Showing papers on "Mach–Zehnder interferometer published in 1994"
TL;DR: In this paper, the extinction ratio was measured for the converted signal compared to the input signal implying signal regeneration as well as wavelength conversion using SOA in a Mach-Zehnder configuration.
Abstract: Penalty free wavelength conversion is demonstrated at 2.5 Gbit/s over a wavelength span of 12 nm by the use of semiconductor optical amplifier (SOA)'s in a Mach-Zehnder configuration. An increase in the extinction ratio is measured for the converted signal compared to the input signal implying signal regeneration as well as wavelength conversion. >
215 citations
TL;DR: In this article, a passive TE/TM mode polarization splitter based on a Mach-Zehnder interferometer is demonstrated, which attains large optical bandwidth employing a pair of multimode interference couplers and a wavelength-tolerant birefringent structure.
Abstract: A passive TE/TM mode polarization splitter based on a Mach-Zehnder interferometer is demonstrated. Insertion loss of 1.5 db and extinction ratios of /spl minus/19 dB for TE and /spl minus/15 dB for TM have been measured at 1510-nm wavelength. The device attains large optical bandwidth employing a pair of multimode interference (MMI) couplers and a wavelength-tolerant birefringent structure. >
148 citations
TL;DR: In this article, the realisation of a thermo-optical Mach-Zehnder interferometer switch based on SOI (silicon-on-insulator) material is reported, at a wavelength of 1.3 mu m, on-off ratios of 13 dB (TE) and 9 dB (TM) are achieved with a switching power of 150 mW.
Abstract: The realisation of a thermo-optical Mach-Zehnder interferometer switch based on SOI (silicon-on-insulator) material is reported. At a wavelength of 1.3 mu m, on-off ratios of 13 dB (TE) and 9 dB (TM) are achieved with a switching power of 150 mW. The measured rise time is 5 mu s.
119 citations
TL;DR: An optical magnetometer based on atomic coherence effects is analyzed using a quantum Langevin approach and effects of Doppler broadening and fluctuations of the driving field are discussed and a comparison to standard optical-pumping magnetometers is made.
Abstract: An optical magnetometer based on atomic coherence effects is analyzed using a quantum Langevin approach. The large dispersion of a phase-coherent atomic medium (``phaseonium'') at a point of vanishing absorption is used to detect magnetic level shifts via optical phase measurements in a Mach-Zehnder interferometer with sensitivities potentially superior to state-of-the-art devices. Effects of Doppler broadening and fluctuations of the driving field are discussed and a comparison to standard optical-pumping magnetometers is made.
119 citations
TL;DR: In this paper, a Mach Zehnder interferometer was used as an optical discriminator to measure the time-resolved frequency chirp of an optical source, which was then used as a discriminator for measuring the optical signal.
Abstract: A Mach Zehnder (MZ) interferometer has been used as an optical discriminator to measure the time-resolved frequency chirp of an optical source.
112 citations
TL;DR: In this article, a symmetric Mach-Zehnder (SMZ) all-optical switch is proposed, which achieves high speed switching and nearly square modulation, achieving the full width at half-maximum of the obtained wave form is 8 ps.
Abstract: We report the experimental results of a novel symmetric Mach–Zehnder (SMZ) all‐optical switch. Although the switching is based on the band‐filling effect in the semiconductor waveguide, the switching speed is not restricted by the slow relaxation time. We obtain fully switched, nearly square modulation, which is characteristic of the SMZ all‐optical switch. We also achieve high‐speed switching; the full width at half‐maximum of the obtained wave form is 8 ps, which is only limited by the time resolution of the detection system.
98 citations
TL;DR: In this article, the design and characteristics of cascaded coupler Mach-Zehnder (CMZ) channel adding/dropping filters that select every nth channel (n=2,3,4,...) from the wavelength division multiplexed (WDM) optical signal were described.
Abstract: We describe the design and characteristics of cascaded coupler Mach-Zehnder (CMZ) channel adding/dropping filters that select every nth channel (n=2,3,4,...) from the wavelength-division-multiplexed (WDM) optical signal. Using the truncated binomial coupling weight distribution, which appears to be optimal, such filters achieve low ( >
89 citations
TL;DR: In this paper, a new configuration for a Mach-Zehnder interferometric electric field sensor device utilizing the electrooptic effect is reported, which uses no metallic electrodes and operates solely by immersion in an electric field.
