| 摘要 |
A surface-emitting laser comprises an optical cavity including a multiple quantum well (MQW) active region (16) providing a source of optical emission in use. Top and bottom mirrors (22 and 12) are disposed respectively above and below the MQW active region (16). The MQW active region (16) is profiled so that it has a greater number of quantum wells in a central portion (16a) thereof than in a peripheral portion (16b) thereof (Figure 2). In alternative embodiments, (a) a current- guiding region (26) is profiled so that it has a first current-guiding portion (26a) with a relatively smaller aperture therethrough extending over a central portion (16a) of the MQW active region (16), and a second current-guiding portion (26b) with a relatively larger aperture therethrough (Figure 3); and (b) one of the mirrors (20) has a layer structure which, in a central portion of the cross-sectional area of such mirror, is different to that in a peripheral portion of said cross-sectional area (Figure 4). <IMAGE> |
