• Proceedings of the Optical Society of Korea Conference
• /
• 2003.02a
• /
• pp.328-329
• /
• 2003

최근 전력 계통의 전압 상승과 측정 정밀도에 대한 요구가 증대됨에 따라 전력 설비의 고장 검출이나 측정 분야의 기술과 비용면에서 경쟁력을 갖춘 광을 이용한 고전압 대전류 측정이 주목받고 있다. 본 연구는 광섬유를 이용하여 보다 안전하고 정밀한 대전류 측정 장치 개발에 목적을 두고 있다. 광을 이용한 전류 센서는 편광된 광이 광섬유를 통과할 때 광섬유 주위의 자장에 의해서 편광면이 회전하는 패러데이 회전을 이용한 것이다. (중략)

• Korean Journal of Optics and Photonics
• /
• v.8 no.2
• /
• pp.142-148
• /
• 1997

The new type of dispersion-free optical isolator is presented and it's performance is verified by theoritical and empirical method. The dispersion-free optical isolator consists of 2 wedged birefringent materials, faraday rotator, collimating unit and focusing unit. In the test it shows that isolation is 40dB, insertion loss is 0.55dB, dispersion is 0.02ps at 1550nm

• Korean Journal of Optics and Photonics
• /
• v.30 no.6
• /
• pp.249-254
• /
• 2019

An optical current sensor device that measures electric current by the principle of the Faraday effect was designed and fabricated. The polarization-rotated reflection interferometer and the quadrature phase interferometer were introduced so as to improve the operational stability. Complex structures containing diverse optical components were integrated in a polymeric optical integrated circuit and manufactured in a small size. This structure allows sensing operation without extra bias feedback control, and reduces the phase change due to environmental temperature changes and vibration. However, the Verdet constant, which determines the Faraday effect, still exhibits an inherent temperature dependence. In this work, we tried to eliminate the residual temperature dependence of the optical current sensor based on polarization-rotated reflection interferometry. By varying the length of the fiber-optic wave plate, which is one of the optical components of the interferometer, we could compensate for the temperature dependence of the Verdet constant. The proposed optical current sensor exhibited measurement errors maintained within 0.2% over a temperature range, from 25℃ to 85℃.

• Korean Journal of Optics and Photonics
• /
• v.35 no.3
• /
• pp.115-120
• /
• 2024

Magneto-optical (MO) materials have attracted much attention, since they can be utilized for various optical applications, such as magnetic field sensors, optical current sensors, optical isolators, and optical circulators. In this study, alumino-borosilicate (ABS) glasses with high concentrations of Dy³⁺ ions were fabricated by a conventional melt-quenching technique, and the dependence of their thermal, optical, and magneto-optical properties on Dy³⁺ ion concentration was investigated. The MO property of the glasses was investigated by measurement of Faraday rotation at 1550 nm. The Faraday rotation angle increased linearly with the increase of Dy³⁺ ion concentration in the glasses. A very high Verdet constant of -6.86 rad/(T·m) was obtained for glass with a Dy³⁺ ion concentration of 30 mol%. In addition, the ABS-Dy glasses showed good thermal stability of greater than 128 ℃ against crystallization, and high optical transmission of 70% in the visible to near-infrared windows of 480-720, 1390-1560, and 1800-2400 nm. Due to the high Verdet constant and good thermal stability, the ABS-Dy glasses in this study could be candidate optical materials for MO device applications at 1550 nm.

• Journal of the Korean Magnetics Society
• /
• v.19 no.5
• /
• pp.186-190
• /
• 2009

We investigated the magneto-optical properties and application of diluted magnetic semiconductors Cd$_{1-x}$Mn$_x$Te crystals with various Mn contents grown using a vertical Bridgman method. This material crystallizes in the zinc-blende structure for values of x < 0.82. The band-gap energy was depended on Mn mole fraction x linearly and increased with decreasing temperature. The Faraday rotation was increased as the photon energy increased near to that of the fundamental band gap and its increased with increasing Mn mole fraction. Optical isolator using the Cd$_{0.62}$Mn$_{0.38}$Te crystal shows that the isolation and insertion loss are 45 dB and 0.35 dB at 650 nm, respectively.

• Korean Journal of Optics and Photonics
• /
• v.14 no.2
• /
• pp.142-145
• /
• 2003

The nonreciprocal phase shift characteristics of infinite slab optical waveguides with magneto-optic materials in the cladding layer was calculated at 1.55 ${\mu}{\textrm}{m}$ for optical isolators. The infinite slab waveguide structures considered in this paper were as follows. rho magneto-optic materials used as a cladding layer were Ce:YIG and LNB(LuNdBi)$_3$(FeAl)$_{5}$)$_{12}$,). Their specific Faraday rotations Θ$_{F}$ are 4500$^{\circ}$/cm, 500$^{\circ}$/cm at wavelength 1.55 ${\mu}{\textrm}{m}$ respectively. The guiding layer with multi-quantum well structure was used, and it consists of 1.3Q and InGaAs. In order to investigate the effect of evanescent field penetrating the cadding, layer, guiding mode characteristics were calculated for the cases when the substrate is InP and air. We calculated the minimum lengths of 90$^{\circ}$ nonreciprocal phase shifters and their optimum guiding layer thicknesses in various optical waveguide structures.res.s.