Comparison of dynamic properties of InP/InAs quantum-dot and quantum-dash lasers

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 109, 161104 (2016) and may be found at https://doi.org/10.1063/1.4965846.The dynamic properties of MOVPE grown InP/InAs quantum-dot and quantum-dash lasers, showing identical structural design, emitting in the C-band are investigated and compared to each other. Based on the small-signal measurements, we show the impact of the density of states function on the cut-off frequency, being larger for quantum dots at low currents, and reaching similar values for quantum dashes only at higher currents. The large-signal measurements show error-free data transmission at 22.5 and 17.5 Gbit/s for the quantum-dot and quantum-dash lasers.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, BauelementeEC/FP7/EU/264687/Postgraduate Research on Photonics as an Enabling Technology/PROPHE

Integration of Internet of Things in University Campuses

U okviru disertacije se ispituje način integracije Interneta stvari (IS) u univerzitetske kampuse. Analizirani su postojeći dostupni modeli za ocenu spremnosti organizacija za IS. Prikazani su aktuelni stavovi o mogućnostima primene IS-a u kampusima. Nakon toga je prikazan razvijeni model za ocenu spremnosti kampusa za primenu IS- a, koji sadrži i segment za ocenu spremnosti stanara studenstkog kampusa za IS. Radi testiranja modela, razvijeni su upitnici i softverski alat za podršku primene modela. Razvijeni model je testiran u Studentskom centru Novi Sad sa zaposlenima i stanarima kampusa, nakon čega su rezultati dobijeni modelom evaluirani.This dissertation discusses possibilities of Internet of Things (IoT) integration in university campuses. Available existing models for assessing an organization readiness for IoT are analyzed. Actual viewpoints concerning possibilities of IoT application in campuses are shown. Further, developed model for assessing university campus readiness assessment for IoT, which also include part for campus clients IoT readiness assessment, is presented. With the purpose of model testing, supporting questionnaires and software tool are developed. The model is tested in Student Center Novi Sad, with both employees and campus habitants, and evaluation of results was done

Integration of Internet of Things in University Campuses

U okviru disertacije se ispituje način integracije Interneta stvari (IS) u univerzitetske kampuse. Analizirani su postojeći dostupni modeli za ocenu spremnosti organizacija za IS. Prikazani su aktuelni stavovi o mogućnostima primene IS-a u kampusima. Nakon toga je prikazan razvijeni model za ocenu spremnosti kampusa za primenu IS- a, koji sadrži i segment za ocenu spremnosti stanara studenstkog kampusa za IS. Radi testiranja modela, razvijeni su upitnici i softverski alat za podršku primene modela. Razvijeni model je testiran u Studentskom centru Novi Sad sa zaposlenima i stanarima kampusa, nakon čega su rezultati dobijeni modelom evaluirani.This dissertation discusses possibilities of Internet of Things (IoT) integration in university campuses. Available existing models for assessing an organization readiness for IoT are analyzed. Actual viewpoints concerning possibilities of IoT application in campuses are shown. Further, developed model for assessing university campus readiness assessment for IoT, which also include part for campus clients IoT readiness assessment, is presented. With the purpose of model testing, supporting questionnaires and software tool are developed. The model is tested in Student Center Novi Sad, with both employees and campus habitants, and evaluation of results was done

1.55-μm mode-locked quantum-dot lasers with 300 MHz frequency tuning range

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 106, 031114 (2015) and may be found at https://doi.org/10.1063/1.4906451.Passive mode-locking of two-section quantum-dot mode-locked lasers grown by metalorganic vapor phase epitaxy on InP is reported. 1250-μm long lasers exhibit a wide tuning range of 300 MHz around the fundamental mode-locking frequency of 33.48 GHz. The frequency tuning is achieved by varying the reverse bias of the saturable absorber from 0 to −2.2 V and the gain section current from 90 to 280 mA. 3 dB optical spectra width of 6–7 nm leads to ex-facet optical pulses with full-width half-maximum down to 3.7 ps. Single-section quantum-dot mode-locked lasers show 0.8 ps broad optical pulses after external fiber-based compression. Injection current tuning from 70 to 300 mA leads to 30 MHz frequency tuning.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, BauelementeEC/FP7/EU/264687/Postgraduate Research on Photonics as an Enabling Technology/PROPHE

Highly efficient non-degenerate four-wave mixing under dual-mode injection in InP/InAs quantum-dash and quantum-dot lasers at 1.55 μm

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 107, 191111 (2015) and may be found at https://doi.org/10.1063/1.4935796.This work reports on non-degenerate four-wave mixing under dual-mode injection in metalorganic vapor phase epitaxy grown InP/InAs quantum-dash and quantum dot Fabry-Perot laser operating at 1550 nm. High values of normalized conversion efficiency of −18.6 dB, optical signal-to-noise ratio of 37 dB, and third order optical susceptibility normalized to material gain χ(3)/g0 of ∼4 × 10−19 m3/V3 are measured for 1490 μm long quantum-dash lasers. These values are similar to those obtained with distributed-feedback lasers and semiconductor optical amplifiers, which are much more complicated to fabricate. On the other hand, due to the faster gain saturation and enhanced modulation of carrier populations, quantum-dot lasers demonstrate 12 dB lower conversion efficiency and 4 times lower χ(3)/g0 compared to quantum dash lasers.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, BauelementeEC/FP7/EU/264687/Postgraduate Research on Photonics as an Enabling Technology/PROPHE

