Patent ID: 6466348
Filing Date: 2002-10-15
Classification: H04B,H04J

Abstract:
A local trunk apparatus of a wavelength-division-multiplex communication system comprises:an optical amplifier; a transmission power monitor for monitoring a transmission power of said local trunk apparatus; a monitoring and controlling signal transmitting and receiving circuit for transmitting and receiving a monitoring and controlling signal; and an automatic gain control circuit for performing an automatic gain control with respect to said optical amplifier; wherein said monitoring and controlling signal transmitting and receiving circuit sends transmission power information regarding the transmission power monitored by said transmission power monitor to an immediately proceeding trunk apparatus located on a downstream side of said local trunk apparatus; said monitoring and controlling signal transmitting and receiving circuit receives transmission power information sent from an immediately preceding trunk apparatus located on an upstream side of said local trunk apparatus, and sends the received transmission power information to said automatic gain control circuit; and said automatic gain control circuit controls said optical amplifier based on the transmission power information received from the immediately preceding trunk apparatus and reception power information regarding reception power at said local trunk apparatus, so as to equalize the transmission power of said local trunk apparatus to the transmission power of said immediately preceding trunk apparatus in consideration of changes in a loss of a transmission path between said local trunk apparatus and said immediately preceding trunk apparatus.