Patents by Inventor Ravi B. Mullapudi
Ravi B. Mullapudi 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: 8105466Abstract: A biased pulse DC reactor for sputtering of oxide films is presented. The biased pulse DC reactor couples pulsed DC at a particular frequency to the target through a filter which filters out the effects of a bias power applied to the substrate, protecting the pulsed DC power supply. Films deposited utilizing the reactor have controllable material properties such as the index of refraction. Optical components such as waveguide amplifiers and multiplexers can be fabricated using processes performed on a reactor according to the present invention.Type: GrantFiled: July 27, 2005Date of Patent: January 31, 2012Assignee: SpringWorks, LLCInventors: Hongmei Zhang, Mukundan Narasimhan, Ravi B. Mullapudi, Richard E. Demaray
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Patent number: 7544276Abstract: A biased pulse DC reactor for sputtering of oxide films is presented. The biased pulse DC reactor couples pulsed DC at a particular frequency to the target through a filter which filters out the effects of a bias power applied to the substrate, protecting the pulsed DC power supply. Films deposited utilizing the reactor have controllable material properties such as the index of refraction. Optical components such as waveguide amplifiers and multiplexers can be fabricated using processes performed on a reactor according to the present invention.Type: GrantFiled: September 16, 2005Date of Patent: June 9, 2009Assignee: SpringWorks, LLCInventors: Hongmei Zhang, Mukundan Narasimhan, Ravi B. Mullapudi, Richard E. Demaray
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Patent number: 7469558Abstract: An as-deposited waveguide structure is formed by a vapor deposition process without etching of core material. A planar optical device of a lighthouse design includes a ridge-structured lower cladding layer of a low refractive index material. The lower cladding layer has a planar portion and a ridge portion extending above the planar portion. A core layer of a core material having a higher refractive index than the low refractive index material of the lower cladding layer overlies the top of the ridge portion of the lower cladding. A slab layer of the core material overlies the planar portion of the lower cladding layer. The lighthouse waveguide also includes a top cladding layer of a material having a lower refractive index than the core material, overlying the core layer and the slab layer. A method of forming an as-deposited waveguide structure includes first forming a ridge structure in a layer of low refractive index material to provide a lower cladding layer.Type: GrantFiled: July 10, 2001Date of Patent: December 30, 2008Assignee: SpringWorks, LLCInventors: Richard E. Demaray, Kai-An Wang, Ravi B. Mullapudi, Qing Zhu, Hongmei Zhang, Harold D. Ackler, John C. Egermeier, Rajiv Pethe
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Patent number: 7413998Abstract: A biased pulse DC reactor for sputtering of oxide films is presented. The biased pulse DC reactor couples pulsed DC at a particular frequency to the target through a filter which filters out the effects of a bias power applied to the substrate, protecting the pulsed DC power supply. Films deposited utilizing the reactor have controllable material properties such as the index of refraction. Optical components such as waveguide amplifiers and multiplexers can be fabricated using processes performed on a reactor according to the present invention.Type: GrantFiled: September 16, 2005Date of Patent: August 19, 2008Assignee: SpringWorks, LLCInventors: Hongmei Zhang, Mukundan Narasimhan, Ravi B. Mullapudi, Richard E. Demaray
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Patent number: 7381657Abstract: A biased pulse DC reactor for sputtering of oxide films is presented. The biased pulse DC reactor couples pulsed DC at a particular frequency to the target through a filter which filters out the effects of a bias power applied to the substrate, protecting the pulsed DC power supply. Films deposited utilizing the reactor have controllable material properties such as the index of refraction. Optical components such as waveguide amplifiers and multiplexers can be fabricated using processes performed on a reactor according to the present inention.Type: GrantFiled: October 1, 2004Date of Patent: June 3, 2008Assignee: SpringWorks, LLCInventors: Hongmei Zhang, Mukundan Narasimhan, Ravi B. Mullapudi, Richard E. Demaray
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Patent number: 7378356Abstract: A biased pulse DC reactor for sputtering of oxide films is presented. The biased pulse DC reactor couples pulsed DC at a particular frequency to the target through a filter which filters out the effects of a bias power applied to the substrate, protecting the pulsed DC power supply. Films deposited utilizing the reactor have controllable material properties such as the index of refraction. Optical components such as waveguide amplifiers and multiplexers can be fabricated processes performed on a reactor according to the present inention.Type: GrantFiled: March 16, 2002Date of Patent: May 27, 2008Assignee: SpringWorks, LLCInventors: Hongmei Zhang, Mukundan Narasimhan, Ravi B. Mullapudi, Richard E. Demaray
