将微流控结构和光波导多模干涉(MMI)结构功能结合在一起, 利用导波的多模干涉效应, 对微通道中的液体变化进行实时监测。液体中成分或浓度的变化导致液体的折射率变化, 通过监测MMI的输出波导的功率, 得到液体折射率的变化, 从而得到液体成分浓度的变化。计算模拟显示, 对液体的折射率变化灵敏度可达到0.0001。对不同流量的要求, 提出了两种微流控结构和光波导MMI复合结构, 有望在微流控生化分析芯片中得到应用。

A new compact microfluidic chip based on multimode interference (MMI) waveguide is designed and simulated, which can be used to measure the refractive index of liquid in micro-channel through the interference of multiple optical guide-mode waves. The change of concentrations or composition in liquid leads to different refractive index, the change of refractive index can be measured by the output power of MMI waveguide, and then the information of liquid can be determined in details, such as the composition and concentrations. The sensitivity of refractive index can reach 0.0001 according to simulation. Two pieces of chips are proposed for different flux fluids, which can be applied to the microfluidic chemical analysis chip.