Patent ID: 7369588

Claim:
An optical semiconductor device providing optical gain or optical loss depending on application of electric current comprising: a lower clad layer; an active layer disposed on the lower clad layer, the active layer being configured to generate optical gain or optical loss depending on injection of carriers; an upper clad layer disposed on the active layer, the upper clad layer being configured to trap light in the active layer in cooperation with the lower clad layer; a temperature control part configured to control temperature distribution of the active layer along a light propagation axis in such a manner that temperature of the active layer varies in the active layer along the light propagation axis comprising: a heat sink, on which the lower clad layer is disposed, configured to discharge heat transferred thereto to exterior; and a plurality of electric resistance layers being disposed on the upper clad layer and being spaced apart from each other, wherein each electric resistance layer is configured to emit heat depending on application of a different level of electric current, and a lower electrode interposed between the heat sink and the lower clad layer, wherein heat conductivity at the interface of the heat sink and the lower electrode remains constant.