Active Dispersion Compensating Systems with Photorefractive Multiple Quantum Well

超快脉冲的整形和控制不仅是利用超快激光源实现高比特率通信的实用问题，而且更重要的是实现量子动力学和化学反应途径的相干控制等过程。本课题研究了利用光折变多量子阱器件的空间光调制器主动补偿超快脉冲色散的光学系统。重点研究了具有光折变多量子阱和光纤光栅的光波调制器。我们得到了下面两个主要结果。我们设计并制作了具有宽频带的光折变多量子阱器件。研究了这些器件中静态光栅发出的超短脉冲的衍射特性，并将其用作主动色散补偿系统中的衍射光学元件。实验观察了该装置衍射脉冲的理想光谱。其中一个设备的带宽为13nm.2。研究了光纤布拉格光栅器件用于光波调制器。我们已经制造了光纤布拉格光栅。提出了一种在控制光纤张力的情况下，利用单掩模制作多通道光纤布拉格光栅的方法。在光印迹过程中，布拉格波长随施加到光纤上的张力的大小而线性变化。利用这种线性关系，利用一个相位掩模成功地制作了一个由五个不同波长的布拉格光栅组成的光学波长滤波器。

Pulse shaping and control of ultrafast pulses are of interest not only from the practical point of view of implementing high-bit-rate communications by use of ultrafast laser sources but also more fundamentally for realizing process such as coherent control of quantum dynamics and chemical reaction pathway. In this project, optical system, which enable us to compensate dispersion of ultrafast pulses actively by using spatial light modulator of photorefractive multiple quantum well device, has been investigated. Particularly, we focused on the lightwave modulator with photorefractive multiple quantum wells and optical fiber gratings. We got two main results below.1. We have designed and fabricated photorefractive multiple quantum well devices, which exhibit broad band width. The diffraction of ultra-short pulses from static gratings in these devices has been investigated for use them as a diffractive optical element in active dispersion compensating system. The desirable spectra of the diffracted pulses from the device were observed experimentally. The bandwidth for one of the device was 13nm.2. Optical fiber Bragg grating devices have been investigated to use them for optical lightwave modulator. We have fabricated fiber Bragg gratings. A method of fabricating multiple channel fiber Bragg gratings using a single mask under control of the applied tension to the optical fiber was presented. The Bragg wavelength changes linearly with the amount of tension applied to the optical fiber during photo-imprinting process. Using the linear relation, an optical wavelength filter consisting of five Bragg gratings with five different wavelengths is fabricated successfully using one phase mask.