Abstract: A storage device stores information regarding a channel from which an optical transmission apparatus at a subsequent stage drops a signal light. A processor determines that switching from second channel transmission using a larger number of channels than a first number of channels to first channel transmission is performed, and controls an attenuation amount, when performing the first channel transmission using the first number of channels, by referring to the storage device according to the determination and making the attenuation amount in a no-signal channel larger than a determine value if the no-signal channel whose wavelength is within a determined range from the wavelength of the signal light channel for the first channel transmission is a channel from which the optical transmission apparatus at the subsequent stage drops a signal light, so as to transmit an amplified spontaneous emission light along the no-signal channel.

Abstract: A control apparatus of an optical amplifier includes a monitoring section that measures power of light inputted to the optical amplifier, a power-wavelength characteristics variable section that is operable to change a wavelength characteristic of power of the light inputted, a wavelength number decrease recognition section that compares the value of the power of light measured by the monitoring section with a predetermined threshold, and a control section that controls the power-wavelength characteristics variable section when the wavelength number decrease recognition section judges that the value of the power of light falls below the threshold.

Abstract: A storage device stores information regarding a channel from which an optical transmission apparatus at a subsequent stage drops a signal light. A processor determines that switching from second channel transmission using a larger number of channels than a first number of channels to first channel transmission is performed, and controls an attenuation amount, when performing the first channel transmission using the first number of channels, by referring to the storage device according to the determination and making the attenuation amount in a no-signal channel larger than a determine value if the no-signal channel whose wavelength is within a determined range from the wavelength of the signal light channel for the first channel transmission is a channel from which the optical transmission apparatus at the subsequent stage drops a signal light, so as to transmit an amplified spontaneous emission light along the no-signal channel.

Abstract: In particular embodiments, providing signal reachability information to a network includes establishing signal reachability information at a network node of the network. The signal reachability information describes attributes that affect reachability of an optical signal. The signal reachability information is inserted into an advertisement, and the advertisement is sent to network nodes of the network.

Abstract: A control apparatus of an optical amplifier includes a monitoring section that measures power of light inputted to the optical amplifier, a power-wavelength characteristics variable section that is operable to change a wavelength characteristic of power of the light inputted, a wavelength number decrease recognition section that compares the value of the power of light measured by the monitoring section with a predetermined threshold, and a control section that controls the power-wavelength characteristics variable section when the wavelength number decrease recognition section judges that the value of the power of light falls below the threshold.

Abstract: In particular embodiments, providing signal reachability information to a network includes establishing signal reachability information at a network node of the network. The signal reachability information describes attributes that affect reachability of an optical signal. The signal reachability information is inserted into an advertisement, and the advertisement is sent to network nodes of the network.

Abstract: Each network device holds as a database parameters relating to the size of a factor of signal degradation of the device, and relays the parameters according to a path through which a signal passes. When each network device receives a relayed parameter, it accumulates the parameter of the device to the received parameter value, and transmits the result to the network device at the next stage. The network device on the terminating side of the path estimates the size of the degradation of the signals in the entire path using the received parameter, thereby determining the reachability as to whether or not a signal can be transmitted through the path.

Abstract: An optical transmission apparatus includes a reception part for receiving a wavelength division multiplexed (WDM) signal reached via optical amplifiers; a measuring part for measuring an optical power level of each wavelength of the WDM signal received by the reception part; a determination part for determining whether an amount of tilt of the WDM signal calculated based on measurement results of the measuring part is suitable or not; an operation part for calculating the tilt correction amount to be applied to tilt correction processing performed by the optical amplifiers if the amount of tilt of the WDM signal is not suitable; and a notification part for notifying the optical amplifiers of the tilt correction amount.