藉由電光取樣量測光電式兆赫波發射器之特性

Characterization of a THz Photonic Transmitter by Electro-Optic Sampling

林均諭(Chun-Yu Lin)

指導教授 ： 潘犀靈

國立清華大學/電機資訊學院/光電工程研究所/碩士(2013年)

摘要

本論文的主要目的是利用電光取樣方式量測光電式兆赫波發射器包括其主要元件近彈道單載子光偵測器的輸出特性。
為此，我們利用中心波長在1.56μm的鎖模摻鉺光纖雷射、碲化鋅電光晶體和平衡偵測器建立一套電光取樣系統。為了確定系統表現，首先我量測共平面波導上的縱向和橫向表面電場分布，並利用保角轉換模擬來應證電場的分布情形，接著利用微波梳狀產生器產生電脈衝訊號並傳輸在相同共平面波導上，並利用電光取樣的量測系統量測到脈衝寬度約110皮秒的訊號。最後，我們利用類似的系統量測到近彈道單載子光偵測器所產生的電脈衝訊號，在時域上會看到由多重反射所組成的訊號，而在頻域上會有中心頻率在26.65 GHz 和80 GHz的兩個頻段，前者是由多重反射所組成的週期現象，後者即為元件所產生的主要訊號，而多重反射的現象初步推測是由於量測系統的阻抗不匹配所造成的結果。最後比較利用電光取樣量測光偵測器的訊號與兆赫波發射器輻射出來的毫米波訊號，並發現此兩種訊號有一致的特性。

關鍵字

電光取樣系統 ； 光電式兆赫波發射器 ； 毫米波

並列摘要

The main purpose of my thesis is the characterization of a THz photonic transmitter (PT) and its main component a near-ballistic uni-traveling-carrier photodiode by using electro optic (EO) sampling.
Here, we constructed an EO sampling system primarily composed of a Mode Locked Er: doped Fiber Laser at 1.56m, a ZnTe EO crystal, polarizing optics and a balanced detector. In order to verify the performance of this system, we first measure the distribution of transverse and longitudinal electric fields on a coplanar waveguide (CPW). The results are in agreement with theoretically predicted field distribution using the conformal transformation. Secondly, we measured the waveform of comb generated picosecond electric pulses propagating on CPW, with a pulse width of about 110ps. Finally, we characterized the waveform of electric pulses generated by the Near-Ballistic Uni-Traveling-Carrier Photodiode. There were multi-reflection signals in time domain. In the frequency domain, we can see that there are two bands one is at 26.65GHz and the other one is near 80GHz. The former one corresponded to the period of multi-reflected spurious signal. The 80GHz band, on the other hand, is the designed output of the PT. Multiple reflections are tentatively attributed by the impedance mismatch of the measured setup. Considering the loading effect, measured EO response of the photodiode is consistent with the sub-THz (millimeter wave) signal radiated from the PT.

並列關鍵字

Electro optic sampling system ； Photonic transmitter ； Millimeter wave

參考文獻

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