Tunable wavelength filter using a Bragg grating fiber thinned by plasma etching

We studied a tunable wavelength filter using a single-mode fiber Bragg grating with a cladding thinned by reactive plasma etching. Reflection wavelength shifts were demonstrated by controlling the effective refractive index or the period of the grating. When liquid paraffin was used for additional cladding on a thinned grating fiber of 19-μm diameter, the shift rate of 0.055 nm//spl deg/C was obtained. In the case of applying the tension to the grating region, the shift rate was 3.4 nm/100 V for the fiber of 41-μm diameter.