本論文主要三個部份：第一部份為改善效益之C-band摻鉺光纖放大器，在架構末端設置極化控制器和極化合光器，來改善訊號和泵激雷射往返兩次所產生的高雜訊指數之問題。當輸入訊號為-20 dBm，建議架構之平均增益為26.03 dB，平均雜訊指數為5.33 dB，增益提升了0.31 dB，雜訊指數降低了2.54 dB，本章建議架構之最高增益和波長為28.28 dB @1530 nm，最低雜訊指數和波長為4.12 dB@1565 nm。
第二部份為改善效益之L-band摻鉺光纖放大器架構，我們使用無泵激光源的L-band架構來作為本章的基礎架構，再利用末端放置反射迴路達到訊號兩次往返的架構。當輸入訊號為-30 dBm，S-DP架構之平均增益為31.47 dB，平均雜訊指數為9.57 dB。改善2架構平均增益為34.73 dB，平均雜訊指數為6.7 dB，增益改善3.26 dB，雜訊指數改善2.87 dB。
第三部份為新型C+L band摻鉺光纖放大器，可以達到低成本的目的。建議架構與習用的架構比較，多了一個光循環器和一個C+L band分波多工器，但減少了泵激雷射63 mW、掺鉺光纖8 m、一個光隔離器、和一個980/1550分波多工器。至於特性方面，習用架構的平均增益為19.01 dB，平均雜訊指數為8.02 dB，而本章建議架構的平均增益為18.29 dB，平均雜訊指數為8.43 dB，和習用的架構做比較，增益少了0.72 dB，雜訊指數高了0.41 dB。
本文所提到之改善架構將可廣泛的應用在各種不同的系統，例如分波多工系統、光通訊系統等其他的系統，都將會有很好的表現。

The thesis includes three parts. In the first part, we investigate in the improvement of pumping efficiency in C-band erbium-doped fiber (EDFA). A polarization controller (PC) and a polarization beam combiner (PBC) are put inside the proposed structure. Thus, we could reduce the non-idea noise-figure (NF) value in EDFA. The non-idea NF is mainly attributed to the signal/pump power double-pass configuration. As the input signal set at -20 dBm, the average gain is 26.03 dB with 0.31 dB improvement. In the meanwhile, the average NF is 5.33 dB with 2.54 dB reduction. Note that in such a proposed structure, the maximum gain occurs at 1530 nm while the lowest NF occurs at 1565 nm. In the second part, we focus on the improvement of pumping efficiency in L-band EDFA. We use one piece of un-pump erbium-doped fiber (EDF) to play the key role, using a terminated reflective loop to double-pass the signal/pump power. As the input signal set at -30 dBm, the performance of the average gain is 34.73 dB with 3.26 dB improvement. In the meanwhile, the average NF is 6.7 dB with 2.87 dB reduction. The design of novel C+L band EDFA is described in the third part. We purpose a new configuration for C+L band EDFA. Although the proposed structure need an extra optical circulator and a C+L band WDM coupler than that of a conventional C+L band EDFA does, nevertheless, it could save a pump laser, an optical isolator, a 980/1550 WDM coupler and one piece of EDF. For the characteristics measurement, the cost effective C+L band EDFA suffers slight 0.72 dB of average gain reduction and 0.41 dB of average NF degradation. On fortune, these degradations in gain and NF still meet the EDFA criteria. The proposed novel EDFAs in this thesis with low NF and/or cost effective may find vast applications in WDM system and optical communication system.

[1] P. C. Becker, N. A. Olsson, and J. R. Simpson, “Erbium-doped fiber amplifiers, fundamentals and technology”, Academic Press, 1999.
[2] 廖協虹, “(C+L)-band 掺鉺光纖放大器的研製及應用”, 台灣科技大學碩士論文, 2004.
[3] S. Yan, A. K. Srivastava, Z. Jianhui, and J. W. Sulhoff, “Optical fiber amplifiers for WDM-optical networks”, Bell labs Tech. J, vol. 4, no 1, pp. 187-206, January-March, 1999.
[4] 蕭淵隆,“高效益光纖放大器之研製”,台灣科技大學碩士論文, 2006.
[5] G. P. Agrawal, Fiber-optical communication system, John Wiley & Sons, Inc., New York, 1997.
[6] 張家綸,“具有高增益低雜訊之雙向激發Double-Pass L-band掺鉺光纖放大器之研究”,清華大學碩士論文, 2005.
[7] Y. Sun, J. L. Zyskind, and A. K. Srivastava, “Average inversion level, modeling, and physics of erbium-doped fiber amplifiers”, IEEE Journal of Quantum Electronics, vol. 3, no 4 , pp .991-107, 1997.
[8] J. F. Michel, “Rare-earth-doped fiber lasers and amplifier”, Marcel Dekker, 2001.
[9] D. Derickson, “Fiber Optical Test and Measurement”, Prentice Hall PTR, New Jersey, 1998.
