Abstract: The invention relates to a method for operating a controllable selective optical add/drop channel for a fiber-optic communication system provided with 2N of wavelength-division multiplexing channels, whose optical frequencies are returnable at a constant frequency separations ?v between adjacent channels, with the aid of the inventive controllable optical add/drop multiplexers (70, 80, 90) that comprise multi-stage structures of optical filters ({75-i}, {85-i}, {95-i}), that are connected in a different manner and provided with devices, for example electro-optical and thermo-optical phase shift devices, for controllable tuning the transmissions characteristics thereof. The optical filters are embodied in the form of single-stage (20), two-stage (40) and/or multi-stage (60) asymmetric Mach-Zehnder interferometers. The controllable optical add/drop multiplexer can be produced according to integrated optic technique in the form of monolithic solid-state device.

Abstract: The inventions relate to a method for operating a controllable selective optical add/drop channel for fiber-optic communication system provided with 2N of wavelength-division multiplexing channels, whose optical frequencies are retunable at a constant frequency separations ?v between adjacent channels, with the aid of the inventive controllable optical add/drop multiplexers (70, 80, 90) that comprise multi-stage structures of optical filters ({75-i}, {85-i}, {95-i}), that are connected in different manner and provided with devices, for example electro-optical and thermo-optical phase shift devices, for controllable tuning the transmissions characteristics thereof. The optical filters are embodied in the form of single-stage (20), two-stage (40) and/or multi-stage (60) asymmetric Mach-Zehnder interferometers. The controllable optical add/drop multiplexer can be produced according to integrated optic technique in the form of monolithic solid-state device.

Abstract: An inventive controllable optical multiplexer for control of multiplexing channels in a fiber-optic communication system provided with 2N of wavelength-division multiplexing channels, whose optical frequencies are re-tunable at a constant wavelength shifting between adjacent channels, comprises a multi-stage structure of optical filters provided with elements for controllable re-tuning transmission coefficients. The optical filters are embodied in the form of single stage, and multi-stage asymmetric Mach-Zehnder interferometers. The electro-optical and thermo-optical phase shift devices are used for controllable re-tuning the transmission coefficients of the optical filters. The demultiplexer can be produced according to integrated optic technologies in the form of a monolithic solid-state device.