光纤通信彻底改变了21世纪的通讯方式，提升了人类的生活质量。作为光通信系统的重要组成，光电子器件的重要性毋庸置疑。光子器件目前正由分立单元向集成转型，并开始在密集波分复用(DWDM)光网络系统中崭露头角。毫无疑问，单片光子集成电路(PIC)必将是未来大容量、低功耗光网络系统的核心部件，是未来智能光网络的神经中枢。本论文作为对PIC芯片的初期探索，开展了MOCVD对接生长、全息光栅制作和RIE波导刻蚀等光子集成关键工艺和技术的研究，深入分析了分布反馈DFB激光器原理、多波长阵列集成方案和多模干涉耦合器(MMI)合波技术，研制出4路波长DFB激光器与MMI和半导体光放大器(SOA)合波输出的PIC芯片。主要研究内容如下：为了实现有源/无源波导之间低损耗、低反射的耦合连接，仔细地优化了对接界面前腐蚀形貌与MOCVD二次外延技术，实现了波导间较高质量对接生长。采用二次曝光工艺在激光器区域制作了等周期全息光栅，由全息光栅制作而成的DFB激光器，激射波长在1550nm波段，边模抑制比保持在35dB以上。研究并优化了低损伤RIE刻蚀的关键工艺参数,得到了一种垂直度高、侧壁形貌良好的脊波导致作方法，并将其应用于集成器件的基波导制作工艺中。利用光学仿真软件Beamprop和传输矩阵法（Transfer Matrix Method）分别对集成器件中的波导元件（多模干涉耦合器和S型弯曲波导）以及DFB激光器的光栅光谱进行了仿真与计算。以理论优化结果为依据，建立了完整的器件制作工艺流程。在25摄氏度的测试温度下，研制的多波长集成光源器件在DFB激光器和SOA各注入电流100mA 时，单个通道的出光功率大于2mW，出射波长在1550nm波段，相邻信道波长间隔约0.8nm，边模抑制比大于40dB。4通道可实现单独和同时工作，并对同时工作时信道间的热串扰影响进行了测试与分析。
Optical fiber communication has completely changed the communication style of 21st century and has improved the quality of human life. As an essential component of the optical communication system, the importance of optoelectronic device is indubitable. Transforming from discrete device to integrated one, photonic devices are now rising to prominence in dense wavelength disvision multiplexing (DWDM) optical network system. There is no doubt that the monolithic photonic integrated circuit (PIC) is bound to be the core component in the high-capacity, low-power consumption optical network system and tends to be nerve centre for the future intelligent optical network.In this dissertation, several key technologies used for the manufacturing PIC devices, have been investigated, including MOCVD butt-joint regrowth, holographic grating fabrication and RIE etching. Comprehensive studies have been carried out on the principle of distributed feedback (DFB) laser, the integration scheme of multi-wavelength laser array and the beam-combining technology of multimode interference (MMI) coupler. As a preliminary attempt for PIC chip, a four-channel DFB laser array integrated with MMI and semiconductor optical amplifier (SOA) is fabricated and demonstrated. The main research contents are as follows:In order to realize butt coupling between active and passive waveguide with low loss and reflection, the butt-joint interface profile and MOCVD regrowth processing have been optimized carefully, and finally an improved butt-joint regrowth with high quality has been achieved successfully.Uniform holographic gratings have been fabricated in DFB laser region by using double-exposure technology. The lasing wavelength of DFB laser formed by the optimized grating was 1550nm range and sidemode suppression ratio (SMSR) maintained above 35dB. The damage effects of CH4/H2/Ar RIE etching was studied, and the key processing for low damage RIE etching have been optimized. An effective method for the fabrication of ridge waveguide with low damage, high quality surface and high-verticality sidewall has been obtained. The ridge waveguide of integrated device has been fabricated using above optimal parameters.The waveguide elements (multimode interference coupler and S bend waveguide) and the grating spectrum of integrated device have been simulated and calculated by optical simulation software Beamprop and Transfer Matrix Method, respectively. Based on the theoretical optimized results, the complete processing flow for the fabrication of the device has been set up. The output power of the multi-wavelength integrated device was higher than 2mW for single channel when the current of DFB laser and SOA both were 100mA at 25oC. The lasing wavelength was 1550nm range and the interval of neighboring channel was about 0.8nm. The sidemode suppression was above 40dB. Four channels can operate separately or simultaneously. Furthermore, the thermal crosstalk among four channels has also been tested and analyzed.