Abstract: A new configuration for a Mach-Zehnder interferometric electric field sensor device utilizing the electrooptic effect is reported. The lithium niobate device uses no metallic electrodes and operates solely by immersion in an electric field. Reverse poling of one arm of the interferometer provides opposing optical phase changes in the two interferometer arms when placed in an electric field. One fabricated device exhibits a measured minimum detectable field of 0.22 V/m/spl radic/Hz and a frequency response of greater than 1 GHz. Theoretical calculations show that detection of 0.11 V/m/spl radic/Hz is attainable while the upper frequency limit can exceed 6 GHz. >
89 citations
TL;DR: In this paper, a self-holding and optical-optical 2×2 switch using a Mach-Zehnder interferometer with a thermally irreversible photochromic (PC) guest/host polymer cladding is reported.
Abstract: A self‐holding and optical–optical 2×2 switch using a Mach–Zehnder interferometer with a thermally irreversible photochromic (PC) guest/host polymer cladding is reported. The device was fabricated using a silica‐based integrated optic Mach–Zehnder interferometer with a PC cladding polymer. Cross‐bar switching was achieved by using ultraviolet (313 nm) and visible (≳500 nm) light. The switching state was self‐holding in the dark. Switching was observed with a crosstalk ratio of −12 dB and an excess loss of 7 dB at 1.55 μm.
68 citations
TL;DR: In this article, the realisation and first static results of a novel monolithic Mach-Zehnder interferometer (MZI) wavelength converter configuration in InGaAsP/InP MQW technology is reported.
Abstract: The realisation and first static results of a novel monolithic Mach-Zehnder interferometer (MZI) wavelength converter configuration in InGaAsP/InP MQW technology is reported. The compact all-active three-port MZI device allows for effective improvement of the on/off ratio up to 18 dB (from 6 to 26 dB) due to direct optical access to one of the interferometer arms by an extra input branch. This device is very attractive for high-capacity optical networks.
52 citations
TL;DR: In this paper, a technique for extending the resolution of an integrated optical multi-interferometer guided-wave analog-to-digital converter is described, where the optical output waveform for each interferometer is symmetrically folded at twice a proper modulus.
Abstract: A technique is described for extending the resolution of an integrated optical multi-interferometer guided-wave analog-to-digital converter. The optical output waveform for each interferometer is symmetrically folded at twice a proper modulus. A small comparator ladder mid-level quantizes each interferometer's detected output to encode the analog signal in a symmetrical number system (SNS) format. By incorporating the SNS encoding, resolution greater than 1 bit per interferometer can be provided. Analog signal levels that can cause possible encoding errors are examined and their impact on the overall amplitude analyzing function is discussed. The maximum laser pulse width and maximum fluctuation in the sampling interval that can be tolerated is also discussed. Results indicate that 11-bit resolution can be provided with three interferometers and 39 comparators.
TL;DR: In this article, a simple and accurate technique for evaluating the chirp factor of Mach-Zehnder modulators is presented, based on the dependence of the α parameter of the modulators on the applied bias voltage.
Abstract: A simple and accurate technique for evaluating of the chirp factor of Mach-Zehnder modulators is presented. The method is based on the dependence of the α parameter of the modulators on the applied bias voltage. It is shown that experimental results and theory are in very good agreement.
TL;DR: In this paper, an interferometric technique using a newly developed Mach-Zehnder interferometer is applied to measure the refractive indices of light transmitting fluids in general.
Abstract: An interferometric technique using a newly developed Mach–Zehnder interferometer is applied to measure the refractive indices of light transmitting fluids in general. It has been particularly used for determining the refractive indices and its variation with temperature for two solvents of laser dyes (toluene and carbon disulphide). Accuracy of 1×10−5 is achieved where no uncertainity of the measurements arising from the naked eye estimation. The obtained optical results have been used to calculate a number of different physical parameters such as the optical permittivity (or dielectric susceptibility), thermal coefficient of refractive index, temperature coefficient of permittivity, specific refraction, molar refraction, polarizability, radius of the molecule, relaxation time, temperature coefficient of volume expansion, characteristic impedance of matter, and the constant electric moment of a molecule. It is shown that the experimental results agree well with the calculated ones. The advantages of this ...
