Generation and detection of 240-Gb/s PDM-64QAM using optical binary synthesizing approach and phase-folded decision-directed equalization

Hyeon Yeong Choi*, Takehiro Tsuritani, Hidenori Takahashi, Wei Ren Peng, Itsuro Morita

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

We present new generation and detection methods for high symbol-rate 64-ary quadrature amplitude modulation (64QAM). The 64QAM signal is created by tandem in-phase/quadrature (I/Q) modulators driven by electrical binary signals. The first I/Q modulator, which has four drive arms (i.e. a dual-drive I/Q modulator), yields 16QAM with an offset at the 1st quadrant of the complex plane. Subsequently, the second modulator switches this 16QAM signal over four quadrants via the typical quadrature phase-shift-keying (QPSK) modulation scheme, hence the desired 64QAM is generated. To mitigate the impacts of transmitter imperfections, we also propose a phase-folded decision-directed (PF-DD) linear equalizer at the receiver. Using these new techniques, we experimentally demonstrate the 120- and 240-Gb/s polarization-division- multiplexed (PDM) return-to-zero (RZ) 64QAM systems. The required optical signal-to-noise ratio (OSNR) for a bit-error rate (BER) of 2.4x10-2 is measured at 20.2 or 23 dB, respectively, which is ∼3.5 dB off the theoretical limit.

Original languageEnglish
Pages (from-to)27933-27940
Number of pages8
JournalOptics Express
Volume20
Issue number25
DOIs
Publication statusPublished - 2012 Dec 3
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Fingerprint

Dive into the research topics of 'Generation and detection of 240-Gb/s PDM-64QAM using optical binary synthesizing approach and phase-folded decision-directed equalization'. Together they form a unique fingerprint.

Cite this