• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.264-268
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• 1990

A guided-wave electro-optic Mach-Zehnder interferometric modulator was fabricated on X-cut LiNbO3 . The channel waveguides were formed by proton diffusion with self-aligned SiO2-cladding. A mach-Zehnder interferometric modulator with arm lengths of 7mm has been fabricated and tested at 0.6328${\mu}{\textrm}{m}$. Its modulation depth with V$\pi$ of only 3.5V was 85% and the 3dB bandwidth was 1.6KHz. For high speed operation, the electrode dimension should be reduced to have smaller R, L, and C.

• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.365-368
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• 2003

We have demonstrated mechanically induced Mach-Zehnder interferometers (MZI) based on a long-period fiber grating pair. The transmission spectra, the interference fringes, and the fringe spacing of the long-period fiber grating pairs have also been investigated experimently and analytically. The fringe spacings of the fabricated LPG pairs agree well with the theoretical results.

• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.194-213
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• 2022

This study comprehensively reviewed four types of integrated-optic electric-field sensors based on titanium diffused lithium-niobate waveguides: symmetric and asymmetric Mach-Zehnder interferometers, 1×2 directional couplers, and Y-fed balanced-bridge Mach-Zehnder interferometers. First, we briefly explain the crystal properties and electro-optic effect of lithium niobate and the waveguide fabrication process. We theoretically analyzed the key parameters and operating principles of each sensor and antennas. We also describe and compare the design, simulation, implementation, and performance tests: dc and ac characteristics, frequency response, dynamic range, and sensitivity. The experimental results revealed that the sensitivity of the sensor based on the Y-fed balanced bridge Mach-Zehnder interferometer (YBB-MZI) was higher than that of the other types of sensors.

• Proceedings of the Optical Society of Korea Conference
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• 1998.08a
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• pp.128-129
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• 1998

• Proceedings of the Optical Society of Korea Conference
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• 1996.09a
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• pp.83-83
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• 1996

• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.454-459
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• 2003

We report the first demonstration of 10 Gb/s wavelength conversion in a Mach-Zehnder interferometric wavelength converter monolithically integrated with a loss-coupled DFB probe source. The integrated device is fabricated using a BRS (buried ridge stripe) structure with an undoped InP clad layer on the top of a passive waveguide to reduce high propagation loss. The device exhibited a static extinction ratio of 11 dB. Good performance at 10 Gb/s is obtained with an extinction ratio of 7 dB and a power penalty of 2.8 dB at a 10$^{-9}$ bit error rate.

• Korean Journal of Optics and Photonics
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• v.23 no.2
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• pp.71-76
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• 2012

A Sagnac-type Mach-Zehnder interferometer(SMZI) is a very stable instrument with respect to phase drift because all optical paths can share common optical components. We have observed very stable interference fringes in single photon interference experiments with an extremely attenuated laser beam, and with heralded single photons prepared from polarization correlated photon pairs in type-II spontaneous parametric down-conversion. The phase stability is measured to be about ${\pm}0.18$ rad for the SMZI, in contrast, conventional MZI showed the phase fluctuation of around ${\pm}1.02$ rad.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.10 s.115
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• pp.1044-1049
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• 2006

The vibration exciter with the accurate calibration requires a low distortion along a single axis over a wide range of frequency. The fabricated piezoelectric exciter was composed of a base, piezoelectric element(Venitron PZT 5A), electrode and seismic mass. Its performance characteristics is evaluated the Mach-Zehnder optical fiber interferometer. The phase of the optical wave passing through the optical fiber around the piezoelectric element was related the vibrational amplitude with a change of the applied sinusoidal voltage on the piezoelectric element. The dynamic characteristics of vibration exciter can be obtained by measuring the vibrational amplitude with a sinusoidal applied voltage on the piezoelectric element. The sensitivity of the fabricated piezoelectric exciter had a 0.4 nm/V which was uniform up to 20 kHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.7
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• pp.479-485
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• 2001

In this paper, we propose optical subcarrier mutiplexing(SCM) transceiver module for base station(BS) that has no optical source and can be used for full-duplex communication over single optical fiber. In this method we retransmit optical modulated signal to the central office(CO) using loop-back system with a ring type Mach-Zehnder modulator(MZM) in BS, where optical source is transmitted from the CO. We have modeled the ring type MZM and were conformed that the measured results were in good agreement with the modeling. In the ring type MZM, the optical symmetric position of the MZM is very important in RF signal transmission.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.50-56
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• 2003

It is well known that a partial-discharge(PD) in insulation oil is the source of various physical and chemical phenomena, such as heat, light, gas, chemical transformation, electric current, electromagnetic radiation and ultrasonics. The PD can be detected by measuring one of these changes. Although some techniques are employed in this purpose, several obstacles interfere with an on-line measurement. Ultrasonic-wave detection is a useful method for the diagnosis of the transformer-insulation condition. Conventionally, ulyrasonic waves are detected by Piezo-electric transducer, but we use optical method that has many advantages. In this paper, we constructed a Mach-Zehnder interferometer with optical fiber and investigated the principle of operation. Test arrangement is based on the needle-plane electrode system in oil and applied AC high voltage. Ultrasonic waves were detected and analyzed with wavelet transform.