本論文在Z切鈮酸鋰基板上成功地製作出具有週期性極化反轉的波導結構。在製程方面,發現鎳擴散在800ºC、4 hr會有較好的TM光傳導模態及較強的光場強度。因此利用此條件來製作波導,並在寬度20μm、高度3μm的脊形光波導和寬度150μm的帶狀波導上製作出有效長度為6mm的週期性極化反轉的結構,文中也會簡介製作極化反轉結構的高電壓致極化反轉系統。 光學量測方面,先量測波導極化特性並觀察其輸出光場強度,再藉著兩種不同的光學量測架構,來量測相位匹配溫度與波導轉換效率。結果顯示,脊形波導在平均輸入功率為6 mW、基頻光強度為25.5MW/cm2時,約有20 %的外部轉換效率;帶狀波導在平均輸入功率為6.7 mW、基頻光強度為12 MW/cm2時,量測到約13 %的外部轉換效率,而在相同極化反轉區長度時,大線寬的極化反轉區因作用寬度較大,所以會有較大的倍頻轉換能量。
Periodically poled lithium niobate (PPLN) is successfully fabricated on optical ridge waveguide for the second harmonic generation (SHG) of green laser. Various nickel in-diffused lithium niobate waveguides were fabricated for optical characterization. Experimental results show diffusion at 800ºC for 4 hr gives rise to the highest output power. For comparison, PPLN structures of the same length 6 mm but two different widths were fabricated. The first type of PPLN structure is fabricated on ridge structure of height 3μm and width 20 μm, and the second type has a width of 150 μm but without the ridge. For optical characterization, the temperature of phase-matching and conversion efficiency are measured by two different optical systems. Experimental results show the ridge waveguide exhibits a conversion efficiency of 20 % when pumped with a diode laser of wavelength 1064 nm, average power 6 mW, and peak intensity 25.5MW/cm2. The strip waveguide has a conversion efficiency of 13 % at an average power of 6.7 mW and a peak intensity of 12 MW/cm2. The results indicate more SHG energy can be obtained in a wider PPLN region.