• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.128-134
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• 2012

The performance evaluation and fabrication of integrated-optic electric-field sensor utilizing $Ti:LiNbO_3$ asymmetric Mach-Zehnder intensity modulator with a push-pull lumped electrode and a plate-type probe antenna to measure an electric field strength is described. The modulator has a small device size of $46{\times}7{\times}1\;mm$ and operates at a wavelength $1.3{\mu}m$. The devices are simulated based on the BPM software and fabricated utilizing Ti-diffused $LiNbO_3$ channel optical waveguides. The minimum detectable electric field is 1.02 V/m and 6.91 V/m, corresponding to a dynamic range of ~35 dB and ~10 dB at the frequencies of 500 KHz and 5 MHz, respectively.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.10
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• pp.706-711
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• 2001

In this paper we propose the simple system for measuring the chromatic dispersion of a fiber by using Sagnac interferometer with a Mach-Zehnder modulator and induce the equivalent model and the transfer function of this system. The chromatic dispersion of fibers with length of 2.235km is measured by using this method in wavelength region from 1500nm to 1580nm and we conform that the measured results had a good agreement with the theoretical results given Corning Fiber.

• Korean Journal of Optics and Photonics
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• v.12 no.4
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• pp.251-256
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• 2001

The influences of decorrelation on phase sensitivity are studied with a computer simulation based on the Bayesian theorem, when correlated photons produced by parametric down-conversion are incident on a Mach-Zehnder interferometer. Although the down-converted photons show a perfect correlation in the production process, this degree of correlation may be decreased by reflection, absorption, and scattering during propagation. It is found that this decorrelation results in phase sensitivity degradation, and that the sensitivity is related to the detector quantum efficiency. The results show that when the phase difference between the two paths is smaller the phase sensitivity is better. etter.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.3
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• pp.10-18
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• 2003

In this paper, we propose an optical encryption system based on the encryption of information using the phase component of a wavefront and orthogonal polarization in a Mach-Zehnder interferometer. Since the incoherence of the two perpendicularly polarized lights removes interference component, the decrypted image is stable. In encryption process, the original image is converted into an image having random polarization state by the relative phase difference of horizontal polarization and vertical polarization, so we cannot obtain the original information from the random polarization distribution. To decrypt an Image, the random polarization distribution of encrypted image is divided into two orthogonal components, then key image must be placed on vertical path of Mach-Zehnder interferometer. The decrypted image is obtained In the form of intensity by use of an analyzer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.390-390
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• 2008

In this paper, we have designed and fabricated optical waveguides based on the Mach-Zehnder Interferometer (MZI) for application to sensor. The evanecent-wave sensor based on the MZI principle has sufficiently high sensitivity to measure the change of the refractive index on surface of a waveguide. The waveguides were optimized at a wavelength of 1550 nm and fabricated according to the design rule of 0.45 delta%, which is the difference of refractive index between the core and clad. The fabrication of MZI optical waveguides was performed by a conventional Planar Lightwave Circuit (PLC) fabrication process. The fabricated MZI optical waveguide device was measured. According to the measurement result, the insertion loss of MZI optical waveguide device was below 3.5 dB and the polarization dependent loss (PDL) was within 0.1dB. In addition, we analyzed optical properties of MZI sensor according to the refractive index change of the sensor arm.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.4
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• pp.255-259
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• 2006

For the intruder detection, a buried fiber-optic sensor based on fiber-optic Mach-Zehnder interferometer is demonstrated. We buried the sensor arm in a styrene board and exerted pressure on it. The pressure-induced deformation speed has almost linear relationship with the output frequencies of the interference signals, and about 4.25 Hz frequency change per 0.01m/s was obtained. Also it has been shown that the amplitude of frequency component increases according to the weight of mass.

• Current Optics and Photonics
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• v.4 no.6
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• pp.558-565
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• 2020

A wavelength-independent optical sensor based on an asymmetric Mach-Zehnder interferometer (AMZI) is proposed. The optical sensor based on an AMZI is very sensitive to wavelength, and wavelength drift will lead to measurement error. The optical sensor is compensated to reduce its dependence on wavelength. The insensitivity of the optical sensor to wavelength mainly depends on the compensation structure, which is composed of an AMZI cascaded with another AMZI and can compensate the wavelength drift. The influence of wavelength drift on the optical sensor can be counteracted by carefully designing the size parameters of the compensation structure. When the wavelength changes from 1549.9 nm to 1550.1 nm, the error after compensation can be lower than 0.066%. Furthermore, the effect of fabrication tolerance on compensation results is analyzed. The proposed compensation method can also be used to compensate the drift of other parameters such as temperature, and can be applied to the compensation of other interference-based optical devices.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.5
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• pp.442-451
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• 1992

Mach-Zehnder type GaAs elcetro-optic waveguide modulator has been designed in this paper.The modulator. Considered is based on the Mach-Zehnder interferometer configuration, consisting of two Y branch couping rib type waveguides formed in two epitaxial layers on GaAs substrate. The mode theory on waveguides and electo-optic effect of GaAs were utilized to determine the design parameters for the modulator proposed. Effective index method was applied to design the of waveguide supporting a single mode were calculated to achieve the optimized operation of the modulator. Considering interrelationships between many parameters.

• Korean Journal of Optics and Photonics
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• v.28 no.5
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• pp.213-220
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• 2017

This paper proposes how to fabricate an educational Mach-Zehnder interferometer that is easy to align and inexpensive, using 3D printers and semiconductor lasers. The interferometer consists of a body $165mm{\times}120mm{\times}57mm$ in size, mirror mounts, a laser holder, beam splitters, and so on. The laser path is adjusted by 4 mirror mounts, each comprised of rubber bands, small metal wires, and a screw. The interference fringe is enlarged by the lens at the final stage. The refractive index of a slide glass was measured by counting the number of moving interference fringes while the slide glass, inserted into one of the two interferometer arms, is rotating. The formula for the refractive index as a function of the optical-path difference and rotation angle was obtained, and used to calculate the refractive index of glass from the interferometer experiment. The use of a rotating glass in one arm of the interferometer nullifies the need for a precision stage, which despite its high cost is often required to observe the moving interference fringe in the classroom. Therefore, the 3D-printed Mach-Zehnder interferometer proposed in this paper can be very useful for education, because of its affordability and performance. It enables students to perform both qualitative and quantitative studies using a 3D-printed interferometer, such as measuring the refractive index of a glass sample, and the wavelength of light.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.165-172
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• 2012

Integrated-optic asymmetric Mach-Zehnder interferometer at $1.3{\mu}m$ wavelength and segmented electrode structure were designed and fabricated as a sensing part for the electric-field measurement system. The device was simulated based on the BPM software and fabricated utilizing Ti-diffused $LiNbO_3$ channel optical waveguides and lumped-type electrodes. Almost half-maximum power transmission was observed for asymmetric interferometers with ${\pi}/2$ intrinsic phase difference. Expected experimental measurements were observed for 1KHz electrical signal bandwidth.