Add-drop filter, packet switch, wavelength multiplexing device, communication device, and communication network

摘要

An add-drop filter capable of being produced at low costs and a 2-way transmission. An optical signal comprising eight wavelengths, lambda 1 to lambda 8, transmitted through an optical fiber (3a) is changed to parallel beams by a lens (4a) to be applied to a dielectric filter (2). A beam of lambda 1 is reflected in a right-angle direction, and beams of the other wavelengths ( lambda 2 to lambda 8) transmit it. The reflected beam of lambda 1 is led to an optical fiber (3b) via a lens (4b). Beams of lambda 2 to lambda 8 passed through it are led to an optical fiber (3c) via a lens (4c). The beam of lambda 1 passed through the optical fiber (3b) is led to the optical fiber (3a) via the lens (4b), the dielectric filter (2) and the lens (4a). The optical signal of lambda 1 is transmitted in 2-way directions between the optical fiber (3a) and the optical fiber (3b). A similar add-drop operation is implemented for optical signals of lambda 1 to lambda 8 that have passed through the optical fiber (3c).