Title :
Addendum to “Feedforward Carrier Recovery for Coherent Optical Communications”
Author :
Ip, Ezra ; Kahn, Joseph M.
Author_Institution :
Dept. of Electr. Eng., Stanford Univ., Stanford, CA, USA
fDate :
7/1/2009 12:00:00 AM
Abstract :
In a previous paper , we noted when the transmitted signal constellations has rotational symmetry, laser phase noise can be mitigated using non-data-aided (NDA) feedforward (FF) carrier recovery. The structures of a FF carrier recovery unit and a NDA soft-decision phase estimator were shown in Fig. 3 and 4(a), respectively. We have found that in an NDA FF carrier recovery unit, the order of the linear filter and phase estimator can be exchanged in a manner not possible with a decision-directed (DD) FF carrier recovery unit. We show that this alternative NDA (ANDA) FF carrier recovery unit exhibits better immunity to cycle slips compared to standard NDA.
Keywords :
optical communication; phase noise; addendum; carrier recovery unit; coherent optical communications; feedforward carrier recovery; laser phase noise; non-data-aided; rotational symmetry; transmitted signal constellations; Bit error rate; Delay estimation; Laser noise; Nonlinear filters; Optical filters; Optical noise; Parity check codes; Phase estimation; Phase noise; Wiener filter;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2008.929416
