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Electromagnetic wave frequency filter

Foreign code F110005596
File No. A112-33US
Posted date Sep 9, 2011
Country United States of America
Application number 54077603
Gazette No. 20060098918
Gazette No. 7184638
Date of filing Dec 24, 2003
Gazette Date May 11, 2006
Gazette Date Feb 27, 2007
International application number JP2003016515
International publication number WO2004068205
Date of international filing Dec 24, 2003
Date of international publication Aug 12, 2004
Priority data
  • P2002-378438 (Dec 26, 2002) JP
  • 2003WO-JP16515 (Dec 24, 2003) WO
Title Electromagnetic wave frequency filter
Abstract (US7184638)
The present invention aims to provide an electromagnetic wave frequency filter capable of transmitting an electromagnetic wave having a predetermined frequency between two waveguides with a high level of efficiency.
This object is achieved by the following construction: A resonator 15 that resonates with the electromagnetic wave having the predetermined frequency is located between an input waveguide 13 and an output waveguide 14 and close to the two waveguides.
The output waveguide 14 is designed so that it extends parallel to the input waveguide 13 within a predetermined section 18 located in proximity to the resonator 15 , and its distance from the input waveguide 13 in the other section is larger than that in the predetermined section 18 .
This construction allows the electromagnetic wave having the predetermined frequency to be transmitted between the input waveguide 13 and the output waveguide 14 via the resonator 15 , while preventing the other electromagnetic waves having different frequencies from being transmitted between the input waveguide 13 and the output waveguide 14 outside of the predetermined section 18 .
The present electromagnetic wave frequency filter can be preferably constructed using a two-dimensional photonic crystal.
Scope of claims [claim1]
1. An electromagnetic wave frequency filter, comprising:
a) a two-dimensional photonic crystal having a slab-shaped body provided with a plurality of modified refractive index areas having a refractive index different from that of the body, which are periodically arranged in the body;
b) an input waveguide defined by a linear defect of the modified refractive index areas;c) an output waveguide defined by a linear defect of the modified refractive index areas, which is positioned so that its distance from the input waveguide at a predetermined section along its length is shorter than its distance at another section;
and
d) a resonator consisting of a point-like defect that resonates with an electromagnetic wave having a predetermined frequency, which is located within the predetermined section between the input waveguide and the output waveguide.
[claim2]
2. The electromagnetic wave frequency filter according to claim 1, wherein the point-like defect is a donor type point-like defect defined by a defect of the modified refractive index areas.
[claim3]
3. The electromagnetic wave frequency filter according to claim 1, wherein at least one of the resonators is partly or entirely created from a material whose refractive index changes due to an external operation.
[claim4]
4. The electromagnetic wave frequency filter according to claim 1, wherein the output waveguide is provided with a reflector for reflecting the electromagnetic wave having frequency equal to the resonant frequency of the resonator, and the distance between the resonator and the reflector is determined so that a phase distance between the electromagnetic wave reflected by the resonator and the electromagnetic wave reflected by the reflector is pi .
[claim5]
5. The electromagnetic wave frequency filter according to claim 1, wherein at least one resonator radiates a portion of the electromagnetic wave resonating.
[claim6]
6. The electromagnetic wave frequency filter according to claim 1, comprising: multiple output waveguides;
and multiple resonators, each of which is located within a predetermined section between the input waveguide and each output waveguide and resonates with an electromagnetic wave having a predetermined frequency.
[claim7]
7. The electromagnetic wave frequency filter according to claim 6, wherein each of the resonators corresponding to each of the output waveguides has a different resonant frequency.
[claim8]
8. The electromagnetic wave frequency filter according to claim 1, wherein one or both of the input waveguide and the output waveguide has a bend section at an end of the predetermined section.
[claim9]
9. The electromagnetic wave frequency filter according to claim 8, wherein the resonant frequency of the resonator is included in a high-transmission band of the bend section.
[claim10]
10. The electromagnetic wave frequency filter according to claim 9, wherein the modified index area at the bend section differs from the other modified index areas in one or more of its refractive index, cycle, shape and size.
[claim11]
11. The electromagnetic wave frequency filter according to claim 1, wherein the output waveguide is provided with a reflector for reflecting the electromagnetic wave having frequency equal to the resonant frequency of the resonator, and the distance between the resonator and the reflector is determined so that a phase distance between the electromagnetic wave introduced from the resonator into the output waveguide and the electromagnetic wave reflected by the reflector is zero.
[claim12]
12. The electromagnetic wave frequency filter according to claim 11, wherein the reflector consists of one of the following parts: an end of the output waveguide;
a bend section formed at an end of the predetermined section;
an end section formed at a position outside the predetermined section;
and a boundary of an adjacent forbidden band region located on said one side.
[claim13]
13. An electromagnetic wave frequency filter, comprising:
a) a two-dimensional photonic crystal having an in-plane heterostructure, which includes: a slab-shaped body provided with two or more forbidden band regions;
and
a plurality of modified refractive index areas having a refractive index different from that of the body, which are periodically arranged within each of the forbidden band regions with a cycle that is differently determined for each of the forbidden band regions;
b) an input waveguide passing through all the forbidden band regions defined by a linear defect of the modified refractive index areas within each of the forbidden band regions;c) an output waveguide defined by a linear defect of the modified refractive index areas within each of the forbidden band regions, which is positioned so that its distance from the input waveguide at a predetermined section along its length is shorter than its distance at another section;
and
d) a resonator consisting of a point-like defect that resonates with an electromagnetic wave having a predetermined frequency, which is located between the input waveguide and the output waveguide within the predetermined section.
[claim14]
14. The electromagnetic wave frequency filter according to claim 13, wherein the point-like defect is a donor type point-like defect defined by a defect of the modified refractive index areas.
[claim15]
15. The electromagnetic wave frequency filter according to claim 13, wherein a portion of a transmission band of the input waveguide in each forbidden band region is outside a transmission band of the input waveguide in all the other forbidden band regions located on one side of the forbidden band region concerned, whereas the same portion is included in the transmission band of the input waveguide in all the other forbidden band regions on the other side, and the resonant frequency of the resonator located within the forbidden band region concerned is included in the aforementioned portion of the transmission band.
[claim16]
16. The electromagnetic wave frequency filter according to claim 15, wherein, for each forbidden band region, the distance between the resonator belonging to the forbidden band region and a boundary with an adjacent forbidden band region located on said one side is determined so that a phase difference between an electromagnetic wave having frequency equal to the resonant frequency of the resonator of the forbidden band region concerned and being reflected by the resonator and an electromagnetic wave having the same frequency and being reflected by the boundary of the forbidden band region after passing by the resonator is pi .
[claim17]
17. The electromagnetic wave frequency filter according to claim 12, wherein the point-like defect is a donor type cluster defect defined by three defects of three modified index areas located on a straight line.
  • Inventor, and Inventor/Applicant
  • NODA SUSUMU
  • ASANO TAKASHI
  • TAKANO HITOMICHI
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
  • PANASONIC ELECTRIC WORKS
IPC(International Patent Classification)
Reference ( R and D project ) CREST Function Evolution of Materials and Devices based on Electron/Photon Related Phenomena AREA
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