Telecom Components Research Articles

On-chip generation of high-dimensional entangled quantum states and their coherent control.

Optical quantum states based on entangled photons are essential for solving questions in fundamental physics and are at the heart of quantum information science. Specifically, the realization of high-dimensional states (D-level quantum systems, that is, qudits, with D > 2) and their control are necessary for fundamental investigations of quantum mechanics, for increasing the sensitivity of quantum imaging schemes, for improving the robustness and key rate of quantum communication protocols, for enabling a richer variety of quantum simulations, and for achieving more efficient and error-tolerant quantum computation. Integrated photonics has recently become a leading platform for the compact, cost-efficient, and stable generation and processing of non-classical optical states. However, so far, integrated entangled quantum sources have been limited to qubits (D = 2). Here we demonstrate on-chip generation of entangled qudit states, where the photons are created in a coherent superposition of multiple high-purity frequency modes. In particular, we confirm the realization of a quantum system with at least one hundred dimensions, formed by two entangled qudits with D = 10. Furthermore, using state-of-the-art, yet off-the-shelf telecommunications components, we introduce a coherent manipulation platform with which to control frequency-entangled states, capable of performing deterministic high-dimensional gate operations. We validate this platform by measuring Bell inequality violations and performing quantum state tomography. Our work enables the generation and processing of high-dimensional quantum states in a single spatial mode.

Quantum-to-the-Home: Achieving Gbits/s Secure Key Rates via Commercial Off-the-Shelf Telecommunication Equipment

There is current significant interest in Fiber-to-the-Home (FTTH) networks, that is, end-to-end optical connectivity. Currently, it may be limited due to the presence of last-mile copper wire connections. However, in near future, it is envisaged that FTTH connections will exist, and a key offering would be the possibility of optical encryption that can best be implemented using Quantum Key Distribution (QKD). However, it is very important that the QKD infrastructure is compatible with the already existing networks for a smooth transition and integration with the classical data traffic. In this paper, we report the feasibility of using off-the-shelf telecommunication components to enable high performance Continuous Variable-Quantum Key Distribution (CV-QKD) systems that can yield secure key rates in the range of 100 Mbits/s under practical operating conditions. Multilevel phase modulated signals (m-PSK) are evaluated in terms of secure key rates and transmission distances. The traditional receiver is discussed, aided by the phase noise cancellation based digital signal processing module for detecting the complex quantum signals. Furthermore, we have discussed the compatibility of multiplexers and demultiplexers for wavelength division multiplexed Quantum-to-the-Home (QTTH) network and the impact of splitting ratio is analyzed. The results are thoroughly compared with the commercially available high-cost encryption modules.

ANALISA FAKTOR – FAKTOR YANG BERPENGARUH TERHADAP KETEPATAN WAKTU PELAPORAN KEUANGAN (STUDI EMPIRIS PADA PERUSAHAAN OTOMOTIF DAN KOMPONEN DAN TELEKOMUNIKASI YANG TERDAFTAR DI BURSA EFEK INDONESIA)

This research aims to examine the effect of the relationship between firm size, profitability, solvency, public ownership, and the audit opinion on the timeliness of financial reporting. The dependent variable in the form of timekeeping company deliver the financial statements to the Stock Exchange. Meanwhile for the independent variables such as firm size measured by total asets of the company, profitability is measured by profit margin ratio, solvency measured by debt-to-equity ratio, public ownership is measured by the percentage of the number of shares owned by the community, and the audit opinion is measured with an unqualified opinion and otherwise unqualified. This study uses secondary data with population automotive companies and telecommunications components and annual financial statements issued on the Stock Exchange in the period 2010-2012. From the analysis conducted in this study it can be concluded that the size of the company significantly influence the timeliness of financial reporting. While profitability, solvency, public ownership, and the audit opinion does not affect the timeliness of financial reporting. 
 
 Keywords: Company Size, Profitability, Solvency, Public Shareholding, Opinion Audit and Financial Reporting Timeliness.

