Showing papers on "Mach–Zehnder interferometer published in 2004"
TL;DR: A high-sensitivity surface plasmon resonance (SPR) biosensor based on the Mach-Zehnder interferometer design is presented and a significant improvement over previously obtained results should allow SPR biosensors to become a possible replacement for conventional biosensing techniques based on fluorescence.
Abstract: A high-sensitivity surface plasmon resonance (SPR) biosensor based on the Mach-Zehnder interferometer design is presented. The novel feature of the new design is the use of a Wollaston prism through which the phase quantities of the p and s polarizations are interrogated simultaneously. Since SPR affects only the p polarization, the signal due to the s polarization can be used as the reference. Consequently, the differential phase between the two polarizations allows us to eliminate all common-path phase noise while keeping the phase change caused by the SPR effect. Experimental results obtained from glycerin-water mixtures indicate that the sensitivity limit of our scheme is 5.5 x 10(-8) refractive-index units per 0.01 degrees phase change. To our knowledge, this is a significant improvement over previously obtained results when gold was used as the sensor surface. Such an improvement in the sensitivity limit should allow SPR biosensors to become a possible replacement for conventional biosensing techniques based on fluorescence. Monitoring of the bovine serum albumin (BSA) binding reaction with BSA antibodies is also demonstrated.
278 citations
TL;DR: A novel two-dimensional photonic-crystal based Symmetric Mach Zehnder type all-optical switch with InAs quantum dots acting as a nonlinear phase-shift source with a 15-ps-wide switching-window at sufficiently low optical-energy of ~100 fJ.
Abstract: We demonstrated a novel two-dimensional photonic crystal (PC) based Symmetric Mach Zehnder type all-optical switch (PC-SMZ) with InAs quantum dots (QDs) acting as a nonlinear phase-shift source. The 600- ?m-long PC-SMZ having integrated wavelength-selective PC-based directional couplers and other PC components exhibited a 15-ps-wide switching-window with 2-ps rise/fall time at a wavelength of 1.3 ?m. Nonlinear optical phase shift in the 500-?m-long straight PC waveguide was also achieved at sufficiently low optical-energy (e.g., ??phase shift at ~100-fJ control-pulse energy) due to the small saturation energy density of the QDs, which is enhanced in the PC waveguide, without using conventional measures such as SOAs with current-injected gain. The results pave the way to novel PC- and QD-based photonic integrated circuits including multiple PC-SMZs and other novel functional devices.
233 citations
TL;DR: In this paper, an integrated SOA-based Mach-Zehnder interferometer (SOA-MZI) at 20 and 40 Gb/s was used for all-optical XOR functionality.
Abstract: All-optical XOR functionality has been demonstrated experimentally using an integrated SOA-based Mach-Zehnder interferometer (SOA-MZI) at 20 and 40 Gb/s. The performance of the XOR results has been analyzed by solving the rate equation of the SOA numerically. The high-speed operation is limited by the carrier lifetime in the SOA. In order to solve the limitations imposed by carrier lifetime, a differential scheme for XOR operation has been experimentally investigated. This scheme is potentially capable of XOR operation to >100 Gb/s.
201 citations
TL;DR: A novel optical coherence tomography method to measure backscattered intensity and birefringence properties (retardation and fast axis orientation) and apply it to imaging of human ocular tissue is presented and the first OCT images of retardation andFast axis orientation of the anterior chamber angle region in vivo are presented.
Abstract: We present a novel optical coherence tomography (OCT) method to measure backscattered intensity and birefringence properties (retardation and fast axis orientation) and apply it to imaging of human ocular tissue. The method is based on a Mach Zehnder interferometer, on transversal scanning, and on a polarization sensitive two-channel detection. A highly stable carrier frequency is generated by acousto-optic modulators (AOMs). This allows a phase sensitive demodulation by the lock-in technique. Since the recording of individual interference fringes is avoided by this method the amount of data to be recorded and processed is considerably reduced. We demonstrate this method on human cornea and anterior chamber angle and present, to the best of our knowledge, the first OCT images of retardation and fast axis orientation of the anterior chamber angle region in vivo.
