• Journal of Sensor Science and Technology
• /
• v.17 no.5
• /
• pp.369-374
• /
• 2008

A novel fiber optic surface plasmon resonance (SPR) sensor using cyclic olefin copolymer (COC) prism with the spectral modulation is presented. The SPR sensor chip is fabricated using the SU-8 photolithography, Ni-electroplating and COC injection molding process. The sidewall of the COC prism is partially deposited with Au/Cr (45/2.nm thickness) by e-beam evaporator, and the thermal bonding process is conducted for micro fluidic channels and optical fibers alignment. The SPR spectrum for a phosphate buffered saline (0.1.M PBS, pH.7.2) solution shows a distinctive dip at 1300.nm wavelength, which shifts toward longer wavelength with respect to the bovine serum albumin (BSA)concentrations. The sensitivity of the wavelength shift is $1.16\;nm{\cdot}{\mu}g^{-1}{\cdot}{\mu}l^{-1}$. From the wavelength of SPR dips, the refractive indices (RI) of the BSA solutions can be theoretically calculated using Kretchmann configuration, and the change rate of the RI was found to be $2.3{\times}10^{-5}RI{\cdot}{\mu}g^{-1}{\cdot}l^{-1}$. The realized fiber optic SPR sensor with a COC prism has clearly shown the feasibility of a new disposable, low cost and miniaturized SPR biosensor for biochemical molecular analyses.

• Journal of the Optical Society of Korea
• /
• v.17 no.1
• /
• pp.57-62
• /
• 2013

We have numerically implemented a receiver side all-optical signal processing method, i.e. optical backward propagation (OBP), by dispersion compensating fiber (DCF) and non-linear compensator (NLC) devised by effective negative Kerr non-linear coefficient using two highly non-linear fibers (HNLFs). The method is implemented for the post-processing of fiber transmission impairments, i.e. chromatic dispersion (CD) and non-linearities (NL). The OBP module is evaluated for dual-polarization (DP) m-ary (m=4,16,32,64,256) quadrature amplitude modulation (QAM) in 112 Gbit/s coherent transmission over 1200 km standard single mode fiber (SMF). We have also investigated an intensity limited optical backward propagation module (IL-OBP) by using a self-phase modulation-based optical limiter with an appropriate pre-chirping to compensate for the intensity fluctuations in the transmission link. Our results show that in highly non-linear sensitive 256QAM transmission, we have observed a 66% increase in the transmission distance by implementing IL-OBP as compared to conventional OBP.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.17 no.2
• /
• pp.142-152
• /
• 1992

This paper presentes a new method to measure high electric field (or high voltage) by using crystalline SiO2 which has very high half wave voltage. There are many difficulties in measuring high electric field using other crystals which have generally low half wave voltage.By applying Stokes parameter and Mueller matrix. We derive optical modulation equation in the sensor which is composed of a polarizer, and Mueller matrix, we derive optical modulation equation in the sensor which is composed of a polarizer, a Pokels material, and an analyzer, We theoretically analyzed electro-optic effect, and calculated the phase retardation and half wave volt age of the birefringent material. The designed optical valtage sensor has very excellent linearity up to 20KV without divided volt-age. The maximum error was measured within 3%. Before annealing of Sio2 crystal, the maximum variation of the output voltage is 7.5% with varying temperature from \ulcorner20˚c to 60˚c. But, after annealing of SiO2 crystal, the output voltage variation is improved within 1%error.

• Journal of the Korean Society of Radiology
• /
• v.5 no.6
• /
• pp.357-361
• /
• 2011

In this study, the liquid-crystal optical modulation X-ray detection system using a CdS which is a family of II-IV compound semiconductor was proposed. The system consist of the detector, the signal processing part, the liquid-crystal driving parts, microcontroller, and I/O parts, and was designed to be suitable for miniaturization and portable. In addition, the system can measure a wide range X-ray by using the detecting range selection. In order to evaluate the performance of the proposed system, the CdS sensor's output characteristics were confirmed in accordance with changes of dose, and excellent correlation was determined. And also, the optical penetration ratio was discussed in accordance with changes of the applied voltage by measuring the change of the liquid-crystal in accordance with changes of the applied voltage. Through these results, the characteristics of the liquid-crystal optical modulation system such as the excellent reproducibility and the noise immunity were confirmed. And we considered that the CdS cell-based liquid-crystal optical modulated portable X-ray detection system could be applied to compact, low-cost, portable system.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.27 no.11
• /
• pp.119-125
• /
• 1990

