Thesis (M. Eng.) - Asian Institute of Technology, 2012

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Nanotechnology

This work introduces design, fabrication and characterization of an optical based integrated flow rate sensor where the light- fluid interaction is maximized by allowing the liquid and light to propagate along the same direction. This is achieved by placing a 10 {uF06D}m deep channel between two waveguides. The optical waveguides are tapered down to the channel width to feed the light in and out, where tapering is done to minimize the coupling and propagation loss. The output signal is detected by a fast receiver (higher than 1MHz) that records the dynamic change of the light intensity when fluid flows through the channel. This scheme allows for the direct measurement of the liquid flow rate with higher interaction length between fluid and light. The initial results showed a dynamic range of measurement up to 0.18.