174 citations
TL;DR: The all-PCF Mach-Zehnder interferometer was formed by mechanically inducing two identical long-period fiber gratings (LPGs) in the PCF by mechanically induced two identicalLong-period Fiber gratings in thePCF to investigate the spectral properties of a LPG and a LGas pair.
Abstract: We demonstrate implementation of an all-fiber Mach–Zehnder interferometer formed in a photonic crystal fiber (PCF). We formed the all-PCF Mach–Zehnder interferometer by mechanically inducing two identical long-period fiber gratings (LPGs) in the PCF. The spectral properties of a LPG and a LPG pair were investigated. The interference fringe formed within the stop band of the LPG pair varied with the period and the strength of the gratings, and the fringe spacing was decreased with increasing grating separation. From the fringe spacing measurement the differential effective group index of the PCF was calculated to be Δm≈2.8×10-3.
170 citations
TL;DR: Stable polarization-insensitive operation was achieved with an interferometer fabricated by PLC technology, and raw key creation at a rate of 3076 bits/s with a 5.0% quantum bit-error rate was achieved over 20 km of fiber.
Abstract: A differential-phase-shift quantum key distribution experiment was carried out with a planar light-wave circuit (PLC) Mach–Zehnder interferometer. This scheme has two advantages: it requires no polarization control and has a high repetition frequency, provided that a stable interferometer is available. Stable polarization-insensitive operation was achieved with an interferometer fabricated by PLC technology. Raw key creation at a rate of 3076 bits/s with a 5.0% quantum bit-error rate was achieved over 20 km of fiber. The stability of the PLC interferometer was examined.
116 citations
TL;DR: In this article, an all-optical Boolean XOR gate implemented with a SOA-based Mach-Zehnder Interferometer (SOA-MZI) is numerically simulated at 10 and 40 Gb/s to extract simple design rules.
111 citations
TL;DR: In this article, a Mach-Zehnder interferometer was fabricated from suspended membrane photonic crystal waveguides, which was shown to be in agreement with theoretical predictions.
Abstract: Mach–Zehnder interferometers were fabricated from suspended membrane photonic crystal waveguides. Transmission spectra were measured and device operation was shown to be in agreement with theoretical predictions.
74 citations
TL;DR: In this paper, the phase behavior of an integrated optical surface plasmon resonance (SPR) sensor is analyzed, in which the complex transmittance of a dielectric waveguide coated with a thin film of gold is determined for varying superstrate index.
Abstract: A theoretical analysis of the phase behaviour of an integrated optical surface plasmon resonance (SPR) sensor is presented, in which the complex transmittance of a dielectric waveguide coated with a thin film of gold is determined for varying superstrate index. Exploitation of the phase sensitivity is studied theoretically by incorporating gold-coated waveguides on both branches of a Mach–Zehnder interferometer (MZI), one or both of which may be exposed to superstrate index variations or thin adlayers. It is proposed that this device can be used to suppress unwanted refractive index changes common to both branches, for example, due to temperature variations, and may show enhanced sensitivity.
66 citations
01 Jul 2004
TL;DR: In this article, a high-speed all-silicon optical phase modulator with a metal-oxide-semiconductor (MOS) capacitance was proposed, which can be used to modulate the phase of the optical mode due to free-carrier plasma dispersion effect.
Abstract: We present design, fabrication, and testing of a high-speed all-silicon optical phase modulator in silicon-on-insulator (SOI). The optical modulator is based on a novel silicon waveguide phase shifter containing a metal-oxide-semiconductor (MOS) capacitor. We show that, under the accumulation condition, the drive voltage induced charge density change in the silicon waveguide having a MOS capacitor can be used to modulate the phase of the optical mode due to the free-carrier plasma dispersion effect. We experimentally determined the phase modulation efficiency of the individual phase shifter and compared measurements with simulations. A good agreement between theory and experiment was obtained for various phase shifter lengths. We also characterized both the low- and high-frequency performance of the integrated Mach-Zehnder interferometer (MZI) modulator. For a MZI device containing two identical phase shifters of 10 mm, we obtained a DC extinction ratio above 16 dB. For a MZI modulator containing a single-phase shifter of 2.5 mm in one of the two arms, the frequency dependence of the optical response was obtained by a small signal measurement. A 3-dB bandwidth exceeding 1 GHz was demonstrated. This modulation frequency is two orders of magnitude higher than has been demonstrated in any silicon modulators based on current injection in SOI.
