Progress in ultra-high modulation efficiency tapered lasers for free-space communications

Simultaneous high power (2W), high modulation speed (1Gb/s) and high modulation efficiency (14 W/A) operation of a two-electrode tapered laser is reported. © 2011 IEEE.

Radio over free space optical link using a directly modulated two-electrode high power tapered laser

The analog modulation performance of a high-power two-electrode tapered laser is investigated. A 25dB dynamic range for 2.4GHz 802.11g signals is achieved with a 26dB loss budget, showing a >1km free space range is possible. © 2010 Optical Society of America.

Gigabit/s modulation of twin-electrode high-brightness tapered laser with high modulation efficiency

Simultaneous high modulation speed and high modulation efficiency operation of a two-electrode tapered laser is reported. 1Gb/s direct data modulation is achieved with 68mA applied current swing for a 0.95W output optical modulation amplitude. © 2009 Optical Society of America.

Życie po wybuchu. Refleksy transformacji w czeskiej dramaturgii po 1989 roku

Niniejszy esej poświęcony jest analizie czeskich, teatralnych refleksji na temat rzeczywistości po transformacji politycznej. Przegląd wybranych sztuk, powstałych w latach 1994-2006, zawiera krótkie literaturoznawcze opracowania tekstów M. Bambuška, L. Baláka i J. Topola, dopełnione uwagami na temat dzieł D. Drábka i M. Urbana. Skatalogowano powtarzające się w sztukach wymienionych autorów motywy: czekania na barbarzyńców, poczucia epistemologicznego i społecznego chaosu, neotrybalizmu i spustoszenia w dziedzinie międzyludzkiej komunikacji (kryzys języka). Pomocną kategorią, wywodzącą się z amerykańskiej socjologii, jest backlash: stan po wybuchu. Backlash jest stanem psychologicznym (również w sensie psycho- logii społecznej), który skłania do podejmowania decyzji nieracjonalnych i niebezpiecznych, służących wyłącznie zniesieniu poczucia niepewności i tęsknoty. Ten stan obserwują i komentują wymienieni autorzy sztuk teatralnych.

Dziecko przedszkolne i wczesnoszkolne wobec literatury i sztuki. Programy, praktyki, propozycje

Wydział Filologii Polskiej i Klasycznej

L’IMMAGINE RIFLESSA: Una lettura antropologico-culturale del teatro di Grotowski. La (de)costruzione dell’identità del Performer tra Parateatro e Teatro delle Fonti

Il continuo sdoppiamento e la riverberazione sono le matrici di sviluppo di questa tesi, in cui le ricerche di Grotowski legate al Parateatro e al Teatro delle Fonti sono indagate e interpretate a partire da un pensiero polivalente che prende avvio nella sociologia della cultura e si radica in un terreno antropologico. La ricerca si configura come un’interpretazione possibile delle scelte operate da Grotowski e, complessivamente, dal Teatro Laboratorio, nel contesto delle trasformazioni socio-culturali successive agli anni Sessanta verificando come nel periodo dal '70 all'82 le scelte stesse rispecchino i valori culturali dell’epoca.La ricerca ricorre alla categoria della “festa” - intesa come realtà quotidiana elevata alla forma rituale, attraverso gli elementi culturali e identitari del gruppo di appartenenza - e, a partire da essa, sovrappone criticamente la logica dell’“identità in performance” con la nozione di “Incontro” elaborata da Grotowski. Questa logica è, successivamente, problematizzata attraverso il “diamante culturale”, un dispositivo di analisi della sociologia della culturache, a sua volta, è discusso eridimensionato a partire dalpresuppostodi “Decostruzione” e dall’idea di “Decondizionamento”legata al lavoro del Performer, inteso come individuo.Tre immagini e un’incognita rivelano i campi d’azioneed i principi che permeano l’intera ricerca raddoppiandosi e congiungendo l’immagine del Performer come individuo riflessivo. L’immagine riflessa si configura nel contrasto fra apparenza e presenza: nella domanda posta da Grotowski “che si può fare con la propria solitudine?” si evidenzia uno dei problemi a cui deve far fronte l’individuo in una determinata struttura culturale e, al contempo, viene suggerita una possibilità di amplificazione della percezione di “se stesso” da parte dell’Attore-Performer come Individuo.

