We propose and demonstrate an all-fiber passively mode-locked laser with a figure-8 cavity, which generates pulsed cylindrical vector beam output based on mode selective coupler (MSC). The MSC made of two fiber standard single is used as both the intracavity transverse converter splitter low insertion loss about 0.65 dB. slope efficiency > 3%. Through adjusting polarization state in radially azimuthally polarized beams have been obtained high purity are measured to be 94%. operates at 1556.3...

This paper proposes a novel error-compensation model that can effectively reduce the impact of incident angle error laser displacement sensor (LDS) measures accuracy. The triangulation method is an effective measurement. It characterized by non-contact, large measuring range and high efficiency. However, measurement accuracy affected incidence angle. To improve accuracy, practical strategy presented. experiment was carried out using standard hard alloy ball calibration LDS. By introducing...

This paper proposes a rapid method to detect aero-engine blade form, according the characteristics of an surface. first deduces inclination error model in free-form surface measurements based on non-contact laser triangulation principle. Then four-coordinate measuring system was independently developed, special fixture designed shape features, and fast measurement features path planned. Finally, by using for correction acquired data, that caused tilt form is compensated. As result accuracy...

We demonstrate a scheme for long-range, high-precision absolute distance measurement based on frequency detection using two optoelectronic oscillators to convert information information. The two-oscillator design offers the unique advantage of self-referencing. By taking accumulative magnification theory, error measured is decreased by approximately 10⁵ fold, which significantly improves precision distance. In our experiments, maximum ±1.5 μm at an emulated 3.35 km, including drift 1 in air...

We experimentally demonstrate simultaneous 3R regeneration of 4 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\times$ </tex></formula> 40-Gbit/s WDM channels, which is based on the four-wave mixing (FWM) in a single dispersion-shifted fiber. The multichannel performance validated by bit-error rate (BER) measurements. Receiver powers at BER Notation="TeX">$10^{-9}$</tex></formula> are improved 5.2...

A new charge-coupled device (CCD) spectrometer has been studied and constructed by using a two-dimensional CCD detector an integrated grating consisting of 10 subgratings. Effective spectral images 268 mm along the dispersion direction have densely folded times to cover full 200-1000 nm working wavelength range without any mechanical moving elements. The results show that system resolution acquisition time better than 0.07 less 100 ms, respectively, in entire after calibration.

Objective Previous studies have shown that patients with obstructive sleep apnea syndrome (OSAS) may various vestibular abnormalities, and these mainly present as subclinical lesions. In this study, we attempted to combine ocular vestibular-evoked myogenic potentials (VEMPs) cervical investigate dysfunction in OSAS. Methods Thirty-eight severe OSAS 42 healthy controls were enrolled divided into two groups according results of polysomnography. All parameters VEMP graphs analyzed. Results The...

Objective To determine the effect of personalized psychological interventions on recovery patients with sudden deafness. Methods Participants were 438 deafness who randomly allocated to observation and control groups. Patients in group received routine nursing care drug treatment. interventions, The Self-Rating Anxiety Scale (SAS) Depression (SDS) used measure anxiety depression. Simple Coping Style Questionnaire (SCSQ) Satisfaction With Life (SWLS) evaluate coping styles, attitude toward...

A new type of infrared spectrometer system working in the optical communication field has been studied and constructed. In order to achieve both high spectral resolution fast data acquisition speed, an integrated grating with five subgratings a set line-array InGaAs detectors are used work 1450–1650nm wavelength range without any scanning mechanical moving parts. The calibrated about 0.08nm time less than 40ms (&amp;gt;5nm∕ms) entire range.

The Laser Displacement Sensor is designed according to the principle of laser triangulation. It a precise geometric measurement sensor, and it characterized by non-contact high measuring efficiency. However, accuracy LDS easily influenced other factors, especially for free-form surfaces where incidence angle has greater impact on research relatively less. paper proposes new error compensation strategy method calculating angle. can effectively improve inclination compensation. experiment...

