Gold-coated optical fiber supermode interferometer for insulin bio-sensing

In this work, we present a supermode interferometer for biosensing application. The interferometer was fabricated with a segment of a seven-core fiber fusion-spliced to a standard single-mode fiber. We have found that when a thin gold layer was deposited on the multicore fiber (MCF) end facet, the response of the interferometer to refractive index (RI) changes was polarization dependent. The highest sensitivity to RI was achieved for a similar to 10 nm-thick gold coated sample when P-polarized light was used. The gold-coated sample was later biofunctionalized and then used for insulin detection. The sensor was able to detect insulin with a concentration level of 10(-8) g/ml.

Automated summary

In this work, a supermode interferometer for biosensing application is proposed, which is fabricated by fusion splicing a segment of a seven-core fiber to a standard single-mode fiber. It is found that the response of the interferometer to refractive index changes is polarization dependent when a thin gold layer is deposited on the multicore fiber end facet. The highest sensitivity to refractive index is achieved for a similar to 10 nm-thick gold coated sample when P-polarized light is used. The gold-coated sample is then biofunctionalized and used for insulin detection, achieving a concentration level of 10(-8) g/ml.