Patents by Inventor Richard T. Sahara

Richard T. Sahara 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: 6891870
    Abstract: An integrated semiconductor device comprising a laser on a substrate, the laser having an active layer and a current-induced grating, such as a current-injection complex-coupled grating, within a laser cavity producing a single-mode output light signal at high data rates (>622 Mb/sec) in isolator-free operation. The grating has a coupling strength product ?L greater than 3, where ? is the coupling coefficient and L is the length of the laser cavity. In certain embodiments, the laser is a distributed feedback (DFB) laser that emits light at a wavelength of about 1.5 ?m. The strong current-induced grating prevents mode hopping between multiple degenerate Bragg modes. The laser is also characterized by excellent immunity from optical feedback, and can be operated without an isolator at high data rates.
    Type: Grant
    Filed: November 9, 2001
    Date of Patent: May 10, 2005
    Assignee: Corning Lasertron, Inc.
    Inventors: Richard T. Sahara, Angela Hohl-Abichedid, Hanh Lu
  • Patent number: 6650675
    Abstract: An integrated semiconductor device comprising a wavelength-tunable laser, such as a distributed Bragg reflector (DBR) laser, where the laser has a gain section that includes an active layer, and a grating section that includes an active layer and a current-induced grating. A first electrical contact is provided over the gain section to supply current to the gain section and control the output power of the light, and a second electrical contact is provided over the grating section to supply current to the grating section and control the wavelength of the emitted light. The current-induced grating of the present device causes gain in the active layer of the laser to be modulated spatially in the direction of light propagation, thus resulting in only one of the degenerate Bragg modes to oscillate. As the degeneracy of the Bragg modes is broken by current-injection, and not facet reflection, substantially continuous wavelength tuning is possible without the deleterious phenomenon of “mode hopping.
    Type: Grant
    Filed: November 9, 2001
    Date of Patent: November 18, 2003
    Assignee: Corning Lasertron, Incorporated
    Inventors: Richard T. Sahara, Randal A. Salvatore, Hanh Lu
  • Patent number: 6574260
    Abstract: An integrated electroabsorption modulated laser (EML) device includes a distributed feedback (DFB) laser and modulator. The DFB laser includes an active layer and a complex index grating. The modulator includes an active layer. The EML device includes a first electrical contact over the DFB laser and a second electrical contact over the modulator. The EML device includes a stop etch layer above the active layer of both the DFB laser and the modulator. An electroabsorption modulated partial grating laser (EMPGL) device includes a distributed feedback (DFB) laser, an amplifier and a modulator. An ion implantation region in the EML/EMPGL devices provides electrical isolation between the DFB laser/amplifier and the modulator.
    Type: Grant
    Filed: March 15, 2001
    Date of Patent: June 3, 2003
    Assignee: Corning Lasertron Incorporated
    Inventors: Randal A. Salvatore, Richard T. Sahara, Hanh Lu
  • Publication number: 20030091081
    Abstract: An integrated semiconductor device comprising a laser on a substrate, the laser having an active layer and a current-induced grating, such as a current-injection complex-coupled grating, within a laser cavity producing a single-mode output light signal at high data rates (>622 Mb/sec) in isolator-free operation. The grating has a coupling strength product &kgr;L greater than 3, where &kgr; is the coupling coefficient and L is the length of the laser cavity. In certain embodiments, the laser is a distributed feedback (DFB) laser that emits light at a wavelength of about 1.5 &mgr;m. The strong current-induced grating prevents mode hopping between multiple degenerate Bragg modes. The laser is also characterized by excellent immunity from optical feedback, and can be operated without an isolator at high data rates.
    Type: Application
    Filed: November 9, 2001
    Publication date: May 15, 2003
    Applicant: Corning Lasertron, Inc
    Inventors: Richard T. Sahara, Angela Hohl-Abichedid, Hanh Lu
  • Publication number: 20030091086
    Abstract: An integrated semiconductor device comprising a wavelength-tunable laser, such as a distributed Bragg reflector (DBR) laser, where the laser has a gain section that includes an active layer, and a grating section that includes an active layer and a current-induced grating. A first electrical contact is provided over the gain section to supply current to the gain section and control the output power of the light, and a second electrical contact is provided over the grating section to supply current to the grating section and control the wavelength of the emitted light. The current-induced grating of the present device causes gain in the active layer of the laser to be modulated spatially in the direction of light propagation, thus resulting in only one of the degenerate Bragg modes to oscillate. As the degeneracy of the Bragg modes is broken by current-injection, and not facet reflection, substantially continuous wavelength tuning is possible without the deleterious phenomenon of “mode hopping.
    Type: Application
    Filed: November 9, 2001
    Publication date: May 15, 2003
    Applicant: Corning Lasertron, Inc
    Inventors: Richard T. Sahara, Randal A. Salvatore, Hanh Lu
  • Publication number: 20020131466
    Abstract: An integrated electroabsorption modulated laser (EML) device includes a distributed feedback (DFB) laser and modulator. The DFB laser includes an active layer and a complex index grating. The modulator includes an active layer. The EML device includes a first electrical contact over the DFB laser and a second electrical contact over the modulator. The EML device includes a stop etch layer above the active layer of both the DFB laser and the modulator. An electroabsorption modulated partial grating laser (EMPGL) device includes a distributed feedback (DFB) laser, an amplifier and a modulator. An ion implantation region in the EML/EMPGL devices provides electrical isolation between the DFB laser/amplifier and the modulator.
    Type: Application
    Filed: March 15, 2001
    Publication date: September 19, 2002
    Applicant: Corning Lasertron, Inc.
    Inventors: Randal A. Salvatore, Richard T. Sahara, Hanh Lu