Optical fiber

• US 6,404,966 B1
• Filed: 05/06/1999
• Issued: 06/11/2002
• Est. Priority Date: 05/07/1998
• Status: Active Grant

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Kawanishi, Satoki, Okamoto, Katsunari
• Primary Examiner(s): Kim, Robert H.
• Assistant Examiner(s): MERLINO, AMANDA H
• Application Number:
  US09/306,498
• Time in Patent Office: 1,132 Days
• Field of Search: 385/123-128, 385/37
• US Class Current: 385/125
• CPC Class Codes: C03B 2201/12 doped with fluorine C03B2201/14 takes precedence
• CPC Class Codes: C03B 2201/28 doped with phosphorus
• CPC Class Codes: C03B 2203/10 Internal structure or shape details
• CPC Class Codes: C03B 2203/16 Hollow core
• CPC Class Codes: C03B 2203/30 Polarisation maintaining [PM], i.e. birefringent products, e.g. with elliptical core, by use of stress rods, "PANDA" type fibres
• CPC Class Codes: C03B 2203/42 Photonic crystal fibres, e.g. fibres using the photonic bandgap PBG effect, microstructured or holey optical fibres
• CPC Class Codes: C03B 37/01205 starting from tubes, rods, fibres or filaments C03B37/014 takes precedence
• CPC Class Codes: G02B 6/02328 Hollow or gas filled core
• CPC Class Codes: G02B 6/02333 Core having higher refractive index than cladding, e.g. solid core, effective index guiding
• CPC Class Codes: G02B 6/02347 Longitudinal structures arranged to form a regular periodic lattice, e.g. triangular, square, honeycomb unit cell repeated throughout cladding
• CPC Class Codes: G02B 6/105 having optical polarisation effects

Abstract

An optical fiber including a core having an area of about several times an optical wavelength and composed of a hollow hole, and a cladding having a diffraction grating which is arranged at least in a peripheral area adjacent to the core and has a grating period equal to ½ the optical wavelength.

Claims

1. A single mode optical fiber comprising:

a core having an area of several times an optical wavelength; and

a cladding disposed around said core in which a diffraction grating is arranged at least in a peripheral area adjacent to said core and forms a photonic band gap;

wherein the refractive index of said core is lower than that of said cladding.

2. The single mode optical fiber as claimed in claim 1, wherein said diffraction grating in said cladding comprises a grating structure in which a high refractive index material is embedded in a low refractive index medium.

3. The single mode optical fiber as claimed in claim 1, where said diffraction grating in said cladding comprises a grating structure in which a low refractive index material is embedded in a high refractive index medium.

8. The single mode optical fiber as claimed in claim 1, wherein said diffraction grating comprises a grating structure arranged in the form of a matrix.

9. The single mode optical fiber as claimed in claim 1, wherein said diffraction grating comprises a grating structure arranged in the form of a triangle.

10. The single mode optical fiber as claimed in claim 1, wherein said diffraction grating comprises a grating structure arranged in the form of a honeycomb.

11. The single mode optical fiber as claimed in claim 1, wherein said diffraction grating comprises a grating structure arranged in the form of a matrix, and has a grating of a columnar or circular hole shape.

12. The single mode optical fiber as claimed in claim 1, wherein said diffraction grating comprises a grating structure arranged in the form of a triangle, and has a grating of a columnar or circular hole shape.

13. The single mode optical fiber as claimed in claim 1, wherein said diffraction grating comprises a grating structure arranged in the form of a honeycomb form, and has a grating of a columnar or circular hole shape.

14. The single mode optical fiber as claimed in claim 1, wherein the cladding has an entire area and the entire area of said cladding comprises a diffraction grating forming said photonic band gap.

4. An optical fiber comprising:

a hollow core having an area of several times an optical wavelength; and

a cladding disposed around said core in which a diffraction grating is arranged at least in a peripheral area adjacent to said core and has a grating period equal to ½

the optical wavelength.

5. The optical fiber as claimed in claim 4, wherein said diffraction grating in said cladding comprises a grating structure in which a high refractive index material is embedded in a low refractive index medium.

6. The optical fiber as claimed in claim 4, wherein said diffraction grating in said cladding comprises a grating structure in which a low refractive index material is embedded in a high refractive index medium.

7. An optical fiber comprising:

a core having an area of several times an optical wavelength; and

a cladding disposed around said core in which a diffraction grating is arranged at least in a peripheral area adjacent to said core and has a grating period equal to ½

the optical wavelength,

wherein said core and said cladding medium are equal in refractive index, and said diffraction grating in said cladding is constructed by a grating structure in which a high refractive index material is embedded in a low refractive index medium.

15. The optical fiber as claimed in claim 7, wherein said grating structure is arranged in the form of a matrix.

16. The optical fiber as claimed in claim 7, wherein said grating structure is arranged in the form of a triangle.

17. The optical fiber as claimed in claim 7, wherein said grating structure is arranged in the form of a honeycomb.

18. The optical fiber as claimed in claim 7, wherein said grating structure is arranged in the form of a matrix, and has a grating of a columnar or circular hole shape.

19. The optical fiber as claimed in claim 7, wherein said grating structure is arranged in the form of a triangle, and has a grating of a columnar or circular hole shape.

20. The optical fiber as claimed in claim 7, wherein said grating structure is arranged in the form of a honeycomb form, and has a grating of a columnar or circular hole shape.

21. The optical fiber as claimed in claim 7, wherein the entire area of said cladding comprises a diffraction grating having a grating period equal to ½

the optical wavelength.

22. A single mode optical fiber comprising:

a hollow core having an area of several times an optical wavelength; and

a cladding disposed around said core in which a diffraction grating is arranged at least in a peripheral area adjacent to said core and forms a photonic band gap.

23. The single mode optical fiber as claimed in claim 22, wherein said diffraction grating in said cladding comprises a grating structure in which a high refractive index material is embedded in a low refractive index medium.

24. The single mode optical fiber as claimed in claim 22, wherein said diffraction grating in said cladding comprises a grating structure in which a low refractive index material is embedded in a high refractive index medium.

25. A single mode optical fiber comprising:

a core having an area of several times an optical wavelength; and

a cladding disposed around said core in which a diffraction grating is arranged at least in a peripheral area adjacent to said core and forms a photonic band gap;

wherein said core and said cladding medium are equal in refractive index, and said diffraction grating in said cladding is constructed by a grating structure in which a high refractive index material is embedded in a low refractive index medium.

26. The single mode optical fiber as claimed in claim 25, wherein said grating structure is arranged in the form of a matrix.

27. The single mode optical fiber as claimed in claim 25, wherein said grating structure is arranged in the form of a triangle.

28. The single mode optical fiber as claimed in claim 25, wherein said grating structure is arranged in the form of a honeycomb.

29. The single mode optical fiber as claimed in claim 25, wherein said grating structure is arranged in the form of a matrix, and has a grating of a columnar or circular hole shape.

30. The single mode optical fiber as claimed in claim 25, wherein said grating structure is arranged in the form of a triangle, and has a grating of a columnar or circular hole shape.

31. The single mode optical fiber as claimed in claim 25, wherein said grating structure is arranged in the form of a honeycomb form, and has a grating of a columnar or circular hole shape.

32. The single mode optical fiber as claimed in claim 25, wherein the cladding has an entire area and the entire area of said cladding comprises said diffraction grating forming said photonic band gap.