Abstract
A scheme of optical four-level pulse amplitude modulation(PAM-4)is proposed based on dual-Raman process in Rydberg atoms.A probe field counter-propagates with a dual-Raman field which drives the ground and the excited states transition,respectively,and the Rydberg transition is driven by a microwave(MW)field.A gain peak appears in the probe transmission and is sensitive to the MW field strength.Optical PAM-4 can be achieved by encoding an MW signal and decoding the magnitude of a probe signal.Simulation results show that the differential nonlinearity and the integral nonlinearity of the proposed scheme can be reduced by 5 times and 6 times,respectively,compared with the counterparts of previous scheme,and the ratio of level separation mismatch is close to the ideal value 1.Moreover,the scheme is extended to optical PAM-8 signal,which may further improve the spectral efficiency.
基金项目
Shandong Natural Science Foundation,China(ZR2021LLZ006)
国家自然科学基金(61675118)
国家自然科学基金(12274123)
Taishan Scholars Program of Shandong Province,China(ts20190936)
Shandong University of Science and Technology Research Fund,China(2015TDJH102)
NETL
NSTL
万方数据