| 摘要 |
PURPOSE:To prevent the main waveguide layer such as an active layer from being damaged by a slit coupler formed in a layer direction to have a required branching ratio by arranging the center of the layer direction distribution of optical waves propagated through an optical waveguide layer on a position shifted upward or downward from a main waveguide layer. CONSTITUTION:An optical wave 12 made incident from the external is branched/ coupled by an integration coupler, optically amplified, multiplexed, and outputted as an optical wave 13. The optical amplification is executed by impressing a forward bias between both electrodes 6, 7. Since the position of the active layer 3 in the optical waveguide layer is shifted from the center of the electromagnetic distribution of guided light in the downward direction, the layer direction leading position of a slit coupler can be set up on a position upper than the layer 3 and the cutting of the slit 9 up to the layer 3 is made unnecessary. As a means for shifting the center, the refractive indexes of AlGaAs clad layers 2, 4 formed on both the layers of double hereto structure are made asymmetrical from that of the layer 3. Consequently, the integrated coupler having excellent durability as a branching coupler can be attained. |
