Biomedical subjects

Kwang Yong Song

Publications and source records attributed to Kwang Yong Song.

4 recordsLinked to original sources

PubMed2007

25 GHz bandwidth Brillouin slow light in optical fibers.

Broadband slow light is demonstrated by using stimulated Brillouin scattering in optical fibers based on a double Brillouin pump, the peaks of which are spectrally separated by twice the Brillouin frequency. The loss spectrum generated by one of the pump waves is fully compensated by the gain spectrum of the other one, which permits the enlargement of the bandwidth to 25 GHz and a variable time delay of up to 10.9 ps with 37 ps pulses.

Journal Article↗

PubMed2006

Distributed strain measurement with millimeter-order spatial resolution based on Brillouin optical correlation domain analysis.

Distributed strain sensing with millimeter-order spatial resolution is demonstrated in optical fibers based on Brillouin optical correlation domain analysis. A novel beat lock-in detection scheme is introduced to suppress background noises coming from the reflection of Brillouin pump waves. The Brillouin frequency shifts of 3 mm fiber sections are successfully measured with a theoretical spatial resolution of 1.6 mm.

Journal Article↗

PubMed2006

Time biasing due to the slow-light effect in distributed fiber-optic Brillouin sensors.

The influence of the slow-light effect on the performance of distributed Brillouin sensors is studied. We show that, while in most situations it can be neglected, it may greatly affect the results obtained for certain experimental configurations. More specifically, for one of the experimental arrangements described in the literature (a strong continuous-wave pump and a weak pulsed probe) we show that this effect induces a large time biasing of the traces that depends not only on the fiber length but also on the frequency separation between pump and probe. This biasing reduces the available resolution in this experimental arrangement.

Journal Article↗

PubMed2005

Long optically controlled delays in optical fibers.

Optically controlled delay lines in optical fibers are demonstrated by use of the group-velocity control of signal pulses based on stimulated Brillouin scattering. We achieve continuous time delay within the range of 150 ns, much larger than the width of the 40 ns signal pulse, using cascaded fiber segments joined by unidirectional optical attenuators. In the meantime, we also observe a large amount of pulse broadening, which agrees well with a theoretical prediction based on linear theory.

Journal Article↗