title: Impact of power allocation strategies in long-haul few-mode fiber transmission systems.
abstract: We report for the first time on the limitations in the operational power range of few-mode fiber based transmission systems, employing 28 Gbaud quadrature phase shift keying transponders, over 1,600 km. It is demonstrated that if an additional mode is used on a preexisting few-mode transmission link, and allowed to optimize its performance, it will have a significant impact on the pre-existing mode. In particular, we show that for low mode coupling strengths (weak coupling regime), the newly added variable power mode does not considerably impact the fixed power existing mode, with performance penalties less than 2dB (in Q-factor). On the other hand, as mode coupling strength is increased (strong coupling regime), the individual launch power optimization significantly degrades the system performance, with penalties up to ~6 dB. Our results further suggest that mutual power optimization, of both fixed power and variable power modes, reduces power allocation related penalties to less than 3 dB, for any given coupling strength, for both high and low differential mode delays.
authors.affiliation: Nokia Siemens Networks, SA Lisbon, Portugal. danish.rafique@nsn.com
authors.forename: Danish
authors.initials: D
authors.lastname: Rafique
authors.forename: Stylianos
authors.initials: S
authors.lastname: Sygletos
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Ellis
mesh_terms: D003195:Computer Communication Networks / Q000295:instrumentation*; D017076:Computer-Aided Design; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation*