Fiber Fabry-Perot interferometer using side exposed fiber Bragg gratings

An all-fiber Fabry-Perot interferometer was made using intracore Bragg grating reflectors fabricated with the side exposure technique.1 This method provides a new and relatively easy way to make such an interferometer that can be used in dense WDM communications. Fiber Bragg reflectors made to date with this technique have spectral bandwidths ranging from 0.1 to 1 nm at the communications band wavelengths for corresponding grating lengths of 15 to 1.5 mm. Reflectivities approaching 100% have been achieved in high germania-doped commercial fibers. Measured fiber grating losses at these wavelengths do not exceed about 0.13%.