在本論文中，我們提出一種新型的光纖雷射設計用以產生高能量似噪音脈衝。此共振腔中有兩段不同的摻鐿光纖，纖核的大小分別為10微米與30微米。此外，共振腔中加入200公尺被動光纖，以降低似噪音脈衝雷射之重複率到920千赫。我們嘗試在共振腔中使用不同頻寬的濾波器，以產生穩定的似噪音脈衝。我們找到較佳的濾波器之頻寬為10奈米。此共振腔之優點為可以降低共振腔中的非線性效應並提升輸出的雷射功率，目前我們可以得到最高2.29瓦的輸出功率，對應的輸出脈衝能量為2.49微焦耳；這是迄今由單一共振腔可以得到的最高能量之似噪音脈衝。

In this thesis, we have designed, constructed and characterized a high-energy all-normal dispersion fiber laser capable of generating noise-like pulses. Two ytterbium-doped fibers with 10 μm and 30 μm core sizes were employed in the same cavity to achieve higher output power and at the same time lower lasing threshold. To further scale up the energy, a 200 meters passive fiber was added to the cavity in order to reduce the repetition rate. The bandpass filter with different bandwidths was inserted into the cavity to study its effect on the generation of stable noise-like pulses. The optimal bandwidth of the bandpass filter is found to be 10 nm. The advantage of this kind cavity is reducing the nonlinear effect and enhancing the output power. This laser can generate noise-like pulses with output power as high as 2.29 W at a repetition rate of 920 kHz, corresponding to the pulse energy of 2.49 μJ. To our best knowledge, this is the highest output energy generated by noise-like pulses from a single laser cavity.

[1] U. Keller, "Recent developments in compact ultrafast lasers," nature, vol. 424, no. 6950, pp. 831-838, 2003.
[2] D. Huang et al., "Optical coherence tomography," Science (New York, NY), vol. 254, no. 5035, p. 1178, 1991.
[3] X. Liu, D. Du, and G. Mourou, "Laser ablation and micromachining with ultrashort laser pulses," IEEE journal of quantum electronics, vol. 33, no. 10, pp. 1706-1716, 1997.
[4] B. Nie, G. Parker, V. V. Lozovoy, and M. Dantus, "Energy scaling of Yb fiber oscillator producing clusters of femtosecond pulses," Optical Engineering, vol. 53, no. 5, pp. 051505-051505, 2014.
[5] R. H. Stolen, E. Ippen, and A. Tynes, "Raman oscillation in glass optical waveguide," Applied Physics Letters, vol. 20, no. 2, pp. 62-64, 1972.
[6] H. Etzel, H. Gandy, and R. Ginther, "Stimulated emission of infrared radiation from ytterbium activated silicate glass," Applied Optics, vol. 1, no. 4, pp. 534-536, 1962.
[7] K. Lu and N. K. Dutta, "Spectroscopic properties of Yb-doped silica glass," Journal of Applied Physics, vol. 91, no. 2, p. 576, 2002.
[8] H. M. Pask et al., "Ytterbium-doped silica fiber lasers: versatile sources for the 1-1.2 μm region," IEEE Journal of Selected Topics in Quantum Electronics, vol. 1, no. 1, pp. 2-13, 1995.
[9] M. C. T. B.E.A. Saleh, Fundamentals of photonics.
[10] M. Horowitz, Y. Barad, and Y. Silberberg, "Noiselike pulses with a broadband spectrum generated from an erbium-doped fiber laser," Optics letters, vol. 22, no. 11, pp. 799-801, 1997.
[11] S. Smirnov, S. Kobtsev, S. Kukarin, and A. Ivanenko, "Three key regimes of single pulse generation per round trip of all-normal-dispersion fiber lasers mode-locked with nonlinear polarization rotation," Optics express, vol. 20, no. 24, pp. 27447-27453, 2012.
[12] D. Tang, L. Zhao, and B. Zhao, "Soliton collapse and bunched noise-like pulse generation in a passively mode-locked fiber ring laser," Optics Express, vol. 13, no. 7, pp. 2289-2294, 2005.
[13] C. Aguergaray, A. Runge, M. Erkintalo, and N. G. Broderick, "Raman-driven destabilization of mode-locked long cavity fiber lasers: fundamental limitations to energy scalability," Optics letters, vol. 38, no. 15, pp. 2644-2646, 2013.
[14] P. Mukhopadhyay, "Femtosecond pulse generation and amplification in Yb-doped fibre oscillator-amplifier system," Pramana, vol. 75, no. 5, pp. 787-805, 2010.
[15] R. Boyd, Nonlinear optics, third edition.
[16] C. V. Raman and K. S. Krishnan, "A new type of secondary radiation," (in English), Nature, vol. 121, no. 3048, pp. 501-502, Jan-Jun 1928.
[17] F. Ilday, J. Buckley, W. Clark, and F. Wise, "Self-similar evolution of parabolic pulses in a laser," Physical review letters, vol. 92, no. 21, p. 213902, 2004.
[18] G. P. Agrawal, Nonlinear Fiber Optics. 2007.
[19] Q. Li, H. Zhang, X. Shen, P. Yan, H. Hao, and M. Gong, "Stimulated Raman scattering threshold for partially coherent light in silica fibers," Optics express, vol. 23, no. 22, pp. 28438-28448, 2015.
[20] S. Wu, B. Chen, and G. Yu, "659.5-nm high-power solid state laser with a two-rod telescope resonator," in International Symposium on Optoelectronic Technology and Application 2014, 2014, pp. 929727-929727-6: International Society for Optics and Photonics.
[21] C. Barnard, P. Myslinski, J. Chrostowski, and M. Kavehrad, "Analytical model for rare-earth-doped fiber amplifiers and lasers," IEEE Journal of Quantum Electronics, vol. 30, no. 8, pp. 1817-1830, 1994.
[22] T. Pfeiffer and H. Bulow, "Analytical gain equation for erbium-doped fiber amplifiers including mode field profiles and dopant distribution," IEEE photonics technology letters, vol. 4, no. 5, pp. 449-451, 1992.
[23] M. C. T. Bahaa E. A. Saleh, Fundamentals of Photonics. p. 1124.