DWDM components with 0.03 nm center wavelength accuracy using a novel adjustment mechanism

WDM transmission systems using multiplexed signals, with a wavelength pitch of about 100 GHz have come into practical use with the progress of wideband optical amplifiers. In these systems, both MUX and DEMUX are key devices used for combining and separating signals and extraordinarily accurate control of wavelength characteristics is required. In conventional dielectric multilayer filter type device, the incident beam angle to the filters are tuned with directly rotating filter plates. However this technique has become inadequate with the narrowing of the wavelength pitch. In this paper a new device configuration having a wavelength characteristics controllability ten to hundred times superior to conventional systems is reported. This controllability is realized by the rotation of a column part having an inclined surface on one end, to which BPFs are attached, around the axis of an optical beam. The performance of this device has also been confirmed and the controllability of the wavelength characteristics is within 0.03 nm accuracy