All-optical flip-flop based on an active Mach-Zehnder interferometer with a feedback loop

A novel architecture for an all-optical flip-flop is validated experimentally. The architecture comprises a single semiconductor optical amplifier-based Mach-Zehnder interferometer with an external feedback loop. The experimental results show optical bistable operation for a latching device with an on-off contrast ratio of 11 dB that employs set and reset pulses of less than 250 pJ, although the energy of these pulses could be greatly reduced by optical integration of the whole device.     

Nonreciprocity of counterpropagating signals in a monolithically integrated Sagnac interferometer

We demonstrate nonlinearly induced nonreciprocity of counterpropagating waves in a monolithically integrated Sagnac interferometer that employs a semiconductor optical amplifier as the nonlinear element. We show that the dependence of the linewidth enhancement factor on charge injection can influence the third-order nonlinearity in the semiconductor gain medium to a surprisingly large degree. This effect is utilized to control the phases of the counterpropagating signals in the interferometer. A theoretical model is used to explain the experimental observations. We show that these effects have significant practical implications by demonstrating an all-optical controlled-NOT gate.     

All-optical circulator based on cross phase modulation in a nonlinear Mach-Zehnder interferometer

We show that by exploiting unequal magnitude of cross phase modulation (XPM) in co-propagating and counter-propagating beams, an all-optical circulator (AOC) using a nonlinear Mach-Zehnder Interferometer (MZI) could be constructed. The proposed circulator is novel, simple and polarization independent.     

All-optical logic OR gate using SOA and delayed interferometer

All-optical OR operation has been demonstrated using a semiconductor optical amplifier (SOA) and delayed interferometer (DI) at 80 Gb/s. The DI is based on a polarization maintaining loop mirror. Q-factor of the operation is discussed through numerical simulations. The results show the OR gate operation rate is limited by the gain recovery time and input pulse energy.     

All-optical switch and limiter based on nonlinear polarization in Mach-Zehnder interferometer coupled with a polarization-maintaining fiber-ring resonator

A novel all-optical switch based on nonlinear polarization mechanism using polarization-maintaining fiber ring with a polarization rotator is proposed. Optical switching with low threshold of mW order and optical limiting with broader limiting range, less fluctuation, higher damage threshold and response speed are demonstrated numerically. The deterioration of switching and the improvement of limiting originating from losses are also studied. Considering the tradeoff between switching power and bandwidth, the way to increase bandwidth is discussed.     

Mach-Zehnder interferometer with a uniform wavelength period

We have realized a first optical filter composed of optical delay lines and couplers that has a periodic response with respect to wavelength, whereas a conventional optical filter is known to have a periodic response to relative optical frequency. This new filter can be constructed by using a phase-generating coupler (PGC) that supplies the optical delay lines with a wavelength-dependent nonlinear phase. The PGC, which is also composed of optical delay lines and couplers, can simultaneously provide a desired phase and an arbitrary amplitude coupling ratio. We applied our transformation method to a conventional Mach-Zehnder interferometer (MZI) as an example of an optical frequency filter and converted it to an optical wavelength filter. We fabricated the designed MZI on a silica-based planar lightwave circuit and successfully realized what is believed to be the first MZI with a uniform wavelength period.     

Ultrafast all-optical XOR logic gate based on a symmetrical Mach-Zehnder interferometer employing SOI waveguides

We present an integrated Silicon-on-Insulator (SOI) based Mach-Zehnder interferometer (MZI) in order to perform ultrafast all-optical XOR logic gate operation with a bit rate of ∼ 0.33 Tb/s. A numerical simulation is carried out in order to study various parameters such as extinction ratio and eye-opening parameters, characterizing the performance of the XOR logic gate. The output XOR logic gate signal can have improved extinction and eye margin if the initial powers of primary signals and the probe continuous-wave (CW), and SOI waveguide length are judiciously adjusted.     

80 Gb/s All-optical logic AND operation using Mach-Zehnder interferometer with differential scheme

An all-optical logic AND gate is demonstrated by using a semiconductor optical amplifier (SOA) based Mach-Zehnder interferometer (MZI). The AND results are numerically analyzed by solving the rate equation of SOA. Q-factor values have been calculated. The operation of the AND logic gate is experimentally demonstrated at 80 Gb/s. Operation at higher data rates is feasible using SOAs with shorter phase recovery time.     

First-order ether drift experiment with a Mach-Zehnder fiber interferometer

The recently proposed first-order ether drift experiment with an asymmetrix Mach-Zehnder interferometer could be used to detect anisotropy in the speed of light. The experiment has been performed, and no effect was detected within the measurement accuracy.     

All-optical DGD monitor for packet-switched networks based on an integrated active Mach–Zehnder interferometer operating as logic XOR gate

An all-optical differential group delay (DGD) monitor for packet-switched networks is proposed. The monitoring approach consists of an integrated active Mach–Zehnder interferometer acting as a logic XOR gate. According to the estimated DGD value, a latching switch is employed to route the input packets “on-the-fly”. The simulation results show a successful operation which has been confirmed with the experimental validation of the XOR-based monitoring subsystem.     

