Abstract
Discussed are all-fiber add/drop filters made of two well-mated side-polished fibers. In the former fiber directional coupler, one half-coupler has intracore Bragg gratings, but the other doesn't. These two polished fibers are separately glued onto a fixed plate and a three-axis translation stage. The coupling efficiency of such a coupler mainly depends on how they are aligned. In this thesis, we use a Si wafer as the polishing substrate in fabricating side-polished fibers. The advantages of these polished samples are low insertion losses, a long interaction length, ease of alignment, and excellent surface flatness. In comparison with those published all-fiber add/drop filters of the same structure, our devices show attractive or much improved characteristics in filtering spectral. The present fiber devices are found applications on optical wavelength division multiplexer (WDM), dense WDM (DWDM) systems, and other optical signal processings.