【作者】 杨光；

【导师】 王琦；

【作者基本信息】 北京邮电大学 ， 电子与通信工程（专业学位）， 2020， 硕士

【摘要】 超辐射发光二极管(SLD)是传感系统光源的一种,其发光特性介于激光器(LD)和发光二极管(LED)之间。因其有着较宽的光谱、较高的功率、弱时间相干性等特点,已经被应用于惯性导航系统、光缆施工检修设备、医疗仪器等领域中。近年来迅速发展的物联网、人工智能等领域对传感系统精度的更高要求,使得SLD光源中决定传感系统精度的重要指标之一——偏振特性成为了当下SLD研究的热点,因此开展SLD偏振特性的研究与控制,对于进一步拓展SLD在实际工程领域中的应用范围与场景将有着重要意义。基于本实验室已有半导体器件工艺积累,本论文以GaAs基量子点SLD和量子阱SLD为研究对象。系统开展SLD的工艺制备与优化,研究不同波导参数、出光方向、刻蚀深度、电流注入位置对偏振特性的影响,主要研究工作与取得的成果如下。1、优化了 SLD器件的关键制备工艺:(1)在光刻显影、脊波导刻蚀中使用玻璃与聚四氟乙烯提篮承载晶片,提升了显影与刻蚀出的图形边缘的陡峭程度;(2)在溅射P面Ti/Pt/Au电极后的带胶剥离中引入水浴槽恒温加热,显著降低了带胶剥离的难度;(3)在晶片减薄工艺中利用特定厚度的薄外延片对晶片进行保护,有效规避了晶片的过度减薄风险。2、基于浅刻蚀的双沟J型脊波导结构,成功制备出了 GaAs基量子点SLD,脊宽10μm、腔长3mm、弯曲角度10°的SLD管芯,在室温下实现了 1300nm波段的连续超辐射发光,注入电流350mA下,靠近弯曲波导的端面出光功率为6mW,光谱宽度24.3nm,功率带宽积为146nm·mW。3、将GaAs基量子点SLD改为靠近直波导的端面出光,再借助探针改变有源区的电流注入位置,利用偏振度测试仪检测SLD发光的偏振特性变化,最后焊接热沉。经实验发现:出光方向、弯曲角度、波导脊宽、电流注入位置、腔长均会影响SLD出射光的偏振度指标,在脊宽5μm、腔长2mm、弯曲角度10°的SLD管芯上、将靠近直波导端面处做为电流注入点时,偏振度变化范围为4%—99%,成功实现了出射光偏振度的大范围变化。4、成功制备出了基于深刻蚀的双沟J型脊波导的GaAs基量子阱SLD,脊宽4μm、腔长2mm、弯曲角度8°的SLD管芯,实现了室温脉冲超辐射发光,注入脉冲电流375mA(占空比10%,重复频率500HZ)时,靠近弯曲波导的端面出光功率为6.5mW。更多还原

【Abstract】 As one of the key light sources of sensing system,the luminescence characteristic of Superluminescent diode(SLD)is between lasers and light emitting diodes.Holding the characteristic of high output power,wide spectrum and weak temporal coherence,SLDs have been used in inertial navigation system,optical cable construction and maintenance equipments,medical instruments.In recent years,high accuracy sensing system has already been urgently-needed in Internet of things,Artificial intelligence and other technologies.As one of the important characteristics of SLDs which determine the accuracy of the sensing system,polarization has become a research focus.Therefore,carring out research on the control of polarization of SLDs will make great significance to expand SLDs’application scopes and scenarios in engineering field.Based on current semiconductor technology accumulation of our lab,we took the polarization characteristics of GaAs-based quantum dot SLDs and GaAs-based multiple quantum well SLDs as the research subject in this thesis.We optimized the fabrication process and studied the effects on polarization of waveguide’s geometric parameters,light output direction,etching depth and current injection position.The main work and achievements are listed as follows:1.Optimized the key fabrication process of SLDs.(1)In photolithography development and ridge waveguide etching,glass and Teflon baskets were used to carry the wafer,which improved the steepness of the edge of the pattern produced by development and etching.(2)Constant temperature water bath was used in the photoresist peeling process after sputtering the Ti/Pt/Au electrode on the P side,which significantly reduces the difficulty of peeling process.(3)In the wafer thinning process,thin epitaxial wafers with specific thickness were used to protect wafers,effectively avoiding the risk of excessive wafer thinning.2.GaAs-based quantum dot SLDs were successfully fabricated based on shallow etched double groove J-shaped ridge waveguide structure.The SLD chip with ridge width of 10μm,length of 3mm,bending angle of 10°could operate at room temperature under continuous wave condition,it has an output power of 6mW and a full width at half maximum(FWHM)of 24.3 nm while the injected current is 350mA,and the corresponding power bandwidth product is 146nm·mW with the degree of polarization is 99%.3.We measured polarization by turned the light direction to straight waveguide and changed the injection position by microprobe.It is found that waveguide’s geometric parameter,output light direction,etching depth,current injection position had an effect on polarization.The polarization between 4%and 99%on SLDs for its ridge width of 5μm,length of 2mm,bending angle of 10°.4.GaAs-based quantum well SLDs based on deeply etched double-groove J-shaped ridge waveguide were successfully fabricated.The SLD chip with a ridge width of 4μm,a length of 2mm,a bending angle of 8°could operate at room temperature under pulse condition(10%,500Hz),and it has an output power of 6.5mW while the injected current is 350mA.更多还原