Multimode optical feedback dynamics in InAs/GaAs quantum dot lasers emitting exclusively on ground or excited states: transition from short- to long-delay regimes

© 2018 Optical Society of America. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reserved.The optical feedback dynamics of two multimode InAs/GaAs quantum dot lasers emitting exclusively on sole ground or excited lasing states is investigated. The transition from long- to short-delay regimes is analyzed, while the boundaries associated to the birth of periodic and chaotic oscillations are unveiled to be a function of the external cavity length. The results show that depending on the initial lasing state, different routes to chaos are observed. These results are of importance for the development of isolator-free transmitters in short-reach networks

Phase noise and jitter reduction by optical feedback on passively mode-locked quantum-dot lasers

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 103, 231101 (2013) and may be found at https://doi.org/10.1063/1.4837716.The noise properties of the pulse trains of passively mode-locked 40 GHz quantum-dot lasers subject to optical feedback are investigated in detail. Five different feedback regimes are discovered and the clearly identified regime of resonant optical feedback is further examined. The feedback parameters yielding minimum phase noise are determined. Here, the radio-frequency (RF)-line-width is reduced from its original value by 99% to 1.9 kHz. The corresponding pulse-to pulse jitter of 23 fs is a record low value for passively mode-locked 40 GHz quantum-dot lasers.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement

Ultrafast and nonlinear dynamics of InAs/GaAs semiconductor quantum dot lasers

© Copyright 2018 Society of Photo‑Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this publication for a fee or for commercial purposes, and modification of the contents of the publication are prohibited.Quantum dot nanostructures are one of the best practical examples of emerging nanotechnologies hence offering superior properties as compared to their quantum well counterparts. InAs/GaAs quantum dots allow producing energy- and cost-efficient devices with outstanding temperature stability, lowest threshold current, ultrafast gain dynamics, and low amplified spontaneous emission. This paper reports on the recent achievements in ultrafast and nonlinear dynamics properties of InAs/GaAs quantum dot lasers for radar systems, wireless communications and high-speed optical communications. Passive mode-locking is shown to exhibit a great potential for microwave, millimeter-wave and Terahertz signal generation with high repetition frequency tuning and jitter reduction. The optical feedback is also used to stabilize the pulse emission leading an integrated timing jitter as low as 90 fs without consuming additional power. Lastly, multimode optical feedback dynamics of InAs/GaAs QD lasers emitting on different lasing states is also studied. In particular, a chaos free operation is observed for the first time from the ground state lasing operation.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement

15 Gb/s index-coupled distributed-feedback lasers based on 1.3 μm InGaAs quantum dots

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 105, 011103 (2014) and may be found at https://doi.org/10.1063/1.4887063.The static properties and large-signal modulation capabilities of directly modulated p-doped quantum-dot distributed-feedback lasers are presented. Based on pure index gratings the devices exhibit a side-mode-suppression ratio of 58 dB and optical output powers up to 34 mW. Assisted by a broad gain spectrum, which is typical for quantum-dot material, emission wavelengths from 1290 nm to 1310 nm are covered by the transversal and longitudinal single-mode lasers fabricated from the same single wafer. Thus, these lasers are ideal devices for on-chip wavelength division multiplexing within the original-band according to the IEEE802.3ba standard. 10 Gb/s data transmission across 30 km of single mode fiber is demonstrated. The maximum error-free data rate is found to be 15 Gb/s.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement

DNA-based molecular identification of Urnula mediterranea (Ascomycota, Pezizales) collected in Central Serbia

organisms. Genetic markers include target sequences of molecules DNA, RNA, and amino acids. The most often used genetic markers are DNA markers, localized on DNA molecules. The study aim was DNA-based molecular identification of species Urnula mediterranea (M. Carbone, Agnello & Baglivo) M. Carbone, Agnello & P. Alvarado (2013), by using molecular systematics methods. This species was recently discovered for the first time in Central Serbia and determined only based on morphological characteristics. For the first time, U. mediterranea sampled in Serbia, was identified with DNA molecular markers. Extraction of DNA molecules was performed from the fruiting body of U. mediterranea. ITS region and the part of the gene for 28S rRNA were amplified and sequenced by the Sanger method. Comparing the analyzed sequences with the sequences from the database, a match of 99.72% was found for the ITS region and 100% for the part of the gene for 28S rRNA. By molecular identification, it has been established that the sample belongs to the species U. mediterranea. Both analyzed DNA sequences of U. mediterranea were deposited into the NCBI database.Publishe