Lossy mode resonance sensors in uncoated optical fiber

This work demonstrates that the use of an unconventional optical fiber allows for generating lossy mode resonances (LMR), without need external high refractive index thin film. The basic idea consists using few centimeters having large core and cladding with higher index, which is spliced between two multi-mode fibers. Here, role such kind got by a commercially available double (DCF) W-type (RI) profile. possibility to induce tune phenomenon demonstrated, where resonance wavelength LMR peaks order can be adjusted varying thickness DCF outer cladding, e.g., through chemical etching. novel sensing scheme becomes valid alternative thin-film coated fibers, LMR-based sensors have been developed so far, due advantages in terms simplicity, cost, stability. response fabricated devices characterized towards surrounding medium demonstrating sensitivity up about 1700 nm/RIU RI range 1.33-1.39, makes this sensor suitable bio-chemical applications. Low cross temperature also found.