Patent ID: 7630644

Claim:
An optical add/drop multiplexer including: an optical switch unit for performing an optical add/drop multiplexing for a wavelength multiplexed light; an optical power control unit for performing a control of an optical power by the unit of each signal light included in the wavelength multiplexed light; and a control information communication unit for transmitting and receiving control information with another apparatus, wherein the optical power control unit includes control logic for implementing a plurality of control modes includes a first control mode and a second mode, the first control mode in which a transition to an automatic control of the optical power and release therefrom are carried out by comparing the optical power with a threshold value, and the second control mode in which a transition to an automatic control of the optical power is carried out based on control information as a notification by another of the optical add/drop multiplexers by way of the control information communication unit and release from the automatic control is carried out based on the comparison between the optical power and the threshold value, wherein said first control mode includes a block state at the time of turning a power on, a shutdown state at the time of recognizing a usage start of said inserted light, an auto level down state for the purpose of judging whether or not to transition to automatic control of an optical power of the inserted light, and an automatic level control state for making an optical power of the inserted light identify with a target level by the automatic control, and said second control mode includes a block state at the time of turning a power on, a shutdown state at the time of recognizing a usage start of said pass-through light, and an automatic level control state for making an optical power of the pass-through light identify with a target level by an automatic control.