Coherent averaging in the frequency domain.
Ontology highlight
ABSTRACT:
SUBMITTER: Khitrin AK
PROVIDER: S-EPMC3377367 | biostudies-other | 2012 Jun
REPOSITORIES: biostudies-other
Similar Datasets
Project description:The dependence of various types of linear signals on the phase profile of broadband optical pulses is examined using fundamental time translation invariance symmetry of multipoint correlation functions. The frequency-domain wave-mixing analysis presented here unifies several arguments made earlier with respect to the conditions whereby coherent control schemes may be used.
| S-EPMC3825527 | biostudies-other
Project description:We present a comprehensive analysis of a frequency multiplexed phase-measuring φ-OTDR sensor platform. The system uses a train of frequency-shifted pulses to increase the average power injected into the fiber and provide a diversity of uncorrelated Rayleigh backscattering measurements. Through a combination of simulations, numerical analysis, and experimental measurements, we show that this approach not only enables lower noise and mitigates interference fading, but also improves the sensor linearity. We investigate the sensor dependence on the length of the pulse train and characterize the sensor performance as a function of range, demonstrating operation from 1 to 50 km. Despite its relative simplicity, this platform enables state-of-the-art performance, including low crosstalk, high linearity, and a minimum detectable strain of only 0.6 p[Formula: see text] in a 10 km fiber with 10 m spatial resolution and a bandwidth of 5 kHz.
| S-EPMC8429562 | biostudies-literature
Project description:Fiber-optical networks are a crucial telecommunication infrastructure in society. Wavelength division multiplexing allows for transmitting parallel data streams over the fiber bandwidth, and coherent detection enables the use of sophisticated modulation formats and electronic compensation of signal impairments. Optical frequency combs can replace the multiple lasers used for the different wavelength channels. Beyond multiplexing, it has been suggested that the broadband phase coherence of frequency combs could simplify the receiver scheme by performing joint reception and processing of several wavelength channels, but an experimental validation in a fiber transmission experiment remains elusive. Here we demonstrate and quantify joint reception and processing of several wavelength channels in a full transmission system. We demonstrate two joint processing schemes; one that reduces the phase-tracking complexity and one that increases the transmission performance.
| S-EPMC6954261 | biostudies-literature
Project description:Optical frequency combs have the potential to revolutionize terabit communications1. Generation of Kerr combs in nonlinear microresonators2 represents a particularly promising option3 enabling line spacings of tens of GHz. However, such combs may exhibit strong phase noise4-6, which has made high-speed data transmission impossible up to now. Here we demonstrate that systematic adjustment of pump conditions for low phase noise4,7-9 enables coherent data transmission with advanced modulation formats that pose stringent requirements on the spectral purity of the comb. In a first experiment, we encode a data stream of 392 Gbit/s on a Kerr comb using quadrature phase shift keying (QPSK) and 16-state quadrature amplitude modulation (16QAM). A second experiment demonstrates feedback-stabilization of the comb and transmission of a 1.44 Tbit/s data stream over up to 300 km. The results show that Kerr combs meet the highly demanding requirements of coherent communications and thus offer an attractive solution towards chip-scale terabit/s transceivers.
| S-EPMC4028627 | biostudies-literature
Project description:Optical multi-dimensional coherent spectroscopy is a powerful technique for studying the structure, properties and ultrafast dynamics of atoms, molecules, semiconductor materials and complex systems. Current implementations of multi-dimensional coherent spectroscopy have long acquisition times and/or limited spectral resolution. In addition, most of the techniques utilize complex geometries or phase cycling schemes to isolate non-linear signals. We demonstrate a novel approach of using frequency combs to perform rapid, high resolution and background free multi-dimensional coherent spectroscopy of semiconductor materials. Our approach is inspired by dual-comb spectroscopy, which has been proven to be a versatile tool for obtaining one dimensional absorption spectra with high resolution in a short acquisition time. We demonstrate the method using a GaAs multi-quantum well sample.
| S-EPMC5656649 | biostudies-literature
Project description:We demonstrate low-frequency interferometric impulsive stimulated Raman scattering (ISRS) imaging with high robustness to distortions by optical scattering. ISRS is a pump-probe coherent Raman spectroscopy that can capture Raman vibrational spectra. Recording of ISRS spectra requires isolation of a probe pulse from the pump pulse. While this separation is simple in nonscattering specimens, such as liquids, scattering leads to significant pump pulse contamination and prevents the extraction of a Raman spectrum. We introduce a robust method for ISRS microscopy that works in complex scattering samples. High signal-to-noise ISRS spectra are obtained even when the pump and probe pulses pass through many scattering layers.