Aiming at the application of a 2D laser profile sensor in detection an aero-engine blade surface, three-point alignment transformation algorithm based on single-standard ball is proposed. In algorithm, standard used to measure coordinate conversion reference, and three characteristic points, such as center ball, vertex, side extremum, are scanned by using once. When measuring rotated blade, scans again, values feature points new system obtained through technology. With these pairs reference...

A corner cube (CC) as a peculiar coherent combination element is first, to the best of our knowledge, theoretically and experimentally proved by authors. When CC used total-reflecting mirror in solid-state laser resonator it can improve far-field energy focalization. Furthermore, differences between characteristics lasers with (CCR) those Fabry–Perot have been investigated, respectively. Theoretical calculation numerical simulation that symmetric output beams CCR are adjacent partially...

Abstract As an advanced optical precision ranging method, FMCW (frequency-modulated continuous-wave) laser interferometric technology can achieve a large-scale and high-precision absolute distance measurement, so it has high research application value in the field of coordinate measurement large space. How to improve resolution stability interferometry is difficulty this technology. Based on relative technology, method for achieving through phase comparison after repeated sampling proposed....

Surface morphology measurement and reconstruction technology based on point cloud data is one of the key technologies for 3D information processing in digital manufacturing industry has been widely applied fields such as reverse engineering, computer vision, unmanned driving system navigation. A method modeling aircraft-engine blade profiles laser proposed to address difficulties measuring blades low accuracy. This first preprocesses measured then uses Poisson's algorithm reconstruct surface...

Based on the atmospheric molecular Doppler wind lidar system using dual-channel Mach–Zehnder interferometer (DMZI) double-edge detection, two important DMZI parameters, such as optical path difference and beam splitter transmittance, are analyzed. Furthermore, changes in transmission response, speed sensitivity, measurement errors of caused by these parameters simulated. The ratio between error non-optimal parameter optimal to at is defined an proportion factor, which can be used...

由于边界网关协议(Border Gateway Protocol, BGP)存在安全问题，路径信息(AS_PATH属性)易遭受各种攻击。已有的路径验证方案中，过程复杂和开销巨大严重阻碍了方案的实际部署。基于对AS_PATH属性的分析，该文提出一种轻量化的BGP路径验证机制FTAPV(First-Two-AS based Path Verification)。FTAPV中，更新报文只需要携带AS_PATH中前两个AS的签名信息就可以有效地为路径信息提供保护。安全分析和性能评估表明，与已有方案相比，该机制在保证安全能力的同时，有效地减少了路由资源的消耗和所需证书的规模，具有良好的可扩展性。

To study concomitant symptoms and disease conditions in sudden deafness. Clinical data of 418 cases deafness treated this department from 2000 to 2007 were reviewed. Of the cases, 201 males 217 females. Right ear was involved 184 left 191 cases. Bilateral involvement seen 43 The average age 44.1 years. Tinnitus reported 369 (88.3%) either before or after hearing loss, which 64.5% low pitch, 27.1% high pitch 8.4% mixed tones. Constant tinnitus 83% muffled feelings 33.3% Hearing loss only...

Phase-locking and coherent beam combination of two individual double-clad fibre lasers by a novel extra-cavity mutual injection-locking method are proposed experimentally demonstrated. Steady interference stripes with high contrast ratio (about 0.5) observed. The output power the phase-locked array exceeds 11 W power-combining efficiency is about 80%. No power-restriction optical components utilised in phase-locking experiment can be further up-scaled.

Frequency-modulated continuous-wave(FMCW) interference measurement has the advantages of length traceability, large range, high precision, simple structure and optical fibre transmission. Based on characteristics axial inductance sensor, a novel laser displacement sensor is developed. The formula FMCW ranging derived in detail mechanical system contact are designed. Integrating interferometric path into rod, converting non-contact with cooperative targets can realize direct workpieces...

This work presents a high-precision fiber optic pressure sensor based on frequency-modulated continuous-wave (FMCW) laser interference. The is primarily composed of diaphragm-type Fabry–Pérot (F–P) cavity, with the diaphragm fabricated using high-elasticity SUS631 stainless steel. external air causes center elastic to deform, and this deformation results in change F–P cavity length. FMCW laser-interference method was used demodulate length realize measurements. experimental showed that when...