Patents by Inventor Kalpendu R. Shastri

Kalpendu R. Shastri 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: 5043992
    Abstract: A laser driver includes a reference circuit, which may be a bandgap reference, mounted in thermal contact with the laser. The reference produces a current component Iptat that is proportional to the absolute temperature. The modulation current is proportional to Iptat, which slowly with temperature, up to a certain junction temperature (e.g., 65 to 70 degrees C.). Above that temperature, the modulation current increases more rapidly by adding an additional current component Icomp. This provides for the required increase in modulation current to compensate for temperature variations in the laser output. This technique allows the laser to be operated without cooling (as by a thermoelectric cooler) in many applications. The laser driver may optionally include circuitry to provide a bias current, which may be controlled by a backface monitor or threshold detector.
    Type: Grant
    Filed: October 6, 1989
    Date of Patent: August 27, 1991
    Assignee: AT&T Bell Laboratories
    Inventors: James J. Royer, Kalpendu R. Shastri