Tunable wavelength filter through bending control of asymmetric single-mode grating fiber

A tunable wavelength filter based on an asymmetric single-mode grating fiber fabricated by anisotropic CF₄ plasma etching is proposed. The reflection wavelength is shown to shift linearly with the degree of curvature of the bent fiber, affording a center wavelength shift of 3.5 nm at 1550 nm. In this region of wavelength shift, the rejection and half-power width of the measured spectra remain almost constant.