The Experts below are selected from a list of 30954 Experts worldwide ranked by ideXlab platform
Nathalie Picque - One of the best experts on this subject based on the ideXlab platform.
-
sensitive multiplex spectroscopy in the molecular fingerprint 2 4 µm region with a cr 2 znse femtosecond laser
Optics Express, 2007Co-Authors: Evgeni Sorokin, Irina T Sorokina, Julien Mandon, G Guelachvili, Nathalie PicqueAbstract:An ultrashort-pulse Cr2+:ZnSe laser is a novel Broadband Source for sensitive high resolution molecular spectroscopy. A 130-fs pulse allows covering of up to 380 cm-1 spectral domain around 2.4 µm which is analyzed simultaneously with a 0.12 cm-1 (3.6 GHz) resolution by a Fourier-transform spectrometer. Recorded in 13 s, from 70-cm length absorption around 4150 cm-1, acetylene and ammonia spectra exhibit a 3800 signal-to-noise ratio and a 2.4·10-7 cm-1·Hz-1/2 noise equivalent absorption coefficient at one second averaging per spectral element, suggesting a 0.2 ppbv detection level for HF molecule. With the widely practiced classical tungsten lamp Source instead of the laser, identical spectra would have taken more than one hour.
-
sensitive multiplex spectroscopy in the molecular fingerprint 2 4 mu m region with a cr 2 znse femtosecond laser
arXiv: Optics, 2007Co-Authors: Evgeni Sorokin, Irina T Sorokina, Julien Mandon, G Guelachvili, Nathalie PicqueAbstract:An ultrashort-pulse Cr^{2+}:ZnSe laser is a novel Broadband Source for sensitive high resolution molecular spectroscopy. A 130-fs pulse allows covering of up to 380 cm^-1 spectral domain around 2.4 $\mu$m which is analyzed simultaneously with a 0.12 cm^-1 (3.6 GHz) resolution by a Fourier-transform spectrometer. Recorded in 13 s, from 70-cm length absorption around 4150 cm^-1, acetylene and ammonia spectra exhibit a 3800 signal-to-noise ratio and a 2.4*10^-7 cm^-1*Hz^-1/2 noise equivalent absorption coefficient at one second averaging per spectral element, suggesting a 0.2 ppbv detection level for HF molecule. With the widely practiced classical tungsten lamp Source instead of the laser, identical spectra would have taken more than one hour.
Michel J F Digonnet - One of the best experts on this subject based on the ideXlab platform.
-
Broadened-Laser-Driven Polarization-Maintaining Hollow-Core Fiber Optic Gyroscope
Journal of Lightwave Technology, 2020Co-Authors: Therice A. Morris, Michel J F DigonnetAbstract:A state-of-the-art fiber optic gyroscope (FOG) using a 250-m quadrupolar-wound coil of polarization-maintaining hollow-core fiber (HCF) interrogated by a broadened laser is demonstrated. The fiber coil is directly connected to the multi-function integrated optics chip (MIOC) to reduce instabilities and reflections. The HCF FOG is first driven with a Broadband Source, yielding an angular random walk (ARW) of 2.12 μrad/√Hz and a drift of 0.375 μrad. This drift is 3.4 times lower than reported in any previous HCF FOG. Measuring the loss and ARW versus wavelength of the HCF FOG driven by a tunable narrow-linewidth laser reveals that the HCF supports a dense spectrum of high-scattering surface modes (~70 modes/nm). The HCF FOG was also interrogated with a 22.5-GHz broadened-laser Source, yielding an ARW of 6 μrad/√Hz. This ARW is most likely limited by backscattering mediated by coupling to the high-scattering surface modes. The drift of the HCF FOG driven by the broadened laser was 0.88 μrad. This drift is limited by polarization coupling, and confirms the holding parameter given by the fiber provider for this fiber (10-3 m-1).
-
experimental observation of low noise and low drift in a laser driven fiber optic gyroscope
Journal of Lightwave Technology, 2013Co-Authors: Seth Lloyd, Shanhui Fan, Michel J F DigonnetAbstract:We demonstrate that by driving a fiber optic gyroscope (FOG) with a laser of relatively broad linewidth ( ~ 10 MHz), both the noise and the bias drift are reduced to very low levels (0.058°/√h and 1.1°/h, respectively), comparable to the performance of the same gyroscope conventionally driven with a Broadband light Source. When the laser linewidth is reduced to a low enough value ( ~ 2.2 kHz), the FOG exhibits a higher drift but an even lower noise, about 4 dB lower than with a Broadband Source, and only 3.5 dB above shot noise. The measured dependencies of the noise and drift on laser linewidth are in good quantitative agreement with the predictions of an advanced model of backscattering errors in a FOG interrogated with coherent light, which confirms that the noise and drift are predominantly limited by backscattering. The use of a laser comes with the additional benefit of a much greater wavelength stability compared to a Broadband Source, which is expected to translate directly into a much more stable scale factor than possible in conventional FOGs. Residual Sources of drift and the prospects for reducing them in order to achieve inertial navigation performance are discussed.
