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Y C Chung - One of the best experts on this subject based on the ideXlab platform.

  • chromatic dispersion Monitoring Technique using pilot tone carried by broadband light source
    IEEE Photonics Technology Letters, 2009
    Co-Authors: Hyunhwan Choi, Paul K. J. Park, Y C Chung
    Abstract:

    We propose and demonstrate a simple chromatic dispersion Monitoring Technique Based on the pilot tone generated by a broadband light source (BLS). Previously, the pilot tone has been obtained by directly modulating each transmitter laser with a small sinusoidal current. Thus, for use in the wavelength-division- multiplexed (WDM) network, each transmitter should be modulated with a unique pilot tone. However, we obtain the pilot tone by modulating an additional BLS such as a reflective semiconductor optical amplifier. Thus, there is no need to modulate each transmitter laser. We evaluate the performance of the proposed Technique in an 8 times10 Gb/s WDM system. The result shows that, unlike the conventional pilot-tone-Based Monitoring Technique, the performance of this Technique is almost insensitive to the polarization-mode dispersion.

  • performance analysis of low frequency pilot tone Based Monitoring Techniques in amplified wavelength division multiplexed networks
    Optical Engineering, 2008
    Co-Authors: Paul K. J. Park, Y C Chung
    Abstract:

    In amplified wavelength-division-multiplexed (WDM) networks, the performance of a low-frequency (<100 kHz) pilot-tone-Based Monitoring Technique could be deteriorated by the slow dynamic properties of erbium-doped fiber amplifiers (EDFAs). We develop a simple model to describe this effect and estimate the maximum size of WDM network that the pilot-tone-Based Monitoring Technique could support. The result shows that 100-kHz pilot tones could be used for the cost-effective Monitoring of metro optical networks (32 channels, 320-km transmission).

  • Performance analysis of low-frequency pilot-tone-Based Monitoring Techniques in amplified wavelength-division-multiplexed networks
    Optical Engineering, 2008
    Co-Authors: Paul K. J. Park, Chul Han Kim, Y C Chung
    Abstract:

    In amplified wavelength-division-multiplexed WDM net- works, the performance of a low-frequency 100 kHz pilot-tone-Based Monitoring Technique could be deteriorated by the slow dynamic proper- ties of erbium-doped fiber amplifiers EDFAs. We develop a simple model to describe this effect and estimate the maximum size of WDM network that the pilot-tone-Based Monitoring Technique could support. The result shows that 100-kHz pilot tones could be used for the cost- effective Monitoring of metro optical networks 32 channels, 320-km transmission. © 2008 Society of Photo-Optical Instrumentation Engineers.

  • pilot tone Based wdm Monitoring Technique for dpsk systems
    IEEE Photonics Technology Letters, 2006
    Co-Authors: Paul K. J. Park, Y C Chung
    Abstract:

    To evaluate the effectiveness of the pilot-tone-Based Monitoring Technique in differential phase-shift keying (DPSK) systems, we measure the mutual interactions between the pilot tones and DPSK signals and compare the results with those of on-off keying (OOK) signals. The results show that, by using the DPSK format instead of OOK, it is possible to increase the number of wavelength-division-multiplexed channels that can be monitored simultaneously by using pilot tones without using optical demultiplexers by more than one hundred times

  • effects of stimulated raman scattering on pilot tone Based wdm supervisory Technique
    IEEE Photonics Technology Letters, 2000
    Co-Authors: H.s. Chung, Keun Joo Park, S.k. Shin, Y C Chung
    Abstract:

    We report on the effects of stimulated Raman scattering (SRS) on the pilot-tone-Based wavelength-division-multiplexing (WDM) Monitoring Technique. The SRS-induced ghost tones were measured after compensating the effects of erbium-doped fiber amplifiers (EDFA's) slow gain dynamics. Using these results, we estimated the maximum size of WDM network that the pilot-tone Based Monitoring Technique could support.

Dragos Axinte - One of the best experts on this subject based on the ideXlab platform.

