Taper biosensor in fiber ring laser cavity for protein detection

Abstract

This paper demonstrates the integration of a bio-functionalized tapered fiber sensor in a fiber laser cavity for sensing of biological molecules. Interferometric effect from the taper generated single wavelength lasing output that was spatially measured to detect any changes. The sensing performance of the integrated system was assessed by immersing the biosensor in various concentrations of avidin ranging from 1 to 10 pM at laser threshold (40 mW) and at the maximum pump power of 200 mW. Selectivity of the sensor was ensured by immobilizing biotin on the surface of the tapered region that would act as complementary molecules to avidin. The proposed setup obtained sensitivity values of 0.40 nm/pM and 1.02 nm/pM at pump power of 40 mW and 200 mW, respectively. The integrated system simplifies the sensing output and analysis without compromising the performance of tapered optical fiber-based biosensor.