Ridge waveguide laser with dielectric current confinement

A direct modulated laser (DML), the DML comprising:

• a substrate;
• a plurality of layers disposed on the substrate to provide a multi quantum well (MQW);
• first and second dielectric structures disposed on the substrate, wherein the first and second dielectric structures are disposed on opposite lateral sides of the MQW, wherein each of the first and second dielectric structures include a base with a first overall width in a horizontal direction and a vertical section that extends from the base in a vertical direction, the vertical section having a second overall width in the horizontal direction, the first overall width of the base being greater than the second overall width of the vertical section such that an inner portion of each base extends inwards from the vertical section and an outer portion of each base extends outwards from the vertical section;
• one or a plurality of layers disposed on the MQW to provide a mesa structure, wherein an overall width of the mesa structure in a horizontal direction is greater than an overall width of the MQW in the horizontal direction, wherein the inside portion of the base of each of the first and second dielectric structures underlies and supports the mesa structure;
• and
• wherein the MQW is disposed between the bases of the first and second dielectric structures and the mesa structure is disposed between the vertical sections of the first and second dielectric structures to provide dielectric current confinement.