DWDM channel detection system
US6911645B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 2003 |
| Grant date | Jun 28, 2005 |
| Priority date | — |
| Expiry date | Dec 24, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/66
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A channel detection system includes an interferometer coupled to a spectrum analyzer to differentiate additive spontaneous emission (ASE) noise from optical channels in a dense wave-division multiplex (DWDM) signal. It is assumed that channels, if present, are centered at frequencies corresponding to a standardized channel grid. The relative delay of the interferometer is chosen to be greater than the coherence time of the ASE noise but less than the coherence time of the channels with the interferometer's free spectral range set to an integer divisor of the channel-to-channel frequency spacing of the grid such that active channels experience a high degree of interference. The phase delay of the interferometer is then adjusted to maximize the interference at each grid-aligned frequency. The spectrum-analyzed outputs are compared (e.g., subtracted from one another and then thresholded) to determine the channels present in the DWDM signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.