Patent ID: 7616848
Filing Date: 2009-11-10
Classification: H04B,H04J

Abstract:
1. An optical transmission apparatus comprising: an optical demultiplexer to receive and to demultiplex a wavelength multiplexing signal into wavelengths each corresponding to one of channels; a unit to measure optical power of each of the wavelengths; an optical multiplexer to generate a wavelength multiplexing signal into which the wavelengths are multiplexed; an optical amplifier to amplify the multiplexed wavelength multiplexing signal; a unit to compare a measured value of the optical power of each of the wavelengths with a predetermined threshold value; a unit to calculate a total value of the measured values of the optical power that are equal to or larger than the threshold value, as a total value of a signal beam power; a unit to calculate a total value of the measured values of the optical power that are less than the threshold value, as a total value of an amplified spontaneous emission (ASE) power; a unit to calculate a number of the measured values of the optical power that are equal to or larger than the threshold value, as a wavelength count of the signal beams contained in the wavelength multiplexing signal; a unit to calculate a ratio of a total value of the signal beam power to a total value of the ASE power, as a signal-to-ASE ratio; a unit to measure an optical power of the wavelength multiplexing signal inputted to the optical amplifier; and a unit to determine a target value of automatic level control by use of the wavelength count, the signal-to-ASE ratio and the measured value of the optical power of the wavelength multiplexing signal inputted to the optical amplifier, in order to execute an automatic level control of the optical amplifier so that the optical power of each of the wavelengths in the wavelength multiplexing signal outputted from the optical amplifier, becomes constant.