Two techniques for the fabrication of fiber gratings with a narrowband filter response are reported. In the first technique, the reflection bandwidth is reduced by increasing the grating length. Fiber gratings 10 mm long have been made with a bandwidth of approximately 0.3 nm. In the second technique, a phase shift is incorporated into the grating to form a resonant structure. Fiber resonators with resonant dips in reflection and peaks in transmission having full-width half-maximum (FWHM) bandwidths of approximately 0.08 nm have been fabricated. A corresponding narrowband transmission peak was also measured. >
['C.M. Ragdale', 'D.C.J. Reid', 'D. J. Robbins', 'J. Buus', 'Ian Bennion']
Narrowband fiber grating filters