65 citations
TL;DR: In this article, an optical set-up based on the combination of new CCD technology, a ruby laser and a Mach-Zehnder shear interferometer is presented for defect detection in composites.
TL;DR: A novel tunable PC waveguide Mach-Zehnder interferometer based on nematic liquid crystals is proposed and its interference properties are investigated numerically by using the finite-difference time-domain method.
Abstract: Photonic crystals (PCs) have many potential applications because of their ability to control light-wave propagation and because PC-based waveguides may be integrated into optical interferometers. We propose a novel tunable PC waveguide Mach–Zehnder interferometer based on nematic liquid crystals and investigate its interference properties numerically by using the finite-difference time-domain method. We can change the refractive indices of liquid crystals by rotating the directors of the liquid crystals. Then we can control the phase of light propagation in a PC waveguide Mach-Zehnder interferometer. The interference mechanism is a change in the refractive indices of liquid-crystal waveguides. The novel interferometer can be used either as an optically controlled on–off switch or as an amplitude modulator in optical circuits.
Patent•
11 Aug 2004TL;DR: In this paper, a folding Mach-Zehnder interferometer (MZI) is proposed to reduce the size and sensitivity of the MZI by cutting across the interferometers arms of a conventional MZI structure and creating reflectors on the exposed ends of the arms.
Abstract: The invention provides novel “folded” Mach-Zehnder interferometers (“folded” MZI's), methods for making folded MZI's, and systems and devices incorporating them. The novel folded MZI's are elaborated from conventional MZI structures by cutting across the interferometer arms of a conventional MZI structure and creating reflectors on the exposed ends of the interferometer arms to form two “folded” MZI's from a single conventional Mach-Zehnder interferometer structure. The novel folded MZI's show promise as sensors having a reduced size and enhanced sensitivity relative to sensors incorporating conventional Mach-Zehnder Interferometers.
TL;DR: In this article, a novel scheme for all-optical exclusive-OR (XOR) operating at 160 Gb/s is proposed and analyzed by means of numerical simulations, which consists of a Mach-Zehnder interferometer (MZI) where a semiconductor optical amplifier (SOA) is placed in each of its arms.
Abstract: A novel scheme for all-optical exclusive-OR (XOR) operating at 160 Gb/s is proposed and analyzed by means of numerical simulations. It consists of a Mach-Zehnder interferometer (MZI) where a semiconductor optical amplifier (SOA) is placed in each of its arms. This SOA-MZI setup is coupled to a delay interferometer, which acts as a signal regenerator. It is shown that error-free operation can be achieved at a data rate of 160 Gb/s, indicating that the proposed scheme is not limited by the SOA recovery time.
TL;DR: In this paper, a 2 × 2 thermo-optic (TO) Mach-Zehnder switch based on silicon waveguides with large cross-section was designed and fabricated on silicon-on-insulator (SOI) wafer.
TL;DR: The dependence on the power spectrum of the field, which is impossible in simpler approaches such as the dephasing terminal, is studied and remarked on as a tool to distinguish thermal smearing from genuine dephase.
Abstract: We analyze shot noise under the influence of dephasing in an electronic Mach-Zehnder interferometer, of the type that was realized recently [Nature (London) 422, 415 (2003)]] Using a model of dephasing by a fluctuating classical field, we show how the usual partition noise expression T(1-T) is modified We study the dependence on the power spectrum of the field, which is impossible in simpler approaches such as the dephasing terminal, against which we compare We remark on shot noise as a tool to distinguish thermal smearing from genuine dephasing
TL;DR: In this article, a review of the literature concerning phase masks and attempt to bridge the gap between two instrumental systems in which they are often found: the Mach-Zehnder interferometer and the coronagraph is presented.
Abstract: Phase masks have numerous applications in astronomical optics, in particular related to two themes: coronagraphy for detection and analysis of extrasolar planets or circumstellar disks, and wavefront analysis for extremely precise adaptive optics systems or cophasing of segmented mirrors. I review some of the literature concerning phase masks and attempt to bridge the gap between two instrumental systems in which they are often found: the Mach-Zehnder interferometer and the coronagraph.
