Wavelength-division add/drop multiplexer using a single wavelength-filter and back-reflector switches

Summary form only given. The increase of the channels in wavelength-division multiplexing (WDM) in optical systems will make possible reconfigurable and transparent WDM networks, such as ring networks with wavelength-division add-drop multiplexer (WD-ADM). The most crucial issue for the WD-ADM system is the limitation of the cascaded-node count caused by passband-frequency misalignment of wavelength multiplexers/demultiplexers. For example, cascadability performance of an arrayed waveguide grating (AWG) spaced at 100-GHz interval is practically limited to several spans. In this paper, we propose a novel WD-ADM configuration using a single AWG and back-reflecting-type Er/sup 3+/-doped fiber amplifier (EDFA) gate switches, which improves the allowable cascaded-node count. The feasibility of the proposed WD-ADM configuration has been confirmed through experiments, and the cascadability of nodes has been estimated.