RZ-4PAM Optical Access Signals with Pre-chirping Technology

Abstract

 In this paper, the generation and transmission of chirped return-to-zero 4-ary pulse amplitude modulation (CRZ-4PAM) signals in passive optical networks (PONs) is proposed and investigated. The optical spectra, eye-diagrams before and after transmission are also analyzed. We demonstrate that CRZ-4PAM signals after transmission over 20km single mode fiber (SMF) at 10Gb/s can be directly detected by using one photo detector, and the original data can also be restored by one M-ary threshold detector and one PAM sequence decoder. The results demonstrate that CRZ-4PAM downlink signals can be received effectively at the BER value of 10-6.