本研究成功地利用鈮酸鋰晶體極化方向可被反轉的特性，將電控偏振可調的功能與電控定向耦合器以較簡單的電極設計整合於單一鈦擴散鈮酸鋰波導晶片上；其傳播損耗在波長1550nm下，可量測得到α_TM =0.166dB/cm、α_TE =1.65dB/cm。在波導間距為4.5μm、耦合區總長度為6mm、在六段交疊反轉式 的設計下，施加Z方向電壓200V時，將原始單段電極無法切換的耦合器成功達成切換功能；並展示出在元件結構誤差時，多段電極設計可能會使工作電壓降低，元件可以繼續運作，但若是設計不良時將會使得工作電壓上升很多。
施加Y方向電場70V後，在45(_^o)C、元件長度6mm、濾波中心波長1555nm可進行偏振模態的轉換，最大轉換效率>99%，濾波頻寬約為5nm，其溫度對頻譜調變率為：dT⁄dλ=-0.8 nm⁄oC 。未來可將本研究中週期性極化反轉結構改成光參量震盪器(OPO)結構或超晶格結構(AOS)等其他積體元件以產生可調光源輸出，搭配其多樣化的功能發展強大且吸引人的主動式元件。

We have designed, fabricated, and demonstrated a unique integrated PPLN switched directional couplers and polarization mode converters in Ti:LiNbO3 waveguides.
A completely crossover coupling was obtained from such a device with a six-domain-inversion coupling section of 6mm long and a waveguide spacing of 4.5 μm when an external voltage of 200 V was applied along the crystal z axis. A completely crossover coupling can also be observed with other samples with single-domain and other multiple-domain-inversion configurations.
We found in general, a device with higher number of domain inversions in the coupling section will have a less constraint on the coupling length for a completely crossover coupling and can perform more times of crossover couplings with EO tuning.
We also successfully demonstrated the unique capability of this PPLN Ti:LiNbO3 waveguide device where the polarization mode and the directional coupling can be EO switched simultaneously or separately to increase its device functionality and applicability.

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