絕緣層上覆矽(Silicon-on-insulator, SOI)是近年來廣泛應用在高速且低功耗電子元件，因為其具有高折射率係數且可大幅縮小元件體積,同時製作方式與互補式金屬氧化物半導體(Complementary Metal Oxide Semiconductor, CMOS)製程相容，有利於光電積體電路的發展。
馬赫詹德延遲干涉儀(Delayed Mach-Zehnder Interferometer, DMZI)可運用於色散(Chromatic Dispersion, CD)監測與差分相位移鍵控(Differential Phase Shift Keying; DPSK) 調制/解調變器。非理想型馬赫詹德延遲干涉儀在相位解調變時，會使得光隔離度(Isolation)下降，導致消光比變小及誤碼率表現不佳，同時系統色散監測之靈敏度也會下降。絕緣層上覆矽為主的馬赫詹德延遲干涉儀主要參數為光波導群折射率及干涉儀的分光率。吾人利用低同調干涉系統搭配絕緣層上覆矽之環形共振器，量測出波導群折射率在TM模態下為4.62，且由此SMF-28光纖組成之低同調干涉系統精準度可以量測到0.01誤差率，將來在極化保持光纖改進系統中，0.00002精準度是可以預期的。
在干涉儀分光率方面，為了同時展現建設性輸出端(Constructive Port)與破壞性輸出端(Destructive Port)最大光隔離度，延遲干涉儀前端使用分光率為50/50，而後端則使用因延遲路徑光損耗有關的分光率，同時為了能應用分波多工(Wavelength Division Multiplexing)光通訊系統，吾人提出了兩種與波長不敏感分光器元件馬赫-詹德方向耦合器(Mach-Zehnder Directional Coupler, MZDC)與混合式電漿波導(Hybrid Plasmon Waveguide, HPW)分光器。
馬克-詹德方向耦合器是由一段短的延遲長度，在前端與後端加上方向耦合器所組成。比多模干涉器(Multimode Interference, MMI)有著任意分光率的優點，也可以克服方向耦合器(Directional Coupler, DC)製程容忍度低及波長敏感的缺點。使用商用軟體RSoft中FullWAVE所設計分光比50:50馬赫詹德方向耦合器，可以獲得在C-Band間分光比變動量0.02，但由於製程上誤差在波導寬度由原先設計350 nm偏離為400 nm，波導間距由350 nm偏離至320 nm，如此使分光比由原先50:50，量測到結果為47:53，分光率變動量為0.08，此量測結果與考慮製程誤差的馬赫詹德方向耦合器計算結果一致。傳統方向耦合器會因相同製程誤差，其分光比會由原本50:50與0.16變動量改變為分光比為61:39及0.14變動量，如此可以看出馬赫詹德方向耦合器比起方向耦合器有更良好誤差容忍度與波長不敏感度。
混合式電漿波導分光器是建構於馬赫詹德方向耦合器理論設計並且利用Photo Design套裝商用軟體進行數值模擬分析所設計的寬頻分光器，其不同於馬赫詹德方向耦合器非耦合區(Uncoupled Region)，寬頻混合式電漿波導中間是類耦合區(Quasi-uncoupled Region)，因此可以獲得更大平坦度，並設計出涵蓋S至L-Band間寬頻分光器，並給出50:50、70:30、90:10三種分光比，所以寬頻混合式電漿波導分光器具有製程不敏感、任意分光比特性，同時更能夠縮小元件尺寸。

Recently silicon-on-Insulator (SOI), used in the high-speed and low-power electronic components, is widely developed for optoelectronic integrated circuits due to its high refractive index, small foot print, and compatible processing with the complementary metal oxide semiconductor (CMOS) technology.
The delayed Mach-Zehnder interferometer (DMZI) can be applied to the chromatic dispersion (CD) monitoring and differential phase shift keying (DPSK) modulator/demodulator. The optical isolation of a non-ideal DMZI is reduced in the phase modulation. Then less extinction ratio and worse bit error rate would be followed besides less sensitive system monitoring. The above is coming from the uneven interferometer splitting ratios and the DMZI frequency offset, which will cause a declined OSNR, which implies the importance of the group index, ng, in the delayed arm. The optical low coherence interferometer (OLCI) was utilized to characterize the group index of 4.62 in the TM polarization using silicon-on-insulator based microring resonator, which deviated from the theoretical value of 4.17 due to the process variation of the waveguide width. The OLCI, constructed by the SMF-28 fibers, could demonstrate 0.01 accuracy on group index and further improvement up to 0.00002 index accuracy could be achieved by the polarization maintained fiber based OLCI.
In the interferometer splitting ratio, the first optical power divider should be 50/50 in order to demonstrate the output maximum optical isolation simultaneously on constructive and destructive output ports. The second optical divider ratio will depend on the additional optical loss on the delalyed arm of the decoupled region. For wavelength division multiplexing (WDM) system applications, two wavelength- insensitive optical power dividers were proposed, Mach-Zehnder directional coupler (MZDC) and hybrid plasmon waveguide (HPW).
MZDC, constructed by two directional couplers connected through a short delayed length in the uncoupled region, demonstrates the arbitrary ratio, insensitivity in wavelength and process variation response compared with the traditional directional coupler (DC). The simulation from the commercial software of RSoft and Photon Design showed that the splitting ratio of 50:50 and 0.02 variation demonstrated on the silicon-wire based MZDC in the C-Band. The manufacture errors caused the waveguide width varied from 0.35 m to 0.4 m and the waveguide spacing from 0.35 m to 0.32 m. The spectral results experimentally showed the splitting ratio of 47:53 with the variation of 0.08, which is the same as the simulation results corrected form the processing variation. Under the same manufacture error, the 50:50 splitting from DC could be theoretically derived as 61:39 and the power divider variation is up to 0.14. It could be concluded that the processing tolerance and wavelength insensitivity in MZDC is better than DC.
The HPW optical power splitter is using the MZDC structure and take advantage of the commercial software of Photo Design to simulate the power divider performance. The difference between two wavelength-insensitive optical power dividers is the uncoupled and quasi-uncoupled regions, individually, for MZDC and HPW. The HPW could demonstrate the insensitivity at the process variation and arbitrary splitting ratios, such as 50:50, 70:30, and 90:10, in the S and L bands besides small footprint.

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