4,821 research outputs found
Minimization of Quantum Circuits using Quantum Operator Forms
In this paper we present a method for minimizing reversible quantum circuits
using the Quantum Operator Form (QOF); a new representation of quantum circuit
and of quantum-realized reversible circuits based on the CNOT, CV and
CV quantum gates. The proposed form is a quantum extension to the
well known Reed-Muller but unlike the Reed-Muller form, the QOF allows the
usage of different quantum gates. Therefore QOF permits minimization of quantum
circuits by using properties of different gates than only the multi-control
Toffoli gates. We introduce a set of minimization rules and a pseudo-algorithm
that can be used to design circuits with the CNOT, CV and CV quantum
gates. We show how the QOF can be used to minimize reversible quantum circuits
and how the rules allow to obtain exact realizations using the above mentioned
quantum gates.Comment: 11 pages, 14 figures, Proceedings of the ULSI Workshop 2012 (@ISMVL
2012
Integrated electroplated heat spreaders for high power semiconductor lasers
Thermal management of high power semiconductor lasers is challenging due to the low thermal conductivity of the laser substrate and the active device layers. In this work, we demonstrate the use of a microfabricated laser test device to study the thermal management of edge emitting semiconductor lasers. In this device, metallic heat spreaders of high thermal conductivity are directly electroplated on structures that mimic edge-emitting semiconductor lasers. The effects of various structural parameters of the heat spreader on the reduction of the thermal resistance of the laser test device are demonstrated both experimentally and theoretically. Without resolving to computational costive simulations, we developed two independent analytical models to verify the experimental data and further utilized them to identify the dominant thermal resistance under different laser mounting configurations. We believe our approach here of using microfabricated devices to mimic thermal characteristics of lasers as well as the developed analytical models for calculating the laser thermal resistance under different mounting configurations can potentially become valuable tools for thermal management of high power semiconductor lasers
Synthesis and Optimization of Reversible Circuits - A Survey
Reversible logic circuits have been historically motivated by theoretical
research in low-power electronics as well as practical improvement of
bit-manipulation transforms in cryptography and computer graphics. Recently,
reversible circuits have attracted interest as components of quantum
algorithms, as well as in photonic and nano-computing technologies where some
switching devices offer no signal gain. Research in generating reversible logic
distinguishes between circuit synthesis, post-synthesis optimization, and
technology mapping. In this survey, we review algorithmic paradigms ---
search-based, cycle-based, transformation-based, and BDD-based --- as well as
specific algorithms for reversible synthesis, both exact and heuristic. We
conclude the survey by outlining key open challenges in synthesis of reversible
and quantum logic, as well as most common misconceptions.Comment: 34 pages, 15 figures, 2 table
An Optical System to Transform the Output Beam of a Quantum Cascade Laser to be Uniform
Quantum cascade lasers (QCLs) are a candidate for calibration sources in space-based remote sensing applications. However, the output beam from a QCL has some characteristics that are undesirable in a calibration source. The output beam from a QCL is polarized both temporally and spatially coherent, and has a non-uniform bivariate Gaussian profile. These characteristics need to be mitigated before QCLs can be used as calibration sources. This study presents the design and implementation of an optical system that manipulates the output beam from a QCL so that it is spatially and angularly uniform with reduced coherence and polarization
Polarization-entangled photon pair sources based on spontaneous four wave mixing assisted by polarization mode dispersion
Photonic-based qubits and integrated photonic circuits have enabled
demonstrations of quantum information processing (QIP) that promises to
transform the way in which we compute and communicate. To that end, sources of
polarization-entangled photon pair states are an important enabling technology,
especially for polarization-based protocols. However, such states are difficult
to prepare in an integrated photonic circuit. Scalable semiconductor sources
typically rely on nonlinear optical effects where polarization mode dispersion
(PMD) degrades entanglement. Here, we directly generate polarization-entangled
states in an AlGaAs waveguide, aided by the PMD and without any compensation
steps. We perform quantum state tomography and report a raw concurrence as high
as 0.910.01 observed in the 1100-nm-wide waveguide. The scheme allows
direct Bell state generation with an observed maximum fidelity of 0.900.01
from the 800-nm-wide waveguide. Our demonstration paves the way for sources
that allow for the implementation of polarization-encoded protocols in
large-scale quantum photonic circuits
A Study on SPICE Modeling of Non-Resonant Plasmonic Terahertz Detector
Department Of Electrical EngineeringThe terahertz (sub-millimeter wave) is the frequency resource, ranging from 100 GHz ~ 10 THz band, located in the middle region of the infrared and millimeter waves in the electromagnetic spectrum. Terahertz waves has unique physical characteristics, which is transparency of radio waves and straightness of light waves, simultaneously. The terahertz wave is applied to the basic science, such as device, spectroscopy, and imaging technology. And also adjust in the applied science, such as biomedical engineering, security, environment, information and communication. Which importance already verified. In the new shape of future market is expected to be formed broadly. For this application, operating in the THz frequency detecting device essential. Recently, Current elements operating in terahertz are present, such as compound semiconductor (???-???HBT, HEMT). But, there are disadvantage to use as a high price. Therefore, research have been made of silicon based THz detector in many research groups. Silicon-based nano-technology utilizes a plasma wave transistor technology. Which is using the space-time change of the channel charge density. That causes plasma wave oscillation in the MOSFET (Metal oxide semiconductor field effect transistor) channel and this effect available MOSET operating terahertz regime beyond MOSFET cut-off frequency. So, PWT (plasma wave transistor) is available terahertz detection and oscillation. For integrated possible post processing circuit development in these of terahertz applications system, silicon based PWT compact model is essential thing. For this compact model for spice simulation beyond cut-off frequency, we consider charge time variance model which is NQS (non-quasi-static) model, not quasi-static model. For NQS model two kinds of model exist, first is RC ladder model. That is seral connect MOSFET get rid of parasitic elements. And these complex circuit making the equivalent circuit model, it called New Elmore model. For post processing circuit simulation, fast simulation speed is essential, RC ladder model has a disadvantage (for simulating each segment). In this thesis we using New Elmore model based on Non-resonant plasmonic THz detector modeling, And verified physical validity of our NQS model using the our TCAD model based on Quasi-plasma 2DEG. And we propose fast and accurate compact modelingope
Optical Gas Sensing: Media, Mechanisms and Applications
Optical gas sensing is one of the fastest developing research areas in laser spectroscopy. Continuous development of new coherent light sources operating especially in the Mid-IR spectral band (QCL—Quantum Cascade Lasers, ICL—Interband Cascade Lasers, OPO—Optical Parametric Oscillator, DFG—Difference Frequency Generation, optical frequency combs, etc.) stimulates new, sophisticated methods and technological solutions in this area. The development of clever techniques in gas detection based on new mechanisms of sensing (photoacoustic, photothermal, dispersion, etc.) supported by advanced applied electronics and huge progress in signal processing allows us to introduce more sensitive, broader-band and miniaturized optical sensors. Additionally, the substantial development of fast and sensitive photodetectors in MIR and FIR is of great support to progress in gas sensing. Recent material and technological progress in the development of hollow-core optical fibers allowing low-loss transmission of light in both Near- and Mid-IR has opened a new route for obtaining the low-volume, long optical paths that are so strongly required in laser-based gas sensors, leading to the development of a novel branch of laser-based gas detectors. This Special Issue summarizes the most recent progress in the development of optical sensors utilizing novel materials and laser-based gas sensing techniques
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