Optical noise monitor
US6075632A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 26, 1997 |
| Grant date | Jun 13, 2000 |
| Priority date | — |
| Expiry date | Nov 26, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/07953
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical noise monitor measures noise power within narrow wavelength regions between channel signals of a dense wavelength division multiplexed (DWDM) signal. The noise monitor receives the DWDM signal and cascades the signal along a multipoint travel path where the signal is incident on a series of multi-pass filters. Each multi-pass filter selects a narrow, predefined wavelength region between channel signals of the DWDM signal. Noise power within the predefined wavelength region is detected and SNR is monitored by comparing the detected noise power to the power in the channel signal. According to a first preferred embodiment of the present invention, the noise monitor includes multi-pass filters that each have reflective surfaces to guide optical energy within a predefined wavelength region through multiple passes of an optical filter. According to a second preferred embodiment of the present invention, the noise monitor includes multi-pass filters each having a serial arrangement of multiple optical filters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.