Switching behaviour of a nonlinear Mach-Zehnder interferometer

In the present paper, a detailed investigation on the switching behaviour of a nonlinear Mach-Zehnder interferometer (NMZI) has been carried out using beam propagation method (BPM). A thorough investigation on input vs. output characteristic has been carried out by varying different parameters like length of the arms, refractive index of the linear/nonlinear arm, wavelength of the input beams and nonlinear coefficient of the material of the nonlinear arm. The input vs. output characteristic has also been investigated by shifting the balance point of the NMZI. The present paper provides a physically intuitive understanding of the effect of change in different parameters of the NMZI on its switching behaviour.     

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.     

光纤Mach-Zehnder干涉仪系统

介绍了光纤Mach-Zehnder(MZ)干涉仪系统的结构.给出了光纤Mach-Zehnder干涉仪系统中信号光与参考光的干涉原理以及影响干涉光强的因素.同时也分析了光纤耦合器的交叉耦合,另外也给出了PZT的作用.阐述了光纤偏振控制器的结构、工作原理及其对光纤Mach-Zehnder干涉仪系统传感臂偏振态的控制,最后给出了光纤Mach-Zehnder干涉仪系统的应用.     

Design of an ultrafast all-optical NOR logic gate based on Mach-Zehnder interferometer using quantum-dot SOA

This paper proposes a design for all-optical NOR logic gate, based on Mach-Zehnder interferometer (MZI) using quantum-dot semiconductor optical amplifier (QD-SOA). In this regard, a theoretical model for an ultrafast all-optical signal processor is developed using QD-SOA to achieve high bit rate operation. We have demonstrated the NOR gate operation in two cases of with and without an optical control pulse. Simulations have been carried out at data bit rates 160 Gb/s, 200 Gb/s, and 250 Gb/s for the case that control pulse is not applied, and also at data bit rates 1 Tb/s and 2 Tb/s in presence of control pulse which leads to improvement of gain recovery time and ultrafast NOR logic operation. In addition, quality factors of the output signals in presence and without the control pulse at different bit rates with different bias currents have been investigated for pseudo-random binary sequence (PRBS) of word length 2⁸–1.     

Coupled Mach-Zehnder interferometer memory element

Two active Mach-Zehnder interferometers are integrated in a monolithic InP/InGaAsP photonic integrated circuit. Together they form a crucial component for optical signal processing: an optical memory element or set-reset flip-flop. The switching time for this initial device is approximately 200 ps. The photonic integrated circuit contains active and passive optical components, including electro-optic phase shifters.     

Slow light Mach-Zehnder fiber interferometer

A slow light structure Mach-Zehnder fiber interferometer is theoretically demonstrated. The sensitivity of the interferometer is significantly enhanced by the dispersion of the slow light structure. The numerical results show that the sensitivity enhancement factor varies with the coupling coefficient and reaches its maximum under critical coupling conditions.     

Error analysis for a Mach-Zehnder type speckle interferometer

A phase shifting speckle interferometer based on a Mach-Zehnder geometry is presented. The displacement field is measured using an electro-optic phase shifting technique. An analytical investigation of the accuracy of the interferometer is performed by considering the most contributing error sources. It is shown that in the case of the use of a low power laser source, the geometrical aberration of the optical component is the main contribution to the systematic errors. The case of the sampling of a full measurement is investigated. It is demonstrated that the systematic error of the full measurement has the same statistics as those given by a simple acquisition. Experimental results are reported in the case of the measurement of the deformation of industrial connectors submitted to a crushing test. It is found that for a peak to valley of 32 μm, the trueness of the measurement appears higher than 160 nm.     

A very compact Mach-Zehnder interferometer with left-handed material

A very compact Mach-Zehnder interferometer (MZI) composed of two parallel straight waveguides with left-handed material (LHM) layers is proposed. The operating principle and characteristics of the MZI with electro-optic material (EOM) core are analyzed by using the supermode theory and coupled mode theory. The result shows that regardless of material loss, a very compact MZI of only 0.87 mm × 0.022 mm can be achieved by utilizing EOM with ultrahigh electro-optic coefficient, which means a new way to fulfill a very compact electro-optic modulator or optical switch. The absorption effect of the proposed MZI is also analyzed by perturbation method which is generated by lossy LHM layers.     

Detecting non-Abelian statistics with an electronic Mach-Zehnder interferometer

Fractionally charged quasiparticles in the quantum Hall state with a filling factor nu=5/2 are expected to obey non-Abelian statistics. We demonstrate that their statistics can be probed by transport measurements in an electronic Mach-Zehnder interferometer. The tunneling current through the interferometer exhibits a characteristic dependence on the magnetic flux and a nonanalytic dependence on the tunneling amplitudes which can be controlled by gate voltages.