OPTICAL SEMICONDUCTOR DEVICE AND OPTICAL WAVEGUIDE DEVICE

摘要

An optical semiconductor device and an optical waveguide device are provided to couple a waveguide such as a silicon wire with an optical waveguide used as an optical functional component such as a semiconductor laser without causing large loss. A first member includes a silicon oxide layer(12) formed on a silicon substrate(11) and a silicon core layer(13) extended in a longitudinal direction or one direction on the silicon oxide layer. A second member includes a compound semiconductor core layer(14) formed on a compound semiconductor substrate(15). The silicon core layer allows propagation of light therein. The compound semiconductor core layer includes a resonator region(21) and a mode conversion region(22). One end of the resonator region is continuous from one end of the mode conversion region. The total length of length of the resonator region in a light propagation direction and length of the mode conversion region in the light propagation direction is shorter than length of the silicon core layer in the light propagation direction. The resonator region is an oscillation region of the semiconductor laser. The mode conversion region has an effective refractive index value reduced toward the light propagation direction. The compound semiconductor core layer is fixed to at least a part of the silicon core layer. The compound semiconductor core layer formed between the silicon substrate and the compound semiconductor substrate has an effective refractive index value higher than an effective refractive index value of the silicon substrate and the compound semiconductor substrate.