Fujitsu Corporation

Fujitsu Telecom Networks Limited

Akihisa Kawaguchi

Kenji Watanabe

Tomoyuki Suzuki

Kazuhiro Minamimoto

Koji Tanonaka

Takehiro Fujita

Eisaku Touma

A transmission system is provided with a transmission apparatus that outputs an ASE light from a transmission light amplifier and with a reception apparatus provided with: a tilt detection unit that detects the optical strength levels of at least two probe lights having different wavelengths from a received ASE light; and a reception light amplifier that performs a first-order tilt correction on light to be output in a linear manner so as to reduce the difference in the optical strength level of the two probe lights detected by the tilt detection unit.

Transmission system and method of correcting tilt of the transmission system

An integrated transmission apparatus includes a plurality of optical supervisory channel (OSC) processing units for processing OSC signals contained in a wavelength division multiplexing (WDM) signal received from a WDM network and a switching unit for performing the path control of synchronous digital hierarchy (SDH) frames. An OSC processing unit transmits the SDH frame, containing wavelength information indicated by, to the switching unit. Another OSC processing unit acquires the SDH frame, containing wavelength information, from the switching unit and sets an OSC signal which is to be appended to the WDM signal to be transmitted, based on the wavelength information.

Transmission apparatus, transmission controlling method, and optical supervisory channel (OSC) processing apparatus

A method of controlling an optical wavelength division multiplexing transmission apparatus achieves stable wavelength division multiplexing optical transmission by switching a control mode of an optical amplification section in accordance with an input state of optical signals of various wavelengths. Accordingly, the method involves, upon startup of the optical wavelength division multiplexing transmission apparatus, initial setting of information such as the wavelengths being used and the number of wavelengths being used, setting the amount of optical attenuation for each wavelength to a maximum value, and setting an optical amplification unit to ALC. Then, upon input of an optical signal corresponding to the wavelengths being used, the amount of optical attenuation corresponding to the input optical wavelength is controlled so that the levels of the input optical signals analyzed by the spectral analysis unit are approximately constant; and moreover, so that the input optical level per single wavelength input into the optical amplification unit is of a level which corresponds with the number of wavelengths being used. Then the apparatus shifts to normal operating conditions. Next, when the number of wavelengths being input varies, the optical amplifier is switched to AGC, and after the power level of the optical signal of each wavelength is adjusted, the optical amplifier is switched to ALC again.

Method of controlling optical wavelength division multiplexing transmission apparatus

A WDM transmission device includes a level adjustment unit adjusting levels of optical signals having different wavelengths, a multiplexer multiplexing the optical signals, an amplifier amplifying a multiplexed optical signal, and a monitor unit monitoring the multiplexed optical signal applied to the amplifier and a level of an output signal of the amplifier and controlling the level adjustment unit so that the levels of the optical signals fall within a predetermined level range in which the amplifier can operate normally.

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Kanagawa, Japan

Akihisa Kawaguchi