Multi-user quantum key distribution with entangled photons from an AlGaAs chip

In view of real-world applications of quantum information technologies, the combination of miniature quantum resources with existing fibre networks is a crucial issue. Among such resources, on-chip entangled photon sources play a central role for applications spanning quantum communications, computing and metrology. Here, we use a semiconductor source of entangled photons operating at room temperature in conjunction with standard telecom components to demonstrate multi-user quantum key distribution, a core protocol for securing communications in quantum networks. The source consists of an AlGaAs chip-emitting polarisation entangled photon pairs over a large bandwidth in the main telecom band around 1550 nm without the use of any off-chip compensation or interferometric scheme; the photon pairs are directly launched into a dense wavelength division multiplexer (DWDM) and secret keys are distributed between several pairs of users communicating through different channels. We achieve a visibility measured after the DWDM of 87% and show long-distance key distribution using a 50-km standard telecom fibre link between two network users. These results illustrate a promising route to practical, resource-efficient implementations adapted to quantum network infrastructures.

Octave-spanning supercontinuum generation via microwave frequency multiplication

We demonstrate a system based on telecom components for the generation of a coherent octave-spanning supercontinuum from a continuous-wave laser. The system utilizes direct multiplication of a 10 GHz signal derived from a commercial synthesizer to carve pulses from the laser, which are then iteratively chirped and compressed in two stages. After reducing the repetition rate of the resulting pulse train to 2.5 GHz using selective transmission through an electro-optic gate, propagation through highly-nonlinear fiber generates an octave-spanning supercontinuum spectrum. We discuss the impact of the noise of the modulation frequency on the coherence of the supercontinuum and discuss its mitigation. Close agreement between experiment and theory is shown throughout, and we use our ability to precisely model the experiment to propose an extension of the system to 20 GHz repetition rate.

A REVIEW ON HEAT TRANSFER FROM DIFFERENT SHAPED FINS

Heat sinks with fins are generally used to enhance the heat transfer rate in many industrial applications such as cooling of electronic, power electronic, telecommunication and automotive components. In many situations where heat transfer is by natural convection fins offer economical and trouble free solutions. The weight and volume of the equipment are the most important parameters of design. Now days the general trend is to use compact systems especially in electronic field which leads to higher packing density of systems causing higher heat generation. It affects the performance of system and may cause the system failure. The most preferred method for cooling electronic and telecommunications devices is passive cooling since it is cost effective and reliable solution. It doesn’t require costly enhancing devices. This features leads to focus on development of efficient fin heat sink. The important element that defines the geometry of the heat sink is its fins. The fins generally used in industry are straight, circular and pin shaped. The objective of this work is review on the heat transfer rate by different shaped fins in different systems. The proper selection of the interruption length increases the heat transfer rate and in addition providing fin interruptions results in considerable weight reduction that can lead to lower manufacturing cost.

Photonic methods of millimeter-wave generation based on Brillouin fiber laser

In optical communication link, generation and delivering millimeter-wave (mm-waves) in radio over fiber (RoF) systems has limitation due to fiber non-linearity effects. To solve this problem, photonic methods of mm-wave generation based on characterizations of Brillouin fiber laser are proposed in this work for the first time. Three novel photonic approaches for mm-wave generation methods based on Brillouin fiber laser and phase modulator are proposed and demonstrated by simulation. According to our theoretical analysis and simulation, mm-waves with frequency up to 80GHz and good signal to noise ratio (SNR) up to 90dB are generated by new and cost effective methods of generation that make them suitable for applications of the fifth generation (5G) networks. The proposed configurations increase the stability and the quality of the mm-wave generation system by using a single laser source as a pump wave and the fiber non-linearity effects are reduced. A key advantage of this research is that proposed a number of very simple generation methods and cost effective which only use standard components of optical telecommunications. Stimulated Brillouin Scattering (SBS) effect that exists in the optical fiber is studied with the characterization of phase modulator. An all optically stable mm-wave carriers are achieved successfully in the three different methods with different frequencies from 20GHz up to 80GHz. Simulation results show that all these carriers have low phase noise, good SNR ranging between 60 and 90dB and tuning capability in comparison with previous methods reported. This makes them suitable for mm-wave transmission in RoF systems to transmit data in the next generation networks.

