Claims
- 1. An optical fibre having a plurality of concentric, spaced, light transmission paths, each path for transmission of the same single optical mode, comprising a core and at least three rings surrounding the core, said rings and core of alternate high refractive index light transmitting material and low refractive index cladding material, relative to one another, to provide at least two concentric light transmitting paths separated by cladding material, the cross-sectional area of each light transmitting path defined by:
- V.apprxeq.2(.pi./.lambda.).sqroot.b.sup.2 -a.sup.2 .multidot.NA
- where NA=numerical aperture; a is the inner radius and b is the outer radius of the light transmitting path, .lambda. is the wavelength and V is less than about 2.4.
- 2. An optical fibre as claimed in claim 1, said core and subsequent alternate rings being of cladding material and the intermediate rings of light transmission material to provide said at least two light transmitting paths.
- 3. A fibre as claimed in claim 1, the cross-sectional areas of the light transmitting paths equal and the difference in refractive index between each light path and the related cladding is constant.
- 4. A fibre as claimed in claim 3, the refractive index of each light path different and the cross-sectional area of the light paths different.
- 5. An optical fibre as claimed in claim 1, said core and subsequent alternate rings comprising said light transmission paths, the intermediate rings of cladding material.
- 6. An optical fibre as claimed in claim 5, the core and each light transmitting ring having a reducing radial thickness and a substantially constant relatively higher refractive index.
- 7. An optical fibre as claimed in claim 5, the core and each light transmitting ring of the same radial thickness, the refractive index of the core and light transmitting rings reducing stepwise.
Parent Case Info
This application is a Continuation of application Ser. No. 615,223, filed Sept. 22, 1975.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3157726 |
Hicks, Jr. et al. |
Dec 1964 |
|
4000416 |
Goell |
Dec 1976 |
|
Continuations (1)
|
Number |
Date |
Country |
Parent |
615223 |
Sep 1975 |
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