非週期性晶格極化反轉鈮酸鋰作為有效率的二倍頻和模態轉換器之研究

Efficient Second-Harmonic Generator and Electro-optic Polarization-Mode converter in Single Aperiodically Poled Lithium Niobate

張正良(Cheng-Liang Chang)

指導教授 ： 陳彥宏

國立中央大學/理學院/光電科學研究所/碩士(2008年)

摘要

積體光學(Integrated Optics, I.O.)是將不同的光學元件整合在同一個基板上，例如鈮酸鋰晶體。若在晶體上做非週期性的反轉晶格(Aperiodic Optical Superlattices ,AOS)，則可以利用準相位匹配的方式來滿足多個波長轉換所需之相位補償。
我們設計且做了第一個同時具有兩種功能( TE-TM mode converter和Wavelength Conversion )的非週期晶格反轉結構。利用APLN (Aperiodic poled LiNbO3; PPLN) 當作在C band 的主動式窄頻寬多波長濾波器和多波長倍頻器。該結構同時滿足4 個波長在1550nm 附近的電光效應和二倍頻波長轉換之準相位匹配條件的反轉區塊分佈。
在兩公分長的 APLN 元件，能夠同時使得 4 個特定波長之二倍頻轉換效率大於0.15%/W( 設計為~0.165%/W)。外加約1200(V/mm)的電場(設設計值為1000V/mm)，能夠有大於90%以上的穿透率(設計上~100%)，每個波長的頻寬約為1.16nm。和串接的APLN結構相比二倍頻轉換效率有 2.45 倍的提升、濾波的頻寬則有 2.6 倍的窄化。

關鍵字

二倍頻 ； 電光元件 ； 非週期性晶格反轉鈮酸鋰

並列摘要

Integrated optics refers to the integration of various optical devices and components on a single common substrate, for example, lithium niobate. an aperiodic domain structure is known to provide more than one reciprocal vector to simultaneously compensate wave-vector mismatches of a plurality of wave-energy coupling processes in a quasi-phase-matched (QPM) material.
We report the design and first experimental on constructing an aperiodically poled LiNbO3 for optimally integrating both the electro-optic and nonlinear optic properties of a material to enable high-efficiency dual optical device functions.
Simultaneous transmission of >90% (~100% in design) of 4 telecom wavelengths with each a bandwidth of ~1.16 nm was achieved in a 2-cm long APLN device when an electro-optic field of ~1200 V/mm (~1000 V/mm in design) was applied. Single-pass SHG conversion efficiency is about 0.15%/W(~0.165% in design). 2.45-times second-harmonic-generation conversion efficiency enhancement and EO transmission bandwidth has 2.6-times reduction over a conventional cascaded periodically poled LiNbO3 is obtained with such a device.

並列關鍵字

Aperiodically poled lithium niobates ； Second harmonic generation ； Electro-optically active device

參考文獻

[23] ”Active narrowband multiple Telecom-Band Fundamental and Second-Harmonic wavelength filter in aperiodically poled lithium niobate”中央大學光電科學研究所碩士論文, 林少偉, 中華民國九十五年十二月。

[25] ”Active multi-channel narrowband wavelength filters and modeconverters in Ti:PPLN waveguides”中央大學光電科學研究所碩士論文,黃俊育, 中華民國九十五年十月。

[1] S. E. Miller, “Integrated Optics : an introduction, ” Bell. Syst. Tech. J.,48, p2059-2069 (1969)

[3] R. C. Alferness, “Efficient waveguide electro-optic TE ↔ TMmode converter/wavelength filter,” Appl. Phys. Lett., 36,p513-515 (1980).

[4] Y. H. Chen, Y. C. Chang, C. H. Lin, and T. Y. Chung, "Diode-pumped, actively internal-Q-switched Nd:MgO:PPLN laser," Opt. Express 16, 2048-2055 (2008)