We discuss about digital signal processing approaches that can enable coherent links based on semiconductor lasers. A state-of-the art analysis on different carrier-phase recovery (CPR) techniques is presented. We show that these techniques are based on the assumption of lorentzian linewidth, which does not hold for monolithically integrated semiconductor lasers. We investigate the impact of such lineshape on both 3 and 20 dB linewidth and experimentally conduct a systematic study for 56-GBaud DP-QPSK and 28-GBaud DP-16QAM systems using a decision directed phase look loop algorithm. We show how carrier induced frequency noise has no impact on linewidth but a significant impact on system performance; which rises the question on whether 3-dB linewidth should be used as performance estimator for semiconductor lasers.
|Title of host publication||Proceedings of the SPIE|
|Number of pages||7|
|Publisher||SPIE - International Society for Optical Engineering|
|Publication status||Published - 2015|
|Event||SPIE Photonics West 2015: Optical Metro Networks and Short-Haul Systems VII - The Moscone Center, San Francisco, United States|
Duration: 7 Feb 2015 → 12 Feb 2015
Conference number: 9388
|Conference||SPIE Photonics West 2015: Optical Metro Networks and Short-Haul Systems VII|
|Location||The Moscone Center|
|Period||07/02/2015 → 12/02/2015|
|Series||Proceedings of SPIE, the International Society for Optical Engineering|
Bibliographical noteCopyright 2015 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic electronic or print reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
- Optical communications
- Coherent communications
- Phase Noise