Patents by Inventor Sumesh Mani K. Thiyagarajan
Sumesh Mani K. Thiyagarajan 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).
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Patent number: 9157949Abstract: A method of accelerating the aging of a laser to thereby determine the reliability of the laser. The method includes an act of providing a laser die for reliability testing, an act of applying a plurality of short signal pulses to the laser die so as to simulate the aging of the laser die, and an act of ascertaining the reliability of the laser die based on its response to the plurality of short signal pulses.Type: GrantFiled: October 22, 2012Date of Patent: October 13, 2015Assignee: FINISAR CORPORATIONInventor: Sumesh Mani K. Thiyagarajan
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Patent number: 8705582Abstract: In one example embodiment, a DFB laser includes a substrate; an active region positioned above the substrate; a grating layer positioned above the active region, the grating layer including a portion that serves as a primary etch stop layer; a secondary etch stop layer positioned above the grating layer; and a spacer layer interposed between the grating layer and the secondary etch stop layer.Type: GrantFiled: July 1, 2013Date of Patent: April 22, 2014Assignee: Finisar CorporationInventors: Ashish K. Verma, Tsurugi Sudo, Sumesh Mani K. Thiyagarajan, David Bruce Young
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Publication number: 20130287405Abstract: In one example embodiment, a DFB laser includes a substrate; an active region positioned above the substrate; a grating layer positioned above the active region, the grating layer including a portion that serves as a primary etch stop layer; a secondary etch stop layer positioned above the grating layer; and a spacer layer interposed between the grating layer and the secondary etch stop layer.Type: ApplicationFiled: July 1, 2013Publication date: October 31, 2013Inventors: Ashish K. Verma, Tsurugi Sudo, Sumesh Mani K. Thiyagarajan, David Bruce Young
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Patent number: 8477817Abstract: In one example embodiment, a DFB laser includes a substrate, an active region positioned above the substrate, and a grating layer positioned above the active region. The grating layer includes a portion that serves as a primary etch stop layer. The DFB laser also includes a secondary etch stop layer located either above or below the grating layer, and a spacer layer interposed between the grating layer and the active region.Type: GrantFiled: October 11, 2010Date of Patent: July 2, 2013Assignee: Finisar CorporationInventors: Ashish K. Verma, Tsurugi Sudo, Sumesh Mani K. Thiyagarajan, David Bruce Young
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Patent number: 8294484Abstract: A method of accelerating the aging of a laser to thereby determine the reliability of the laser. The method includes an act of providing a laser die for reliability testing, an act of applying a plurality of short signal pulses to the laser die so as to simulate the aging of the laser die, and an act of ascertaining the reliability of the laser die based on its response to the plurality of short signal pulses.Type: GrantFiled: May 30, 2008Date of Patent: October 23, 2012Assignee: Finisar CorporationInventor: Sumesh Mani K. Thiyagarajan
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Patent number: 8085824Abstract: One example disclosed herein relates to a method of at least partially optimizing one or more output performance parameters of a laser die. The method includes an act of identifying one or more output performance parameters to be at least partially optimized, an act of identifying one or more design parameters associated with the one or more output performance parameters, an act of determining a subset of the one or more design parameters that should be varied so as to at least partially effect the one or more output performance parameters, an act of varying the subset of design parameters to produce one or more intermediate results, and an act of using the intermediate results to determine values for the one or more design parameters such that the one or more performance parameters are at least partially optimized.Type: GrantFiled: May 29, 2008Date of Patent: December 27, 2011Assignee: Finisar CorporationInventors: Sumesh Mani K. Thiyagarajan, Ashish K. Verma
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Patent number: 7848375Abstract: Embodiments disclosed herein relate to a laser die. The laser die includes a base epitaxial portion, a mesa portion, and first and second facets, wherein at least one of the first and second facets is flared such that an area of the facet is increased. Embodiments disclosed herein also relate to a high-speed laser. The high-speed laser includes a substrate, an active region positioned above the substrate, a mesa positioned above the active region, and one or more facets, wherein at least one of the one or more facets includes a flared portion configured to increase an area of the facet.Type: GrantFiled: May 30, 2008Date of Patent: December 7, 2010Assignee: Finisar CorporationInventor: Sumesh Mani K. Thiyagarajan
