Text

國立台灣大學林清富教授實驗室

研究領域摘要

主題三: III-V semiconductor lasers and semiconductor optical amplifiers

研究人員: 趙俊傑

英文摘要:

The development of semiconductor lasers and amplifiers results in revolutionary advances in the information technology, such as laser disks and fiber

communications. Because these devices are pumped directly by current injection, they are suitable to be combined with various electronic circuits in different

applications. However, like other optical gain materials, the gain-bandwidth of the semiconductor materials is limited by the intrinsic material properties, such as

bandgap. Our research is focused on increasing the gain bandwidth of active semiconductor optical devices by band-gap engineering technique. Combining

QWs with different transition wavelengths is one example. We have successfully applied this technique on InP based devices and wavelength tunable lasers with

240nm tuning range (1300nm~ 1540nm) is demonstrated. Combining QDs with different sizes is another example. The gain bandwidth of the QD SOAs

fabricated in our lab also achieves more than 200nm(1050nm~1250nm).

Because carriers in these broad band optical devices are distributed among states with large energy separation, the carrier dynamics of these devices are different

from conventional QW and QD devices. When two laser modes share the gain provided by one broad-band device and the wavelength separation of the two

laser modes is large, the increase of intensity in one lasing mode could enhance the intensity of another mode. This contrasts the usual competition effects in

which the intensity increment of one lasing mode suppressed the intensity of another mode.

中文摘要:

半導體雷射以及半導體光放大器的進步促成了雷射光碟片以及光纖通訊等資訊科技的革命性發展。因為這些元件事以電流直接激發，它們很適

合在各種應用裡與電子電路做直接的結合。然而，與其他光學增益材料相同的，半導體材料的光學增益頻寬也是被材料本身的特性所限制(如能

隙)。的我門的研究主題是以能帶工程的方式增加主動半導體光學元件的增益頻寬。在單一元件裡組合有不同發光波長的量子井即是此類方法的

一個例子。我們把這個技術應用在以InP為基礎的材料上，並成功的做出有240nm(1300nm~ 1540nm)可調頻寬的波長可調雷射。在單一元件裡組

合有不同發光波長的量子點則是能帶工程的另一個例子。用這個技術，我們實驗室所製造出來的量子點光學放大器其增益頻寬可以達到

200nm(1050nm~1250nm)以上。

在這些元件裡，載子所分布的能態其能量差異比較大，因此這些光學元件裡的載子動力學與一般的量子井及量子點元件不同。如果兩道雷射光

共用同一個寬頻元件所提供的增益而且其波長差異頗大，增加其中一道雷射光的強度會使得另一道雷射光的強度也會隨之增加。這與一般所觀

察到的載子競爭效應，增加其中一道雷射光的強度使得另一道雷射光的強度減弱，恰恰相反。

圖示: