Patents by Inventor Ranko Hatsuda

Ranko Hatsuda 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: 7509014
    Abstract: The present invention intends to provide a two-dimensional photonic crystal having a high level of mechanical strength and functioning as a high-efficiency resonator. The two-dimensional photonic crystal according to the present invention includes a slab layer 31 under which a clad layer 32 is located. In the slab layer 31, areas 35 having a refractive index different from that of the slab layer 31 are cyclically arranged to create a two-dimensional photonic crystal. A portion of the cyclic arrangement of the areas 35 are omitted to form a point-like defect 36. This defect 36 functions as a resonator at which a specific wavelength of light resonates. An air-bridge cavity 37 facing the point-like defect 36 is formed over a predetermined range of the clad layer 32. In this construction, the clad layer 32 supports the slab layer 31 except for the range over which the air-bridge space 37 is formed. Therefore, the two-dimensional photonic crystal has a high level of mechanical strength.
    Type: Grant
    Filed: December 20, 2007
    Date of Patent: March 24, 2009
    Assignees: Kyoto University, TDK Corporation
    Inventors: Ranko Hatsuda, Susumu Noda, Takashi Asano, Yoshinori Tanaka, Eiji Miyai
  • Patent number: 7509013
    Abstract: An objective of the present invention is to provide a two-dimensional photonic crystal in which a complete photonic band gap (PBG), i.e. a photonic band gap that is effective for both a TE-polarized light and a TM-polarized light within a predetermined wavelength range, is created and an adequate width of the complete PBG can be ensured. A slab-shaped body 21 consisting of a birefringent material is provided with holes 22 periodically arranged in a triangular lattice pattern, where a plane shape of the hole is an equilateral triangle. The PBG for the TE-polarized light and the PBG for the TM-polarized light can be independently set by adjusting anisotropy in the refractive index of the body 21, i.e. a refractive index in a direction vertical to the body 21 and a refractive index in a direction parallel to the body 21. This construction makes it possible to ensure an adequate width of the complete PBG.
    Type: Grant
    Filed: January 31, 2006
    Date of Patent: March 24, 2009
    Assignee: TDK Corporation
    Inventors: Susumu Noda, Takashi Asano, Seiichi Takayama, Ranko Hatsuda
  • Publication number: 20080145012
    Abstract: The present invention intends to provide a two-dimensional photonic crystal having a high level of mechanical strength and functioning as a high-efficiency resonator. The two-dimensional photonic crystal according to the present invention includes a slab layer 31 under which a clad layer 32 is located. In the slab layer 31, areas 35 having a refractive index different from that of the slab layer 31 are cyclically arranged to create a two-dimensional photonic crystal. A portion of the cyclic arrangement of the areas 35 are omitted to form a point-like defect 36. This defect 36 functions as a resonator at which a specific wavelength of light resonates. An air-bridge cavity 37 facing the point-like defect 36 is formed over a predetermined range of the clad layer 32. In this construction, the clad layer 32 supports the slab layer 31 except for the range over which the air-bridge space 37 is formed. Therefore, the two-dimensional photonic crystal has a high level of mechanical strength.
    Type: Application
    Filed: December 20, 2007
    Publication date: June 19, 2008
    Applicants: KYOTO UNIVERSITY, TDK CORPORATION
    Inventors: Ranko Hatsuda, Susumu Noda, Takashi Asano, Yoshinori Tanaka, Eiji Miyai
  • Publication number: 20080112679
    Abstract: An objective of the present invention is to provide a two-dimensional photonic crystal in which a complete photonic band gap (PBG), i.e. a photonic band gap that is effective for both a TE-polarized light and a TM-polarized light within a predetermined wavelength range, is created and an adequate width of the complete PBG can be ensured. A slab-shaped body 21 consisting of a birefringent material is provided with holes 22 periodically arranged in a triangular lattice pattern, where a plane shape of the hole is an equilateral triangle. The PBG for the TE-polarized light and the PBG for the TM-polarized light can be independently set by adjusting anisotropy in the refractive index of the body 21, i.e. a refractive index in a direction vertical to the body 21 and a refractive index in a direction parallel to the body 21. This construction makes it possible to ensure an adequate width of the complete PBG.
    Type: Application
    Filed: January 31, 2006
    Publication date: May 15, 2008
    Applicants: KYOTO UNIVERSITY, TDK CORPORATION
    Inventors: Susumu Noda, Takashi Asano, Seiichi Takayama, Ranko Hatsuda
  • Patent number: 7333703
    Abstract: The present invention intends to provide a two-dimensional photonic crystal having a high level of mechanical strength and functioning as a high-efficiency resonator. The two-dimensional photonic crystal according to the present invention includes a slab layer 31 under which a clad layer 32 is located. In the slab layer 31, areas 35 having a refractive index different from that of the slab layer 31 are cyclically arranged to create a two-dimensional photonic crystal. A portion of the cyclic arrangement of the areas 35 are omitted to form a point-like defect 36. This defect 36 functions as a resonator at which a specific wavelength of light resonates. An air-bridge cavity 37 facing the point-like defect 36 is formed over a predetermined range of the clad layer 32. In this construction, the clad layer 32 supports the slab layer 31 except for the range over which the air-bridge space 37 is formed. Therefore, the two-dimensional photonic crystal has a high level of mechanical strength.
    Type: Grant
    Filed: August 27, 2004
    Date of Patent: February 19, 2008
    Assignees: Kyoto University, TDK Corporation
    Inventors: Ranko Hatsuda, Susumu Noda, Takashi Asano, Yoshinori Tanaka, Eiji Miyai
  • Publication number: 20070009219
    Abstract: The present invention intends to provide a two-dimensional photonic crystal having a high level of mechanical strength and functioning as a high-efficiency resonator. The two-dimensional photonic crystal according to the present invention includes a slab layer 31 under which a clad layer 32 is located. In the slab layer 31, areas 35 having a refractive index different from that of the slab layer 31 are cyclically arranged to create a two-dimensional photonic crystal. A portion of the cyclic arrangement of the areas 35 are omitted to form a point-like defect 36. This defect 36 functions as a resonator at which a specific wavelength of light resonates. An air-bridge cavity 37 facing the point-like defect 36 is formed over a predetermined range of the clad layer 32. In this construction, the clad layer 32 supports the slab layer 31 except for the range over which the air-bridge space 37 is formed. Therefore, the two-dimensional photonic crystal has a high level of mechanical strength.
    Type: Application
    Filed: August 27, 2004
    Publication date: January 11, 2007
    Inventors: Ranko Hatsuda, Susumu Noda, Takashi Asano, Yoshinori Tanaka, Eiji Miyai