Open AccessPseudo Optical PAM‐ N Signal Using Externally Modulated Lasers
Author(s) -
Huh Joon Young,
Lee Joon Ki,
Kang SaeKyoung,
Lee Jyung Chan
Publication year - 2015
Publication title -
etri journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 46
eISSN - 2233-7326
pISSN - 1225-6463
DOI - 10.4218/etrij.15.0114.0746
Subject(s) - extinction ratio , signal (programming language) , optics , physics , dispersion (optics) , laser , pulse amplitude modulation , wavelength , pulse (music) , detector , computer science , programming language
We propose a pseudo optical N ‐level pulse‐amplitude modulation (PO PAM‐ N ) signal using a few externally‐modulated lasers (EMLs) operating at different wavelengths, which is suitable for upgrading the transmission speed over an optical link of 10 km single‐mode fiber with low‐cost components. To compare a PO PAM‐ N signal with that of a standard optical PAM‐ N signal, we perform experiments for evaluating the performance of a 51.56‐Gb/s PO PAM‐4 signal and standard 51.56‐Gb/s optical PAM‐4 signal. The receiver sensitivity (atBER = 10 − 5) of the PO PAM‐4 signal is 1.5 dB better than the receiver sensitivity of a standard optical PAM‐4 signal. We also investigate the feasibility of PO PAM‐ N( N = 4 , 8 , and 16 ) signals operating at 103.12 Gb/s, considering relative intensity noise, timing jitter, extinction ratio (ER) of EMLs, and dispersion. From the results, a PO PAM‐8 signal performs better than PO PAM‐4 and PO PAM‐16 signals at 103.12 Gb/s. Finally, we suggest a timing control method to suppress the effect of dispersion in a PO PAM‐ N signal. We show that the tolerance to dispersion of a 103.12‐Gb/s PO PAM‐8 signal can be improved to ±40 ps/nm by applying a proposed scheme.