頻率可調之側向入薄膜式兆赫波發射器

Frequency-tunable Edge-coupled Membrane Terahertz Photonic Transmitters

張書豪(Hsu-Hao Chang)

指導教授 ： 孫啟光

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.10394

摘要

隨著現在資訊流通量的大幅增加，資訊處理的速度由gigahertz往terahertz邁進已經儼然成為必然的趨勢。然而傳統的電子電路方式所產生的信號在一、二百gigahertz時便會因嚴重的RC delay而遭遇瓶頸，所以如果要以此方式朝terahertz元件發展勢必將遭遇到很大的困難，因此我們便設計了光電轉換式的兆赫波元件。
光電轉換式的兆赫波元件具有許多的優點，例如可室溫操作、發射出的操作頻率具有可調性以及容易與其他半導體元件整合等等。因此我們在此論文中提出並展示了一種側向入射薄膜式兆赫波發射器。它是利用一個金屬-半導體-金屬行波式光偵測器和一個由共平面波導饋入之開槽天線所組成；由於我們所設計的金屬-半導體-金屬行波式光偵測器具有寬頻高效率的優點，因此我們可以用一個在時間上具有調制信號的光脈衝來激發兆赫波發射器，並且以熱輻射偵測器來偵測由兆赫波發射器所發射出的兆赫波功率大小。在頻率為404.5GHz的激發下，我們的兆赫波發射器有著極高的光電轉換效率(0.567%)以及量子轉換效率(526%)。並且利用Febry-Perot filter，我們可以得知我們的兆赫波發射器所輻射出來的兆赫波頻譜特性，並且對於影響元件頻寬的變因也做了初步的討論；而這也意味著面對著將來各式各樣的兆赫波應用層面，我們可以藉由我們對於元件頻譜特性的了解來設計以及控制元件的頻譜響應，進而來達成特定實驗目的。
在此論文中，我們使用了高速光偵測器以及薄膜側向入射式的架構，並且配合開槽天線設計，使得我們所設計出的兆赫波輻射器不但具有頻率可調的特性外，更比其他的兆赫波元件具有和其他半導體元件整合的優勢，相信這對未來的資訊處理以及生物影像等等的兆赫波應用層面上，會帶來更大的便利與可能性。

關鍵字

兆赫波發射器

並列摘要

With the great increase in the amount of the application data, it is clear that the in crease in the data processing speed is necessary. However, the operation speed of the devices fabricated by traditional electrical circuit designs would suffer a bottleneck due to the serious RC time delay when the operation frequency is around hundreds of gigahertz. It will be very hard to make the devices operating at the terahertz regime by the traditional electrical circuit designs. Therefore we design the terahertz photonic transmitters.
A terahertz photonic transmitter is a kind of terahertz emitter with the advantages of tunable operation frequency, room temperature operation, and ease of integrating with other semiconductor devices, such as semiconductor lasers and amplifiers… Therefore we propose and demonstrate a edged-coupled membrane terahertz photonic transmitter in this thesis. The edged-coupled membrane terahertz photonic transmitter consists of a metal-semiconductor-metal traveling-wave photodetector(MSM-TWPD) and a coplanar waveguide (CPW) fed slot antenna. Owing to the ultra-highspeed and high efficiency properties of the MSM-TWPD, we could use an optical pulse with a temporal modulation to excite the photonic transmitter and use a bolometer to detect the power of the radiated terahertz. The photonic transmitter exhibits a record high light-terahertz conversion efficiency of and the external quantum efficiency of 526% at 404.5GHz. By utilizing the Febry-Perot filter, we could get the information of the radiated terahertz wave and do some preliminary survey in the frequency response of the photonic transmitters. This implies the possibility of the design and control of the frequency response of the photonic transmitters in various terahertz applications to achieve certain specific experiments.
In this thesis, we adopt a highspeed photodetector and a slot antenna with a membrane and edge-coupled structure in the photonic transmitters to achieve the tunable operating frequency property and make it possible for our device to be integrated with other semiconductor devices, which would facilitate the terahertz applications in the data processing and biological imaging in the near future.

並列關鍵字

Photonic Transmitter ； terahertz

參考文獻

[2.11] J.-W. Shi, Metal-semiconductor-metal traveling–wave photodetector, PhD thesis, Nation Taiwan University, Institute of Electro-Optical Engineering.

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