Tunable add drop optical filtering method and apparatus
US5488500A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 31, 1994 |
| Grant date | Jan 30, 1996 |
| Priority date | — |
| Expiry date | Aug 31, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2011/0032
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The present invention includes a tunable add/drop filter that utilizes the unique operational characteristics of a wavelength grating router. The filter comprises a 1.times.N switch, a wavelength grating router (WGR) having a plurality of inputs and outputs, and a multiplexer. The WGR demultiplexes an incoming wavelength division multiplexed (WDM) signal, providing the frequency components of the WDM signal at different outputs. The WGR outputs include a set of retain outputs that are coupled directly to the multiplexer and a drop output that is connected to a drop line. The particular WDM signal frequency component that is provided to the drop output depends directly on the WGR input at which the WDM signal is received. The 1.times.N switch controllably provides the WDM signal to the proper WGR input so that a select frequency is provided at the drop output, which in turn drops the select frequency from the WDM signal. The undropped signals, as well as any added signals are multiplexed into a new WDM signal by the multiplexer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.