• Title/Summary/Keyword: Multiwavelength

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Module-based Easily Scalable Ultra-large Capacity WDM Optical Exchange (모듈 단위의 용량 확장이 용이한 대용량 WDM 광 교환기)

  • 김정범;송홍석;신서용
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.7C
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    • pp.641-652
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    • 2002

  • We introduce a new ultra-large capacity time- and wavelength-division hybrid optical switching system, called ESCIMONET(Easily SCalable Interconnected Multiwavelength Optical NETwork). We describe its architecture, principle of operation, and performance characteristics. ESCIMONET is very effective system in terms of its handling capacity versus number of wavelength needed. It can handle n$^3$number of channels using only n number of different wavelengths. The insertion loss of the whole system is less than conventional optical switching system so that the number of optical amplifiers in the system can be minimized. We analyzed the performance of the system by investigation the characteristics of the buffer used in the system such as throughput and average waiting time of the signal in a buffer.

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Comb-spacing-swept Source Using Differential Polarization Delay Line for Interferometric 3-dimensional Imaging

  • Park, Sang Min;Park, So Young;Kim, Chang-Seok
    • Current Optics and Photonics
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    • v.3 no.1
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    • pp.16-21
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    • 2019

  • We present a broad-bandwidth comb-spacing-swept source (CSWS) based on a differential polarization delay line (DPDL) for interferometric three-dimensional (3D) imaging. The comb spacing of the CSWS is repeatedly swept by the tunable DPDL in the multiwavelength source to provide depth-scanning optical coherence tomography (OCT). As the polarization differential delay of the DPDL is tuned from 5 to 15 ps, the comb spacing along the wavelength continuously varies from 1.6 to 0.53 nm, respectively. The wavelength range of various semiconductor optical amplifiers and the cavity feedback ratio of the tunable fiber coupler are experimentally selected to obtain optimal conditions for a broader 3-dB bandwidth of the multiwavelength spectrum and thus provide a higher axial resolution of $35{\mu}m$ in interferometric OCT imaging. The proposed CSWS-OCT has a simple imaging interferometer configuration without reference-path scanning and a simple imaging process without the complex Fourier transform. 3D surface images of a via-hole structure on a printed circuit board and the top surface of a coin were acquired.

  • https://doi.org/10.3807/COPP.2019.3.1.016 인용 PDF KSCI HTML

Multiwavelength Study of an Off-nuclear Active Galactic Nucleus in NGC 5252

  • Kim, Minjin;Lopez, Kristhell M.;Jonker, Peter G.;Ho, Luis C.;Mezcua, Mar;Im, Myungshin
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.36.3-36.3
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    • 2019

  • We present a multiwavelength study of an ultraluminous X-ray source (ULX) in NGC 5252, which is known as a candidate for an intermediate-mass black hole. The ULX, located 22 arcsec away from the center of NGC 5252, was first discovered with the Chandra X-Ray Observatory. In the optical spectra, the strong narrow emission lines are found at the position of the ULX. It reveals that the ULX is likely associated with NGC 5252. The VLBA data of the ULX yields that the black hole mass of the ULX is smaller than 106 solar mass, inferred from the black hole fundamental plane. From the near-infrared imaging data, we find that the stellar mass associated with the ULX is smaller than ~107.9 solar mass, implying that the ULX can be a remnant of a merging dwarf. We also find that K-band luminosity of the ULX is two orders of magnitude smaller than typical active galactic nuclei at a given [OIII] luminosity. It may suggest the ULX lacks the dusty torus possibly due to the disappearance of dusty material during the recoiling process.

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