| 摘要 |
There is provided a semiconductor laser element, which has a small capacitance outside a ridge portion and high response speed and is able to effect pulse oscillation with a satisfactory pulse waveform. On a GaAs substrate 101, there are provided an n-type buffer layer 102, an n-type first clad layer 103, an MQW active layer 104, a p-type second clad layer 105, a p-type etching stop layer 106 that has an energy bandgap smaller than that of this second clad layer 105, a p-type third clad layer 107 that constitutes a ridge portion and a p-type protective layer 108. On both sides in the widthwise direction of the ridge portion are laminated a p-type spacer layer 109, an n-type current light confining layer 110, an n-type current confining layer 111 and a p-type flattening layer 112. On these layers is laminated a p-type contact layer 113. A depletion layer spreads into the spacer layer 109 when a bias voltage is applied. Therefore, a capacitance between the spacer layer 109 and the current light confining layer 110 is reduced, and a response speed during the pulse oscillation of the semiconductor laser element becomes fast. <IMAGE> |
