Patents by Inventor Ligeng Xu

Ligeng Xu 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).

  • Photonic integration using a twin waveguide structure
    Patent number: 5859866
    Abstract: A monolithically integrated vertical twin-waveguide structure reduces the sensitivity of the device performance characteristics due to the laser cavity length and variations in the layer structure. This is achieved by the introduction of an absorption or loss layer between the active and passive regions. This layer eliminates the propagation of the even mode, while having minimal effect on the odd mode. The threshold current densities and differential efficiencies of the devices are unaffected by the loss layer. A coupling efficiency of 45% from the laser to the external passive waveguide is obtained.
    Type: Grant
    Filed: February 7, 1997
    Date of Patent: January 12, 1999
    Assignee: The Trustees of Princeton University
    Inventors: Stephen Forrest, Chih-Ping Chao, Miland Gokhale, Ligeng Xu