Study on the Electrooptic Properties of Semiconductor Heterojunction and Their Application to Optical Modulation

（1）分子束外延（MBE）制备双异质结和量子阱结构利用现代控制理论，建立了一种新的MBE系统。建立了具有良好重复性的双异质结和量子阱结构的制备技术。（2）利用线性电光效应的GaAs基定向耦合器型光调制器为了获得GaAs基定向耦合器型光调制器的更高的开关速度，进行了行波型器件的设计和制造。首次成功地制备了8 mm长的样品，开关电压为10.4V，在1.06 μ m波长处的调制带宽为9.1GHz。还提出并设计了一种基于双折射器的偏振无关定向耦合器型光调制器，其在（111）衬底上而不是传统的（100）衬底上。（3）载流子注入型光调制器， ...更多信息 对双极晶体管载流子注入型光调制器的吸收损耗、消光比和啁啾参数等特性进行了详细的理论分析，揭示了这种器件的优越性。首次成功地研制出了性能较好的分子束外延单波导型光强度调制器。基于该结果，已经发现双极晶体管结构适用于X交叉全反射型光开关。（4）量子阱波导中的电场诱导效应利用量子限制斯塔克效应制作了吸收型光调制器，在5.5V偏压下，消光比为13 dB，工作波长为880 nm。此外，量子限制结构的修改，这可能会提供高性能和多种功能的光调制器件，已在理论和实验上进行了研究。在渐变带隙量子阱、抛物量子阱和耦合量子阱中，证实了一些有趣的性质。（5）量子阱中的载流子感生效应通过载流子注入GaAs / AlGaAs单量子阱结构，详细研究了二维电子的带填充效应、电子的多体效应引起的带隙收缩效应以及它们的磁场感生效应。此外，物理常数的变化。例如由上述现象引起的折射率，也已经被研究，并且发现其适用于光调制器件。少

(1)Fabrication of double-hetero and quantum well structures by molecular beam epitaxy (MBE) A new MBE system, which utilize the modern control theory for temperature control, has been constructed. Techniques for the fabrication of the double-hetero and quantum well structures with good reproducibility has been established.(2)GaAs-based directional coupler type optical modulators by use of the linear electrooptic effect Design and fabrication of a traveling-wave type device have been performed to obtain the higher switching speed of the GaAs-based directional coupler type optical modulators. The 8mm-long sample, with a switching voltage of 10.4V and a modulation bandwidth of 9.lGHz at a wavelength of 1.06mum, has been successfully fabricated for the first time. A semiconductor-based polarization-independent directional coupler type optical modulator, on a (111) substrate instead of the conventional (100), has also been proposed and designed.(3)Carrier-injection type optical modulator wi … More th bipolar transistor structure Theoretical analyses on the characteristics, such as absorption loss, extinction ratio and chirping parameters, of the bipolar transistor carrier-injection type optical modulator have been performed in detail , and the advantage of the device has been revealed. An MBE-grown single-guide type optical intensity modulator with fairly good performance has been successfully fabricated for the first time. On the basis of the result, it has been found that the bipolar transistor structure is applicable to an X-cross total reflection type optical switch.(4)Electric field induced effect in quantum well waveguides An absorption type optical modulator by use of the quantum confined Stark effect, with an extinction ratio of 13dB at 5.5V bias operating at 880nm, has been fabricated. In addition, modifications in quantum confinement structures, which may provide the optical modulation devices with high performance and various functions, have been investigated both theoretically and experimentally. Some interesting properties in a graded-gap quantum well, a parabolic quantum well and a coupled quantum well have been confirmed. (5)Carrier induced effect in a quantum well A band filling effect by two-dimensional electrons, a band gap shrinkage effect by the many body effect of electrons and their magnetic field induced effects have been studied in detail through carrier injection into a GaAs / AlGaAs single quantum well structure. In addition, changes in the physical constants. such as the refractive index, which are induced by the phenomena described above, have been also investigated, and found to be applicable to the optical modulation devices. Less