Through systematic density-functional theory-based ab initio calculations, various performance indicators such as $G/B$, the ratio of shear modulus $G$ over bulk $B$, ${\ensuremath{\sigma}}_{s}/{\ensuremath{\sigma}}_{t}$, ideal strength ${\ensuremath{\sigma}}_{s}$ tensile ${\ensuremath{\sigma}}_{t}$, and Cauchy pressure defined ${C}_{12}\text{\ensuremath{-}}{C}_{44}$ were evaluated for a selection fcc metals assessed in relation to characteristics their electronic distributions obtained from...

The linewidth, the threshold, and frequency shift of stimulated Rayleigh scattering (STRS) in single mode fiber (SMF-28e), large effective area (LEAF) polarization maintaining (PMF) have been studied using heterodyne detection to separate Brillouin with a laser for first time best our knowledge. Experimental results show that linewidth STRS spontaneous are ~9 kHz, ~10 ~11 ~25 ~30 ~27 kHz SMF-28e, LEAF PMF, respectively. threshold power 2 km 7 LEAF, 100 m PMF 11 dBm, 4.5 dBm 16.5 measured...

We have realized a novel tunable narrow linewidth fiber laser with single-longitudinal-mode operation based on the homogenous gain broadening effect of Er-doped and stimulated Rayleigh scattering (STRS) in nonuniform optical ring configuration. A 3 dB less than 2.0 kHz is achieved 70 extinction. The minimum bandwidth determined by balance bandpass filter (in GHz), relaxation time fiber, cavity loss. tuning range within spectrum. This technique applicable to any much higher Brillouin...

Polarization mode dispersion (PMD), which can be induced by circulators or even moderate lengths of optical fiber, is known to a dominant source instrumentation noise in fiber-based PS-OCT systems.In this paper we propose novel PMD compensation method that measures system using three fixed calibration signals, numerically corrects for these instrument effects and reconstructs an improved sample image.Using frequency multiplexed PS-OFDI setup, validate the proposed comparing birefringence...

We present a novel approach for the generation of high extinction-ratio square pulses based on self-phase modulation sinusoidally modulated optical signals (SMOS). A SMOS in nonlinear medium experiences induced by Kerr effect leading to distinct sidebands. small variation peak power leads large Impressing pulse and filtering sideband component results higher pulse. The advantage is demonstrated reduced background noise level Rayleigh backscattering traces phase-OTDR vibration measurement system.

In the present work, semiempirical formulae for both bulk $B$ and shear $G$ moduli of diamondlike zinc-blende covalent crystals are elaborated in terms bond length ionicity fraction bonding. The resulting expressions can be applied to a broad selection materials their modulus predictions good agreement with experimental data those from ab initio calculations. Furthermore, correlation between ratio $G∕B$ aforementioned bonding parameters was investigated. analysis this relationship...

A method for storing optical data pulse sequences, frequency shifted with respect to the original frequency, is theoretically described and experimentally demonstrated. Data pulses are converted into long-living acoustic waves via stimulated Brillouin scattering in fiber by counterpropagating write of one later they retrieved read at a different giving rise frequency-shifted stored pulses. The governed phase-matching condition between wave, which can be satisfied using birefringent fibers....

Brillouin fiber laser with ultranarrow linewidth of 30 Hz is demonstrated for the first time without phase locking loop, operates single longitudinal mode, while mode selection achieved by a Fabry-Perot interferometer and section coreless Farday rotation mirror through optical conjugation, gain provided 25-km fiber. The output factor 100 reductions comparing pump laser. Moreover, exhibits an ultralow-frequency noise (<;15 Hz/Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...

Studies about random lasing phenomena taking place in disordered structures with amplification are gaining great interest, as they can support dual wavelength without cavity length restriction and, hence, the tunable beat frequency a microwave be created and amplified for applications information communication technology. Here, we present novel Brillouin fiber laser scheme using stimulated scattering gain strong Rayleigh feedback (10 km) single-mode fiber. The high degree of mutual coherence...

The distributed temperature profile of hydrogen flame based on optical frequency-domain reflectometry (OFDR) was experimentally demonstrated for the first time. Spatial field at different flow rate H2 monitored by OFDR via a telecom fiber (Corning SMF-28, CPC6) inside over seconds, and highest is sides center separated ∼1.4mm with difference 140∼190°C dimension 2.5 mm above 900°C. Uniformity level studied varying distance between tube entrance, largest uniform region 1-millimeter length...

