Abstract
Quadrature amplitude modulation (QAM) is an excellent modulation format for realizing optical communication systems with a high spectral efficiency of much greater than 1 bit/s/Hz. We describe QAM coherent optical communication that we achieved by using heterodyne detection with a frequency- stabilized fiber laser and an optical phase-locked loop (OPLL) technique. The phase error variance of the intermediate frequency signal of the OPLL was 6.1 × 10-3 rad. A 1-Gsymbol/s 64-QAM coherent signal was successfully transmitted over 150 km.
Original language | English |
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Pages (from-to) | 638-640 |
Number of pages | 3 |
Journal | IEEE Photonics Technology Letters |
Volume | 19 |
Issue number | 9 |
DOIs | |
Publication status | Published - 2007 May 1 |
Keywords
- Coherent transmission
- Frequency-stabilized laser
- Optical phase-locked loop (OPLL)
- Quadrature amplitude modulation (QAM)
- Spectral efficiency
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering