The constant envelope characteristic of CPM signal is particularly interesting for use in fiber optic links since it can be leveraged to avoid nonlinear phase modulation. Implementation complexity of CPM systems is generally higher than their QPSK counterpart, partly due to the nontrivial task of generating the signal as well as the need to observe the received signal over multiple symbol periods to make an optimal decision. Because of this complexity, the use of full-response CPM systems is favorable for complexity since optimal reception is achieved with lower order, however, partial response systems can achieve higher minimum distance. We analyze parameter selection for CPM transmission, optimizing error performance and spectral efficiency in a tightly filtered reconfigurable optical add-drop multiplexor (ROADM) application. We illustrate their impact on the normalized minimum Euclidean distance (as a proxy for error performance). The impact of parameters on spectral efficiency is implicit on the choice of ROADM filters. The results provide guidance for a suitable choice of CPM scheme for consideration in DWDM systems. Optimal parameters are given for full and partial response systems for a variety of filter scenarios.

Date Published: 24 January 2012
PDF: 5 pages
Proc. SPIE 8284, Next-Generation Optical Communication: Components, Sub-Systems, and Systems, 828408 (24 January 2012); doi: 10.1117/12.909592

Published in SPIE Proceedings Vol. 8284:
Next-Generation Optical Communication: Components, Sub-Systems, and Systems
Guifang Li; Dieter Stefan Jäger, Editor(s)