Patent ID: 7167301
Filing Date: 2007-01-23
Classification: B82Y,H01S

Abstract:
1. A semiconductor optical amplifier comprising: an active layer containing quantum structures of any of quantum dots, quantum wires and quantum dashes, the active layer amplifying light propagating therein while current is injected therein; electrodes provided for a plurality of sections of the active layer sectionalized along a light propagation direction, the electrodes being able to inject different currents into the sections; and a power supply for supplying current to the electrodes, the power supply injecting current into at least one first section selected from the sections of the active layer at a current density such that a gain coefficient of the quantum structures at the longest transition wavelength of the quantum structures becomes larger than a gain coefficient at the second longest transition wavelength, and injecting current into at least one other section different from the first section at a current density such that the gain coefficient of the quantum structures at the longest transition wavelength becomes smaller than the gain coefficient at the second longest transition wavelength.