TL;DR: The authors describe a general method to extract the frequency chirping of Mach-Zehnder modulators based on direct measurements of the output spectrum and allows measurement of the intrinsic chirp parameter to an accuracy of 5%.
Abstract: The authors describe a general method to extract the frequency chirping of Mach-Zehnder modulators based on direct measurements of the output spectrum. This method is independent of the modulator extinction ratio and allows measurement of the intrinsic chirp parameter to an accuracy of 5%.
TL;DR: The first wind-velocity profiles obtained with a direct-detection Doppler lidar that uses a Mach-Zehnder interferometer (MZI) as spectral discriminator are presented.
Abstract: We present the first wind-velocity profiles obtained with a direct-detection Doppler lidar that uses a Mach-Zehnder interferometer (MZI) as spectral discriminator. The measurements were performed in the lower stratosphere, between 10 and 40 km in altitude, at the Observatoire de Haute Provence (OHP), France, during nighttime. They are in excellent agreement with those obtained simultaneously and independently with the already validated double Fabry-Perot interferometer (FPI) of the OHP Doppler lidar (mean difference lower than the combined standard deviation). A statistical analysis shows that the random error obtained with this experimental MZI is 1.94 times the Cramer-Rao lower bound and is approximately half of that given by the FPI (both operating in photometric mode). Nevertheless, the present MZI measurements are sensitive to the presence of atmospheric particles and need an additional correction, whereas the OHP FPI is designed to be insensitive to particulate scattering.
TL;DR: In this paper, a 40 GHz mode-locked fiber-ring laser based on an optically controlled modulator is presented and analyzed in detail, which allows optical pulse generation synchronized to an external optical clock pulse stream.
Abstract: A 40-GHz mode-locked fiber-ring laser based on an optically controlled modulator is presented and analyzed in detail. The modulator is a monolithic InGaAsP-InP Mach-Zehnder interferometer with integrated semiconductor optical amplifiers, which allows optical pulse generation synchronized to an external optical clock pulse stream. The laser generates nearly transform-limited Gaussian pulses of 2.5-ps width and up to 9-mW mean output power with less than 130 fs of timing jitter, and it is wavelength tunable over more than 30 nm. The relationship between key laser parameters and the output pulse characteristics is analyzed experimentally and numerically. An improved cavity design permits the generation of shorter pulses of 1.0-ps width.
TL;DR: It is shown that such a setup permits coherent wave packet splitting and leads to the appearance of interference fringes for both single-mode and thermal input states, evidencing thus the robustness of the interferometer.
Abstract: We present a detailed theoretical investigation of the coherence properties of beam splitters and Mach-Zehnder interferometers for guided neutral atoms. We show that such a setup permits coherent wave packet splitting and leads to the appearance of interference fringes for both single-mode and thermal input states, evidencing thus the robustness of the interferometer.
TL;DR: In this article, a method for increasing the all-optical modulation bandwidth of SOAs by use of a cross-gain-modulated (XGM) holding signal is suggested and analyzed.
Abstract: A method for increasing the all-optical modulation bandwidth of semiconductor optical amplifiers (SOAs) by use of a cross-gain-modulated (XGM) holding signal is suggested and analyzed. The bandwidth improvement is numerically demonstrated by studying wavelength conversion in an SOA-based Mach-Zehnder interferometer (MZI) at 160 and 40 Gb/s. The new scheme is predicted to improve the extinction ratio and the minimum mark output power, as well as to reduce the amplitude jitter of the wavelength converted signal.
TL;DR: In this paper, the authors theoretically analyzed the chromatic dispersion characteristics of waveguide all-pass filters, in which the round-trip loss of a ring resonator was taken into account.
Abstract: The chromatic dispersion characteristics of waveguide all-pass filters were theoretically analyzed, in which the round-trip loss of a ring resonator was taken into account. Although an all-pass filter based on a ring resonator is lossless in principle, a finite round-trip loss of an actual filter changes an amplitude response and a group delay response drastically. The negative group delay resonance peak was confirmed both theoretically and experimentally.