We report for the first time that transmission of optical pulses centered at a wavelength 1550 nm through tapered dual-core As2Se3-PMMA fiber inscribes an antisymmetric long-period grating. The pulse power is equally divided between even and odd modes superpose along to form intensity distribution. A permanent refractive-index change matches distribution inscribed due photosensitivity central wavelength. evolution spectrum experimentally measured as accumulated exposed increased. theoretical...

Laser with high spectral purity plays a crucial role in high-precision optical metrology and coherent communication. Thanks to the rapid development of laser frequency stabilization, phase noise can be remarkably compensated, allowing its ultra-narrow linewidth subject mostly quantum limit. Nevertheless, accurate characterization statistics highly remains ambiguous challenging. Here, we present an approach capable revealing delay-time-resolved based on time domain reflectometry (COTDR),...

Distributed optical fiber sensors with the capability of dynamic temperature and strain discrimination can be used for various applications, including perimeter security, structural health monitoring, seismic sensing, as they access tolerance structures sites to natural hazards, such earthquakes, fires, overflows. Here, we propose a hybrid Brillouin/Rayleigh sensing system that combines distributed phase matching measurement via Brillouin grating inhomogeneity-induced Rayleigh scatting in...

We present a new all-optical method for the magnification of small-intensity fluctuations using nonlinear Kerr effect. A fluctuation interest is impressed onto sinusoidally modulated optical signals (SMOS) and spectral sidebands are generated as SMOS experiences self-phase modulation in medium. Magnification these temporal variation obtained by filtering one sidebands. For small fluctuations, amount proportional to (2m + 1), with m being sideband order. This technique enhances fiber-based...

Frequency fluctuation is a major problem in high-precision metrology as real-time optical frequency measurement not available with commercial photodetectors; alternatively, frequency-stabilized lasers reference are also accessible most laboratories. In this study, we propose and demonstrate polarization-maintaining random fiber grating ring (PM-RFGR) resonator PM Brillouin laser (BRFL) to achieve sub-MHz drift, which measured by the beat of pump laser. Experimental results show that...

A linearly polarized multi-wavelength Brillouin laser comb in the 1.5-μm telecom spectral window is established by cascading multiple random lasing oscillations a semi-open polarization maintaining fiber (PMF)-based composite cavity. Distributed Rayleigh scattering offers broadband reflector to build up efficient resonance along kilometer-long PMFs, yielding four orders of Stokes radiation with high degree (>99.67%) and extinction ratio >20 dB. Each component kilohertz linewidth as well over...

Synchronously pumped optical parametric oscillators (OPOs) provide ultra-fast light pulses at tuneable wavelengths. Their primary drawback is the need for precise cavity control (temperature and length), with flexibility issues such as fixed repetition rates marginally pulse widths. Targeting a simpler versatile OPO, we explore inherent disorder of refractive index in single-mode fibres realising first random OPO - analogous lasers. This novel approach uses modulation instability (χ(3)...

A vector theoretical model involving the polarization spectrum behavior of stimulated Brillouin scattering (SBS) is proposed. It reveals a phenomenon spectral spreading, i.e., states different frequency components signal light experience distinct SBS pulling. The behaviors in birefringence-free single-mode fiber (SMF), practical SMF, and maintaining (PMF) are investigated by analytical discussion, simulation, experiment. found that arbitrary fiber, concurrent evolution induced birefringence...

The effect of local PMD and PDL directional correlation is considered for the first time in a single mode fiber communication link. It shown that autocorrelation between real imaginary part complex principal state vector nonzero general. Experimental results verifying are reported.

We report the results of our investigations on dispersion compensation fiber optic communication systems in presence nonlinearity by numerically studying impact a Gaussian pulse. Pulse degradation can be reduced significantly optimization map and launch power. Results show importance optimizing along with optimum power to enhance system performance

Phase effect of the optical duobinary (ODB) modulation on chromatic dispersion (CD) tolerance is more important than ODB modulation-induced bandwidth effect. To show this, we evaluate, respectively, filter and phase partial bit delay correlative (PBDCM) CD tolerance. Due to cancellation between CD-induced PBDCM-induced effects, PBDCM method can increase CD-limited transmission 2 ??? 3 times that using standard 1-bit modulation, while optimized by 50% or less, depending input signal format....

A novel method for distributed fiber beat length, birefringence and differential group delay (DGD) measurement based on Brillouin optical time domain analysis (BOTDA) technique is proposed. The difference of local maximum minimum gain determined by scanning input state polarization (SOP) pulsed probe wave to recover length. average DGD measured 100m SMF28 at 1550nm wavelength with 1m spatial resolution 11.8m, 1.4×10^-7 0.21ps respectively.