Single resonant and widely tunable ultrathin cladding long-period fiber grating filters

A spectrally single resonant and widely tunable, ultrathin cladding long-period fiber grating (UCLPG) is demonstrated in the present paper. Both experimental and theoretical analyses of the characteristics for the proposed device are accomplished. Since the single resonant and widely tunable characteristics of the proposed UCLPG are strongly influenced by the waveguide structure and surrounding material, both material dispersion and waveguide dispersion were included in the calculation for determining the wideband tuning range and resonant spectra of the UCLPG. The tuning range covered wavelength from 1.41 to 1.56 μm for the variation of refractive index of 1–1.445 (optical liquid nD 1:456 for λ 1:5 mm) is achieved in the study.