| 摘要 |
<p>Each of a plurality of semiconductor optical amplifiers (2-1, 2-2, 2-3, 2-4) operates as an optical gate switch and selects an optical signal indicated by a gate control signal from an optical gate switch control unit (32). A plurality of photodetectors (22-1, 22-2, 22-3, 22-4) monitor the power of an optical signal input through a corresponding input port. A VOA control unit (33) calculates an amount of attenuation corresponding to each input port based on the power of each optical signal. A variable optical attenuator (11) attenuates the selected optical signal according to the calculated amount of attenuation in synchronization with the gate control signal.</p> |
