Optical add/drop multiplexer/demultiplexer
US5959749A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 20, 1997 |
| Grant date | Sep 28, 1999 |
| Priority date | — |
| Expiry date | May 20, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2011/0069
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An add/drop multiplexer/demultiplexer (ADM) for switching, modulating and attenuating optical signals in a fiber optic network employing wavelength division multiplexing (WDM) is disclosed. The ADM is equipped an optical multiplexer for splitting an input WDM signal into individual optical signals, leading to respective 2.times.2 switches. Each switch has another input originating from a plurality of "add lines", and selects one of its inputs to be dropped and the other to continue along a main signal path. The retained signals may be modulated and attenuated prior to being tapped and finally multiplexed together by a WDM multiplexer. The tapped signals are optoelectronically converted and fed back to a controller, preferably a digital signal processor running a software algorithm, which controls the switching, modulation and attenuation. This permits remote control of the ADM functions by encoding instructions for the controller into a low-frequency dither signal that is embedded within the individual optical signals. The ADM can accordingly be instructed to reroute traffic, dynamically equalize or otherwise change optical channel power levels, and add or remove dither, all in rea…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.