Optical Time Division Switching Using Multiple Stages of Fiber Optic Delay Lines.

Science.gov (United States)

Spanke, Ronald Anthony

Optical Time Slot Interchanges (OTSIs) can be realized by guided wave LiNbO_3 optical switches performing space division switching of optical fiber delay lines. In this dissertation the problems of reducing the total length of fiber required and also of improving the SNR characteristics of this OTSI function are addressed. Several new OTSI architectures are proposed to reduce the total fiber length while still obtaining excellent SNR characteristics. These reduced fiber architectures include the Distributed Input Delay, Distributed Output Delay, the 2-Stage decomposition and the Distributed Input/Output Delay architectures. A Parallel Feedback (PFB) OTSI architecture is proposed that achieves the theoretical minimum number of delay fibers and the theoretical minimum total length of delay fiber for a given OTSI function. Broadcast OTSI architectures are proposed that enable the data in an incoming time slot to be broadcast to one or more outgoing time slots. These broadcast OTSI architectures include the Time-Dup-Time (TDT) system, Passive Splitter/Active Combiner (PS/AC) equivalents of the point -to-point reduced fiber architectures, and the broadcast PFB architecture. For each of the point-to-point and the broadcast OTSI architectures proposed, a detailed characterization of the architecture is performed including an analysis of number of fibers, total fiber length, number of optical switches and drivers, attenuation and SNR characteristics. This dissertation also proposes several new techniques for improving the system SNR and for calibration of the OTSI architectures. A cascaded noise reduction and a differential attenuation compensation technique are used to achieve a significantly higher system SNR at the output of the OTSI. In-situ calibration techniques are discussed to determine the optimum operating voltages for the LiNbO _3 switches when alternating between states every time slot. These techniques attempt to compensate for an output power drift problem

Improved Resolution Optical Time Stretch Imaging Based on High Efficiency In-Fiber Diffraction.

Science.gov (United States)

Wang, Guoqing; Yan, Zhijun; Yang, Lei; Zhang, Lin; Wang, Chao

2018-01-12

Most overlooked challenges in ultrafast optical time stretch imaging (OTSI) are sacrificed spatial resolution and higher optical loss. These challenges are originated from optical diffraction devices used in OTSI, which encode image into spectra of ultrashort optical pulses. Conventional free-space diffraction gratings, as widely used in existing OTSI systems, suffer from several inherent drawbacks: limited diffraction efficiency in a non-Littrow configuration due to inherent zeroth-order reflection, high coupling loss between free-space gratings and optical fibers, bulky footprint, and more importantly, sacrificed imaging resolution due to non-full-aperture illumination for individual wavelengths. Here we report resolution-improved and diffraction-efficient OTSI using in-fiber diffraction for the first time to our knowledge. The key to overcome the existing challenges is a 45° tilted fiber grating (TFG), which serves as a compact in-fiber diffraction device offering improved diffraction efficiency (up to 97%), inherent compatibility with optical fibers, and improved imaging resolution owning to almost full-aperture illumination for all illumination wavelengths. 50 million frames per second imaging of fast moving object at 46 m/s with improved imaging resolution has been demonstrated. This conceptually new in-fiber diffraction design opens the way towards cost-effective, compact and high-resolution OTSI systems for image-based high-throughput detection and measurement.

Töötervishoid laias maailmas / refereerinud Hubert Kahn

Index Scriptorium Estoniae

2010-01-01

Töötervishoiu uudiseid Hiinast, Jaapanist, Aafrikast ja Euroopast ajakirjadest Asian-Pasific Newsletter on Occupational Health and Safety ja African Newsletter on Occupational Health and Safety (2009) nr. 3

Leading South African lawyer tours Tallinn = Lõuna-Aafrika tippadvokaat Tallinnas / Peter Whelan

Index Scriptorium Estoniae

Whelan, Peter

2007-01-01

Eesti advokaadibüroo Lepik & Luhaäär LAWIN kutsel külastas septembris 2007 Tallinna maailma tuntuima sõltumatute advokaadibüroode assotsiatsiooni Lex Mundi Lõuna-Aafrikast pärit juhatuse liige Peter Whelan

Novosti modõ / Jevgenija Fedorovskaja

Index Scriptorium Estoniae

Fedorovskaja, Jevgenija

2001-01-01

Kõrgmoenädalast Londonis - muudatusi seoses terroriaktiga New Yorgis. Jasper Conrani, Oscar de la Renta, Markus Lüpferi, John Rocha, Londoni kunstnike-dueti Blaak (pärit Lõuna-Aafrikast) kollektsioonidest ja poola kunstniku Arkadiuse art-objektide esitlusest