-
improving fiber optic gyroscope performanceusing a laser and photonic bandgap fiber
OFS2012 22nd International Conference on Optical Fiber Sensors, 2012Co-Authors: Seth Lloyd, Shanhui Fan, Michel J F DigonnetAbstract:Based on insights from a new model of scattering in FOGs for high-coherence Sources, we demonstrate experimentally that a fiber optic gyroscope (FOG) can be driven with a laser of suitable linewidth and exhibit short and long-term performance matching that of a FOG driven by a Broadband Source. This innovation can be combined with the use of hollow-core fiber in the sensor coil to produce new FOGs exceeding current standards.
-
tactical grade interferometric fiber optic gyroscope driven with a narrow linewidth laser
21st International Conference on Optical Fibre Sensors (OFS21), 2011Co-Authors: Seth Lloyd, Michel J F Digonnet, Shanhui FanAbstract:We report for the first time a tactical-grade fiber optic gyroscope interrogated with a laser instead of a Broadband Source. The measured bias drift is 2.5 °/h and the random walk 0.016 °/√ h. This random walk is lower than when the same gyroscope is interrogated with a Broadband Source, while the drift is only ~3 times higher. This significant development was enabled by an appropriate choice of laser linewidth to mitigate backscattering effects, and careful control of spurious reflections. The benefits of using a laser include a much higher scale factor stability, lower power consumption, and lower component cost.
-
Fiber-optic gyroscope operated with a frequency-modulated laser
19th International Conference on Optical Fibre Sensors, 2008Co-Authors: Stéphane Blin, Michel J F Digonnet, Gordon S KinoAbstract:We propose using a frequency-modulated laser in a fiber-optic gyroscope (FOG) in a minimum configuration. Compared to the traditional Broadband Source, a narrow-band laser offers two significant advantages, namely the elimination of excess noise and thus improved sensitivity to rotation, and a more stable mean wavelength, hence a greater scale-factor stability. We show that the strong back-reflection and coherent backscattering noise introduced by the use of a laser is greatly reduced by modulating the laser frequency. In both a conventional FOG and in a FOG using an air-core fiber, we demonstrate experimentally that this technique reduces these two Sources of noise by at least a factor of 4 compared to the same gyros operated with an unmodulated laser.
Salvador Sales - One of the best experts on this subject based on the ideXlab platform.
-
Multicore fiber-Bragg-grating-based directional curvature sensor interrogated by a Broadband Source with a sinusoidal spectrum
Optics Letters, 2017Co-Authors: Di Zheng, Hailan Chen, Javier Madrigal, David Barrera, Salvador SalesAbstract:A simple, spectral-drift-insensitive interrogation scheme for a multicore fiber Bragg grating (FBG)-based directional curvature sensor is proposed. The basic principle is to transform the wavelength shift of FBGs into the reflected power variation, which is accomplished by utilizing a Broadband Source with a sinusoidal spectrum. The closed-form expression of the relationship between the reflected power of the FBG and the corresponding peak wavelength is derived for the first time, to the best of our knowledge; therefore, the peak wavelength of the FBG can be precisely interrogated by using a single photodiode. The experimental results show that, with respect to conventional wavelength measurement by an optical spectrum analyzer, the demodulated wavelength error by our proposed interrogation scheme is within ±20 pm. The proposed scheme is further extended to interrogate the direction and curvature using a multicore FBG-based curvature sensor; the interrogated curvature with an error less than 8% is achieved.
-
tunable all optical negative multitap microwave filters based on uniform fiber bragg gratings
Optics Letters, 2003Co-Authors: J Mora, Dominique Pastor, Miguel V. Andrés, J L Cruz, Beatriz Ortega, José Capmany, Salvador SalesAbstract:We present a novel and simple technique for obtaining transversal filters with negative coefficients by using uniform fiber Bragg gratings. We demonstrate a wide tuning range, good performance, low cost, and easy implementation of multitap filters in an all-optical passive configuration in which negative taps are obtained by use of the transmission of a Broadband Source through uniform Bragg gratings.
Evgeni Sorokin - One of the best experts on this subject based on the ideXlab platform.