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Patent number: 7813395Abstract: In one example embodiment, a DFB laser includes a substrate, an active region positioned above the substrate, and a grating layer positioned above the active region. The grating layer includes a portion that serves as a primary etch stop layer. The DFB laser also includes a secondary etch stop layer located either above or below the grating layer, and a spacer layer interposed between the grating layer and the active region.Type: GrantFiled: June 12, 2008Date of Patent: October 12, 2010Assignee: Finisar CorporationInventors: Ashish K. Verma, Tsurugi Sudo, Sumesh Mani K. Thiyagarajan, David Bruce Young
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Patent number: 7606279Abstract: Embodiments disclosed herein relate to high-speed lasers such as FP and DFB lasers. In one embodiment, the high speed laser comprises a substrate, an active region positioned above the substrate, a mesa positioned above the active region, and one or more layers disposed between the active region and the mesa, wherein the thickness of at least one of the one or more layers is implemented to at least partially minimize the distance between the mesa and active region such that lateral current spreading between the mesa and the active region is at least partially minimized.Type: GrantFiled: May 15, 2007Date of Patent: October 20, 2009Assignee: Finisar CorporationInventors: Ashish K. Verma, Sumesh Mani K. Thiyagarajan, David Bruce Young, Yuk Lung Ha, Roman Dimitrov
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Patent number: 7567601Abstract: A laser diode having a composite passivation layer configured to control parasitic capacitance, especially in high speed laser applications, is disclosed. In one embodiment, a ridge waveguide laser is disclosed and includes: a substrate, an active layer disposed on the substrate, a ridge structure disposed on the active layer, and a contact layer disposed on the ridge structure. A composite passivation layer is disposed substantially laterally to the ridge structure. The composite passivation layer includes a silicon nitride bottom layer, a silicon nitride top layer, and a silicon dioxide middle layer interposed between the bottom and top layers. The passivation layers possess differing stress components that, when combined, cancel out the overall mechanical stress of the passivation layer. This enables relatively thick passivation layers to be employed in high speed laser diodes without increasing the risk of layer stress cracking and laser damage.Type: GrantFiled: May 15, 2007Date of Patent: July 28, 2009Assignee: Finisar CorporationInventors: Tsurugi Sudo, Ashish Verma, Jing Chai, Sumesh Mani K. Thiyagarajan
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Publication number: 20080301595Abstract: One example disclosed herein relates to a method of at least partially optimizing one or more output performance parameters of a laser die.Type: ApplicationFiled: May 29, 2008Publication date: December 4, 2008Applicant: FINISAR CORPORATIONInventors: Sumesh Mani K. Thiyagarajan, Ashish K. Verma
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Patent number: 6878565Abstract: A distributed feedback (DFB) laser is constructed such that a laser stripe has a minimum tilt angle with respect to a cleaved facet in order to reduce the facet reflectivity. A method for improving the yield of distributed feedback lasers is also provided. The method includes selecting a tilt angle and antireflection coating to achieve a desired effective facet reflectivity. In one embodiment, a range of tilt angles and facet coatings is tested to determine a statistical correlation between yield of a desired laser characteristic, such as side mode suppression ratio, and tilt angle.Type: GrantFiled: October 27, 2003Date of Patent: April 12, 2005Assignee: Finisar CorporationInventor: Sumesh Mani K. Thiyagarajan
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Publication number: 20040131099Abstract: A distributed feedback (DFB) laser is constructed such that a laser stripe has a minimum tilt angle with respect to a cleaved facet in order to reduce the facet reflectivity. A method for improving the yield of distributed feedback lasers is also provided. The method includes selecting a tilt angle and antireflection coating to achieve a desired effective facet reflectivity. In one embodiment, a range of tilt angles and facet coatings is tested to determine a statistical correlation between yield of a desired laser characteristic, such as side mode suppression ratio, and tilt angle.Type: ApplicationFiled: October 27, 2003Publication date: July 8, 2004Applicant: Finisar CorporationInventor: Sumesh Mani K. Thiyagarajan