Jean-Francois Morizur

Efficient and mode selective spatial mode multiplexer based on multi-plane light conversion

We demonstrate a new spatial mode multiplexer based on Multi-Plane Light Conversion with very low intrinsic loss (<; 4.1 dB) and high mode selectivity (crosstalk <; -23 dB). This multiplexer can perform any mode conversion, and we demonstrate its performance for 6 eigenmodes of a few-mode fiber.

Programmable multimode quantum networks

Entanglement between large numbers of quantum modes is the quintessential resource for future technologies such as the quantum internet. Conventionally, the generation of multimode entanglement in optics requires complex layouts of beamsplitters and phase shifters in order to transform the input modes into entangled modes. Here we report the highly versatile and efficient generation of various multimode entangled states with the ability to switch between different linear optics networks in real time. By defining our modes to be combinations of different spatial regions of one beam, we may use just one pair of multi-pixel detectors in order to measure multiple entangled modes. We programme virtual networks that are fully equivalent to the physical linear optics networks they are emulating. We present results for N=2 up to N=8 entangled modes here, including N=2, 3, 4 cluster states. Our approach introduces the highly sought after attributes of flexibility and scalability to multimode entanglement.

Programmable unitary spatial mode manipulation

Free space propagation and conventional optical systems such as lenses and mirrors all perform spatial unitary transforms. However, the subset of transforms available through these conventional systems is limited in scope. We present here a unitary programmable mode converter (UPMC) capable of performing any spatial unitary transform of the light field. It is based on a succession of reflections on programmable deformable mirrors and free space propagation. We first show theoretically that a UPMC without limitations on resources can perform perfectly any transform. We then build an experimental implementation of the UPMC and show that, even when limited to three reflections on an array of 12 pixels, the UPMC is capable of performing single mode tranforms with an efficiency greater than 80% for the first four modes of the transverse electromagnetic basis.

6-mode spatial multiplexer with low loss and high selectivity for transmission over few mode fiber

We present a spatial 6-mode multiplexer with low loss and high mode selectivity. We demonstrate 100Gbit/s error-free transmission over 20km for 6 modes and over 40km bi-directional transmission with 3 modes in each direction.

Efficient and mode-selective spatial multiplexer based on multi-plane light conversion

We report on a 6-mode spatial multiplexer based on multi-plane light conversion with 4.6dB insertion loss and -23dB mode-to-mode crosstalk, designed for few-mode fiber transmission systems that do not rely on complex electronic post-processing.

Asymmetric EPR entanglement in continuous variable systems

Continuous variable entanglement can be produced in nonlinear systems or via the interference of squeezed states. In many optical systems such as parametric down conversion, the production of two perfectly symmetric subsystems is usually assumed when demonstrating the existence of entanglement. This symmetry simplifies the description of entanglement. However, asymmetry in entanglement may arise naturally in a real experiment, or be intentionally introduced in a given quantum information protocol. These asymmetries can emerge from having the output beams experience different losses and environmental contamination, or from the availability of non-identical input quantum states in quantum communication protocols. In this paper, we present a visualization of entanglement using quadrature amplitude plots of the twin beams. We quantitatively discuss the strength of asymmetric entanglement using EPR and inseparability criteria and theoretically show that the optimal beamsplitter ratio for entanglement is dependent on the asymmetries and may not be 50 : 50. To support this theory, we present experimental results showing one particular asymmetric entanglement where a 78 : 22 beamsplitter is optimal for observing entanglement.

30 Gbit/s transmission over 1 km of conventional multi-mode fiber using mode group multiplexing with OOK modulation and direct detection

We demonstrate a 3×10 Gbit/s transmission with BER below 10-11 over 1 km of conventional graded-index multi-mode fiber using OOK modulation and direct detection. Reach and capacity boosts are enabled by selective mode-group multiplexing based on Multi-Plane Light Converters in 3 full mode groups of an OM2 fiber.

Amplification sharing of non-degenerate modes in an elliptical-core few-mode erbium-doped fiber

We report on the study of a possible first step integration of mode division multiplexed optical component for single-mode fiber networks. State-of-the-art on few-mode erbium-doped fiber amplifiers is used to integrate the amplification function in a single component, which is expected to save energy in comparison to parallelized active components. So as to limit the impact of modal cross-talk, an elliptical-core few-mode erbium-doped fiber has been used to assemble an amplifier sharing setup for different single mode fibers, using non-degenerate modes. With this simple setup, we show the level of performances that can be reached for cross-talk, gain, differential modal gain and losses and discuss the ways to improve them for a possible integration in a real network.

Optical amplifier sharing for single mode fibers: Amplification of 5 non-degenerate modes in an elliptical-core FM-EDFA

In this paper we investigate a possible first step upgrade for long-haul optical communications, before Spatial Division Multiplexing is fully ready. State-of-the-art on few-mode EDFA is used to integrate amplification function in a single system.

Six mode multi-plane light converter for mode-selective spatial multiplexing

We report a six mode spatial multiplexer with high efficiency and high mode selectivity, based on the technique of Multi-Plane Light Conversion (MPLC). Using this mode selective multiplexer, we demonstrate a total insertion loss in a six-mode fiber below 5 dB and a mode-to-mode selectivity greater than 20 dB over a broad wavelength range from 1530 to 1565 nm. Furthermore, this device can address any spatial mode profile of any few-mode fiber with high fidelity. This mode-multiplexer proves to be fully compatible with a wavelength- and space-division multiplexed optical transmission line.