  • a time frequency acoustic emission Based Monitoring Technique to identify workpiece surface malfunctions in milling with multiple teeth cutting simultaneously
    International Journal of Machine Tools & Manufacture, 2009
    Co-Authors: Iulia Marinescu, Dragos Axinte
    Abstract:

    Abstract In the view of implementing automated solutions for Monitoring complex machining processes such as milling, the usage of acoustic emission (AE) in machining is regarded as a promising way for assessing machine tool condition and for in-process detection of workpiece malfunctions. Correlating AE signal events with the occurrence of workpiece surface anomalies (e.g. laps, material drag) can be a powerful method for scrap reduction of expensive components such as those employed in aerospace industry. This paper proposes new methods for supervising cutting processes with multiple teeth cutting simultaneously, i.e. milling, by use of AE signals backed-up by force data. This is done by taking into account signals patterns when one, two or three teeth are cutting simultaneously, situation that often occurs in real milling applications. The research shows for the first time that identification of milling conditions (i.e. cutting with one/two/three teeth) is possible using only AE signal in time–frequency (T–F) domain. Moreover, detection of surface anomalies, such as folded laps that are generated by damaged cutting edges can be successfully identified in various milling conditions. The paper demonstrates that time–frequency analysis of AE signals empowered with advanced processing Techniques has great potential to be used in flexible and easily to implement Monitoring solutions to enable milling of anomaly-free workpiece surfaces in difficult-to-cut aerospace materials.

  • A time–frequency acoustic emission-Based Monitoring Technique to identify workpiece surface malfunctions in milling with multiple teeth cutting simultaneously
    International Journal of Machine Tools and Manufacture, 2009
    Co-Authors: Iulian Marinescu, Dragos Axinte
    Abstract:

    Abstract In the view of implementing automated solutions for Monitoring complex machining processes such as milling, the usage of acoustic emission (AE) in machining is regarded as a promising way for assessing machine tool condition and for in-process detection of workpiece malfunctions. Correlating AE signal events with the occurrence of workpiece surface anomalies (e.g. laps, material drag) can be a powerful method for scrap reduction of expensive components such as those employed in aerospace industry. This paper proposes new methods for supervising cutting processes with multiple teeth cutting simultaneously, i.e. milling, by use of AE signals backed-up by force data. This is done by taking into account signals patterns when one, two or three teeth are cutting simultaneously, situation that often occurs in real milling applications. The research shows for the first time that identification of milling conditions (i.e. cutting with one/two/three teeth) is possible using only AE signal in time–frequency (T–F) domain. Moreover, detection of surface anomalies, such as folded laps that are generated by damaged cutting edges can be successfully identified in various milling conditions. The paper demonstrates that time–frequency analysis of AE signals empowered with advanced processing Techniques has great potential to be used in flexible and easily to implement Monitoring solutions to enable milling of anomaly-free workpiece surfaces in difficult-to-cut aerospace materials.

H.s. Chung - One of the best experts on this subject based on the ideXlab platform.

  • Optical performance Monitoring Techniques Based on pilot tones for WDM network applications
    Journal of Optical Networking, 2004
    Co-Authors: Ho-chul Ji, Keun Joo Park, H.s. Chung, Yun Chur Chung
    Abstract:

    Feature Issue on Optical Performance Monitoring (OPM). We report on the pilot-tone-Based optical performance Monitoring Techniques for use in the wavelength-division multiplexing (WDM) network. We first described the operating principle of the pilot-tone-Based Monitoring Technique and estimated its scalability by analyzing potential problems. We then reviewed the Techniques proposed for Monitoring various optical parameters of WDM signals--such as optical power, wavelength, optical path, and cross talk--using pilot tones. We also presented examples of various network elements using the pilot-tone-Based Monitoring Technique. In addition, we reviewed the pilot-tone-Based Monitoring Techniques used in adaptive compensators for chromatic dispersion and polarization-mode dispersion, and we discussed their limitations and possible solutions. For example, we demonstrated a simple Technique for Monitoring the chromatic dispersion and polarization-mode dispersion simultaneously, without their affecting each other, by scrambling the state of polarization of the optical signal.

  • effects of stimulated raman scattering on pilot tone Based wdm supervisory Technique
    IEEE Photonics Technology Letters, 2000
    Co-Authors: H.s. Chung, Keun Joo Park, S.k. Shin, Y C Chung
    Abstract:

    We report on the effects of stimulated Raman scattering (SRS) on the pilot-tone-Based wavelength-division-multiplexing (WDM) Monitoring Technique. The SRS-induced ghost tones were measured after compensating the effects of erbium-doped fiber amplifiers (EDFA's) slow gain dynamics. Using these results, we estimated the maximum size of WDM network that the pilot-tone Based Monitoring Technique could support.

