Open AccessInjection-locked 256 QAM WDM coherent transmissions in the C- and L-bands
Author(s) -
Takashi Kikuchi,
Keisuke Kasai,
Masato Yoshida,
Toshihiko Hirooka
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.404786
Subject(s) - wavelength division multiplexing , optics , transmission (telecommunications) , terabit , quadrature amplitude modulation , physics , optical amplifier , four wave mixing , phase noise , c band , telecommunications , computer science , bit error rate , nonlinear optics , laser , channel (broadcasting) , wavelength
We demonstrate WDM 256 QAM coherent transmissions with injection locking in the C- and L-bands and compare the transmission performance in the two bands. Although four-wave mixing (FWM) is more significant in an L-band EDFA than in a C-band EDFA, the FWM did not accumulate through the transmission and the FWM components were hidden by the ASE noise level. Since the FWM was weakened by the decorrelation of the WDM signals during the transmission, the transmission performance in the L-band was the same as that in the C-band. The injection locking circuit enabled precise carrier-phase synchronization between a data signal and a local oscillator regardless of the transmission band. By using this circuit, we successfully transmitted 58.2 and 57.6 Tbit/s 256 QAM WDM signals over 160 km with a spectral efficiency of 12 bit/s/Hz in the C- and L-bands, respectively.