All-Optical Wavelength Conversion of a 100-Gb/s Polarization-Multiplexed Signal

Abstract

We present the results of an in-depth experimental investigation about all-optical wavelength conversion of a 100-Gb/s polarization-multiplexed (POLMUX) signal. Each polarization channel is modulated at 25 Gbaud by differential quadrature phase-shift keying (DQPSK). The conversion is realized exploiting the high nonlinear chi((2)) coefficient of a periodically poled lithium niobate waveguide, in a polarization-independent configuration. We find that slight non-idealities in the polarization independent setup of the wavelength converter can significantly impair the performance of POLMUX systems. We show that high-quality wavelength conversion can be nevertheless achieved for both the polarization channels, provided that an accurate optimization of the setup is performed. This is the first demonstration, to the best of our knowledge, of the possibility to obtain penalty-free all-optical wavelength conversion in a 100-Gb/s POLMUX transmission system using direct-detection.

Ultra-high four wave mixing efficiency in slot waveguides with silicon nanocrystals

“…On the other hand, these devices are not compatible with Si-based photonics, they have a very large foot-print and require a critical thermal stabilization of the chip. 18,19 In conclusion, we reported a four-wave-mixing experiment, performed by using a low-loss Si:nc slot-waveguide, showing very large conversion efficiency. This result, combined with data obtained on the conversion bandwidth, indicates that this kind of structure is a promising candidate for the development of all optical processing devices.…”

Polarization-Insensitive 320-Gb/s In-Line All-Optical Wavelength Conversion in a 320-km Transmission Span

“…1, the key device of the in-line wavelength converter is the polarization insensitive PPLN subsystem, which is a polarization maintaining loop configuration enabling bidirectional nonlinear wavelength conversion in a low-loss dB/cm 80 mm long Ti:PPLN-waveguide operated at C. This loop represents a polarization diversity scheme with an intrinsic equalization of the differential group delay [4], [7]- [9]. The two polarization components of the signal wave are routed by the PBS and PM-fibers contra-directionally as TM-modes through the PPLN-waveguide and the corresponding components of the converted signal (idler) wave are recombined in the PBS and routed to port 3 of the circulator.…”

Minimizing inter-channel cross-phase modulation with optical phase conjugation in asymmetric fibre links

“…OPC is modulation format transparent, optical in nature, well suited to high bit rates and the FWM process can conjugate many channels in the same nonlinear element [8,9]. It has also recently been shown to improve signal quality in polarization multiplexed [10] and coherent orthogonal frequency division multiplexed (CO-OFDM) signals [4,5]. To date, transmission experiments have demonstrated improvements in Q factor of a few dB over several hundred km links using OPC in few channel wavelength division multiplexed (WDM) systems with a variety of modulation formats [11][12][13][14].…”