Mõtisklus kivirannal : Visby rahvusvaheline heliloojate keskus kui loominguline pelgupaik / Mirjam Tally

Index Scriptorium Estoniae

Tally, Mirjam, 1976-

2008-01-01

Gotlandi saarel asuvast heliloojate keskusest. Lühiintervjuu hiljuti keskuses töötanud kahe heliloojaga - Lõuna-Koreast pärit, ent Floridas elava Suk-Jun Kim'i ja Lõuna-Aafrikast vabariigist pärit Clare Loveday'ga

Jumalaema kiriku kellamees tuli Tartu Toome varemetesse / Andres Laasik

Index Scriptorium Estoniae

Laasik, Andres, 1960-2016

2007-01-01

13. juulil esietendus Emajõe Suveteatris "Jumalaema kiriku kellamees". Victor Hugo romaani järgi tegi instseneeringu Urmas Lennuk, lavastaja Andres Dvinjaninov. Mängitakse Tartu Toomkiriku varemetes

A theory of solar type III radio bursts

International Nuclear Information System (INIS)

Goldstein, M.L.; Smith, R.A.

1979-01-01

A theory of type III bursts is reviewed. Energetic electrons propagating through the interplanetary medium are shown to excite the one dimensional oscillating two stream instability (OTSI). The OTSI is in turn stabilized by anomalous resistivity which completes the transfer of long wavelength Langmuir waves to short wavelengths, out of resonance with the electrons. The theory explains the small energy losses suffered by the electrons in propagating to 1 AU, the predominance of second harmonic radiation, and the observed correlation between radio and electron fluxes. (Auth.)

Kliimamuutus ajas ürginimese rändama / Kaarel Kressa

Index Scriptorium Estoniae

Kressa, Kaarel, 1983-

2008-01-01

DNA abil inimeste iidseid rändeteid uuriva projekti "Geneographic" teadlased kinnitasid seni teada olnud tõde, et kõik maailma rahvad on alguse saanud kunagi Aafrikast välja rännanud eellastest. Vastavasisulise loenguga esines Rahvusraamatukogus geeniteadlane Spencer Wells

Evidence for four- and three-wave interactions in solar type III radio emissions

Directory of Open Access Journals (Sweden)

G. Thejappa

2013-08-01

Full Text Available The high time resolution observations obtained by the STEREO/WAVES experiment show that in the source regions of solar type III radio bursts, Langmuir waves often occur as intense localized wave packets with short durations of only few ms. One of these wave packets shows that it is a three-dimensional field structure with WLneTe ~ 10−3, where WL is the peak energy density, and ne and Te are the electron density and temperature, respectively. For this wave packet, the conditions of the oscillating two-stream instability (OTSI and supersonic collapse are satisfied within the error range of determination of main parameters. The density cavity, observed during this wave packet indicates that its depth, width and temporal coincidence are consistent with those of a caviton, generated by the ponderomotive force of the collapsing wave packet. The spectrum of each of the parallel and perpendicular components of the wave packet contains a primary peak at fpe, two secondary peaks at fpe ± fS and a low-frequency enhancement below fS, which, as indicated by the frequency and wave number resonance conditions, and the fast Fourier transform (FFT-based tricoherence spectral peak at (fpe, fpe, fpe + fS, fpe − fS, are coupled to each other by the OTSI type of four-wave interaction (fpe is the local electron plasma frequency and fS is the frequency of ion sound waves. In addition to the primary peak at fpe, each of these spectra also contains a peak at 2fpe, which as indicated by the frequency and wave number resonance conditions, and the wavelet-based bicoherence spectral peak at (fpe, fpe, appears to correspond to the second harmonic electromagnetic waves generated as a result of coalescence of oppositely propagating sidebands excited by the OTSI. Thus, these observations for the first time provide combined evidence that (1 the OTSI and related strong turbulence processes play a significant role in the stabilization of the electron beam, (2 the coalescence

Getter Jaani osaleb nukuteatri muusikalis / Karilin Engelbrecht

Index Scriptorium Estoniae

Engelbrecht, Karilin

2009-01-01

2010. aasta kevadel jõuab nukuteatri lavale Walt Disney menufilmi "High School Musical" samanimeline muusikal kohalike lauljate esituses. Tüdrukutest peetakse suurimaks favoriidiks Getter Jaanit. Muusikali lavastab Andres Dvinjaninov

