PDM-QPSK: on the system benefits arising from temporally interleaving polarization tributaries at 100Gb/s.

We experimentally study, over a dispersion-managed link relying on low chromatic dispersion fibre, the origins of the system benefits provided by temporally interleaving the polarization tributaries of 100Gb/s coherent RZ-PDM-QPSK by half a symbol period. Hence, we demonstrate that the amount of benefits provided by this technique is dependent on the configuration of the WDM transmission system

Optical terabit transmitter and receiver based on passive polymer and InP technology for high-speed optical connectivity between datacenters

We demonstrate the hybrid integration of a multi-format tunable transmitter and a coherent optical receiver based on optical polymers and InP electronics and photonics for next generation metro and core optical networks. The transmitter comprises an array of two InP Mach-Zehnder modulators (MZMs) with 42 GHz bandwidth and two passive PolyBoards at the back- and front-end of the device. The back-end PolyBoard integrates an InP gain chip, a Bragg grating and a phase section on the polymer substrate capable of 22 nm wavelength tunability inside the C-band and optical waveguides that guide the light to the inputs of the two InP MZMs. The front-end PolyBoard provides the optical waveguides for combing the In-phase and Quadrature-phase modulated signals via an integrated thermo-optic phase shifter for applying the pi/2 phase-shift at the lower arm and a 3-dB optical coupler at the output. Two InP-double heterojunction bipolar transistor (InP-DHBT) 3-bit power digital-to-analog converters (DACs) are hybridly integrated at either side of the MZM array chip in order to drive the IQ transmitter with QPSK, 16-QAM and 64-QAM encoded signals. The coherent receiver is based on the other side on a PolyBoard, which integrates an InP gain chip and a monolithic Bragg grating for the formation of the local oscillator laser, and a monolithic 90° optical hybrid. This PolyBoard is further integrated with a 4-fold InP photodiode array chip with more than 80 GHz bandwidth and two high-speed InP-DHBT transimpedance amplifiers (TIAs) with automatic gain control. The transmitter and the receiver have been experimentally evaluated at 25Gbaud over 100 km for mQAM modulation showing bit-error-rate (BER) performance performance below FEC limit

Phase correlation and linewidth reduction of 40 GHz self-pulsation in distributed Bragg reflector semiconductor lasers

In this paper, self-pulsation (SP) in a distributed Bragg reflector (DBR) semiconductor laser without a saturable absorber is experimentally and theoretically investigated. Detailed experimental characterizations of the SP DBR laser are reported in the optical and radio-frequency domains. Phase correlation between the longitudinal modes selected by the DBR mirror has been experimentally demonstrated. A theoretical model based on coupled rate equations for three modes has been developed to study the time evolution of phases and amplitudes of the modes. The carrier density modulation, resulting from the beating between adjacent longitudinal modes generates four-wave mixing (FWM) and is responsible for mutual injection locking, leading to passive mode-locking. The calculated power spectral density of the frequency noise derived from the model is in agreement with experimental results and proves that the phases of the longitudinal modes are identically correlated through the FWM process in this type of SP laser

High-Rate Continuous Variable Quantum Key Distribution Based on Probabilistically Shaped 64 and 256-QAM

International audienceWe designed a CV-QKD system with off-the-shelf components and established the feasibility of distributing 67.6 and 66.8 Mb/s secret key rates on average over a 9.5 km SMF link, using respectively probabilistically shaped 64 and 256 QAM, and relying on a novel analytical security proof

High-Rate Continuous Variable Quantum Key Distribution Based on Probabilistically Shaped 64 and 256-QAM

International audienceWe designed a CV-QKD system with off-the-shelf components and established the feasibility of distributing 67.6 and 66.8 Mb/s secret key rates on average over a 9.5 km SMF link, using respectively probabilistically shaped 64 and 256 QAM, and relying on a novel analytical security proof

Feasibility study of wide-band in-line SOA amplification for PDM-MQAM long-haul WDM transmission systems

International audienceWe present a numerical investigation for the use of semiconductor optical amplifiers (SOA) as broadband amplifiers in a context of quasi-Nyquist WDM long-haul transmission using PDM-QPSK, 8-QAM and 16-QAM modulation formats. The SOAs nonlinear behavior is assessed for each format considering different numbers of channels and cumulative dispersio