TL;DR: In this paper, the birefringence induced by compressive strain in silica waveguides on silicon substrates is compensated with a silicon nitride patch placed below the core.
Abstract: The birefringence induced by compressive strain in silica waveguides on silicon substrates is compensated with a silicon nitride patch placed below the core. We demonstrate Mach-Zehnder interferometers with polarization-independent spectral response, including a compensated Mach-Zehnder interferometer suitable for stabilization of multiple laser sources in a dense wavelength division multiplexed fiber optic communication network. Furthermore, we show how silicon nitride can also be used to compensate polarization dependent losses. Polarization independence achieved with a silicon nitride patch is applicable to a wide variety of other devices such as arrayed waveguide grating multiplexers and Bragg reflectors. >
TL;DR: In this article, the propagation effects of a modulated lightwave signal in an unbalanced Mach-Zehnder interferometer (UMZI) were studied and the experimental results of the microwave frequency response of the structure were obtained using two lightwave network analyzers HP8702A and HP8510B with an optoelectronic HP83420A.
Abstract: In this work, we study the propagation effects of a modulated lightwave signal in an unbalanced Mach-Zehnder interferometer (UMZI). Experimental results of the microwave frequency response of the structure are obtained using two lightwave network analyzers HP8702A and HP8510B with an optoelectronic HP83420A. It is shown that such an optical device could be used to perform a number of interesting microwave applications. The problems appearing in the coherent working regime and the possibility of integrated device realizations for millimeter-frequency signal processing are also discussed. >
TL;DR: This work investigates the feasibility of making a single-mode glass ion-exchanged interferometer designed especially to obtain an interference pattern, based on the use of tapered waveguides to obtain a collimated beam.
Abstract: Glass ion exchange is an attractive method for fabricating integrated optical components. We investigate the feasibility of making a single-mode glass ion-exchanged interferometer designed especially to obtain an interference pattern. The design of the interferometer is based on the use of tapered waveguides to obtain a collimated beam. This interferometer could be used as a chemical or biological sensor.
TL;DR: A possible realistic implementation of a method for interaction-free measurements, due to Elitzur and Vaidman, is proposed and discussed in this article, where it is argued that the effect can be observed in an optical laboratory.
Abstract: A possible realistic implementation of a method for interaction-free measurements, due to Elitzur and Vaidman, is proposed and discussed. It is argued that the effect can be observed in an optical laboratory.
TL;DR: In this article, an integrated optical Mach-Zehnder interferometer was used to detect triazines in the presence of an antigen layer as a superstrate on top of one of its surface waveguides.
Abstract: Integrated optical Mach-Zehnder interferometers supply information on changes in refractive index and/or thickness of a film placed as a superstrate on top of one of its surface wave-guides. The internal propagation of light is influenced by the evanescent field reaching into the superstrate. This propagating light interferes with an uninfluenced wave in the second arm after recombination. The result is an intensity modulation depending on the refractive index parameters of the substrate, the waveguide itself and the properties of the superstrate. Taking an antigen layer as the superstrate, its interaction with antibodies changes its thickness by several nanometers. This can be observed by recording the change in intensity of the signal of the interferometer. The sensitivity of such a device depends on particular values of the optical parameters of substrate and waveguide with respect to the given superstrate properties. Computer calculations help to select optimum glass and waveguide fabrication conditions. The numerical results of a variety of assumed conditions have been tested experimentally. The application to the improved detection of triazines is discussed.
TL;DR: In this paper, a pair of light quanta with different colors (155.9-nm difference in center wavelength) generated from parametric down-conversion was injected collinearly into one input port of a Mach-Zehnder interferometer.
Abstract: A pair of light quanta with different colors (155.9-nm difference in center wavelength) generated from parametric down-conversion was injected collinearly into one input port of a Mach-Zehnder interferometer. Coincidence interference behavior was studied over a wide range of optical path differences of the interferometer. A measurement of 75% interference visibility with oscillation of the pump frequency for a large optical path difference of the interferometer (43 cm) is the signature of a quantum two-photon entangled state, which reflects both particle and wave nature of the light quanta in one experiment.
