可調式鈮酸鋰微碟形共振元件

Tunable LiNbO3 Microdisk Resonators

李鎮安(Cheng-an Lee 李鎮安)

指導教授 ： 王子建

國立臺北科技大學/電資學院/光電工程系研究所/碩士(2013年)

摘要

本論文研究在鈮酸鋰-z面上微碟形元件的熱光調變特性與在鈮酸鋰+z面上製作底切微碟形結構，分別討論參數對於所製作元件特性或結構的影響。在熱光調變的研究方面，所製作直徑40μm鈮酸鋰微碟形元件具有高達5.8×10^4的品質因子，與相同製程條件的直徑20μm微碟形元件相較，品質因子值提高三倍，與碟形直徑愈大，共振損耗降低，使得品質因子變大的理論推論一致。使用此一直徑40μm微碟形元件進行熱光調變傳輸頻譜量測，實驗結果顯示，溫度升高時共振波長會有紅移的現象，在1535nm至1560nm的波長範圍下，存在有三個共振模態，其熱光調變率分別為21.5pm/°C、22.2pm/°C及22.6pm/°C，其熱光調變結果與理論推論結果相符。在鈮酸鋰+z面上製作底切微碟形結構方面，研究中藉由質子交換破壞鈮酸鋰的晶格結構，使得此區域能被氫氟酸所侵蝕，當氫氟酸垂直向下蝕刻到達佈植區域的深度後，便開始進行橫向蝕刻，此時底切碟形結構便會形成。由於碟形下表面為可被氫氟酸蝕刻的鈮酸鋰-z面，蝕刻過程中碟形直徑會逐漸縮小，最後形成橫向底切蝕刻範圍1μm的六邊微碟形，此一形狀是由於鈮酸鋰不同晶格方向的氫氟酸蝕刻速率相異所造成。

關鍵字

鈮酸鋰 ； 微碟形 ； 錐形光纖 ； 熱光效應

並列摘要

This thesis studies the tuning characteristics of the microdisk device produced on the –z face of LiNbO3 by thermo-optic effect and the fabrication the undercut microdisk structure on the +z face of LiNbO3. The influences of the parameters on the device characteristics and the produced structures are discussed. For the first studied topic, it is found that the 40μm-diameter microdisk device has the quality factor as high as 5.8×10^4, which is three times higher than the 20μm-diameter one. The thermo-optic tuning characteristics of the 40μm-diameter microdisk device show that the temperature increase causes the resonant wavelength to have a red shift, which is the same as theoretical inference. In the wavelength range from 1535nm to 1560nm, the thermo-optic tuning rates for the three resonant modes were 21.5pm/°C, 22.2pm/°C and 22.6pm/°C. For the second studied topic, the fabrication techniques, including proton exchange, ion implantation, and wet etching, are used to produce the undercut microdisk structure on the +z face of LiNbO3. The proton-exchanged region can be etched by HF acid. When the etching depth achieves the depth of ion implantation, the etching would proceed laterally and the undercut microdisk structure is formed. Because the bottom face of the microdisk is the -z face of LiNbO3, which is easily etched by HF acid, the microdisk diameter would become smaller during the etching process. The hexagon shape of the microdisk structure is caused by the dependence of the etching rate on the lattice plane in LiNbO3.

並列關鍵字

lithium niobate ； microdisk ； tapered fiber ； thermal optic

參考文獻

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