| 摘要 |
PURPOSE:To shorten the distance between upper and lower conduction parts and to decrease propagation loss by using compd. semiconductors having a large carrier density between a switch part and electrodes. CONSTITUTION:An n<->GaAsAl clad layer 8, an n<->GaAs waveguide layer 9, and an n<->GaAsAl clad layer 8a are successively laminated on an N<+>GaAsAl substrate 7 and two pieces of waveguides 11a, 12a are intersected in ridge structure with the waveguide layer 9. The optical switch part 13 which is de creased in refractive index when impressed with an electric field is provided in the intersected part thereof. The substrate 7 having the large carrier density and the switch part 13 are connected by interposing the lower conduction part 16 formed of the ridge structure in the position of the substrate 7. The impres sion of the large electric field to the switch part where the distance between the upper and a lower conduction parts 16 and 17 is large is permitted and since the absorption of light therebetween is slight, the propagation loss is decreased. |
