| 摘要 |
PURPOSE:To prevent the deterioration of oscillation spectrum and improve characteristics by arranging a plurality of electrode isolation trenches, making the bottom parts thereof reach current blocking layers, and electrically isolating electrodes. CONSTITUTION:Electrode isolation trenches 10 are dug up to current blocking layers 6, 7, in the manner in which the distance between the rough of the trench and an active layer 1 becomes (d). Hence, the isolation resistance between electrodes becomes nearly equal to material resistance of a clad layer 3 of the following dimension; the depth is (d), the width is nearly equal to the width of a light emitting region, and the length is equal to the width of the trench 10. As a result, high resistance is easily realized. When the trench width is small, the length of a region in which the current of an active layer 1 is not injected can be neglected, and current-optical output characteristics of the device do not change. Thereby, P-side electrodes 9 can be isolated by the trench 10 without deteriorating distributed feedback type semiconductor laser, and oscillation wavelength is changed by making nonuniform current flow in the active layer 1. Further, a modulation signal can be applied to one of the P-side electrodes 9, and stable modulation characteristics are obtained, so that characteristics of the device are improved. |