Implementation of continuous-variable quantum key distribution with composable and one-sided-device-independent security against coherent attacks.

Secret communication over public channels is one of the central pillars of a modern information society. Using quantum key distribution this is achieved without relying on the hardness of mathematical problems, which might be compromised by improved algorithms or by future quantum computers. State-of-the-art quantum key distribution requires composable security against coherent attacks for a finite number of distributed quantum states as well as robustness against implementation side channels. Here we present an implementation of continuous-variable quantum key distribution satisfying these requirements. Our implementation is based on the distribution of continuous-variable Einstein–Podolsky–Rosen entangled light. It is one-sided device independent, which means the security of the generated key is independent of any memoryfree attacks on the remote detector. Since continuous-variable encoding is compatible with conventional optical communication technology, our work is a step towards practical implementations of quantum key distribution with state-of-the-art security based solely on telecom components.

Multicore optical fibres for next generation telecommunication transmission systems and components

We report on a new type of multicore fibres dedicated to a new generation of telecommunication networks. We designed and fabricated seven core fibres for (i) passive signal transmission, (ii) signal amplification and (iii) 1×7 signal division. In each case, the same cores and air-holes arrangement is used. However different operation is achieved by employing different cores doping and varying structural parameters of fibre, such as air-holes and cores diameters. We present experimental results of measurements performed for developed multicore fibres and multicore fibre components. Full Text: PDF References D.J. Richardson, J.M. Fini, L.E. Nelson, "Space-division multiplexing in optical fibres", Nat. Photonics 7, 354 (2013). CrossRef R.G.H. van Uden et al., "Ultra-high-density spatial division multiplexing with a few-mode multicore fibre", Nat. Photonics 8, 865 (2014). CrossRef H. Takara et al., "1.01-Pb/s (12 SDM/222 WDM/456 Gb/s) Crosstalk-managed Transmission with 91.4-b/s/Hz Aggregate Spectral Efficiency", ECOC Tech. Dig. 3, paper Th.3.C.1. (2012). CrossRef H. Takara et al., "1000-km 7-core fiber transmission of 10 x 96-Gb/s PDM-16QAM using Raman amplification with 6.5 W per fiber", Opt. Expr. 20, 10100 (2012). CrossRef M. Koshiba, K. Saitoh, Y. Kokubun, "Heterogeneous multi-core fibers: proposal and design principle", IEICE Electron. Expr. 6, 98 (2009). CrossRef Y. Kokubun, T. Watanabe, "Dense heterogeneous uncoupled multi-core fiber using 9 types of cores with double cladding structure", 17th Microoptics Conference, Sendai, (2011). DirectLink J. Tu et al., "Optimized Design Method for Bend-Insensitive Heterogeneous Trench-Assisted Multi-Core Fiber With Ultra-Low Crosstalk and High Core Density", J. Light. Technol. 31, 2590 (2013). CrossRef B. Yao et al., "Reduction of Crosstalk by Hole-Walled Multi-Core Fibers", Optical Fiber Communication Conference and Exposition (OFC/NFOEC) OFC, Los Angeles (2012). CrossRef K. Imamura et al., "Multi-core holey fibers for ultra large capacity wide-band transmission", 34th European Conference on Optical Communication (2008). CrossRef K. Saitoh, Y. Tsuchida, M. Koshiba, "Bending-insensitive single-mode hole-assisted fibers with reduced splice loss", Opt. Lett. 30, 1779 (2005). CrossRef A. Ziolowicz et al., "Hole-assisted multicore optical fiber for next generation telecom transmission systems", Appl. Phys. Lett. 105, 081106 (2014). CrossRef

A Fiber-Optic System for the Quasi-Distributed Detection of Liquids

This letter presents a multiplexed fiber-optic sensor array suitable for detection of liquid intrusions, spills, and leaks. The proposed detection systems is based on active heating and observation of temperature changes in short sections of optically absorbing (vanadium-doped) optical fibers that were interconnected into a sensing array by a standard single-mode optical fiber. The heating of the vanadium-doped fiber sections was achieved by application of a common 980-nm pump laser source. The associated signal processing and integration utilizes a simple, custom-designed optical time domain reflectometry that relies on only a few low-cost standard telecom components.

