Patent ID: 7839910

Claim:
A laser device comprising: a gain medium; a first clad and a second clad sandwiching the gain medium in a thickness direction thereof; and a cavity structure for resonating an electromagnetic wave generated in the gain medium, wherein the gain medium includes a plurality of active regions for generating an electromagnetic wave and at least one connecting region laid among the active regions to connect the active regions, the active regions and the connecting region each including quantum wells and barriers, wherein the first clad and the second clad each include a negative permittivity medium, a real part of a permittivity thereof being negative for the electromagnetic wave, wherein a potential-adjusting portion is arranged between the connecting region and the first clad and between the connecting region and the second clad, for adjusting an electric potential of the connecting region, and wherein voltages applied to active regions arranged adjacent to the connecting region are equalized by adjusting the electric potential of the connecting region.