A micrometer size, simple, and low-cost sensor for continuous monitoring of human blood during malarial infection at its various stages is proposed in this work. The sensor comprises a light source, silica fiber directional coupler, and an optoelectronic photodetector. The sensor is
simulated for fiber diameters from 1–1.8 #x03BC;m and optimization is done. The sensor produces a photocurrent of a few mA, which gives the level of infection. It can detect a change in refractive index, of the order of 10−5, and needs a small sensing length of
a few μm. It can be potentially built as an integrated embedded device.
Fiber-interface directional coupler inscribed by femtosecond laser for refractive index measurements