Thermal, dynamic mechanical, and creep behavior of carbon nanotube reinforced ASA/Na‐ionomer blend

The present manuscript is aimed at the development of the protective layer for metal components for outdoor applications such as telecommunication components. Multiwalled carbon nanotubes at varying weight (from 0.5% to 5.0% by weight) were incorporated into newly developed 50/50 blend of acrylonitrile styrene acrylate (ASA) and ethylene acrylic acid‐based Na‐ionomer blend. ASA has inherent weather‐resistant property whereas Na‐ionomer has high affinity to adhere metal components. Nanocomposites were prepared by melt blending technique and were evaluated for thermal properties (thermogravimetric analysis and differential scanning calorimetry), dynamic mechanical analysis, and creep as well as recovery properties. Up to 1% nanotube content, there were predominant polymer/nanotube interactions; further addition resulted in nanotube networks formation that reduced polymer/nanotube interactions. These interactions increased both the thermal stability and storage modulus till 1% nanotube concentration, and after that, decreasing trend is observed. The creep deformation, as well as recovery, shows the opposite trend. In addition, the nanotube/nanotube sliding above 1% nanotube content increased the creep deformation further. The higher temperature played an altogether different role during recovery of the nanocomposite. The different polymer chain parts of the “brush” type ASA/Na‐ionomer blend interacted differently with carbon nanotubes; the ionic aggregates peak position of Na‐ionomer in differential scanning calorimetry thermogram was influenced by multiwalled carbon nanotubes, but the endotherm peak due to polyethylene crystallites of Na‐ionomer was unaffected. Carbon nanotubes also affected the glass transition temperature of polystyrene acrylonitrile matrix of ASA. Copyright © 2015 John Wiley & Sons, Ltd.

Design of a dual species atom interferometer for space

Atom interferometers have a multitude of proposed applications in space including precise measurements of the Earth's gravitational field, in navigation & ranging, and in fundamental physics such as tests of the weak equivalence principle (WEP) and gravitational wave detection. While atom interferometers are realized routinely in ground-based laboratories, current efforts aim at the development of a space compatible design optimized with respect to dimensions, weight, power consumption, mechanical robustness and radiation hardness. In this paper, we present a design of a high-sensitivity differential dual species $^{85}$Rb/$^{87}$Rb atom interferometer for space, including physics package, laser system, electronics and software. The physics package comprises the atom source consisting of dispensers and a 2D magneto-optical trap (MOT), the science chamber with a 3D-MOT, a magnetic trap based on an atom chip and an optical dipole trap (ODT) used for Bose-Einstein condensate (BEC) creation and interferometry, the detection unit, the vacuum system for $10^{-11}$ mbar ultra-high vacuum generation, and the high-suppression factor magnetic shielding as well as the thermal control system. The laser system is based on a hybrid approach using fiber-based telecom components and high-power laser diode technology and includes all laser sources for 2D-MOT, 3D-MOT, ODT, interferometry and detection. Manipulation and switching of the laser beams is carried out on an optical bench using Zerodur bonding technology. The instrument consists of 9 units with an overall mass of 221 kg, an average power consumption of 608 W (819 W peak), and a volume of 470 liters which would well fit on a satellite to be launched with a Soyuz rocket, as system studies have shown.

