| 摘要 |
PROBLEM TO BE SOLVED: To obtain the optical element which realizes nondependence of the gain on the polarization forming a group of active layers waveguide mode an active area. SOLUTION: A current blocking layer 3 is put nearby the center and active layers 1 are arranged on the right and left sides of this current stop layer 3. Each active layer 1 is, for example, 0.3μm thick and <=1μm, e.g. 0.5μm wide. The gain is generated when a current is impressed to the active layer 1, and the current is narrowed down by the blocking layers 3 and 6 and effectively impressed to the active layer 1. The active layers 1 are arranged on both the right and left sides of the blocking layer 3, so the light confinment coefficient can be made small as compared with that in the absence of the blocking layer 3. Further, the light confinment coefficient can be varied by adjusting the width of the blocking layer 3. Consequently, the signal gain in TM mode and signal gain in TE mode can be made equivalent to each other and a gate type semiconductor optical switch with low polarization, a low working current, and a high gain can be obtained. |
