Sang-Hoon Chin

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The real remoteness of a distributed optical fiber sensor based on Brillouin optical time-domain analysis is considerably extended in this paper using seeded second-order Raman amplification and optical pulse coding. The presented analysis and the experimental results demonstrate that a proper optimization of both methods combined with a well-equalized(More)
A novel scheme is proposed to extend the sensing range of Brillouin optical time-domain analyzers (BOTDA). Specially-designed erbium doped fiber amplifier (EDFA) repeaters are located every 65km fiber along the sensing cable to achieve a total sensing length of 325km, corresponding to a 650km loop. At the end of the sensing fibre, we experimentally(More)
A method to achieve an extremely wide and flexible control of the group velocity in an optical fiber is presented. Group velocities below 71,000 km/s on one hand, well exceeding the speed of light in vacuum on the other hand and even negative group velocities can readily be obtained. OCIS codes: (999.9999) Slow light; (060.4370) Nonlinear optics, fibers;(More)
Slow light systems are particularly attractive for analog signal processing, since their inherent limitation to a delaybandwidth product of 1 is less critical for analog systems such as those used in microwave photonics. We present here the implementation of two basic functions – phase shifting and true time delaying – fully optically controlled using(More)
We demonstrate a method to achieve an extremely wide and flexible external control of the group velocity of signals as they propagate along an optical fibre. This control is achieved by means of the gain and loss mechanisms of stimulated Brillouin scattering in the fibre itself. Our experiments show that group velocities below 71,000 km/s on one hand, well(More)
This paper reviews the major advances in Brillouin slow light devices along the last two years. We also focus on the positive and negative implications of this effect in the development of fiber sensors. © 2006 Optical Society of America OCIS codes: (999.9999) Slow light; (060.4370) Nonlinear optics, fibers; (290.5900) Scattering, Brillouin
A couple of experiments are here presented to clarify the impact of slow light on light-matter interaction. The experiments are designed, so that the process generating slow light and the probed light-matter interaction only present a marginal cross-effect. The impact of slow light on simple molecular absorption could be separately evaluated under either(More)
A novel configuration for precise temperature sensing in an array of optical fibre sections is reported. The sections are chosen to have different Brillouin shifts, to enable separation of scattered light signals in the frequency domain, rather than the traditional time domain, allowing lower-noise CW operation and greater precision due to the 100% duty(More)
A four-wavelength low-power continuous-wave frequency laser reference system has been realised in the 935.4-nm range for water vapour differential absorption lidar (DIAL) applications. The system is built around laboratory extended-cavity and DFB diode lasers. Three lasers are directly locked to three water vapour absorption lines of different strength,(More)
Kerr effect accounts for the change in refractive index of a material with the light intensity and appears in all known optical materials. In this work we analyze Kerr effect in structured superluminal media (e.g some specific types of resonators). We show that Kerr effect in these structures can be cancelled or even reversed (in comparison with the Kerr(More)