Optical equalizer
US6411417B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1998 |
| Grant date | Jun 25, 2002 |
| Priority date | — |
| Expiry date | Sep 22, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/2942
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An optical equalizer for a wavelength division multiplexed optical signal in an optical communications system utilises an array of parallel waveguides using planar waveguide technology. Waveguides having a range of different lengths have transmission controlled respectively in amplitude and/or phase in accordance with parameters calculated from a Fourier transform of an input frequency characteristic. Calculation of the parameters may be simplified by a Hilbert transform applied to determine phase values of the input terms of the Fourier transform. Feedback may be utilized by measuring the equalizer output and generating difference signals applied to the input to improve accuracy of equalization response by iteration or to overcome systematic errors. The equalizer has application to optical systems having line amplifiers where fiber amplifiers result in gain tilt, the equalizer allowing gain tilt to be corrected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.