Auxiliary-signal transmission system
US5625481A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 14, 1995 |
| Grant date | Apr 29, 1997 |
| Priority date | — |
| Expiry date | Feb 14, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2210/078
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Spontaneous emission occurring in association with direct optical amplification using an erbium-doped optical fiber is modulated with an auxiliary signal, such as a supervisory signal, for transmission of the auxiliary signal. In a first aspect of the invention, the output of an optical amplifier is passed through a variable optical band-pass filter whose transmission characteristic is varied in accordance with the auxiliary signal, to modulate the spontaneous emission component contained in the optical amplifier output. In a second aspect of the invention, the output of the optical amplifier is separated by an optical branching device into a main optical signal and part of the spontaneous emission. The separated spontaneous emission component is modulated by being passed through a variable optical band-pass filter whose transmission characteristic is varied in accordance with the auxiliary signal, and then, the modulated spontaneous emission component is wavelength-division multiplexed with the main optical signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.