Vector modulation by laser and electroabsorption modulator with digital pre-coding and pre-compensation

Ukrit Mankong*, Praimezt Mekbungwan, Keizo Inagaki, Tetsuya Kawanishi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


We present a method to achieve vector modulation of lightwave using an electroabsorption modulator intregrated laser. The laser section is used for direct phase modulation followed by an amplitude modulation of the electroabsorption modulator section in a cascade manner, which is an alternative method to conventional IQ modulator. To allow an improved phase demodulation, we propose a digital pre-compensation technique for a transmitter in optical coherent system for the first time, which includes a phase-balanced differential phase shift keying encoding and a digital domain pre-equalization filtering. The phase-balanced encoding technique applies parallel DC-balance coding with a phase-balanced symbol mapping, which results in a bounded cumulative phase and a constant statistical characteristic of the modulating signal in differential M-ary phase shift keying and M-ary quadrature amplitude modulation formats. The digital pre-equalization filter also compensates for the phase response of the laser section. Experimental results show that the pre-digital compensation technique allows the improved complex signal demodulation compared to conventional DQPSK modulation in a back-to-back setup.

Original languageEnglish
Article number8383977
Pages (from-to)4633-4639
Number of pages7
JournalJournal of Lightwave Technology
Issue number19
Publication statusPublished - 2018 Oct 1


  • Digital coherent
  • digital pre-compensation
  • directly modulated laser
  • electroabsorption modulator
  • phase modulation
  • radio-over-fiber

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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