Multi-ion Mach–Zehnder interferometer with artificial nonlinear interactions

We propose a method to implement a Mach-Zehnder interferometry based upon a string of trapped ions with artificial nonlinear interactions. By manipulating the coupling strength between two involved internal states of the ions, we could achieve the beam splitting/recombination with NOON states. Using current techniques for manipulating trapped ions, we discuss the experimental feasibility of our scheme and analyze some undesired uncertainty under realistic experimental environment.     

Theoretical analysis of soliton NOR gate with semiconductor optical amplifier-assisted Mach–Zehnder interferometer

Optical and Quantum Electronics - We developed gigawatt laser system on diode-pumped Nd:Cr:YAG microchip sub-nanosecond laser and lamp pumped Nd:YAG multistage amplifier. Pulse energy up to...     

Ultrafast all-optical demultiplexer based on monolithic Mach–Zehnder interferometer with integrated semiconductor optical amplifiers

A monolithically integrated and fully packaged Mach–Zehnder interferometer with semiconductor optical amplifiers (MZI-SOA) is demonstrated as polarisation-independent high-speed demultiplexer for up to 160 Gbit/s optical time division multiplexed (OTDM) data streams.     

Spectra in nested Mach–Zehnder interferometer experiments

By the means of the standard quantum mechanics formalism I present an explicit derivation of the structure of power spectra in Danan et al. and Zhou et al. experiments with nested dynamically changing Mach–Zehnder interferometers. The analysis confirms that we observe prominent, first-order peaks on frequencies related to some of the elements of the interferometer, but not on others. However, as I shall demonstrate, there are also other, weaker effects related to all relevant elements of the setup. In case of the Danan et al. setup, there are even peaks at all frequencies of element oscillations. When confronted in an experiment, these observations shall challenge the interpretation of the experiments based on anomalous trajectories of light.     

All-optical negabinary adders using Mach–Zehnder interferometer

In contrast to optoelectronics, all-optical adders are proposed where all-optical signals are used to represent the input numbers and the control signals. In addition, the all-optical adders use the negabinary modified signed-digit number representation (an extension of the negabinary number system) to represent the input digits. Further, the ultra-speed of the designed circuits is achieved due to the use of ultra-fast all-optical switching property of the semiconductor optical amplifier and Mach–Zehnder interferometer (SOA–MZI). Furthermore, two-bit per digit binary encoding scheme is employed to represent the trinary values of the negabinary modified signed-digits.     

Creating λ /3 focal holes with a Mach–Zehnder interferometer

We report the formation of doughnut-shaped focal intensity distributions with hole diameters of /3.3=232 nm full-width-at-half-maximum. The doughnut shape is created by illuminating a high-numerical-aperture lens with the output of a Mach–Zehnder interferometer, in which half of the wavefront in each arm is phase retarded by . The focal intensities are probed with a point-like scatterer and compared with the predictions of a vectorial focusing theory. The orientation of the phase-discontinuity line with respect to the electric field determines whether a strong longitudinal or a vanishing electric field is produced at the focal point. Conditions are given for creating high-contrast focal holes at the sub-micron scale. PACS 42.25.-p; 42.30.-d; 42.79.-e     

Refractometer based on a tapered Mach–Zehnder interferometer with Peanut-Shape structure

A novel refractometer based on tapered Mach–Zehnder modal interferometer (MZI) is proposed and experimentally demonstrated. This sensor is composed of a pair of Peanut-Shape structures and an embedded taper – the former excites high-order cladding modes, while the latter enhances the evanescent field. As the effective refractive index (RI) of cladding is based on the changes of surrounding RI, thus extinction ratio will change due to the alteration of the distribution of power in the fiber which is induced by various differences of core and cladding for RI. As a result, the maximum RI sensitivity of 240.78 extinction ratio/RIU (refractive index unit) is achieved within the range from 1.3334 to 1.4081.     

