電光調制積體週期性晶疇極化反轉鈮酸鋰自發參量下轉換晶片產生雙偏振正交光子對之研究;The study of electro-optically controlled integrated periodically poled lithium niobate spontaneous parametric down-conversion chip for dual orthogonal-polarization photon-pair generation

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題名:	電光調制積體週期性晶疇極化反轉鈮酸鋰自發參量下轉換晶片產生雙偏振正交光子對之研究;The study of electro-optically controlled integrated periodically poled lithium niobate spontaneous parametric down-conversion chip for dual orthogonal-polarization photon-pair generation
作者:	邱承中;Chiu, Cheng-Chung
貢獻者:	光電科學與工程學系
關鍵詞:	鈮酸鋰;非週期;波導;偏振模轉換器;相位調製器;量子光源;lithium niobate;nonperiodic;waveguide;polarization mode converter;phase modulator;quantum light source
日期:	2022-11-22
上傳時間:	2024-09-19 15:25:23 (UTC+8)
出版者:	國立中央大學
摘要:	本論文研究設計四段式的鈮酸鋰鈦擴散波導結構，利用兩段type 0的自發性參量下轉換(spontaneous parametric down-conversion,SPDC)週期晶疇極化反轉結構且兩段SPDC之間加上一段基於鈮酸鋰的電光效應利用基因演算法計算出的非週期晶疇極化反轉結構最後再加上一段加z方向電場的電極結構，達成以一片晶片產生兩對偏振正交\|HH⟩和\|VV⟩的光子對，並利用半導體製程的技術，將此四段式的晶片結構實現。在此四段式的晶片上，第一段為透過特定的週期性極化反轉結構設計滿足準相位匹配藉此產生\|VV⟩的光子對，接著利用基因演算法計算並設計出電光非週期極化反轉結構產生在施加55V y方向電壓時，得到模態轉換在波長為1569nm處可高達99%，且有7nm的頻寬其模態轉換可達90%以上，使此晶片可透過此非週期的結構設計使前段\|VV⟩的光子對轉換為\|HH⟩的光子對，在經由第三段與第一段相同的週期性結構設計產生\|VV⟩的光子對，並且設計第四段的結構利用加z方向電場進行相位調製。所以利用單一晶片即可產生兩對偏振正交\|HH⟩和\|VV⟩的光子對，且對其相位進行調製，所以此晶片基於能產生兩對偏振正交的光子對，在未來透過後續的量測架設，將可產生量子糾纏態1/√2(\|HH⟩+\|VV⟩)。 ;In this thesis, we report on the study of a highly integrated polarization-correlated photon-pair source at telecom L-band, based on two equal subsequent type-0 spontaneous parametric down-converters (SPDC) in a Ti-diffused periodically poled lithium niobate (Ti:PPLN) waveguide. By introducing an electro-optic polarization mode converter (EOPMC) between the two identical SPDC sections, the polarization correlation states of the dual output photon pairs can be fast controlled simply by tuning the applied field. Finally, another EO phase modulation section is added into the chip to control the phase shifts between the dual output photon pairs. Corresponding theoretical analyses and experimental verifications were carried out to investigate the characteristics of the source with classical and quantum approaches. The generated photon pair can be efficiently controlled its polarization, making the chip provide two orthogonal two-photon states and even generate an entangled state with a tunable phase without further optical setup. The developed chip provides a compact and robust platform for generating and manipulating nonclassical light, which has huge potential for application to optical quantum computing and quantum communication. In this four-stage chip, the first stage is designed to generate \|VV⟩ photon pairs. And then by using genetic algorithms, we calculate and design the aperiodic poling structure, which can achieve high efficiency polarization mode conversion when a y-direction voltage of 55V is applied. The mode conversion efficiency can be up to 99% at a wavelength of 1569nm, and it can reach more than 90% with a bandwidth of 7nm. The aperiodic structure converts the photon pairs of \|VV⟩ states to \|HH⟩ ones, and then the photon pairs of \|VV⟩ are generated through the same periodic structure as the first one. Finally, the fourth phase-modulated section is designed by applying an electric field in the z-direction to the waveguide. By using this approach, we can generate two pairs of photons with orthogonal polarizations \|HH⟩ and \|VV⟩ by just only one single chip, and their phase differences can be modulated by tuning the electric field. The chip, with an external measurement setup, can achieve quantum entangled states 1/√2(\|HH⟩+\|VV⟩) in the future.
顯示於類別:	[光電科學研究所] 博碩士論文

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