Provably secure and practical quantum key distribution over 307 km of optical fibre

Proposed in 1984, quantum key distribution (QKD) allows two users to exchange provably secure keys via a potentially insecure quantum channel. Since then, QKD has attracted much attention and significant progress has been made in both theory and practice. On the application front, however, the operating distance of practical fibre-based QKD systems is limited to about 150 km, which is mainly due to the high background noise produced by commonly used semiconductor single-photon detectors (SPDs) and the stringent demand on the minimum classical- post-processing (CPP) block size. Here, we present a compact and autonomous QKD system that is capable of distributing provably-secure cryptographic key over 307 km of ultra-low-loss optical fibre (51.9 dB loss). The system is based on a recently developed standard semiconductor (inGaAs) SPDs with record low background noise and a novel efficient finite-key security analysis for QKD. This demonstrates the feasibility of practical long-distance QKD based on standard fibre optic telecom components.

Simultaneous broadband laser ranging and photonic Doppler velocimetry for dynamic compression experiments.

A diagnostic was developed to simultaneously measure both the distance and velocity of rapidly moving surfaces in dynamic compression experiments, specifically non-planar experiments where integrating the velocity in one direction does not always give the material position accurately. The diagnostic is constructed mainly from fiber-optic telecommunications components. The distance measurement is based on a technique described by Xia and Zhang [Opt. Express 18, 4118 (2010)], which determines the target distance every 20 ns and is independent of the target speed. We have extended the full range of the diagnostic to several centimeters to allow its use in dynamic experiments, and we multiplexed it with a photonic Doppler velocimetry (PDV) system so that distance and velocity histories can be measured simultaneously using one fiber-optic probe. The diagnostic was demonstrated on a spinning square cylinder to show how integrating a PDV record can give an incorrect surface position and how the ranging diagnostic described here obtains it directly. The diagnostic was also tested on an explosive experiment where copper fragments and surface ejecta were identified in both the distance and velocity signals. We show how the distance measurements complement the velocity data. Potential applications are discussed.

Efficient generation of twin photons at telecom wavelengths with 2.5 GHz repetition-rate-tunable comb laser.

Efficient generation and detection of indistinguishable twin photons are at the core of quantum information and communications technology (Q-ICT). These photons are conventionally generated by spontaneous parametric down conversion (SPDC), which is a probabilistic process, and hence occurs at a limited rate, which restricts wider applications of Q-ICT. To increase the rate, one had to excite SPDC by higher pump power, while it inevitably produced more unwanted multi-photon components, harmfully degrading quantum interference visibility. Here we solve this problem by using recently developed 10 GHz repetition-rate-tunable comb laser, combined with a group-velocity-matched nonlinear crystal, and superconducting nanowire single photon detectors. They operate at telecom wavelengths more efficiently with less noises than conventional schemes, those typically operate at visible and near infrared wavelengths generated by a 76 MHz Ti Sapphire laser and detected by Si detectors. We could show high interference visibilities, which are free from the pump-power induced degradation. Our laser, nonlinear crystal, and detectors constitute a powerful tool box, which will pave a way to implementing quantum photonics circuits with variety of good and low-cost telecom components, and will eventually realize scalable Q-ICT in optical infra-structures.

Embedded optical probes for simultaneous pressure and temperature measurement of materials in extreme conditions

We present recent efforts at Los Alamos National Laboratory (LANL) to develop sensors for simultaneous, in situ pressure and temperature measurements under dynamic conditions by using an all-optical fiber-based approach. While similar tests have been done previously in deflagration-to-detonation tests (DDT), where pressure and temperature were measured to 82 kbar and 400°C simultaneously, here we demonstrate the use of embedded fiber grating sensors to obtain high temporal resolution, in situ pressure measurements in inert materials. We present two experimental demonstrations of pressure measurements: (1) under precise shock loading from a gas-gun driven plate impact and (2) under high explosive driven shock in a water filled vessel. The system capitalizes on existing telecom components and fast transient digitizing recording technology. It operates as a relatively inexpensive embedded probe (single-mode 1550 nm fiber-based Bragg grating) that provides a continuous fast pressure record during shock and/or detonation. By applying well-controlled shock wave pressure profiles to these inert materials, we study the dynamic pressure response of embedded fiber Bragg gratings to extract pressure amplitude of the shock wave and compare our results with particle velocity wave profiles measured simultaneously.

