On-chip Multiphase Tunable Grating Interferometer for Chemical and Protein Analysis

This paper reports the realization of long-period grating (LPG) interferometer in an integrated micro-optical fluidic system (MOFS) using droplet microfluidics. Comparing to normal fiber LPG, it provides a wide tuning range in the parameters of LPG, such as the grating period by changing the flow rate of the liquids and the index variation in the core by changing the types of liquid used. LPG interferometer is extensively used as sensors especially as a biochemical refractometer. The results show that the designed microfluidic chip can be used to measure the refractive indices of Fetal Bovine Serum (FBS) solutions. It has potential applications in chemical and protein analysis.