Judišer wahlglok : an di ernsṭe judiše wehler in Wien

Digitalisat der Ausg. Wien, [1928]

High-brightness all semiconductor laser at 1.57 µm for space-borne lidar measurements of atmospheric carbon dioxide: device design and analysis of requirements

The availability of suitable laser sources is one of the main challenges in future space missions for accurate measurement of atmospheric CO2. The main objective of the European project BRITESPACE is to demonstrate the feasibility of an all-semiconductor laser source to be used as a space-borne laser transmitter in an Integrated Path Differential Absorption (IPDA) lidar system. We present here the proposed transmitter and system architectures, the initial device design and the results of the simulations performed in order to estimate the source requirements in terms of power, beam quality, and spectral properties to achieve the required measurement accuracy. The laser transmitter is based on two InGaAsP/InP monolithic Master Oscillator Power Amplifiers (MOPAs), providing the ON and OFF wavelengths close to the selected absorption line around 1.57 µm. Each MOPA consists of a frequency stabilized Distributed Feedback (DFB) master oscillator, a modulator section, and a tapered semiconductor amplifier optimized to maximize the optical output power. The design of the space-compliant laser module includes the beam forming optics and the thermoelectric coolers.The proposed system replaces the conventional pulsed source with a modulated continuous wave source using the Random Modulation-Continuous Wave (RM-CW) approach, allowing the designed semiconductor MOPA to be applicable in such applications. The system requirements for obtaining a CO2 retrieval accuracy of 1 ppmv and a spatial resolution of less than 10 meters have been defined. Envelope estimated of the returns indicate that the average power needed is of a few watts and that the main noise source is the ambient noise.

Monolithic master oscillator power amplifier at 1.58 µm for lidar measurements

Nowadays the interest in high power semiconductor devices is growing for applications such as telemetry, lidar system or free space communications. Indeed semiconductor devices can be an alternative to solid state lasers because they are more compact and less power consuming. These characteristics are very important for constrained and/or low power supply environment such as airplanes or satellites. Lots of work has been done in the 800-1200 nm range for integrated and free space Master Oscillator Power Amplifier (MOPA) [1]-[3]. At 1.5 ?m, the only commercially available MOPA is from QPC [4]: the fibred output power is about 700 mW and the optical linewidth is 500 kHz. In this paper, we first report on the simulations we have done to determine the appropriate vertical structure and architecture for a good MOPA at 1.58 ?m (section II). Then we describe the fabrication of the devices (section III). Finally we report on the optical and electrical measurements we have done for various devices (section IV).

High brightness semiconductor lasers as transmitters for space lidar systems

High brightness semiconductor lasers are potential transmitters for future space lidar systems. In the framework of the European Project BRITESPACE, we propose an all-semiconductor laser source for an Integrated Path Differential Absorption lidar system for column-averaged measurements of atmospheric CO2 in future satellite missions. The complete system architecture has to be adapted to the particular emission properties of these devices using a Random Modulated Continuous Wave approach. We present the initial experimental results of the InGaAsP/InP monolithic Master Oscillator Power Amplifiers, providing the ON and OFF wavelengths close to the selected absorption line around 1572 nm.

Random-modulation cw lidar system for space-borne carbon dioxide remote sensing based on a high-brightness semiconductor laser

In this paper, we report on the progresses of the BRITESPACE Consortium in order to achieve space-borne LIDAR measurements of atmospheric carbon dioxide concentration based on an all semiconductor laser source at 1.57 ?m. The complete design of the proposed RM-CW IPDA LIDAR has been presented and described in detail. Complete descriptions of the laser module and the FSU have been presented. Two bended MOPAs, emitting at the sounding frequency of the on- and off- IPDA channels, have been proposed as the transmitter optical sources with the required high brightness. Experimental results on the bended MOPAs have been presented showing a high spectral purity and promising expectations on the high output power requirements. Finally, the RM-CW approach has been modelled and an estimation of the expected SNR for the entire system is presented. Preliminary results indicate that a CO2 retrieval precision of 1.5 ppm could be achieved with an average output power of 2 W for each channel.

Tri ėpokhi : Ekaterininskai͡a, Aleksandrovskai͡a, Nikolaevskai͡a : temy, biblīografīi͡a, voprosniki : posobīe dli͡a vyssheĭ shkoly i samoobrazovanīi͡a /

"Prilozhenīi͡a: 1) Russkīĭ teatr XVIII v. 2) Voronezhskoe kulʹturnoe gni͡ezdo. 3) Turgenev i 60-ye gody."

Zapiski rezhissera /

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