The present invention relates to an optical transmission apparatus capable of suppressing a transitional gain variation when a number of signal wavelengths changes, and maintaining communication quality in optical signals. The optical transmission apparatus is provided with an optical power control device that varies light power of light for each wavelength component corresponding to a wavelength channel, the light including signal light and spontaneous emission light; a wavelength arrangement information obtaining unit that obtains arrangement information of the wavelength channel of the signal light; and a control unit that controls the power control device based on the arrangement information obtained at the wavelength arrangement information obtaining unit so that light power of a wavelength component of the signal light and light power of a wavelength component other than the wavelength component of the signal light become substantially equal.

Optical transmission apparatus and method of controlling the same

A method, a controller, and an optical section include performing an analysis to determine an amount of power offset on any in-service channels in an optical section due to a capacity change with a channel; defining a step size to ensure the capacity change does not exceed an offset limit based on the analysis; performing the capacity change in one or more iterations using the step size to limit the capacity change; and performing an optimization between each of the one or more iterations to adjust amplifier gains in the optical section to compensate for offsets on the in-service channels caused by a previous iteration.

Systems and methods for capacity changes in DWDM networks including flexible spectrum systems

An optical add/drop multiplexer (OADM) and system incorporating the same for maintaining loading of WDM channels with loading signals or information signals when signals are added or dropped. The OADM may include reconfigurable band pass filters having a transmittance characteristic controllable using a command signal. Selective filtering of loading signals and/or information signals received from branch and trunk paths allows an output WDM signal including information signals on utilized channels and loading signals on all unutilized channels.

Optical add/drop multiplexer including reconfigurable filters and system including the same

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

Optical transmission apparatus and optical attenuation amount control method

A transmission-path-type specifying apparatus includes an optical filter that extracts a plurality of different wavelength components from light including wavelength components occurring at the time of communication; an optical switch that simultaneously transmits same pulse signals superposed on light of the extracted wavelength components. The apparatus also includes an ASE modulation controlling unit that obtains a delay-time difference among the transmitted pulse signals when arriving at a destination via a transmission path; a characteristic-value calculating unit that calculates a characteristic value of the transmission path corresponding to a reference time varied depending on the obtained delay-time difference and a type of the transmission path; and a fiber-type determining unit that specifies the type of the transmission path based on the calculated characteristic value.

Transmission-path-type specifying apparatus and transmission-path-type specifying method

An optical transmission apparatus comprises a preamplifier controlling unit for controlling a preamplifier so that amplified spontaneous emission including all wavelength bands of a wavelength-multiplexed signal beam is outputted toward a wavelength demultiplexing unit, with the wavelength-multiplexed signal beam not inputted, power monitors for monitoring optical powers of the amplified spontaneous emission fed from the preamplifier and wavelength-demultiplexed by the wavelength demultiplexing unit, and a determining unit for determining the continuity state of an optical propagation path of each wavelength component on the basis of a result of monitoring by the power monitors. The optical transmission apparatus allows the continuity test on optical propagation paths of channels including a channel not used at the time of a start of the operation to be made easier than the known techniques.

Optical transmission apparatus, continuity testing method therein and optical transmission system

PROBLEM TO BE SOLVED: To carry out a continuity test of an optical propagation path including a channel which is not used in the initial operation, more easily than the conventional technology. SOLUTION: The optical transmission apparatus comprises: a preamplifier controlling portion 121 which controls a preamplifier 5 in such a manner that spontaneous emission light including all the wavelength bands of wavelength multiplex signal light may be output into a wavelength division portion 6 under a state that the wavelength multiplex signal light is not inputted; power monitors 8b-1, 8b-2, and 11a for monitoring the optical power of the spontaneous emission light which has been wavelength-divided by the wavelength division portion 6 and then is emitted from the preamplifier 5; and a judging portion 124 which judges the continuity state of the optical propagation path for each wavelength component on the basis of the monitoring results of the power monitors. COPYRIGHT: (C)2007,JPO&INPIT

Takehiro Fujitsu Limited Fujita

Papers

Optical transmission apparatus, continuity testing method therein and optical transmission system

Optical transmission apparatus and its continuity testing method, and optical transmission system