• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.2
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• pp.46-54
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• 2007

We have fabricated and characterized MMI (Multimode Interference) coupled ring resonator with the total internal reflection mirrors and the semiconductor optical amplifier for the integration of the WDM (Wavelength Division Multiplexing) system. The TIR (Total Internal Reflection) mirrors were fabricated by self-aligned process and had losses of about 0.71 dB per mirror. Coupling in and out of a resonator was achieved using the extremely small MMI couplers. The MMI length and width used in the experiment were $119{\mu}m$ and $9{\mu}m$, respectively. The resulting FSR (Free Spectral Range) and on-off ratio were approximately 1.333 nm (162 GHz) and 13 dB, respectively.

• Korean Journal of Optics and Photonics
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• v.4 no.4
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• pp.420-427
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• 1993

Dielectric thin film mirrors are embedded in multimode and single-mode fibers by a fusion splicing technique. The fibers with $45{\circ}$ angled embedded mirrors serve as ultra-compact directional couplers with low excess optical loss of 0.2 dB for multimode and 0.5 dB for single mode at 1.3 ${\mu}m$ and excellent mechanical properties. The reflectance is wavelength dependent and strongly polarization depencient. Far-field scans of the reflected output power measured with a white-light source show a pattern which is almost circularly symmetric with aspect ratio of 1.09 at 5% of the peak power. The splitting ratio in a multimode coupler measured with a diode laser source is much less dependent on input coupling conditions than in conventional fused biconical-taper couplers, indicating that these couplers are less susceptible to modal noise occuring in optical fiber communication systems. Spectral properties of multilayer internal mirrors normal to the fiber axis have been investigated experimentally, and a matrix analysis has been used to explain the results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.165-170
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• 2016

Nano-scale power splitter based on curved plasmonic waveguides are designed by utilizing the multimode interference (MMI) coupler. To analyze easily the adaptive properties of plasmonic curverd multimode interference coupler(PC-MMIC), the curved form transforms equivalently into a planar form by using conformal transformation method. Also, effective dielectric method and longitudinal modal transmission-line theory are used for simulating the light propagation and optimizing the structural parameters at 3-D guiding geometry. The designed $2{\times}2$ PC-MMIC does not work well for quasi-TM mode case due to the bending structure, and it does not exist 3dB coupling property, in which the power splitting ratio is 50%:50%, for quasi-TE mode case. Further, the coupling efficiency is better when the signal is incident at channel with large curvature radius than small curvature radius.

• Korean Journal of Optics and Photonics
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• v.31 no.2
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• pp.105-110
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• 2020

A compact beam combiner based on two-mode interference (TMI) in multimode waveguides is proposed, and its feasibility is shown through simulation with the three-dimensional beam propagation method. The input waveguides are separated by about 1 ㎛ at the interface with the multimode waveguide, so that the fabricated waveguide pattern is well repeated. The power transmission to the output port from the red, green, and blue input port is 93.5%, 94%, and 93%, respectively. When the wavelength deviation from a center wavelength is 10 nm, the power transmission is maintained to be greater than 90%. When the waveguide width error is 40 nm, the power transmission is maintained to be greater than 85% for all the three colors. The polarization dependence of the beam combiner is almost negligible, and its size is as tiny as 0.02 × 4 ㎟.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.8
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• pp.34-42
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• 2001

The 1${\times}$2, 1${\times}$4 and 1${\times}$8 multimode interference(MMI) optical power splitters are fabricated by using $Ag^+-Na^+$ ion exchange on BK7 glass. Before fabricating the MMI optical power splitters, we find the refractive index of the channel waveguide and calculate the multimode section length and width. The multimode section lengths and widths are 887${\mu}m$, 1666${\mu}m$ and 1834${\mu}m$ and 40${\mu}m$, 80${\mu}m$ and 120${\mu}m$ for 1${\times}$2, 1${\times}$4 and 1${\times}$8 MMI optical power splitters respectively. The measured properties of the fabricated MMI optical power splitters show that the unbalance ratios of the 1${\times}$2, 1${\times}$4 and 1${\times}$8 MMI optical power splitters are 1.4[dB], 1.7[dB] and 2.0[dB] and the excess losses of those sre 0.96[dB], 2.26[dB] and 1.67[dB]. respectively.

• Proceedings of the KIEE Conference
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• 1986.07a
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• pp.599-603
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• 1986

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.305-306
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• 2009

This paper shows through detailed simulations that the length of conventionally designed multimode-interference couplers can be shorted significantly by stepped-width and stepped-index design. For the cross-coupling device, this stepped-design results in 9% or more length reduction.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.127-128
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• 2007

• Korean Journal of Optics and Photonics
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• v.13 no.3
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• pp.223-227
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• 2002

Polymeric multi-mode optical waveguides were fabricated for parallel optical interconnection. Waveguide structures were molded by a Ni mold master using a hot embossing technique. The Ni mold master was manufactured by LIGA process. Multimode optical waveguides with a 48$\times$47 ${\mu}{\textrm}{m}$$^2$cross-section were produced by a simple two-step process. The propagation losses of the multimode waveguide measured at 0.85 ${\mu}{\textrm}{m}$ and 1.3 ${\mu}{\textrm}{m}$ wavelengths were 0.38 dB/cm and 0.66 dB/cm, respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.47-52
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• 2013

A novel architecture to reduce dramatically the coupling length of multimode interference-based couplers (MMICs) is proposed by replacing conventionally designed MMICs by cascaded two-section plasmonic stepped MMICs (PS-MMIC). For the 60% cross power splitting ratio in a stepped-width MMIC, the coupling length of device results in around 42% length reduction. Furthermore, the power splitting ratio and coupling length of plasmonic MMIC just vary around 1~2% along the variation of refractive index. On the contrast, those factors for the variation of MMIC's width strongly vary around 30~40%.