Duobinary pulse shaping for optical transmission systems employing pulse amplitude modulation techniques
US7257329B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 2003 |
| Grant date | Aug 14, 2007 |
| Priority date | — |
| Expiry date | Sep 27, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/5167
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A duobinary optical communication system is disclosed that employs pulse amplitude modulation (PAM) techniques to provide further improvements in spectral efficiency. A disclosed PAM duobinary optical transmitter converts a plurality of input bits to an N level signal using PAM techniques; adds a current N level signal to a previous N level signal to produce a 2N−1 level signal; and converts the 2N−1 level signal to an optical signal for transmission to a receiver. A disclosed PAM duobinary optical receiver detects a power level of the received optical signal (encoded using pulse amplitude modulation and duobinary encoding techniques to encode a plurality of bits) and maps the detected power level to a plurality of bits to return the transmitted information. An exemplary PAM-4 duobinary optical communication system combines PAM-4 modulation techniques with duobinary pulse shaping techniques to provide an overall factor of four improvement in spectral efficiency by reducing the bandwidth of the optical signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.