Quantum non-demolition optical tapping
US5333220A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 25, 1992 |
| Grant date | Jul 26, 1994 |
| Priority date | — |
| Expiry date | Mar 25, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/3519
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A single silica optical fiber (4) is formed in a Sagnac interferometer (2) by forming a fused, dichroic optical fiber coupler (8) having four ports (10, 12, 14 and 16). A 1.3 .mu.m optical data signal is coupled to the port (10) via a dichroic optical fiber coupler (18) which combines it with a 1.53 .mu.m c-w probe signal from laser (16). The coupler (8) splits the 1.53 .mu.m probe signal into two equal intensity, counter-propagating portions and couples the 1.3 .mu.m data signal so it propagates in one direction round the loop (6). The loop (6) exhibits a non-linearity such that the data signal provides a relative phase shift of the counter-propagating c-w probe portions causing a portion of the 1.53 .mu.m signal is switched to port (12). This 1.53 .mu.m switched output provides tapping of the data signal without affecting its intensity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.