Gaussian-modulated coherent-state measurement-device-independent quantum key distribution

Measurement-device-independent quantum key distribution (MDI-QKD), leaving the detection procedure to the third partner and thus being immune to all detector side-channel attacks, is very promising for the construction of high-security quantum information networks. We propose a scheme to implement MDI-QKD, but with continuous variables instead of discrete ones, i.e., with the source of Gaussian-modulated coherent states, based on the principle of continuous-variable entanglement swapping. This protocol not only can be implemented with current telecom components but also has high key rates compared to its discrete counterpart; thus it will be highly compatible with quantum networks.

Tuneable magneto-optical metamaterials based on photonic resonances in nickel nanorod arrays

We investigate the magneto-optical properties of a nanostructured metamaterial comprised of arrays of nickel nanorods embedded in an anodized aluminum oxide template. The rods are grown using a self-assembly bottom-up technique that provides a uniform, quasi-hexagonal array over a large area, quickly and at low cost. The tuneability of the magneto-optic response of the material is investigated by varying the nanorod dimensions: diameter, length and inter-rod spacing as well as the overall thickness of the template. It is demonstrated that the system acts as a sub-wavelength light trap with enhanced magneto-optical properties occurring at reflectivity minima corresponding to photonic resonances of the metamaterial. Changes in dimensions of the nickel rods on the order of tens of nanometers cause a spectral blue-shift in the peak magneto-optical response of 270 nm in the visible range. A plasmonic enhancement is also observed at lower wavelengths, which becomes increasingly damped with larger diameters and increased volume fraction of nickel inclusions. This type of structure has potential applications in high density magneto-optical data storage (up to 1011–12 rods per square inch), ultrafast magneto-plasmonic switching and optical components for telecommunications.

Dielectric behavior of ternary mixtures: epoxy resin plus titanates (MgTiO3, CaTiO3or BaTiO3) associated to oxides (CaO, MnO2or ZnO)

In the present work, we study the dielectric behavior of various ternary mixtures composed of epoxy resin (RE), of one of three different titanates (barium titanate, BaTiO 3 ; calcium titanate, CaTiO 3 ; magnesium titanate, MgTiO 3 ) respectively with one of three oxides (calcium oxide, CaO; manganese dioxide, MnO 2 ; zinc oxide, ZnO) using time domain reflectometry (TDR). The different composites are mixed at room temperature in different volume fractions keeping the epoxy resin at a constant volume fraction. Several mixture combinations are studied to see the oxides influence on the titanates dielectric behavior in the range from DC to 10 GHz. This is done through the experimental determination of the dielectric constant e s . A noticeable effect has been recorded at the low frequency and which consists of an increase of this dielectric permittivity when growing the volume fraction of manganese dioxide. One meaningful point of this study is the lowest static conductivity value (8 . 017 × 10 − 3 / (Ωm)) being reached with an incursion of 7.5% of MnO2 in a ternary mixture composed of RE, MgTiO 3 and MnO 2 . In addition, the behavior obtained experimentally has been validated by the Lichtenecker modified model. This study interest lies on an application of these materials in microelectronics and particularly in telecommunication components manufacturing.

All-Fiber, Wavelength and Repetition-Rate Tunable, Ultrafast Pulse Generation in the 2.0 μm Region Without Mode-Locking

We show 3.0 ps pulses from 1877 nm to 2008 nm at variable repetition rates up to 18 GHz using time-lens compression of a tunable CW laser. The center wavelength is changed by tuning the CW seed laser, and the repetition rate is changed by electronically tuning the drive of the master RF clock. The repetition rate of 18 GHz represents a record speed for pulse generation in this spectral region. This simple all-fiber platform uses standard 1550 nm telecom components, offering a turn-key, flexible, robust alternative to pulse generation in the 2.0 μm region with both wavelength and repetition rate tunability.