title: Pump-linewidth-tolerant optical wavelength conversion for high-order QAM signals using coherent pumps.
abstract: Optical wavelength conversion (OWC) is expected to be a desirable function in future optical transparent networks. Since high-order quadrature amplitude modulation (QAM) is more sensitive to the phase noise, in the OWC of high-order QAM signals, it is crucial to suppress the extra noise introduced in the OWC subsystem, especially for the scenario with multiple cascaded OWCs. Here, we propose and experimentally demonstrate a pump-linewidth-tolerant OWC scheme suitable for high-order QAM signals using coherent two-tone pumps. Using 3.5-MHz-linewidth distributed feedback (DFB) lasers as pump sources, our scheme enables wavelength conversion of both 16QAM and 64QAM signals with negligible power penalty, in a periodically-poled Lithium Niobate (PPLN) waveguide based OWC. We also demonstrate the performance of pump phase noise cancellation, showing that such coherent two-tone pump schemes can eliminate the need for ultra-narrow linewidth pump lasers and enable practical implementation of low-cost OWC in future dynamic optical networks.
authors.forename: Guo-Wei
authors.initials: GW
authors.lastname: Lu
authors.forename: André
authors.initials: A
authors.lastname: Albuquerque
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Puttnam
authors.forename: Takahide
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Miguel
authors.initials: M
authors.lastname: Drummond
authors.forename: Rogério
authors.initials: R
authors.lastname: Nogueira
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kanno
authors.forename: Satoshi
authors.initials: S
authors.lastname: Shinada
authors.forename: Naoya
authors.initials: N
authors.lastname: Wada
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kawanishi