Kwang Ryong Oh

Chirality of a resonance in the absence of backscatterings.

Chirality of a resonance localized on an islands chain is studied in a deformed Reuleaux triangular-shaped microcavity, where clockwise and counter clockwise traveling rays are classically separated. A resonance localized on a period-5 islands chain exhibits chiral emission due to the asymmetric cavity shape. Chirality is experimentally proved in a InGaAsP multi-quantum-well semiconductor laser by showing that the experimental emission characteristics well coincide with the wave dynamical ones.

Optical heterodyne detection for ultra-high Q micro-disk laser sensor

In this paper, we propose a bio-sensing method using optical heterodyne detection for ultra-high Q micro-disk laser (MDL) sensor platform. MDL structure with ultra-high Q-factor (> 108) has advantage in detecting a small variation of the lasing wavelength. For example, when a single molecule is attached to sidewall of MDL, the lasing wavelength is changed by sub-pm. Optical spectrum analyzer (OSA) has limits to detect sub-pm variation in the resonant wavelength because of the spectral resolution. In order to overcome this limitation, we used a heterodyne detection method which needs two MDLs with the same characteristics.

Enhancement of sensitivity using double cascaded triangular ring resonators(DTRR) sensor based on Vernier effect

Double cascaded triangular ring resonators(DTRR) based on silicon-on-insulator(SOI) has been proposed and demonstrated for sensitivity enhancement. Each TRR is composed of three total internal reflection(TIR) mirrors, and multi-mode interference(MMI) is used for coupling. Significant sensitivity enhancement has been demonstrated using DTRR.

Emission characteristics of a microcavity laser comprized of half circle and half ellipse

We experimentally investigate emission characteristics of a microcavity laser, which is comprised of a half ellipse and a half circle. The emission direction of the fabricated InGaAsP semiconductor laser is unidirectional. At high injection current, the laser emits a single mode.

Unidirectional emission in asymmetric Reuleaux triangle 2-D microcavity laser

In an asymmetric Reuleaux triangle microcavity laser, we experimentally confirm that the laser unidirectionally emits at a single window. In this shape, because the quality factor of the clockwise traveling wave is higher than that of the counter clockwise one, the clockwise traveling wave emits at a single window.

Optical devices integrated with semiconductor optical amplifier

Semiconductor optical amplifiers have been used as key optical components for high capacity communication systems. Monolithic integration is necessary for the stable operation of these devices and for wider applications. In this paper, the coupling technique between different waveguides was discussed and research results about optical devices integrated with SOAs were presented. In particular laser amplifier gate switch arrays have been discussed.