Optoelectronic coherent Ising machine for combinatorial optimization problems.

Hopfield networks are iterative procedures able to solve combinatorial optimization problems. New studies regarding algorithm-architecture adequacy are fostered by the re-emergence of hardware implementations of such methods in the form of Ising machines. In this work, we propose an optoelectronic architecture suitable for fast processing and low energy consumption. We show that our approach allows effective optimization relevant to statistical image denoising.

Pulse rate multiplier based on the temporal Talbot effect in birefringent optical filters.

In this paper, we propose a novel approach to implement a pulse rate multiplier based on the temporal self-imaging effect using, for the first time to our knowledge, a birefringent optical filter. The proposed filter, with periodic quadratic phase-only filtering induced through engineered polarization mode dispersion, contains N-stage hybrid birefringent crystals set between an input polarizer and an analyzer. Each stage is composed of an identical section and a variable section. An optimization algorithm is used to determine the opto-geometrical parameters of the filter. Preliminary results for 10-stage, 12-stage, 16-stage, and 20-stage birefringent filters show very high fidelity for multiplying a 10 GHz input pulse rate by factors of two, four, six, and eight, respectively, without distorting the individual pulse properties.

Voice characteristics from isolated rapid eye movement sleep behavior disorder to early Parkinson's disease.

BACKGROUND: Speech disorders are amongst the first symptoms to appear in Parkinson's disease (PD). OBJECTIVES: We aimed to characterize PD voice signature from the prodromal stage (isolated rapid eye movement sleep behavior disorder, iRBD) to early PD using an automated acoustic analysis and compare male and female patients. We carried out supervised learning classifications to automatically detect patients using voice only. METHODS: Speech samples were acquired in 256 French speakers (117 participants with early PD, 41 with iRBD, and 98 healthy controls), with a professional quality microphone, a computer microphone and their own telephone. High-level features related to prosody, phonation, speech fluency and rhythm abilities were extracted. Group analyses were performed to determine the most discriminant features, as well as the impact of sex, vocal tasks, and microphone type. These speech features were used as inputs of a support vector machine and were combined with classifiers using low-level features. RESULTS: PD related impairments were found in prosody, pause durations and rhythmic abilities, from the prodromal stage. These alterations were more pronounced in men than in women. Early PD detection was achieved with a balanced accuracy of 89% in males and 70% in females. Participants with iRBD were detected with a balanced accuracy of 63% (reaching 70% in the subgroup with mild motor symptoms). CONCLUSION: This study provides new insight in the characterization of sex-dependent early PD speech impairments, and demonstrates the valuable benefit of including automated voice analysis in future diagnostic procedures of prodromal PD.

X-Vectors: New Quantitative Biomarkers for Early Parkinson's Disease Detection From Speech.

Many articles have used voice analysis to detect Parkinson's disease (PD), but few have focused on the early stages of the disease and the gender effect. In this article, we have adapted the latest speaker recognition system, called x-vectors, in order to detect PD at an early stage using voice analysis. X-vectors are embeddings extracted from Deep Neural Networks (DNNs), which provide robust speaker representations and improve speaker recognition when large amounts of training data are used. Our goal was to assess whether, in the context of early PD detection, this technique would outperform the more standard classifier MFCC-GMM (Mel-Frequency Cepstral Coefficients-Gaussian Mixture Model) and, if so, under which conditions. We recorded 221 French speakers (recently diagnosed PD subjects and healthy controls) with a high-quality microphone and via the telephone network. Men and women were analyzed separately in order to have more precise models and to assess a possible gender effect. Several experimental and methodological aspects were tested in order to analyze their impacts on classification performance. We assessed the impact of the audio segment durations, data augmentation, type of dataset used for the neural network training, kind of speech tasks, and back-end analyses. X-vectors technique provided better classification performances than MFCC-GMM for the text-independent tasks, and seemed to be particularly suited for the early detection of PD in women (7-15% improvement). This result was observed for both recording types (high-quality microphone and telephone).

Generalized temporal synthesis method for a birefringent laser pulse shaper.

We propose a new method for the synthesis of arbitrary temporal output pulse profiles by using a birefringent laser pulse shaper. This shaper contains a series of N birefringent crystals placed between input and output polarizers. The synthesis method starts with the linear time-invariant system theory to determine the optimal amplitudes of the replica pulses at the output polarizer and the time delay between them, and then uses the temporal Jones matrix formalism to obtain the angle of each crystal. The design procedure is demonstrated for an eight-stage birefringent laser pulse shaper. Several examples of predefined output pulse profiles are given to show the potential of the proposed birefringent laser pulse shaper.

Single-section quantum well mode-locked laser for 400 Gb/s SSB-OFDM transmission.

Successful use of a single-section quantum well (QW) passively mode-locked laser (MLL) as a comb source for optical interconnects is demonstrated for the first time. Sixteen comb lines spaced by 37.6 GHz are modulated using 25 Gb/s compatible single sideband orthogonal frequency division multiplexed (SSB-OFDM) signals and transmitted over 50 km of standard single-mode fiber with bit error ratio below the 7% forward error correction limit. The system performance, analyzed on the basis of the relative intensity noise of the device, reveal the suitability of single-section QW MLLs as inexpensive comb sources for inter- and intra-data center communication scenarios.

Bragg mirror inscription on LiNbO3 waveguides by index microstructuration.

Numerous applications in integrated optics, especially those related to multiwavelength telecommunications, require dichroic reflectors for use as narrowband or broadband wavelength-selective filters. Bragg mirrors are excellent candidates for this purpose, and we describe a method of fabricating Bragg grating reflectors in Ti-indiffused Lithium Niobate single-mode waveguides based on holographic masking in association with proton exchange. The holographic setup is employed to record a photolithographic mask directly on the substrate, enabling the inscription of waveguides with both periodic and aperiodic distributed parameters.