• Current Optics and Photonics
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• v.4 no.2
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• pp.134-140
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• 2020

A significant enhancement of the magneto-optical Faraday rotation and extraordinary optical transmission (EOT) in the cascaded double-fishnet (CDF) structure with periodic rectangular apertures is theoretically predicted by using the extended finite difference time domain (FDTD) method. The results demonstrate that the transmittance spectrum of the CDF structure has two EOT resonant peaks in a broad spectrum spanning visible to near-infrared wavebands, one of them coinciding with the enhanced Faraday rotation and large figure of merit (FOM) at the same wavelength. It is most important that the resonant position and intensity of the transmittance, Faraday rotation and FOM can be simply tailored by adjusting the incident wavelength, the thickness of the magnetic layer, and the offset between two metallic rectangular apertures, etc. Furthermore, the intrinsic physical mechanism of the resonance characteristics of the transmittance and Faraday rotation is thoroughly studied by investigating the electromagnetic field distributions at the location of resonance. It is shown that the transmittance resonance is mainly determined by different hybrid modes of surface plasmons (SPs) and plasmonic electromagnetically induced transparency (EIT) behavior, and the enhancement of Faraday rotation is mostly governed by the plasmonic electromagnetically induced absorption (EIA) behavior and the conversion of the transverse magnetic (TM) mode and transverse electric (TE) mode in the magnetic dielectric layer.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.2
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• pp.26-38
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• 1994

We demonstrate a repeatless transmission of 2.5 Gbps digital signal over 98 km opticla filbers using optical transmitter and optcial receiver which are designed and implemented using commercially available devices. The optical transmitter is realized by using a distributed feedback(DFB) laser. Temperature of the laser is thermoelectrically stabilized and the output optical power is also stabilized by using negative feedback. The output power of the transmitter is 0 dBm. The optical receiver consists of an InGaAs avalanche photodiode, a preamplifier. an automatic gain control amplifier, and a clock/data regenerator. We find an optimum decision threshold that gives the best receiver sensitivity form the measured V curve. The best sensitivity is -35.5dBm( BER-1*10S010T, PRBS=2S023T -1 ) and the overload power is -9 dBm. Finally, we achieve error free optical transmission with 98 km optical fibers. The exinction ration penalty of 2 dB. the chromatic dispersion penalty of 1 dB, and the total power penalty of 3.0 dB are measured. These results satisfy CCITT recommendation.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.668-676
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• 2010

Optimal net residual dispersions (NRDs) of inline dispersion management (DM) for compensating the signal distortion of $24{\times}40$ Gbps WDM channels in optical transmission links, in which optical phase conjugator (OPC) is placed from 250 km to 750 km by spacing 50 km in 1,000 km total transmission length of single mode fiber (SMF), are induced as a function of various ope positions. And, performance improvement of WDM channels in transmission links with the induced optimal NRD is investigated by comparing with that in transmission links with NRD = 0 ps/nm. It is confirmed that optimal NRDs are decided by displacement of OPC from mid-way of total transmission length, i.e. 500 km, and the determinating and applying of optimal NRD in case of ope displacement into transmitters is more stable and effective than that in case of ope displacement into receivers from 500 km. Also, it is shown that eye opening penalties (EOPs) of WDM channels in transmission links with optimal NRD are improved by 1.5 dB to 3 dB, which are related with OPC position, from that obtained in transmission links with fixed NRD of 0 ps/nm.

• Korean Journal of Optics and Photonics
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• v.33 no.6
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• pp.252-259
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• 2022

We have conducted a study to control the light-intensity distribution at the output end of a multimode optical fiber via estimating the transmission matrix. A circularly arranged Hadamard eigenmode phase distribution was implemented using a spatial light modulator, and the transmission matrix of a multimode optical fiber was experimentally obtained using a four-phase method. Based on the derived transmission matrix, the spatial phase distribution of light incident upon the optical fiber was adjusted via the spatial light modulator in advance, to focus the light at a desired position at the optical fiber output. The light could be focused with an intensity up to 359.6 times as high as that of the surrounding background signal at a specific position of the multimode fiber's output end, and the intensity of the focused beam was on average 104.6 times as large as that of the background signal, across the area of the multimode fiber's core.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.2-3
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• 2002