-
sensitive multiplex spectroscopy in the molecular fingerprint 2 4 µm region with a cr 2 znse femtosecond laser
Optics Express, 2007Co-Authors: Evgeni Sorokin, Irina T Sorokina, Julien Mandon, G Guelachvili, Nathalie PicqueAbstract:An ultrashort-pulse Cr2+:ZnSe laser is a novel Broadband Source for sensitive high resolution molecular spectroscopy. A 130-fs pulse allows covering of up to 380 cm-1 spectral domain around 2.4 µm which is analyzed simultaneously with a 0.12 cm-1 (3.6 GHz) resolution by a Fourier-transform spectrometer. Recorded in 13 s, from 70-cm length absorption around 4150 cm-1, acetylene and ammonia spectra exhibit a 3800 signal-to-noise ratio and a 2.4·10-7 cm-1·Hz-1/2 noise equivalent absorption coefficient at one second averaging per spectral element, suggesting a 0.2 ppbv detection level for HF molecule. With the widely practiced classical tungsten lamp Source instead of the laser, identical spectra would have taken more than one hour.
-
sensitive multiplex spectroscopy in the molecular fingerprint 2 4 mu m region with a cr 2 znse femtosecond laser
arXiv: Optics, 2007Co-Authors: Evgeni Sorokin, Irina T Sorokina, Julien Mandon, G Guelachvili, Nathalie PicqueAbstract:An ultrashort-pulse Cr^{2+}:ZnSe laser is a novel Broadband Source for sensitive high resolution molecular spectroscopy. A 130-fs pulse allows covering of up to 380 cm^-1 spectral domain around 2.4 $\mu$m which is analyzed simultaneously with a 0.12 cm^-1 (3.6 GHz) resolution by a Fourier-transform spectrometer. Recorded in 13 s, from 70-cm length absorption around 4150 cm^-1, acetylene and ammonia spectra exhibit a 3800 signal-to-noise ratio and a 2.4*10^-7 cm^-1*Hz^-1/2 noise equivalent absorption coefficient at one second averaging per spectral element, suggesting a 0.2 ppbv detection level for HF molecule. With the widely practiced classical tungsten lamp Source instead of the laser, identical spectra would have taken more than one hour.
Aydogan Ozcan - One of the best experts on this subject based on the ideXlab platform.
-
design of task specific optical systems using Broadband diffractive neural networks
Light-Science & Applications, 2019Co-Authors: Yi Luo, Deniz Mengu, Nezih Tolga Yardimci, Yair Rivenson, Muhammed Veli, Mona Jarrahi, Aydogan OzcanAbstract:Deep learning has been transformative in many fields, motivating the emergence of various optical computing architectures. Diffractive optical network is a recently introduced optical computing framework that merges wave optics with deep-learning methods to design optical neural networks. Diffraction-based all-optical object recognition systems, designed through this framework and fabricated by 3D printing, have been reported to recognize hand-written digits and fashion products, demonstrating all-optical inference and generalization to sub-classes of data. These previous diffractive approaches employed monochromatic coherent light as the illumination Source. Here, we report a Broadband diffractive optical neural network design that simultaneously processes a continuum of wavelengths generated by a temporally incoherent Broadband Source to all-optically perform a specific task learned using deep learning. We experimentally validated the success of this Broadband diffractive neural network architecture by designing, fabricating and testing seven different multi-layer, diffractive optical systems that transform the optical wavefront generated by a Broadband THz pulse to realize (1) a series of tuneable, single-passband and dual-passband spectral filters and (2) spatially controlled wavelength de-multiplexing. Merging the native or engineered dispersion of various material systems with a deep-learning-based design strategy, Broadband diffractive neural networks help us engineer the light-matter interaction in 3D, diverging from intuitive and analytical design methods to create task-specific optical components that can all-optically perform deterministic tasks or statistical inference for optical machine learning.
-
design of task specific optical systems using Broadband diffractive neural networks
arXiv: Neural and Evolutionary Computing, 2019Co-Authors: Yi Luo, Deniz Mengu, Nezih Tolga Yardimci, Yair Rivenson, Muhammed Veli, Mona Jarrahi, Aydogan OzcanAbstract:We report a Broadband diffractive optical neural network design that simultaneously processes a continuum of wavelengths generated by a temporally-incoherent Broadband Source to all-optically perform a specific task learned using deep learning. We experimentally validated the success of this Broadband diffractive neural network architecture by designing, fabricating and testing seven different multi-layer, diffractive optical systems that transform the optical wavefront generated by a Broadband THz pulse to realize (1) a series of tunable, single passband as well as dual passband spectral filters, and (2) spatially-controlled wavelength de-multiplexing. Merging the native or engineered dispersion of various material systems with a deep learning-based design strategy, Broadband diffractive neural networks help us engineer light-matter interaction in 3D, diverging from intuitive and analytical design methods to create task-specific optical components that can all-optically perform deterministic tasks or statistical inference for optical machine learning.