[10] R. S. Tucker and D. M. Baney, “Optical noise figure：Theory and Measurements”, European Conference on Optical Communications (ECOC2000), vol. 3, pp. 1176-1184, 2000.
[11] K. lizuka, “Elements of photonics volume II”, Wiley-Interscience, 2002.
[12] R. D. Muro, S. J. Wilson, N. E. Jolley, B. S. Farley, A. Robinson, and J. Mun, “Measurement of the quantum efficiency of long wavelength EDFAs with and without an idler signal”, Optical Fiber Communications Conference (OFC1999), vol. 1, pp. 419- 420, 1999.
[13] P. F. Wysocki, R.F. Kalman, M. J. F. Digonnet, and B. Y. Kim, “A comparison of 1.48 μm and 980 nm pumping for Er-doped superfluorescent fiber sources,”, in Fiber Laser Sources and Amplifiers Ⅲ, M. J. F. Digonnet and E. Snitzer, Ed., Proc. SPIE 1581, pp. 40 – 58, 1992.
[14] S. W. Harun, P. Poopalan, and H. Ahmad, “Gain enhancement in L-band EDFA through a double-pass technique”, IEEE Photon. Tech. Lett. , vol. 14, pp. 296-297, 2002.
[15] H. Ahmad and S. W. Harun, “Double pass L-band EDFA with an improved gain coefficient”, Asia-Pacific Conference Communicationson (APCC2003) , vol. 1, pp. 31-33, 2003.
[16] S. Hwang, K. W. Song, H. J. Kwon, J. Koh, Y. J. Oh, and K. Cho, “Broad-band erbium-doped fiber amplifier with double-pass configuration”, IEEE Photon. Tech. Lett., vol. 13, pp. 1289-1291, 2001.
[17] A. A. Rieznik, W. A. Arellano, G. S. Wiederhecker, T. P. M. Alegre, and H. L. Fragnito, “EDFAs gain and noise figure dependence on the fiber length: comparison between L and C Bands”, International Microwave and Optoelectronics Conference (IMOC2003), vol. 1, pp. 115-119, 2003.
[18] www.itri.org.tw/chi/services/transferable/itri_show.jsp?idx=236,工業技術研究院-光通訊元件技術.
[19] E. Hecht, “Optics”, Addison Wesley, 4thedition, pp. 604-605, 2002.
[20] E. Desurvire, “Erbium-doped fiber amplifiers: principles and applications”, New York : Wiley, 1994.
[21] Y. H. Lu and S. Chi, “Two-stage L Band EDFA applying C/L Band wavelength-division multiplexer with the counterpropagating partial gain-clamping”, IEEE Photon. Tech. Lett., vol. 15, pp. 1710-1712, 2003.
[22] A. Buxens, H. N. Poulsen, A. T. Clausen and P. Jeppesen, “Gain flattened L-band EDFA based on upgraded C-band EDFA using forward ASE pumping in an EDF section”, Electronic Letters, vol. 36, no 9, April, 2000.
[23] L. Juhan, U. C. Ryu, J. A. Seong and P. Namkyoo, “Enhancement of power conversion efficiency for an L-band EDFA with a secondary pumping effect in the unpumped EDF section”, IEEE Photon. Tech. Lett. , vol. 11, no 1, pp. 42-44, January, 1999.
[24] Felton A. Flood , “L-band erbium-doped fiber amplifiers”, Photonics Research Center, Corning Incorporated.
[25] B. H. Choi, H. H. Park, M. Chu and S. K. Kim, “High-gain coefficient long-wavelength-Band erbium-doped fiber amplifier using 1530 nm Band pump”, IEEE Photon. Tecl. Lett., vol.13, pp. 109-111, 2001.
[26] T. Yamashita, M. Yoshida, H. Tanaka, S. Tanaka and T. Yazaki, “A novel method to improve noise figure for a wide bandwidth single stage L band EDFA”, Optical Fiber Communications Conference (OFC2002), pp. 455–457, 2002.
[27] 董德國, 陳萬清,“光纖通訊”,東華書局, 2001.
[28] M. Yamada, H. Ono, T. Kanamori, S. Sudo, and Y. Ohishi, “Broadband and gain-flattened amplifier composed of a 1.55 μm-Band and a 1.58 μm-Band Er3+-doped fibre amplifier in a parallel configuration”, Electron Lett., vol. 33, pp. 710-711, 1997.
[29] H. Ono, M. Yamada, T. Kanamori, S. Sudo and Y. Ohishi , “1.58-μm Band gain-flattened erbium-doped fiber amplifiers for WDM transmission systems”, J. Lightwave Technol., vol.17, Issue.3, pp. 490 – 496, 1999.
[30] U. C. Ryu, K. Oh, W. Shin and U. C. Paek, “Inherent enhancement of gain flatness and achievement of broad gain Bandwidth in erbium-doped silica fiber amplifiers”, IEEE Journal of Quantum Electronics, vol. 38, Issue. 2, pp. 149-161, 2002.