp and M. R. Hofmann, Spectroscopic image analysis with pattern recognition in frequency domain optical coherence tomography, OSA/BIOMED/DH conf, paper BSuD8, 2010.
[60] Y. Tanaka, Y. Itoh, K. Aizawa, T. Kurokawa and H. Tsuda, Optical Spectrum Analyzer Based on Arrayed Waveguide Grating for High-Speed Optical Communication Systems, IEEE Photonics Technology Letters, Vol. 17 (2), pp. 432-434 (2005).
[61] A. V. Zvyagin, E. D. J. Smith and D. D. Sampson, Delay and dispersion characteristics of a frequency-domain optical delay line for scanning interferometry, J. Optical Society of America, Vol. 20 (2), pp. 333-341 (2003).
[62] C. Kasseck, V. Jaedicke, N. C. Gerhardt, H. Welp and Martin R. Hofmann, Frequency domain optical coherence tomography with subsequent depth resolved spectroscopic image analysis, Proc. of SPIE Vol. 7554 (75542T), pp. 1-5 (2010).
[63] K. M. Tan, M. Mazilu, T. H. Chow, W. M. Lee, K. Taguchi, B. K. Ng, W. Sibbett, C. S. Herrington, C. T. A. Brown and K. Dholakia, In-fiber common-path optical coherence tomography using a conical-tip fiber, Optics Express, Vol. 17 (4), pp. 2375-2384 (2009).
[64] A. R. Tumlinson, L. P. Hariri, U. Utzinger and J. K. Barton, Miniature endoscope for simultaneous optical coherence tomography and laser-induced fluorescence measurement, Applied Optics, Vol. 43 (1), pp. 113-121 (2004).
[65] Z. Chen, T. E. Milner, X. Wang, S. Srinivas and J. S. Nelson, Optical Doppler Tomography: Imaging in vivo Blood Flow Dynamics Following Pharmacological Intervention and Photodynamic Therapy, Photochemistry and Photobiology, Vol. 67, pp. 1-7 (1998).
[66] F. A. M. Saccon, M. Muller and J. L. Fabris, Optical fiber characterization by optical coherence tomography, International Microwave & Optoelectronics Conference, pp. 625-628 (2009).
[67] T. L. Troy and S. N. Thennadil, Optical properties of human skin in the near infrared wavelength range of 1000 to 2200 nm, Journal of Biomedical Optics, Vol. 6 (2), pp. 167-176 (2001).
[68] C. S. Seelamantula and M. Unser, Performance Analysis of Reconstruction Techniques for Frequency-Domain Optical-Coherence Tomography, IEEE Transactions on signal processing, Vol. 58 (3), pp. 1947-1951 (2010).
[69] Y. Yasuno, S. Makita, T. Endo, G. Aoki, M. Itoh and T. Yatagai, Real time and full-range complex Fourier domain optical coherence tomography, Optical and Quantum Electronics, Vol. 37, pp. 1157–1163 (2005).
[70] P. Blazkiewicz, P. M. Gourlay, J. R. Tucker , A. D. Rakic , A. V. Zvyagin, Experimental Demonstration of Signal-to-Noise-Ratio Improvement of Fourier-Domain Optical Coherence Tomography, OCIS conf, pp. 1-14.
[71] P. Li, Y. He and H. Ma, Spectral-Domain Optical Coherence Tomography and Applications for Biological Imaging, IEEE, 2006.
[72] C. Kasseck, V. Jaedicke, N. C. Gerhardt, H. Welp and M. R. Hofmann, Substance identification by depth resolved spectroscopic pattern reconstruction in frequency domain optical coherence tomography, Optics Communications (2010), Journal homepage: www.elsevier.com/locate/optcom.
[73] M. A. Choma, M. V. Sarunic, C. Yang and J. A. Izatt, Sensitivity advantage of swept source and Fourier domain optical coherence tomography, Optics Express, Vol. 11 (18), pp. 2183-2189 (2003).
[74] P. H. Tomlins and R. K. Wang, Theory, developments and applications of optical coherence tomography, Journal of Physics D: Applied Physics, 38, pp. 2519–2535 (2005).
[75] B. Cense and N. A. Nassif, Ultrahigh-resolution high-speed retinal imaging using spectral-domain optical coherence tomography, Optics Express, Vol. 12 (11), pp. 2435-2447 (2004).