Optical system with tunable in-fiber gratings
US5579143A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 4, 1993 |
| Grant date | Nov 26, 1996 |
| Priority date | — |
| Expiry date | Jun 4, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J14/0226
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical cable television system provides a large channel capacity and uses shared resources, whereby the more expensive hardware is shared over a large number of customers so as to minimize the cost per customer. A video switch network is provided which minimizes the temptation of subscribers to pirate signals since pay per view or on demand signals are provided only upon request of someone within a node corresponding to a neighborhood. An on demand program center continuously plays programs, such as movies, at time-staggered starts such that any subscriber will have only Very minimal delays before seeing a particular program which is requested. A tuneable optical filter is provided in order to switch video signals onto an optical fiber going to the node in a particular neighborhood. An arrangement uses in-fiber grating in order to remove and insert different optical frequencies. Local insertion of various program sources, such as local commercials, is accomplished effectively by making such insertion at a relatively high point in the video distribution chain. An interface arrangement to provide on demand video signals to telephone company twisted pair wires is utilized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.