TL;DR: In this article, the concept of a tunable erbium-doped fiber ring laser based on a reflection Mach-Zehnder interferometer was presented, which gave a tuning range of 39 nm.
Abstract: The concept of a tunable erbium-doped fiber ring laser based on a reflection Mach-Zehnder interferometer is presented. The principle of operation is demonstrated with a fiber version of the interferometer which gave a tuning range of 39 nm. With current electro-optic devices, high speed tuning should be possible. >
TL;DR: In this paper, a new fiber-optic sensing technique for electric current measurement is proposed, which is based on the use of the sensitive thermal detection in which two metal-coated singlemode fibers in an interferometer of Mach-Zehnder type are used.
Abstract: A new fiber-optic sensing technique for electric current measurement is proposed in this paper. The technique is based on the use of the sensitive thermal detection in which two metal-coated single-mode fibers in an interferometer of Mach-Zehnder type are used. In the proposed method, a constant bias current with enough accuracy is employed to amplify the detected phase variation caused by the current to be measured. The experimental results prove that not only can the sensitivity of measurement be well enhanced, but also that a wide dynamic range and good linearity can be obtained using the proposed method. In the case of coating resistances of 60.6 and 60.56 /spl Omega/, the measurement sensitivity can be enhanced by more than 20 times if a bias current of 50 mA is used for measuring 4-mA dc current, compared to the traditional method in which only one fiber arm of the interferometer is coated with metal. In the linear measurement of electric current ranging from /spl sim/0.01 to /spl sim/10 mA the current-to-phase sensitivity is found to equal 1.13/spl times/10/sup 4/ rad/amp. >
TL;DR: In this article, the experimental verification of the spectral modulation arising from interference of light beams having different degrees of correlation in a Mach-Zehnder interferometer was done by Agarwal and James (1993, J. mod. Optics, 40 1431).
Abstract: We illustrate here the experimental verification of the spectral modulation arising from interference of light beams having different degrees of correlation in a Mach-Zehnder interferometer for which the theoretical study was done by Agarwal and James (1993, J. mod. Optics, 40 1431). Through a theoretical fitting for the observed spectral modification, path difference between the beams in the two arms is calculated and compared with the experimental values.
Patent•
13 Apr 1994TL;DR: In this article, a Mach-Zehnder filter with optical delay devices was proposed, which exhibits greater finesse per stage than previous MZF devices, finesse being the ratio of the wavelength separation between adjacent peaks to the peak widths.
Abstract: A Mach-Zehnder filter includes an input coupler (20) for splitting an input signal into N equal output signals, where N>2, and a signal combining coupler (28) for combining N optical signals into a single output signal. It further includes N optical waveguide fibers (22,23,24) for connecting the N outputs from the input coupler to the signal combining coupler. Each of the N optical fibers subjects the light propagating therethrough to a delay (25,26,27) that is different from the delay experienced by light propagating through each of the other optical fibers. This Mach-Zehnder filter exhibits greater finesse per stage than previous Mach-Zehnder devices, finesse being the ratio of the wavelength separation between adjacent peaks to the peak widths. This can be achieved by employing optical fibers of different lengths, by employing optical fibers of identical lengths but having different refractive index profiles, or by inserting optical delay devices in at least two of the fibers.
TL;DR: In this article, the complex electrooptic constants of DR1 dye molecules doped in polymethylmethacrylate film were measured by a scanning Mach-Zehnder interferometric technique.
Abstract: The complex electro‐optic constants of disperse red 1 (DR1) dye molecules doped in polymethylmethacrylate film were measured by a scanning Mach–Zehnder interferometric technique. Despite a very small absorbance at 632.8 nm, DR1 molecules still have a measurable imaginary part of the EO constants. Two independent complex components, r13 and r33 were determined by incident angle dependence. The ratios Re[r33]/Re[r13] and Im[r33]/Im[r13] are 3.5±0.5 and 3.2±0.9, respectively. These results show that EO response is dominated by the electronic mechanism. The influence of multiple reflection in polymer film on the experimental results are briefly discussed.
