Fiber optic cable monitoring method and apparatus including moisture detection and bending loss detection
US5262639A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 15, 1992 |
| Grant date | Nov 16, 1993 |
| Priority date | — |
| Expiry date | Apr 15, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08C23/06
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention provides a monitor for monitoring the condition of fibre optic communication cables. The system employs one or more of the optical fibres of a cable to monitor the cable structure for damage or kinks. By using two separate laser sources and simultaneously monitoring the optical losses at two distinct and separate wavelengths, the loss signature of the monitored fibre is determined, analyzed and related to the mechanical condition of the cable structure. To monitor splice points for moisture, a special optical splice sensor unit detects any penetration of water into the splice and transmits a coded alarm signal over the monitored fibre to the optical receiver. Every splice location is assigned a unique sensor code. The optical splice sensor is driven by moisture detection cell, which forms a single cell water activated battery. Water entering the monitored splice closure wets the tape, which activates the cell. The cell generates sufficient voltage and current to power timing, code generation and modulator circuits in the sensor unit for an extended period of time. The activated circuit drives a modulator which modulates the light travelling down the fibre. The modulat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.