Wang Dongbo, Kannojia Harindra Kumar, Jouy Pierre, Giraud Etienne, Suter Kaspar, Maulini Richard, Gachet David, Hetier Léo, Van Steenberge Geert, Kuyken Bart
Photonics Research Group, Department of Information Technology, Ghent University-imec, 9052 Ghent, Belgium.
Center for Microsystem Technology (CMST), Ghent University-imec, 9052 Ghent, Belgium.
Micromachines (Basel). 2024 Aug 22;15(8):1055. doi: 10.3390/mi15081055.
For the first time, we demonstrate the hybrid integration of dual distributed feedback (DFB) quantum cascade lasers (QCLs) on a silicon photonics platform using an innovative 3D self-aligned flip-chip assembly process. The QCL waveguide geometry was predesigned with alignment fiducials, enabling a sub-micron accuracy during assembly. Laser oscillation was observed at the designed wavelength of 7.2 μm, with a threshold current of 170 mA at room temperature under pulsed mode operation. The optical output power after an on-chip beam combiner reached sub-milliwatt levels under stable continuous wave operation at 15 °C. The specific packaging design miniaturized the entire light source by a factor of 100 compared with traditional free-space dual lasers module. Divergence values of 2.88 mrad along the horizontal axis and 1.84 mrad along the vertical axis were measured after packaging. Promisingly, adhering to i-line lithography and reducing the reliance on high-end flip-chip tools significantly lowers the cost per chip. This approach opens new avenues for QCL integration on silicon photonic chips, with significant implications for portable mid-infrared spectroscopy devices.
我们首次展示了使用创新的3D自对准倒装芯片组装工艺，在硅光子平台上对双分布式反馈（DFB）量子级联激光器（QCL）进行混合集成。QCL波导几何结构预先设计有对准基准，在组装过程中实现了亚微米精度。在脉冲模式操作下，在室温下观察到在7.2μm的设计波长处有激光振荡，阈值电流为170 mA。在15°C稳定连续波操作下，片上光束组合器后的光输出功率达到亚毫瓦水平。与传统的自由空间双激光器模块相比，特定的封装设计使整个光源小型化了100倍。封装后测量的水平轴发散值为2.88 mrad，垂直轴发散值为1.84 mrad。很有前景的是，采用i线光刻并减少对高端倒装芯片工具的依赖，显著降低了每芯片的成本。这种方法为在硅光子芯片上集成QCL开辟了新途径，对便携式中红外光谱设备具有重要意义。