This paper describes fiber optic voltage sensor using EOM-BSO (Electro-Optic Modulator-Bismuth Silicon Oxcide). Transceiver has an electical/optical converter and an optical/electrical converter which consist of light emitting diode, PIN-PD, and electronic circuits. Multimode fiber cable of $100/140{\mu}m$ core/clad diameter is used for connecting the transceiver to fiber cable and fiber optic voltage sensor. Before our experiments, by applying the Maxwell equations and wave equations, We derive matrix equation on wave propagation in the BSO single crystal. And also we derive optimal equation on intensity modulation arising through an analyzer. According to experi-mental results, fiber optic voltage sensor has maximum $2.5{\%}$ error within the applied AC voltage of 800V. As the applied voltage increases, saturation values of voltage sensor also increase. This phenomenon is caused by optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optic voltage sensor in the temperature range from$-20^{\circ}C\to\60^{\circ}C$ are measured within ${\pm}0.6{\%}$. And frequency characteristics of the voltage sensor has good frequency characteristics from DC to 100kHz.

• Journal of electromagnetic engineering and science
• /
• v.10 no.1
• /
• pp.18-24
• /
• 2010

A Ka-band microstrip array antenna for wide-range detection of moving targets is analyzed through a photonicassisted reactive-near-field characterization technique. The antenna array employs a 3-dB-tapered feed network to suppress the sidelobe level while retaining a wide azimuth beamwidth for a wide detection range. The relative nearelectric field patterns of the array and its 3-dB-tapered feed lines have been measured using an electro-optic fieldmapping technique for minimally invasive millimeter-wave sensing. A number of typical limitations on the technique, involving bandwidth, low signal-modulation depth, and high laser-induced noise in high-frequency applications, have been overcome by suppressing the carrier portion of the optical interrogation beam.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.2
• /
• pp.330-335
• /
• 2009

A fiber-optic liquid level sensor based on bending cantilever beam has been proposed. A fiber Bragg grating(FBG) embedded in the cantilever beam is used to sensing elements. The basic concept is elongation and constriction of the FBG corresponding to the liquid level variation. The best FBG position on the cantilever for obtaining the high sensitivity was 4 cm from the fixing point. When the liquid level moves up and down vertically, the Bragg wavelength is linearly shifted. But, the wavelength sensitivity of the FBG installed on the upper side of cantilever was four times better than that of the FBG equipped in the lateral side due to the difference of unit strain applied to the FBG. Intensity demodulation using the low-cost edge filter is used to interrogate the Bragg wavelength through converting the wavelength signals into the optical intensity ones. Experiment results show that the electrical output is exponentially proportional to the liquid level. But, it should be overcome for applying to the ships.

• Korean Journal of Optics and Photonics
• /
• v.5 no.1
• /
• pp.158-165
• /
• 1994

A fiber optic voltage sensor is demonstrated with a new signal processing scheme that displays the magnitude and the waveform of applied voltage with immunity from the signal frequency change. The sensor is based on a Mach-Zehnder interferometer with a PZT phase modulator as a sensing element. We observed a linear relationship between applied voltage and the number of fringe shift during a half cycle of the ac signal. The temperature dependence of the sensor output is experimentally evaluated over the temperature range from $-20^{\circ}C to 80^{\circ}C$. It is demonstrated that the detrimental polarization modulation effect can be overcome by using polarization maintaining fibers or a half-wave plate. plate.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.28A no.9
• /
• pp.721-728
• /
• 1991

In this paper, a magneto-optic modulator has been designed by using single crystal BSO and polycrystal ZnSe as Faraday cells. And practical core-type optical current sensors using pure iron and permalloy have been prepared and experimented. In order to obtain efficient magnetic field detection, LED(NEC OD08358, 0.87 $\mu$m) was used as optical source, PIN-PD(OD-8454)as optical receiver and multi-mode optical fiber (100/140$\mu$m) as transmission line. The characteristics matrix of the optical element was calculated by Stokes parameter, and optic modulation characteristics equations were derived by Muller matrix. Electromagnetic analysis program (FLUX 2D, micro VAX 3600) by finite element method was used to find the magnetic flux density around the core. The measuring error of the output voltage to input current has been masured below 5% in the range of 50A to 1000A. As the temperature was changed from -20$^{\circ}C$ to 60$^{\circ}C$, the maximum measurement error of the optical output has been found to be 0.5% at 60$^{\circ}C$. These experimental results show good temperature and linearity characteristics. The SNR of the overall system was 47dB in case of 600A (250.2 Oe) conductor current and the system has good noise immunity.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.9 no.1
• /
• pp.16-24
• /
• 1998

In a high speed long haul fiber optic communication system using modulation, fiber chromatic dispersion and laser chirping can cause serious performance degradations. In this paper, the combined effect of laser chirping and chromatic dispersion on the per- formance of 2.5[Gbps] rate lightwave systems operating at a wavelength of 1550[nm] was investigated. Also we used an optical equalizer to compensate the laser chirping and fiber dispersion, and knew that the receiver sensitivity was improved by about 2 ~ 4[dB].