Patents by Inventor Spilios Riyopoulos

Spilios Riyopoulos has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6913940
    Abstract: A semiconductor laser, for example a Vertical Cavity Surface Emitting Laser (VCSEL), includes one or more photoactive layers to improve the fundamental mode operation of lasing. The photoactive layer(s) provides on-axis current channeling, resulting from the selective drop in resistance around the center of the photoactive layer(s) due to photo-excitation, and counteracts “hole burning” (i.e., carrier depletion) of the center axis region of the VCSEL cylinder. The photoactive layer(s) act as a variable resistivity screen(s) whose radial aperture is controlled by the light itself. The absorption of a small traction of the light intensity suffices for significant on-axis current peaking with minimum efficiency loss and optical mode distortion. Thus, the VCSEL has optically pumped photoactive layers that induce significant, self-regulated, on-axis current channeling and fundamental mode stability at high operation current, improving lasing operation.
    Type: Grant
    Filed: May 14, 2004
    Date of Patent: July 5, 2005
    Assignee: Science Applications International Corporation
    Inventor: Spilios Riyopoulos