Tipprežissöör Leni / Tiit Tuumalu

Index Scriptorium Estoniae

Tuumalu, Tiit, 1971-

2004-01-01

Eesti Televisioon näitab kaht legendaarse Leni Riefenstahli (1902-2003) osalusega dokumentaalfilmi - "Leni Riefenstahl : Unistus Aafrikast" : režissöör Ray Müller : Saksamaa 2000 ja "Vetesügavuste lummus" : režissöör Leni Riefenstahl : Saksamaa 2002

Aafrika kunst Rakveres / Teet Veispak

Index Scriptorium Estoniae

Veispak, Teet, 1955-

2003-01-01

4. VIII Rakvere Kesklinna galeriis avatav näitus tutvustab Lääne-Aafrikast (Burkina Faso, Ghana ja Elevandiluuranniku lobide ning Elevandiluuranniku baoulede kunst) pärit rituaalseid ja olmelisi objekte. Koostaja Roger-Pierre Turine. Eksponeeritud Kadri Viirese fotod nende rahvaste kodukandist

Armastusest ja ebausust Tartu Toomkirikus / Katre Väli

Index Scriptorium Estoniae

Väli, Katre

2007-01-01

13. juulil esietendus Emajõe Suveteatris "Jumalaema kiriku kellamees". Victor Hugo romaani järgi tegi instseneeringu Urmas Lennuk, lavastaja Andres Dvinjaninov, kujundus Iir Hermeliinilt. Mängitakse Tartu Toomkiriku varemetes

Suveteatri juubelikellad Toomel / Kadri Selge

Index Scriptorium Estoniae

Selge, Kadri

2007-01-01

13. juulil esietendus Emajõe Suveteatris "Jumalaema kiriku kellamees". Victor Hugo romaani järgi tegi instseneeringu Urmas Lennuk, lavastaja Andres Dvinjaninov, kujundus Iir Hermeliinilt. Mängitakse Tartu Toomkiriku varemetes

Teater

Index Scriptorium Estoniae

2005-01-01

Eesti Nukuteater osaleb Valgevenes 12.-17. IX Bresti rahvusvahelisel draama-, muusika-, tantsu- ja nukuteatrite festivalil "Belaja Vezha - 2005". Mängitakse A. Perviku "Kunksmoori", dramatiseerija, lavastaja ja muusika autor A. Dvinjaninov

Viis meest ja kolm saatuslikku naist / Heili Vaus-Tamm

Index Scriptorium Estoniae

Vaus-Tamm, Heili, 1961-

2009-01-01

Muusikalisest etendusest "Saatuslik naine" Saint-Saensi ooperi "Simson ja Delila", Massenet' ooperi "Don Quijote" ja Bizet' ooperi "Carmen" põhjal 14. aprillil Vene kultuurikeskuses, esinesid Jaroslava Kozina, Andres Dvinjaninov ja SaxEst

Elina Reinold: "Laulmine - see tõesti pole minu ampluaa" / Aigi Viira

Index Scriptorium Estoniae

Viira, Aigi

2006-01-01

Näitleja, kes mängib peaosa Urmas Lennuki lavaloos "Koidula", lavastaja Andres Dvinjaninov. Esietendus 29. juunil Tartus Jaama 14 pargis. Lisaks ülevaade "Elina Reinoldi teatritoimimised" ja tutvustus "Koidula vaatab tagasi"

Kirikukell kuuseladvas ja äraõitsenud pärn / Pille-Riin Purje

Index Scriptorium Estoniae

Purje, Pille-Riin, 1963-

2006-01-01

Endla teatri ja Rakvere Teatri ühisest suvelavastusest "Vargamäe kuningriik" A. H. Tammsaare "Tõe ja õiguse" I ja V osa ainetel (lavastaja Jaanus Rohumaa) ja Urmas Lennuki "Koidula" Emajõe Suveteatris (lavastaja Andres Dvinjaninov)

Tele2 kutsus kliendid teatrisse ja kontsertidele

Index Scriptorium Estoniae

2007-01-01

Suvel kutsus Tele 2 kliendid Victor Hugo loo "Jumalaema kiriku kellamees" muusikalisele vaatemängule Tartus (lavastajad Urmas Lennuk ja Andres Dvinjaninov), Muhu Tulevikumuusika festivalile "Juu Jääb" ja Tallinna Linnateatri suvelavastusele "Ronk" (lavastaja Elmo Nüganen)