Fujitsu Corporation

Hiroaki Nakazato

Takashi Okuda

Yasuo Suzuki

Masashige Kawarai

Hiroyuki Hanazawa

A disclosed optical add/drop multiplexing device demultiplexes a first signal into multiple signals according to wavelengths, drops one or more of the demultiplexed signals to a transponder, adds one or more signals output from the transponder, multiplexes these signals into a second signal, and outputs it. The device includes an injecting unit for injecting one of measurement signals, each of whose wavelength corresponds to that of a different demultiplexed signal, into a core of a multicore cable within the device, the core being used to transmit the different demultiplexed signal having the corresponding wavelength; a preventing unit for preventing the one measurement signal from emanating; a measuring unit for measuring, for each wavelength, levels of the one measurement signal before and after the corresponding core; a calculating unit for calculating loss of the corresponding core, based on the measured levels; and an informing unit for reporting the calculated loss.

Optical add/drop multiplexer

A contents information delivery method for delivering a desired contents information by transmitting an optical signal from a central station to each of a plurality of user stations via a transmission line includes: a first step (S) of outputting an optical signal containing the contents information as an optical signal having mutually different wavelengths each assigned for the each user station in advance, in the central station; a second step (S) of transmitting an optical signal having a plurality of wavelengths outputted via the transmission line in the first step; and a third step (S), in which each user station receives the optical signal having the wavelength assigned from among the transmitted optical signals, whereby, this simple configuration does not limit the transmission rate, the coding format, or the like in an optical access system, i.e., making it possible to cope with a super-large capacity.

Delivery method and delivery system of contents information, and central station thereof

An optical attenuation device to attenuate the intensity of incident light, comprising an optical attenuation unit including at least two different type magneto-optical optical attenuation elements coupled in a cascade together.

Growing community of inventors

Kawasaki, Japan

Hiroaki Nakazato