Optical communications system with wavelength division multiplexing
US5940196A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 1997 |
| Grant date | Aug 17, 1999 |
| Priority date | — |
| Expiry date | May 16, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J14/0307
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A wavelength division multiplexer (WDM) in an optical fiber transmission system launches analog signals, for instance a multi-channel television signal. The WDM enhances signal quality by transmitting along a single fiber two different optical wavelength signals, each carrying identical RF information. This results in a 3 dB improvement in carrier to noise ratio. The WDM combines two or more wavelengths centered around for instance 1550 nm or 1310 nm. A typical difference between the two wavelengths is 3 nm. In other embodiments, more than two wavelengths are used. The receiver is for instance a single photosensitive element. The phase of the two RF signals is adjusted in the optical or RF domain to be the same upon arrival at the receiver. In other embodiments, the receiver includes two photosensitive elements, each receiving from a receiver end WDM a single wavelength. In this case, the phase adjustment may be applied at the receiver in the optical or RF domain.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.