Monolithically Integrated Semiconductor Laser-modulator Based On Quantum Well Intermixing

Photonic integration technology is a key technology for resolving the contradiction between the developing communication bandwidth and the costly discrete optoelectronic devices. The emergences of mobile internet, big data, and cloud computing are leading to the rapid growth of the communication capacity. But the current optical communication systems are mainly based on the assembly of discrete optoelectronic devices. A simple increase in scale is not able to solve the problems such as high cost, large size, and high energy consumption. According to the successful experience of the large scale integrated circuits (LSICs) in micro-electronic systems, photonic integrated circuits will be the only way to solve these problems. This thesis is mainly devoted to the integrated optoelectronic devices based on â…¢/â…¤ materials, particularly the monolithically integrated laser-modulator in InP.First, the InP based monolithic integration platform is introduced. After a survey of the popular integration methods, we choose the quantum well intermixing (QWI) as our integration platform for its fabrication simplicity and cost effectiveness. We developed the dielectric sputtering induced disordering based on Al2O3 and Si3N4, which expand the range of the dielectric materials. The method based on Si3N4 not only leads to a blue-shift about 90nm of photoluminescence (PL), but also leads to a slight enhancement of the peak intensity compared to a decrease under the usual methods. We also developed the copper induced disordering method. The peak wavelength of PL has a blue-shift as large as 180nm, and the peak intensity of PL is enhanced about 220%. By using deeply etched trenches to confine the diffusion of the copper at high temperature, we resolved the problem of high copper mobility that results in very poorly defined boundaries between the active and passive regions. Base on the copper induced disording method, the integration platform was established in our laboratory.Then, the integrated device of a v-coupled cavity laser (VCCL) and an electro-absorption modulator (EAM) is investigated, including the structure parameters of each component, the distribution of active and passive regions, and the choice of deeply and shallowly etched waveguides. The integrated device was designed, fabricated, and tested without and with QWI step. For the incompatibility of the QWI method and the planarization by organicmaterials, we developed a single layer planarization by SiO2. Besides, we also developed a simple process of reflective film by depositing metal layer on the residual SiO2 attached to the cavity facet.Finally, the novel high-speed Q-modulated distributed feedback laser (QML) is investigated. The device is theoretically modeled based on the complete physical structure by using the traveling wave method. Based on the simulation, the relationship between the phase value and injection current of the phase section is presented. The extinction ratio, jitter and peak fluctuation of the output power are discussed under different injection currents of the gain section. The integrated device of QML was designed without and with QWI step. Preliminary results are presented, showing a good distribution of active and passive region.