Higher order soliton pulse compression in dispersion-decreasingoptical fibers

Compression of higher order optical solitons in fibers with anomalous dispersion decreasing along their length is investigated. We demonstrate high-quality compression of pulses with initial soliton order 1相似文献   

Cervical intraepithelial neoplasia in HIV seropositive patients

In order to assess the frequency of cervical intraepithelial neoplasia (CIN) in a high risk population, 32 women infected with human immunodeficiency virus (HIV), with no AIDS-related symptoms, underwent colposcopic, cytologic and histologic examinations of the uterine cervix. In seven cases (21.9%) cervical smears showed dysplasia and in nine cases (28.1%) histologic evaluation indicated CIN. No invasive carcinomas were observed. In seven of the nine women CIN was associated with lesions due to human papillomavirus infection (HPV). These data confirm that HIV-positive women are at increased risk for developing neoplasias in the lower genital tract and are in need of regular and careful cytologic and, in particular, colposcopic and histologic examinations.     

Applications of Highly-Nonlinear Chalcogenide Glass Devices Tailored for High-Speed All-Optical Signal Processing

Ultrahigh nonlinear tapered fiber and planar rib Chalcogenide waveguides have been developed to enable highspeed all-optical signal processing in compact, low-loss optical devices through the use of four-wave mixing (FWM) and cross-phase modulation (XPM) via the ultra fast Kerr effect. Tapering a commercial As₂Se₃ fiber is shown to reduce its effective core area and enhance the Kerr nonlinearity thereby enabling XPM wavelength conversion of a 40 Gb/s signal in a shorter 16-cm length device that allows a broader wavelength tuning range due to its smaller net chromatic dispersion. Progress toward photonic chip-scale devices is shown by fabricating As₂S₃ planar rib waveguides exhibiting nonlinearity up to 2080 W^-1ldr km^-1 and losses as low as 0.05 dB/cm. The material's high refractive index, ensuring more robust confinement of the optical mode, permits a more compact serpentine-shaped rib waveguide of 22.5 cm length on a 7-cm- size chip, which is successfully applied to broadband wavelength conversion of 40-80 Gb/s signals by XPM. A shorter 5-cm length planar waveguide proves most effective for all-optical time-division demultiplexing of a 160 Gb/s signal by FWM and analysis shows its length is near optimum for maximizing FWM in consideration of its dispersion and loss.     

Fourth-order dispersion compensation for 250-fs pulse transmissionover 139-km optical fiber

Record distance transmission of 250-fs pulses over 139-km optical fiber at 6-GHz repetition is realized by compensating chromatic dispersion up to fourth-order using a novel approach. The link is designed combining 108.5-km standard single-mode fiber (SMF), 17.5-km dispersion-shifted fiber, and 13-km negative-slope dispersion-compensating fiber to achieve both zero total chromatic dispersion and slope at the 1.55-μm carrier. Fourth-order pulse dispersion caused by the fiber dispersion curvature around 1.55 μm is then suppressed by adding the quadratic phase of opposite sign from excess SMF to produce 503-fs output. However, both higher quality and shorter 390-fs output is achieved after applying 6-GHz electrooptic phase modulation (3.5 π O-peak) to prestretched pulses and adding a further 50-m SMF to the link     

Generation of 20-fs optical pulses from a gain-switched laser diodeby a four-stage soliton compression technique

7.5-ps optical pulses generated from a gain-switched semiconductor laser at 2 GHz are successfully compressed down to 20 fs using a four-stage fiber soliton pulse compressor consisting of standard single-mode transmission, Er-doped, dispersion-decreasing, and dispersion-flattened fibers, respectively. We have experimentally confirmed that the soliton self-frequency shift plays an important role in obtaining such high compression in very short fibers, and also in minimizing the inherent undesirable pedestal component     

A framework for crime data analysis using relationship among named entities

Neural Computing and Applications - Many crime reports are available online in various blogs and Newswire. Though manual annotation of these massive reports is quite tedious for crime data...     

Intelligent system for COVID-19 prognosis: a state-of-the-art survey

Applied Intelligence - This 21st century is notable for experiencing so many disturbances at economic, social, cultural, and political levels in the entire world. The outbreak of novel corona virus...     

Subpicosecond pulse transmission over 144 km using midway opticalphase conjugation via a cascaded second-order process in a LiNbO3 waveguide

We demonstrate for the first time the feasibility of 600-fs pulse transmission over 144 km using midway optical phase conjugation via a cascaded second-order process in a periodically poled LiNbO₃ waveguide. The output pulses are negligibly distorted and broadened to 680 fs. This result could not be obtained without complete compensation for fourth-order dispersion performed by midway optical phase conjugation     

EEG data analysis with stacked differentiable neural computers

Neural Computing and Applications - Differentiable neural computer (DNC) has demonstrated remarkable capabilities in solving complex problems. In this paper, we propose to stack an enhanced version...     

Pedestal suppression from compressed femtosecond pulses using anonlinear fiber loop mirror

The compression of higher order soliton pulses in dispersion decreasing fibers (DDF's) generates ultrashort fundamental soliton-like pulses accompanied by a broad low-intensity pedestal component. In this paper, we investigate the subsequent removal of the pedestal using a nonlinear optical fiber loop mirror (NOLM) to produce high-quality pulses. The influence of higher order effects such as stimulated Raman scattering and third-order fiber dispersion on the pedestal removal from ultrashort pulses are considered, and the effectiveness of using dispersion-flattened fiber within the loop is shown. The technique is experimentally demonstrated for 540-fs pulses generated by compression in DDF. In this case, high-quality pulses are produced by pedestal removal using a NOLM constructed from dispersion-shifted fiber