| S-EPMC11351428 | biostudies-literature
Project description:Frequency modulated continuous wave laser ranging (FMCW LiDAR) enables distance mapping with simultaneous position and velocity information, is immune to stray light, can achieve long range, operate in the eye-safe region of 1550 nm and achieve high sensitivity. Despite its advantages, it is compounded by the simultaneous requirement of both narrow linewidth low noise lasers that can be precisely chirped. While integrated silicon-based lasers, compatible with wafer scale manufacturing in large volumes at low cost, have experienced major advances and are now employed on a commercial scale in data centers, and impressive progress has led to integrated lasers with (ultra) narrow sub-100 Hz-level intrinsic linewidth based on optical feedback from photonic circuits, these lasers presently lack fast nonthermal tuning, i.e. frequency agility as required for coherent ranging. Here, we demonstrate a hybrid photonic integrated laser that exhibits very narrow intrinsic linewidth of 25 Hz while offering linear, hysteresis-free, and mode-hop-free-tuning beyond 1 GHz with up to megahertz actuation bandwidth constituting 1.6 × 1015 Hz/s tuning speed. Our approach uses foundry-based technologies - ultralow-loss (1 dB/m) Si3N4 photonic microresonators, combined with aluminium nitride (AlN) or lead zirconium titanate (PZT) microelectromechanical systems (MEMS) based stress-optic actuation. Electrically driven low-phase-noise lasing is attained by self-injection locking of an Indium Phosphide (InP) laser chip and only limited by fundamental thermo-refractive noise at mid-range offsets. By utilizing difference-drive and apodization of the photonic chip to suppress mechanical vibrations of the chip, a flat actuation response up to 10 MHz is achieved. We leverage this capability to demonstrate a compact coherent LiDAR engine that can generate up to 800 kHz FMCW triangular optical chirp signals, requiring neither any active linearization nor predistortion compensation, and perform a 10 m optical ranging experiment, with a resolution of 12.5 cm. Our results constitute a photonic integrated laser system for scenarios where high compactness, fast frequency actuation, and high spectral purity are required.
| S-EPMC9209488 | biostudies-literature
Project description:Photon loss in optical fibers prevents long-distance distribution of quantum information on the ground. Quantum repeater is proposed to overcome this problem, but the communication distance is still limited so far because of the system complexity of the quantum repeater scheme. Alternative solutions include transportable quantum memory and quantum-memory-equipped satellites, where long-lived optical quantum memories are the key components to realize global quantum communication. However, the longest storage time of the optical memories demonstrated so far is approximately 1 minute. Here, by employing a zero-first-order-Zeeman magnetic field and dynamical decoupling to protect the spin coherence in a solid, we demonstrate coherent storage of light in an atomic frequency comb memory over 1 hour, leading to a promising future for large-scale quantum communication based on long-lived solid-state quantum memories.
| S-EPMC8062444 | biostudies-literature
Project description:Coherent longitudinal acoustic phonon is generated and detected in multilayer Molybdenum Disulphide (MoS2) with number of layers ranging from 10 to over 1300 by femtosecond laser pulse. For thin MoS2, the excited phonon frequency exhibits a standing wave nature and shows linear dependence on the sample thickness. The frequency varies from 40 GHz to 0.2 THz (10 layers), which promises possible application in THz frequency mechanical resonators. This linear thickness dependence gradually disappears in thicker samples above about 150 layers, and the oscillation period shows linear dependence on the probe wavelength. From both the oscillation period of the coherent phonon and the delay time of acoustic echo, we can deduce a consistent sound velocity of 7.11*10(3) m/s in MoS2. The generation mechanisms of the coherent acoustic phonon are also discussed through pump power dependent measurement.
| S-EPMC4101472 | biostudies-literature
Project description:Optomechanical cavities have been studied for applications ranging from sensing to quantum information science. Here, we develop a platform for nanoscale cavity optomechanical circuits in which optomechanical cavities supporting co-localized 1550 nm photons and 2.4 GHz phonons are combined with photonic and phononic waveguides. Working in GaAs facilitates manipulation of the localized mechanical mode either with a radio frequency (RF) field through the piezo-electric effect, which produces acoustic waves that are routed and coupled to the optomechanical cavity by phononic crystal waveguides, or optically through the strong photoelastic effect. Along with mechanical state preparation and sensitive readout, we use this to demonstrate an acoustic wave interference effect, similar to atomic coherent population trapping, in which RF-driven coherent mechanical motion is cancelled by optically-driven motion. Manipulating cavity optomechanical systems with equal facility through both photonic and phononic channels enables new architectures for signal transduction between the optical, electrical, and mechanical domains.
| S-EPMC4941791 | biostudies-literature