• Journal of the Microelectronics and Packaging Society
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• v.18 no.1
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• pp.7-13
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• 2011

According to increasing of data transfer rate, printed circuit board (PCB) is required improvement of transmission speed. Optical PCB and its packaging technology can be one of the solutions that overcome the limitations of conventional electrical PCB. The data transmission capacity will be increased 10 Tbps at 2015. To this end, studies on various OPCB technologies are being conducted. For cost-effective and high- performance OPCB, studies of optical coupling by polymer replication process are conducted. In this work, optical waveguide and optical fiber array block were sequentially fabricated by polymer pattern replication method. Using this method we successfully demonstrate low loss optical fiber coupling between optical waveguide and optical fiber arrays. And researches on flip chip bonding process and using electro-optic connectors for packaging are conducted.

• Journal of the Optical Society of Korea
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• v.10 no.3
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• pp.112-117
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• 2006

We experimentally investigated the transmission characteristics of 400 Gbit/s (10 Gbit/s ${\times}$ 40 channels) WDM signals with 100 GHz channel spacing over 323 km of installed NZ_DSF. The installed fiber has optical properties of 0.28 dB/km attenuation, 4.3 ps/nm/km dispersion, $0.083ps/nm^2/km$ dispersion slope and less than $0.05ps/km^{1/2}$ PMD coefficient. In this experiment, two cases of dispersion compensation schemes, the lumped type and the distributed type, were compared. The results implied that the distributed type dispersion compensation in which dispersion compensation devices are inserted at the end of the each span showed better transmission performance than the lumped one in which dispersion compensation devices are located at the transmitter and receiver sites. From the analysis of the experimental results, we verified that different transmission performance comes from the power penalty induced by XPM in the distributed scheme is lower than the lumped scheme case.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.550-553
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• 1993

Methods of Alternating Noise Canceling were previously developed for the optical instrumentation;one using a dual photo sensor and another using a single photo sensor that could cancel normal mode noise on a transmission line, even if the noise was of equal status noise. But the methods could not remove noise on sensor line. This paper discusses a new method of using a photo sensor with a resistance sensordummy, effectively canceling equal status normal mode noise not only on a sensor line but also on a transmission line of an optical instrumentation. The accuracy of this method has been verified by experiments using sinusoidal wave as an equal status noise on a sensor line and/or rectangular wave as an equal status wide band noise on a transmission line respectively.

• Journal of information and communication convergence engineering
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• v.5 no.4
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• pp.377-381
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• 2007

Nonlinear effects and chromatic dispersion are the main causes of pulse degradation in high bit-rate WDM transmission systems and several architectures have been proposed to compensate them by means of optical phase conjugation. In this paper, a new method to exploit an optical phase conjugator (OPC) for nonlinearity and dispersion cancellation is disclosed. The proposed method is using optimal total dispersion of each fiber sections and it is simpler than those previously described in literature. Power penalty between WDM channels and the maximum launch power in $28{\times}40$ Gbps WDM transmission system designed by optimal total dispersion are more decreased and more increased than those in the conventional WDM transmission system with OPC, respectively. Furthermore, optimal total dispersion proposed in this research should provide the flexible design of WDM system, which less depends on OPC position.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8A
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• pp.735-744
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• 2006

In this paper, the optimum pump light powers of optical phase conjugator(OPC) are numerically investigated as a function of amplifier spacing in 1,200 km $8{\times}40$ Gbps WDM systems with 0.1, 0.4, 0.8, or 1.6 ps/nm/km dispersion coefficient. It is confirmed that the variation of optimal pump light power dependence on amplifier spacing for NRZ transmission system is smaller than that for RZ transmission system through the evaluations and analysis of eye opening penalty(EOP) characteristics. And, in both cases of NRZ and RZ transmission, the variation of optimal pump light power is more increased as amplifier spacing becomes longer. Additionally, it is confirmed that the best amplifier spacing in NRZ and RZ transmission system is 50 km.