• ETRI Journal
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• v.34 no.5
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• pp.763-766
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• 2012

This letter proposes an iterative multimode precoding scheme with limited feedback for nonreciprocal MIMO interference channels. Based on analysis of game theory, we model the iterative multimode precoding as a noncooperative game with a finite set of strategies. Numerical results are presented to verify the sum rate performance of the proposed scheme.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.4
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• pp.62-72
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• 1997

The optical power splitter/couplers based on MMI(multimode interference) in GaAs/AlGaAs are studied. We presetn a design of optical power splitter/couplers, which have deeply etched multimode waveguide. The properties and fabrication tolerance on the etching depth, multimode waveguide width are simulatedusing a FD-BPM (finite difference beam propgation method). Proposed 1*N optical of designed device is 0.7dB smaller than the optical power splitter with a shallowly etched MMI section. For 0.5dB excess loss, the predicted fabrication tolerance is 0.6.mu.m on the multimode waveguide width of the 14 optical power splitter with a deeply etched MMI section. Also excess loss and uniformity of poposed 32*32 optical power coupler are below 0.3dB. The excess loss of proposed 32*32 optical power coupler is 2dB smaller than the optical power coupler with a shallowly etched MMI section. It is shown that the optical power splitters/couplers with a deeply etched mMI section have low loss, good uniformity, and improved fabriction tolerance.

• Journal of the Optical Society of Korea
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• v.18 no.1
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• pp.15-22
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• 2014

We present a novel bandwidth measurement scheme for multimode optical fibers. Amplified spontaneous emission (ASE) radiation was utilized for a source of intrinsically modulated light with a wide modulation bandwidth. In our measurement scheme, the continuous-wave (CW) ASE light that passed through a multimode fiber (MMF) under test was analyzed by the fourth-order power with a high-speed photodetector and an electric spectrum analyzer. The modulation transfer function of the multimode fiber could be directly measured with the photoelectric spectra in the modulation frequency domain. The measurement result of our method was experimentally compared to that of the conventional measurement scheme based on the impulse response measurement. It has been found that our scheme provides a stable measurement means of MMF characterization that is suitable for the field testing due to the simplicity of the system.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.834-838
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• 2004

We report on a simple method of fabricating multimode transflective liquid crystal displays (LCDs) using the photoalignment technique. Using a self-masking process of ultraviolet light by the reflector as a photomask as well as a reflective mirror, the periodic multimode is obtained with no additional fabrication processes. Moreover, variations of the cell gap are not required for such trasflective LCDs

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.2099-2108
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• 1996

The performance of the E-plane monopulse feeder is shown to e improved by using corrugated horn and multimode design. The proposed multimode corrugated horn is analyzed by the mode matching technique. an E-plane monopulse feeding horn is designed and fabricated to show the performance of the multimode corrugated horn. The experiment agrees quite well with the thoretical analysis. The results can be used in the design of monopulse type tracking radar antenna.

• Macromolecular Research
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• v.12 no.3
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• pp.290-292
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• 2004

Multimode channel waveguides were fabricated using a direct UV patterning technology from thick films deposited by the one-step dip-coating of an organic/inorganic hybrid material (ORMOCER(equation omitted). The core size of the covered ridge waveguide was 43${\times}$51 $\mu\textrm{m}$$^2$; the waveguides can be readily prepared for multimode applications by direct UV patterning. The waveguides exhibited smooth surface profiles and a low optical loss of 0.07 ㏈/cm at the most important wavelength (850nm) used for optical interconnects.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.199-203
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• 2005

We present a method to implement a $M{\times}N$ switching system by use of an $M{\times}1$ multimode waveguide and N hologram filters. The pass of optical signals is provided by an $M{\times}1$ multimode waveguide. The complex speckle patterns generated from the multimode waveguide are recorded into the N hologram filters and used as the code for destination. The feasibility of our method is experimentally demonstrated.

• Journal of Information Display
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• v.5 no.3
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• pp.8-13
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• 2004

We demonstrate a transflective liquid crystal display (LCD), doped with a chiral agent to produce a low helical twisting power, in a multimode configuration consisting of the homogeneous alignment and the hybrid alignment. The multimode transflective LCD with a single cell gap was fabricated using a single-step photoalignment technique with a self-masking process of an array of metal reflectors in the reflective region. In our configuration, the electro-optical disparity between the transmissive region and the reflective region was found to be significantly reduced by the low helical twisting power of the chiral dopant.

• Journal of the Korean Institute of Telematics and Electronics
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• v.16 no.1
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• pp.9-13
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• 1979

Multimode characteristics of a dielectrically loaded rectangular cavity are analyzed by a graphical method. Coupled transcendental equations for multimode frequencies may be solved graphlially. This shows that the resonant frequencies of the partially flued cavity with a dielectic are shifted toward lower frequencies compared to those of the empty cavity. It is shown that a perturbational scheme can not be employed to calculate multimode frequencies because of relatively large frequency shrift. Existence of the surface wave modes In the dielectric and their resonant frequencies are early predicted from this graphical method.

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.337-341
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• 2010

A high sensitivity fiber optic temperature sensor based on a side-polished fiber (SPF) coupled to a tapered multimode overlay waveguide (MMOW) is proposed and studied. Both tapered and non-tapered MMOW were considered to study the effect of tapering of MMOW on the characteristics of the device and to investigate the criticality of the uniformity of the multimode overlay waveguide over the SPF. Present study shows that tapering of the MMOW can be used to tune the desired wavelength range without any loss in the sensitivity. Sensitivity up to 9 nm/$^{\circ}C$ within the temperature range of 25 to $100^{\circ}C$ can be achieved with the proposed sensor, almost 6 times higher compared even to state-of-the-art high-sensitivity grating-based fiber optic temperature sensors.