  • Effects of stimulated Raman scattering on pilot-tone Based WDM supervisory Technique
    Optical Fiber Communication Conference. Technical Digest Postconference Edition. Trends in Optics and Photonics Vol.37 (IEEE Cat. No. 00CH37079), 2000
    Co-Authors: H.s. Chung, S.k. Shin, Yun Chur Chung
    Abstract:

    We report on the effects of stimulated Raman scattering (SRS) on the pilot-tone Based WDM Monitoring Technique. We measured the SRS-induced ghost ones after compensating the effects of EDFA's slow gain dynamics. Using these results, we estimated the maximum size of WDM network that the pilot-tone Based Monitoring Technique could support.

Paul K. J. Park - One of the best experts on this subject based on the ideXlab platform.

  • chromatic dispersion Monitoring Technique using pilot tone carried by broadband light source
    IEEE Photonics Technology Letters, 2009
    Co-Authors: Hyunhwan Choi, Paul K. J. Park, Y C Chung
    Abstract:

    We propose and demonstrate a simple chromatic dispersion Monitoring Technique Based on the pilot tone generated by a broadband light source (BLS). Previously, the pilot tone has been obtained by directly modulating each transmitter laser with a small sinusoidal current. Thus, for use in the wavelength-division- multiplexed (WDM) network, each transmitter should be modulated with a unique pilot tone. However, we obtain the pilot tone by modulating an additional BLS such as a reflective semiconductor optical amplifier. Thus, there is no need to modulate each transmitter laser. We evaluate the performance of the proposed Technique in an 8 times10 Gb/s WDM system. The result shows that, unlike the conventional pilot-tone-Based Monitoring Technique, the performance of this Technique is almost insensitive to the polarization-mode dispersion.

  • performance analysis of low frequency pilot tone Based Monitoring Techniques in amplified wavelength division multiplexed networks
    Optical Engineering, 2008
    Co-Authors: Paul K. J. Park, Y C Chung
    Abstract:

    In amplified wavelength-division-multiplexed (WDM) networks, the performance of a low-frequency (<100 kHz) pilot-tone-Based Monitoring Technique could be deteriorated by the slow dynamic properties of erbium-doped fiber amplifiers (EDFAs). We develop a simple model to describe this effect and estimate the maximum size of WDM network that the pilot-tone-Based Monitoring Technique could support. The result shows that 100-kHz pilot tones could be used for the cost-effective Monitoring of metro optical networks (32 channels, 320-km transmission).

  • Performance analysis of low-frequency pilot-tone-Based Monitoring Techniques in amplified wavelength-division-multiplexed networks
    Optical Engineering, 2008
    Co-Authors: Paul K. J. Park, Chul Han Kim, Y C Chung
    Abstract:

    In amplified wavelength-division-multiplexed WDM net- works, the performance of a low-frequency 100 kHz pilot-tone-Based Monitoring Technique could be deteriorated by the slow dynamic proper- ties of erbium-doped fiber amplifiers EDFAs. We develop a simple model to describe this effect and estimate the maximum size of WDM network that the pilot-tone-Based Monitoring Technique could support. The result shows that 100-kHz pilot tones could be used for the cost- effective Monitoring of metro optical networks 32 channels, 320-km transmission. © 2008 Society of Photo-Optical Instrumentation Engineers.

  • pilot tone Based wdm Monitoring Technique for dpsk systems
    IEEE Photonics Technology Letters, 2006
    Co-Authors: Paul K. J. Park, Y C Chung
    Abstract:

    To evaluate the effectiveness of the pilot-tone-Based Monitoring Technique in differential phase-shift keying (DPSK) systems, we measure the mutual interactions between the pilot tones and DPSK signals and compare the results with those of on-off keying (OOK) signals. The results show that, by using the DPSK format instead of OOK, it is possible to increase the number of wavelength-division-multiplexed channels that can be monitored simultaneously by using pilot tones without using optical demultiplexers by more than one hundred times

S.k. Shin - One of the best experts on this subject based on the ideXlab platform.