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Patent number: 6827826Abstract: Physical vapor deposition processes provide optical materials with controlled and uniform refractive index that meet the requirements for active and passive planar optical devices. All processes use radio frequency (RF) sputtering with a wide area target, larger in area than the substrate on which material is deposited, and uniform plasma conditions which provide uniform target erosion. In addition, a second RF frequency can be applied to the sputtering target and RF power can be applied to the substrate producing substrate bias. Multiple approaches for controlling refractive index are provided. The present RF sputtering methods for material deposition and refractive index control are combined with processes commonly used in semiconductor fabrication to produce planar optical devices such surface ridge devices, buried ridge devices and buried trench devices. A method for forming composite wide area targets from multiple tiles is also provided.Type: GrantFiled: November 4, 2002Date of Patent: December 7, 2004Assignee: Symmorphix, Inc.Inventors: Richard E. Demaray, Kai-An Wang, Ravi B. Mullapudi, Douglas P. Stadtler, Hongmei Zhang, Rajiv Pethe
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Publication number: 20030175142Abstract: A target material for deposition of rare-earth doped optical materials is described. The rare-earth ions, for example erbium and ytterbium, is prealloyed with host materials. In some embodiments a ceramic target material can be formed by pre-alloying Er2O3 and/or Yb2O3 with Al2O3 and/or SiO2. In some embodiments, a metal target material can be formed by pre-alloying Er and/or Yb with Al and/or Si. In some embodiments, ceramic or metallic tiles are formed which can be mounted on a backing plate. In some embodiments, an intermetallic mixture can be formed and flame sprayed onto the backing plate.Type: ApplicationFiled: March 16, 2002Publication date: September 18, 2003Inventors: Vassiliki Milonopoulou, Richard E. Demerary, Ravi B. Mullapudi
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Publication number: 20030173207Abstract: A biased pulse DC reactor for sputtering of oxide films is presented. The biased pulse actor couples pulsed DC at a particular frequency to the target through a filter which filters effects of a bias power applied to the substrate, protecting the pulsed DC power supply. deposited utilizing the reactor have controllable material properties such as the index of ion. Optical components such as waveguide amplifiers and multiplexers can be fabricated processes performed on a reactor according to the present inention.Type: ApplicationFiled: March 16, 2002Publication date: September 18, 2003Applicant: Symmorphix, Inc.Inventors: Hongmei Zhang, Mukundan Narasimhan, Ravi B. Mullapudi, Richard E. Demaray
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Publication number: 20030127319Abstract: Physical vapor deposition processes provide optical materials with controlled and uniform refractive index that meet the requirements for active and passive planar optical devices. All processes use radio frequency (RF) sputtering with a wide area target, larger in area than the substrate on which material is deposited, and uniform plasma conditions which provide uniform target erosion. In addition, a second RF frequency can be applied to the sputtering target and RF power can be applied to the substrate producing substrate bias. Multiple approaches for controlling refractive index are provided. The present RF sputtering methods for material deposition and refractive index control are combined with processes commonly used in semiconductor fabrication to produce planar optical devices such surface ridge devices, buried ridge devices and buried trench devices. A method for forming composite wide area targets from multiple tiles is also provided.Type: ApplicationFiled: November 4, 2002Publication date: July 10, 2003Inventors: Richard E. Demaray, Kai-An Wang, Ravi B. Mullapudi, Douglas P. Stadtler, Hongmei Zhang, Rajiv Pethe
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Publication number: 20030063883Abstract: An as-deposited waveguide structure is formed by a vapor deposition process without etching of core material. A planar optical device of a lighthouse design includes a ridge-structured lower cladding layer of a low refractive index material. The lower cladding layer has a planar portion and a ridge portion extending above the planar portion. A core layer of a core material having a higher refractive index than the low refractive index material of the lower cladding layer overlies the top of the ridge portion of the lower cladding. A slab layer of the core material overlies the planar portion of the lower cladding layer. The lighthouse waveguide also includes a top cladding layer of a material having a lower refractive index than the core material, overlying the core layer and the slab layer. A method of forming an as-deposited waveguide structure includes first forming a ridge structure in a layer of low refractive index material to provide a lower cladding layer.Type: ApplicationFiled: July 10, 2001Publication date: April 3, 2003Inventors: Richard E. Demaray, Kai-An Wang, Ravi B. Mullapudi, Qing Zhu, Hongmei Zhang, Harold D. Ackler, John C. Egermeier, Rajiv Pethe
