Optical fibre network
First Claim
1. An optical fiber network comprising a length of single mode optical fiber having a core and cladding thereon, means for transmitting continuous wave optical power through the fiber from one or both of its ends, and non-intrusive node means associated with the fiber, the node means including transducer means, for introducing information into the fiber by modulating the optical power being transmitted therethrough, and the node means including tapping means for extracting information from the fiber, wherein the transducer means and the tapping means involve periodic gratings and are such as to provide wavelength dependent resonant mode coupling between the guided mode in the core and a mode or modes in the cladding of the optical fiber whereby the modulation and tapping at the node means is wavelength selective, information being introduced into and extracted from the optical fiber at the node means by said mode coupling.
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Accused Products
Abstract
An optical fibre network which does not require the fibre (1) to be broken to introduce new terminals (nodes) (3). Information is introduced into the fibre by modulating, particularly by modulating mode coupling, optical power transmitted into the fibre from a source at one or both of its ends. The nodes include tapping means for extracting information. If resonant mode coupling is employed a common grating may be used for introducing and extracting information. Such a non-intrusive network may be overlaid on a conventional local area optical network between two nodes thereof, the fibre being common to both networks. The nodes of the conventional network communicate in one direction along the fibre, whereas the nodes of the non-intrusive network communicate in the opposite direction along the fibre.
25 Citations
8 Claims
- 1. An optical fiber network comprising a length of single mode optical fiber having a core and cladding thereon, means for transmitting continuous wave optical power through the fiber from one or both of its ends, and non-intrusive node means associated with the fiber, the node means including transducer means, for introducing information into the fiber by modulating the optical power being transmitted therethrough, and the node means including tapping means for extracting information from the fiber, wherein the transducer means and the tapping means involve periodic gratings and are such as to provide wavelength dependent resonant mode coupling between the guided mode in the core and a mode or modes in the cladding of the optical fiber whereby the modulation and tapping at the node means is wavelength selective, information being introduced into and extracted from the optical fiber at the node means by said mode coupling.
Specification