High bit rate optical telecommunications

High bit rate solutions based on advanced multilevel optical modulation formats have been developed on the platform, including the generation of RZ/NRZ-QPSK, DQPSK, 16 QAM, etc. formats using either an arbitrary waveform generator and a dual Mach-Zehnder modulator or an home-made field programmable gate array solution. The generation of high-speed wavelength division multiplexed signals is naturally within the capability of the platform.

Our recent work includes:

• Phase-preserving amplitude regeneration assessment in a recirculating loop using a multi quantum-well vertical-cavity saturable absorber.
• Development of a linear optical sampling oscilloscope in order to characterise both amplitude and phase.
• WDM/OTDM transmission reaching a total capacity of 680 Gbit/s using one single laser at the transmitter.
• 20 Gbit/s wavelength conversion using a hybrid III-V on silicon photonic crystal nanocavity.
• 56 Gbit/s DQPSK wavelength conversion using highly non-linear microstructured chalcogenide fibres.
• Second harmonic signal generation in a III‑V photonic crystal waveguide used as signal monitor at 160 Gbit/s.

Access networks and optical interconnects

PERSYST has developed testbeds for the validation of components for future optical access networks at 10 Gbit/s and above. The technology and feasibility of new types of passive optical networks (PONs) for broadband access have notably been investigated.

This area includes studies of:

• Silicon photonics modulators for frequency division multiplexing (FDM) and frequency division multiple access (FDMA).
• Direct modulation of quantum-dash DFB lasers for OOK and orthogonal frequency-division multiplexing (OFDM).
• WDM receivers using photonic crystal based filtering functions.
• Silicon photonic integration of an optical packet add-drop multiplexer.