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Patent number: 6533907Abstract: A specialized physical vapor deposition process provides dense amorphous semiconducting material with exceptionally smooth morphology. In particular, the process provides dense, smooth amorphous silicon useful as a hard mask for etching optical and semiconductor devices and as a high refractive index material in optical devices. DC sputtering of a planar target of intrinsic crystalline semiconducting material in the presence of a sputtering gas under a condition of uniform target erosion is used to deposit amorphous semiconducting material on a substrate. DC power that is modulated by AC power is applied to the target. The process provides dense, smooth amorphous silicon at high deposition rates. A method of patterning a material layer including forming a hard mask layer of amorphous silicon on a material layer according to the present DC sputtering process is also provided.Type: GrantFiled: January 19, 2001Date of Patent: March 18, 2003Assignee: Symmorphix, Inc.Inventors: Richard E. Demaray, Jesse Shan, Kai-An Wang, Ravi B. Mullapudi
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Patent number: 6506289Abstract: Physical vapor deposition processes provide optical materials with controlled and uniform refractive index that meet the requirements for active and passive planar optical devices. All processes use radio frequency (RF) sputtering with a wide area target, larger in area than the substrate on which material is deposited, and uniform plasma conditions which provide uniform target erosion. In addition, a second RF frequency can be applied to the sputtering target and RF power can be applied to the substrate producing substrate bias. Multiple approaches for controlling refractive index are provided. The present RF sputtering methods for material deposition and refractive index control are combined with processes commonly used in semiconductor fabrication to produce planar optical devices such surface ridge devices, buried ridge devices and buried trench devices. A method for forming composite wide area targets from multiple tiles is also provided.Type: GrantFiled: July 10, 2001Date of Patent: January 14, 2003Assignee: Symmorphix, Inc.Inventors: Richard E. Demaray, Kai-An Wang, Ravi B. Mullapudi, Douglas P. Stadtler, Hongmei Zhang, Rajiv Pethe
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Publication number: 20020134671Abstract: A specialized physical vapor deposition process provides dense amorphous semiconducting material with exceptionally smooth morphology. In particular, the process provides dense, smooth amorphous silicon useful as a hard mask for etching optical and semiconductor devices and as a high refractive index material in optical devices. DC sputtering of a planar target of intrinsic crystalline semiconducting material in the presence of a sputtering gas under a condition of uniform target erosion is used to deposit amorphous semiconducting material on a substrate. DC power that is modulated by AC power is applied to the target. The process provides dense, smooth amorphous silicon at high deposition rates. A method of patterning a material layer including forming a hard mask layer of amorphous silicon on a material layer according to the present DC sputtering process is also provided.Type: ApplicationFiled: January 19, 2001Publication date: September 26, 2002Inventors: Richard E. Demaray, Jesse Shan, Kai-An Wang, Ravi B. Mullapudi
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Publication number: 20020033330Abstract: Physical vapor deposition processes provide optical materials with controlled and uniform refractive index that meet the requirements for active and passive planar optical devices. All processes use radio frequency (RF) sputtering with a wide area target, larger in area than the substrate on which material is deposited, and uniform plasma conditions which provide uniform target erosion. In addition, a second RF frequency can be applied to the sputtering target and RF power can be applied to the substrate producing substrate bias. Multiple approaches for controlling refractive index are provided. The present RF sputtering methods for material deposition and refractive index control are combined with processes commonly used in semiconductor fabrication to produce planar optical devices such surface ridge devices, buried ridge devices and buried trench devices. A method for forming composite wide area targets from multiple tiles is also provided.Type: ApplicationFiled: July 10, 2001Publication date: March 21, 2002Inventors: Richard E. Demaray, Kai-An Wang, Ravi B. Mullapudi, Douglas P. Stadtler, Hongmei Zhang, Rajiv Pethe