Authors:
Diogo G. Sequeira
1
;
Luís G. Cancela
2
and
João L. Rebola
2
Affiliations:
1
Optical Communications and Photonics Group, Instituto de Telecomunicações, Lisbon and Portugal
;
2
Optical Communications and Photonics Group, Instituto de Telecomunicações, Lisbon, Portugal, Department of Information Science and Technology, Instituto Universitário de Lisboa (ISCTE-IUL), Lisbon and Portugal
Keyword(s):
ASE Noise, Broadcast and Select, In-Band Crosstalk, Nyquist Pulse, Optical Filtering, ROADMs, Route and Select.
Related
Ontology
Subjects/Areas/Topics:
Optical Communication Systems
;
Optical Networks Performance Modeling
;
Telecommunications
Abstract:
Nowadays, reconfigurable optical add/drop multiplexers (ROADMs) are mainly based on broadcast and select (B&S) and route and select (R&S) architectures. Moreover, the most used components to implement the colorless, directionless and contentionless (CDC) ROADM add/drop structures are the multicast switches (MCSs) and the wavelength selective switches (WSSs). In-band crosstalk, amplified spontaneous emission (ASE) noise accumulation and optical filtering are physical layer impairments (PLIs) that become more enhanced in a CDC ROADM cascade. In this work, we investigate the impact of these PLIs in a cascade of CDC ROADMs based on both B&S and R&S architectures, with MCSs and WSSs-based add/drop structures and for nonreturn-to-zero (NRZ) rectangular and Nyquist pulse shaped signals. We show that the optical filtering impairment is more limiting for a R&S architecture. We also show that the ASE noise accumulation after 32 cascaded ROADMs leads to a 10 dB optical signal-to-noise ratio (OS
NR) penalty for all ROADM degrees investigated. We have also concluded that the in-band crosstalk leads to a 1 dB OSNR penalty, after 13 and 24 cascaded 16-degree CDC ROADMs based on B&S for, respectively, NRZ rectangular and Nyquist pulse shapes. For a R&S architecture, the in-band crosstalk is not so harmful.
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