TL;DR: In this article, a phase reversal electrode section in tandem with inverted ferroelectric domains was introduced to improve the frequency-chirping behavior of Z-cut LiNbO/sub 3/Mach-Zehnder modulators.
Abstract: Domain inversion under coplanar waveguide electrodes is proposed to improve the frequency-chirping behavior of Z-cut LiNbO/sub 3/ Mach-Zehnder modulators. This is achieved by introducing a phase reversal electrode section in tandem with inverted ferroelectric domains. The method opens the way to broad-band single-drive modulators with predetermined chirp parameter. The experimental results obtained at 10 Gb/s confirm the possibility of lowering the chirp parameter of a Z-cut modulator, while keeping a halfwave voltage lower than 5 V.
TL;DR: A new experimental setup is demonstrated to produce high-order Bessel beams based on the field decomposition of the Bessel beam into its even and odd field components that have only discrete phase changes of pi radians instead of a continuous change of phase.
Abstract: A new experimental setup is demonstrated to produce high-order Bessel beams. It is based on the field decomposition of the Bessel beam into its even and odd field components. The implementation is performed over the spectral components with a Mach-Zehnder interferometer that synthesizes the components into the desired Bessel beam. The main advantage of our setup is that the required annular transmittances have only discrete phase changes of π radians instead of a continuous change of phase.
Patent•
27 Sep 2004TL;DR: In this article, a photonic crystal structure including a Mach Zehnder interferometer with a reference arm and a sensor arm configured to provide an evanescent field through a sensed medium region adjacent to the sensor arm is presented.
Abstract: A sensor apparatus includes a photonic crystal structure including a Mach Zehnder interferometer with a reference arm and a sensor arm configured to provide an evanescent field through a sensed medium region adjacent to the sensor arm.
Patent•
24 Nov 2004TL;DR: In this article, an improved LIDAR system is presented, which consists of a beam generating mechanism, mirrors which reflect those beams, and detection devices for detecting an interference pattern of overlapping reflected beams.
Abstract: An improved lithographic interferometer system, is presented herein. The lithographic interferometer system comprises a beam generating mechanism, mirrors which reflect those beams, and detection devices for detecting an interference pattern of overlapping reflected beams. The beam generating mechanism comprises a beam-splitter, which splits the beams into reference beams and measuring beams, a reference mirror that provides a plane mirror interferometer, and a reflective surface that emits at least one reference beam used in a differential plane mirror interferometer.
Patent•
01 Nov 2004
TL;DR: In this paper, a method and a system for measuring a physical quantity by means of a tandem interferometer optical sensor system based on low-coherence interferometry is presented.
Abstract: The invention provides a method and a system for measuring a physical quantity by means of a tandem interferometer optical sensor system based on low-coherence interferometry. The system comprises a light system, a sensing interferometer and a polarization readout interferometer. The invention provides a polarization interferometer comprising a single birefringent wedge. The invention also provides for a dispersion-compensated optical sensor system. The invention also provides an interferometer sensitive to temperature that comprises a trajectory in a LiB3O5 crystal with an x-cut orientation.
Patent•
29 Mar 2004TL;DR: In this paper, an apparatus for generating a quantum state of a two-qubit system including two qubits, each qubit being represented by a particle which invariably travels through one of two paths, includes a quantum gate composed of an interferometer for implementing an-interaction-free measurement.
Abstract: An apparatus for generating a quantum state of a two-qubit system including two qubits, each qubit being represented by a particle which invariably travels through one of two paths, includes a quantum gate composed of an interferometer for implementing an-interaction-free measurement. The apparatus receives two particles having no correlation and generates a Bell state with asymptotic probability 1. A Bell measurement of a state of a two-qubit system is performed by observing a quantum gate composed of the interferometer after the quantum gate has processed the state and selecting the state from the Bell bases. An approximate fidelity of a quantum gate composed of the interferometer is calculated, if an absorption probability with which a first particle absorbs a second particle in the interferometer is less than 1, under the condition that the number of times the second particle hits beam splitters in the interferometer is sufficiently large.
TL;DR: In this article, an all-optical switch that is operated by the nonlinear phase shift introduced by optical pulses with duration of 200 fs in a semiconductor optical amplifier (SOAs) was investigated.