Open AccessIn-line phase-sensitive amplification of QPSK signal using multiple quasi-phase matched LiNbO_3 waveguide
Author(s) -
Masaki Asobe,
Takeshi Umeki,
Hirokazu Takenouchi,
Yutaka Miyamoto
Publication year - 2014
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.22.026642
Subject(s) - phase shift keying , optics , lithium niobate , optical amplifier , signal regeneration , amplifier , phase noise , phase (matter) , materials science , quadrature amplitude modulation , signal (programming language) , phase modulation , optoelectronics , physics , optical fiber , bit error rate , telecommunications , laser , computer science , channel (broadcasting) , cmos , quantum mechanics , programming language
Phase-sensitive amplifiers (PSA) using periodically poled (PPLN) LiNbO₃ waveguides are promising as low-noise optical amplifiers. However, it is difficult to realize in-line operation for multi-level phase modulated signals using a PPLN based PSA with the conventional configuration. In this paper, we report a PPLN based in-line PSA that can regenerate quadrature phase shift keying (QPSK) signals. Multi-stage frequency mixing in a multiple quasi-phase matched LiNbO₃waveguide allows carrier phase recovery from a QPSK signal. Non-degenerate parametric amplification enables the phase-sensitive amplification of a QPSK signal. Amplitude and phase regeneration is examined utilizing gain saturation and phase squeezing capability.