Taper biosensor in fiber ring laser cavity for protein detection

• Published in: Optics and laser technology 2020-05, Vol.125, p.106033, Article 106033
• Main Authors: Mansor, M., Abu Bakar, M.H., Omar, M.F., Mustapha Kamil, Y., Zainol Abidin, N.H., Mustafa, F.H., Mahdi, M.A.
• Format: Article
• Language: English
• Subjects: Biological effects; Biosensor; Biosensors; Biotin; Change detection; Detection; Fiber laser; Fiber lasers; Lasers; Optical fiber sensor; Optical fibers; Ring lasers; Selectivity; Tapered optical fiber; Tapering
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2019.106033

•Functionalized tapered fiber biosensor integrated in ring-cavity fiber laser.•Single wavelength lasing output generated from optimized taper dimension.•Highly linear quantitative response with high specificity towards target protein.•Higher gain yielded better sensitivity due to enhanced evanescent wave interaction. 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.