Quadrature optical phase modulators for lightwave systems
US5101450A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 23, 1991 |
| Grant date | Mar 31, 1992 |
| Priority date | — |
| Expiry date | Jan 23, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J14/0298
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Optical communication methods and apparatus are disclosed for transmitting two or more optical signals with different optical carrier frequencies on a single optical fiber with high spectral efficiency. Each optical carrier is typically modulated with multiple modulated subcarriers. In one embodiment, an optical phase modulator provides cancellation of second order intermodulation products in each optical signal, thereby permitting the optical carrier frequencies to be spaced by 2f.sub.max, where f.sub.max is the maximum modulation frequency. In another embodiment, a single sideband optical phase modulator provides cancellation of second order intermodulation products and one signal sideband, thereby permitting the optical carrier frequencies to be spaced by f.sub.max. Quadrature optical phase modulators for simultaneous transmission of two independent baseband digital data signals or two independent subcarrier multiplexed signals are disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.