Proposal for all-optical NOR gate using single quantum-dot semiconductor optical amplifier-based Mach–Zehnder interferometer

The feasibility of realizing an all-optical NOR gate for 160 Gb/s return-to-zero data pulses using a single quantum-dot semiconductor optical amplifier (QD-SOA)-based Mach–Zehnder interferometer is theoretically investigated and demonstrated. The proposed scheme exploits a modified Fredkin gate driven not only by the pair of data streams between which the Boolean NOR function is executed but by the complement of one of these signals as well. A numerical simulation is conducted to evaluate the performance of the scheme against the extinction ratio and find for which choice of the critical data signals and QD-SOAs parameters this metric becomes acceptable. Provided that the specified requirements are satisfied, which is technologically feasible, the NOR gate can be realized for data signals of the same wavelength both with logical correctness and high quality.     

Accurate measurement of aerosol optical properties using the multilongitudinal mode high-spectral-resolution lidar with self-tuning Mach–Zehnder interferometer

The multilongitudinal mode[MLM) high-spectral-resolution lidar[HSRL) based on the Mach±Zehnder interferometer[MZI) is constructed in Xi’an for accurate measurements of aerosol optical properties.The critical requirement of the optimal match between the free spectral range of MZI and the longitudinal mode interval of the MLM laser is influenced by the laboratory temperature,pressure,and vibration.To realize the optimal separation of aerosol Mie scattering signals and molecular Rayleigh scattering...     

Temperature-insensitive refractive index sensor based on Mach–Zehnder interferometer with two microcavities

We propose a temperature-insensitive refractive index(RI) fiber sensor based on a Mach–Zehnder interferometer. The sensor with high sensitivity and a robust structure is fabricated by splicing a short photonic crystal fiber(PCF) between two single-mode fibers, where two microcavities are formed at both junctions because of the collapse of the PCF air holes. The microcavity with a larger equatorial dimension can excite higher-order cladding modes, so the sensor presents a high RI sensitivity, which can reach 244.16 nm/RIU in the RI range of1.333–1.3778. Meanwhile it has a low temperature sensitivity of 0.005 nm/°C in the range of 33°C–360°C.     

基于拉曼协议的量子存储

量子存储器是实现按照需要存储/读出诸如单光子、纠缠或者压缩态等非经典量子态的系统,是实现量子通信和量子计算必不可少的核心器件.量子存储协议多种多样,其中拉曼方案由于具有存储宽带大、可用于存储短脉冲信号的优点而引起了人们的广泛关注.然而实现真正单光子和光子纠缠的拉曼存储具有挑战性.本文简要介绍了量子存储器的主要性能和评价指标,在回顾了量子存储器特别是拉曼量子存储器的发展现状后,重点介绍了本研究组最近基于拉曼协议实现各种量子态存储的系列研究,取得的研究成果对于构建高速量子网络具有重要参考价值.     

von Neumann Mutual Information for Anisotropic Coupled Oscillators Interacting with a Single Two-Level Atom

We consider the interaction between a two-level atom and two electromagnetic fields injected simultaneously within a cavity, with the interaction between the fields in parametric frequency-converter form. The wave function in Schr ödinger picture is obtained under certain conditions and consequently the density matrix. By employing a generalization of the von Neumann mutual information (in the context of Tsallis' nonextensive statistics) we measure the degree of entanglement for the present system. An important change is observed in the generalized mutual information depending on the entropic index. We also measure the minimum degree of entanglement during the transition from collapse to revival and vice-versa. Successive revival peaks show a lowering of the local maximum point indicating a dissipative irreversible change in the atomic state.     

Best Fidelity Conditions for Three Party Quantum Teleportation

Using the entangled three qubit states classified by Acin et al. we find the best fidelity conditions for quantum teleportation among three parties.     

Alternative New Notation for Quantum Information Theory

The notation [Li, Song, and Luo (2002) Physics Letters A 297, 121] has been generalized to quantum information theory. By this notation,we present three useful criteria for bipartite entanglement, a formula for general quantum swapping, and a formula for quantum teleportation of bipartite state by two EPR pairs.