Patent•
13 Jan 1994TL;DR: In this paper, a two-beam interference type filter (15) coupled with an optical cable (10) was used for bothway optical communication between two terminal stations (11a, 12a) for multiplexing and/or de-multiplexing transmitted and received light.
Abstract: Bothway optical communication is carried out through a wavelength division multiplex system between two terminal stations (11a, 12a), each having a two-beam interference type filter (15) coupled with an optical cable (10) for multiplexing and/or de-multiplexing transmitted light and received light. The filter (15) has passbands and attenuation bands having periodic characteristics for the wavelength in the communication wavelength band. The wavelength of the transmitted light is essentially the same as the wavelength of the received light in each terminal station, with a small offset of the two wavelengths less than 5 nm. The oscillation wavelength of the laser (21) for transmission is adjusted so that it coincides with the passband of the filter, which doubles as a reference wavelength of the oscillation wavelength of the laser. Preferably, the two-beam interference type filter (15) is a Mach Zehnder type asymmetrical interferometer having a pair of directional couplers (F1, F2) connected to each other through a pair of optical fibers (f1, f2) so that the period of the passbands and/or the attenuation bands of the filter (15) is adjustable.
TL;DR: A laser interferometric measurement technique that uses a Mach-Zehnder interferometer is developed that permits studies of the physical processes that involve a change in the refractive index with temperature to a high degree of accuracy.
Abstract: A laser interferometric measurement technique that uses a Mach-Zehnder interferometer is developed. This technique permits studies of the physical processes that involve a change in the refractive index with temperature to a high degree of accuracy. A theoretical derivation has been formulated to permit computation of the refractive index of transparent materials. The technique is particularly useful in studying slight changes in refractive index of various gases, solutions over a considerable region, and flow patterns in wind tunnels.
Patent•
NEC1
TL;DR: The Mach-Zehnder type all-optical device for controlling a signal light with a control light, including two arms for constituting a MZ configuration, each of the arms being constituted at least partially of material having third order optical nonlinearity as mentioned in this paper.
Abstract: The Mach-Zehnder type all-optical device for controlling a signal light with a control light, includes two arms for constituting a Mach-Zehnder configuration, each of the arms being constituted at least partially of material having third order optical nonlinearity, and an introducer of a control light to a portion of each of the arms revealing the optical nonlinearity.
TL;DR: In this article, a novel form of Mach-Zehnder interferometer based on multimode interference (MMI) phenomena in multimode waveguides is predicted and demonstrated.
TL;DR: In this paper, the authors demonstrate Mach-Zehnder interferometric waveguide intensity modulators which employ electrorefraction due to the quantum-confined Stark effect in multiple quantum well (MQW) GaAs/AlGaAs.
Abstract: We demonstrate Mach-Zehnder interferometric waveguide intensity modulators which employ electrorefraction due to the quantum-confined Stark effect in multiple quantum well (MQW) GaAs/AlGaAs. These devices exhibit average half-wave voltage-length products as low as 3.0 V/spl middot/mm and extinction ratios greater than 23.8 dB, which are superior to any MQW devices of this type. An effective index based model is developed to extract linear and quadratic electro-optic coefficients from the modulation data. Also, the power handling limitations of MQW modulators are discussed in terms of device performance and catastrophic electrical failure. >
TL;DR: By using a silica-on-terraced-silicon platform (STS-platform) for optical hybrid integration, this article fabricated a hybrid Mach-Zehnder interferometric circuit consisting of silica waveguide directional couplers and a LiNbO/sub 3/ phase shifter array.
Abstract: By using a silica-on-terraced-silicon platform (STS-platform) for optical hybrid integration, we fabricated a hybrid Mach-Zehnder interferometric circuit consisting of silica-waveguide directional couplers and a LiNbO/sub 3/ phase-shifter array. The circuit functioned as an optical switch with an insertion loss of 6.0 dB including input and output fiber coupling loss and an extinction ratio of better than 20 dB. The STS-platform was thus confirmed to incorporate both a high-performance planar lightwave circuit and a silicon optical bench. >