Development of A Semiconductor Optical Modulator basing on Electron Depleting Absorption Control

表面照明型光调制器的研制1)基于电子耗尽吸收控制(EDAC)的半导体调制器的理论分析我们的调制器的光吸收利用了三种吸收机制：电子数变化、能级屏蔽效应和电场效应。在这三种机制中，最有效的机制是电效应。改进了密度矩阵法的理论处理方法，提出了“微观密度矩阵”的概念，使之能更准确地考虑电弛豫效应，从而更好地解释了实验中观察到的吸收尾现象。该理论对光调制器的设计更加有效。2)表面照明型光调制器的制作我们制作了由6×6个二维EDAC元件和19个p-n^-n Junc…组成的表面照明型光调制器更多的挑战。实现二维集成的对象存在元件间电气隔离较差、各元件布线困难的问题。我们开发了通过机械刻槽实现各元件电气隔离的工艺，并将衬底由掺铬改为n型。元件之间的隔离电阻增加到数百个KOMEGA。我们还制作了EDAC器件，将杂质扩散作为形成电接触的过程。在这些器件中，对于施加电压的5V变化，获得了60%的消光比。作为每个元件的布线方法，我们尝试将半导体基板粘贴在已绘制布线图案的玻璃基板上，以支持100个EDAC元件的运行。谐振型光调制器的研究提出了一种获得任意波长色散分布的设计方法。获得宽波长范围的新型光谐振腔的可能性正在研究中。较少

Development of surface-illuminate type oftical modulator1) Theoretical analysis of semiconductor modulator basing on electron depleting absorption control (EDAC) Optical absorption of our modulator are utilizing three types of absorption mechanisms ; variation in the number of electrons, screening effect on an energy level and the electric field effect. The most effective mechanism is found to be the electric effect among these three mechanisms. We improved the theoretical treatment of the density matrix method by proposing concept of "the microscopic density matrix" to take account into the electric relaxation effect in more exact form.So called the absorption tail observed in experiment were well explained by this improved theory.This theory becomes more effective for designing of the optical modulator.2) Fabrication of surface illuminated-type optical modulatorWe fabricated a surface illuminated-type optical modulator consist of 6*6 two dimensional EDAC elements with 19 p-n^--n junc … More tions. Subjects achieving two dimensional integration had been on inferior electrical isolation among elements and difficulty on electrical wiring for each element.We developed the process to isolate each element electrically by making grooves mechanically and changed substrate from Cr-dopped to n-type ones. Isolation resistance among elements increased up to several hundred KOMEGA. We also fabricated EDAC devices with impurity diffusion as a process forming electric contact. Performance of a 60% extinction ratio for 5V variation of the applied voltage was obtained in these devices. As the wiring method for each element, we tried to stick a semiconductor substrate on a glass substrate which had been drawn a wiring-pattern to support operation of one hundred EDAC elements.2. Study of resonance-type optical modulatorA designing method getting arbitral wavelength-dispersion profile was proposed. Possibity getting a new optical resonator having wide wavelength region is under investigation. Less