Time domain multiplexed amplified sensor array with improved signal to noise ratios
US5866898A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1997 |
| Grant date | Feb 2, 1999 |
| Priority date | — |
| Expiry date | Mar 11, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01H9/004
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention significantly improves the signal to noise ratio (SNR) in a passive optical array by adding erbium-doped optical amplifiers between the sensor couplings to offset the coupler splitting losses. Optical amplifiers are inserted between the sensor couplings along the signal path, and the gain of the amplifiers is designed to offset losses due to the previous coupling. The overall SNR can be maintained without significant degradation even for large numbers of sensors. In a first aspect of the present invention, the amplifiers are located along the distribution and return buses directly after the couplers, except possibly for the last sensor. In a second aspect of the present invention, the amplifiers are located directly before the couplers. The optical amplifiers preferably are made of short lengths of erbium-doped fiber spliced into the distribution and return buses. Improvements can be made to the SNR when the distribution bus coupling ratios are set at optimal values. The value of the optimal coupling ratio depends upon the amplifier configuration, the excess loss and other configuration parameters. In alternative embodiments, sensors are grouped into parallel …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.