Open AccessTunable optical second-order Volterra nonlinear filter using wave mixing and delays to equalize a 10–20 Gbaud 4-APSK channel
Author(s) -
Kaiheng Zou,
Peicheng Liao,
Huibin Zhou,
Ahmad Fallahpour,
Amir Minoofar,
Ahmed Almaiman,
Fatemeh Alishahi,
Moshe Tur,
Alan E. Willner
Publication year - 2021
Publication title -
optics letters/optics index
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.524
H-Index - 272
eISSN - 1071-2763
pISSN - 0146-9592
DOI - 10.1364/ol.418088
Subject(s) - optics , four wave mixing , filter (signal processing) , signal (programming language) , mixing (physics) , comb filter , all pass filter , optical filter , physics , nonlinear optics , materials science , low pass filter , computer science , band stop filter , laser , quantum mechanics , computer vision , programming language
We experimentally demonstrate a tunable optical second-order Volterra filter using wave mixing and delays. Wave mixing is performed in a periodically poled lithium niobate waveguide with the cascaded sum-frequency generation and difference-frequency generation processes. Compared to conventional optical tapped delay line structures, second-order taps are added through the wave mixing of two signal copies. We measure the frequency response of the filter by sending a frequency-swept sinusoidal wave as the input. The tap weights are tuned with a liquid-crystal-on-silicon waveshaper for different filter configurations. With the additional second-order taps, the filter is able to perform a nonlinear function. As an example, we demonstrate the compensation of a nonlinearly distorted 10-20 Gbaud 4-amplitude and phase shift keying signal.