提出了一种利用分布反馈DFB(Distributed Feedback laser)激光器的非线性对射频光传输系统动态范围进行优化的方案。实验研究了半导体分布反馈激光器的非线性,基于实验结果分析了DFB激光器的偏置电流与线性性能的关系。在此基础上建立了对马赫曾德外调制(Mach-Zehnder modulator,MZM)射频光传输系统线性优化方案。实验结果表明,该实验系统有效抑制了系统三阶交调量,系统的动态范围得到改善,当输入射频信号中心频率4 GHz,双音号间隔10 k Hz时,三阶交调失真抑制23.1 d B,无杂散动态范围提高8.68 d B。
The alignment coupling between optical waveguide chips and optical fiber arrays is the basis of the alignment coupling of planar optical waveguide devices, and the precise position detection with angle and spacing adjustments is one of the key steps of alignment coupling. A methodology for position detection, and angle and spacing adjustment was proposed for optical waveguide chips and optical fiber arrays based on machine vision. The experimental results show angle detection precision levels higher than 0.05°, line detection precision levels higher than 0.1 μm, and detection time less than 2 s. Therefore, the system developed herein meets the precise requirements necessary for position detection, and angle and spacing adjustments for optical waveguide chips and optical fiber arrays.
以2种不同截面尺寸的阵列波导光栅芯片(截面长×宽为6.0μm×6.0μm和4.5μm×4.5μm)与单模光纤的对准耦合为对象,基于光束传播法建立对准耦合仿真模型,分析输入端/输出端几何位置偏差对耦合损耗的影响规律,并进行实验验证,以指导AWG器件的耦合封装。研究结果表明:长×宽为6.0μm×6.0μm的截面光通道输入端横向位错、轴向间距和角度偏移的0.15 d B容差分别为0.77μm,19μm和0.57°,输出端横向位错、轴向间距和角度偏移的0.15 d B容差分别为0.77μm,18.00μm和0.49°;4.5μm×4.5μm截面光通道输入端横向位错、轴向间距和角度偏移的0.15 d B容差分别为0.69μm,18.00μm和0.57°,输出端横向位错、轴向间距和角度偏移的0.15 d B容差分别为0.68μm,19.00μm和0.71°;在耦合过程中,首先应考虑横向偏移误差和角度偏移,最后应考虑轴向间距误差。
