Sung-Kee Kim

Analysis of frequency chirping and extinction ratio of optical phase conjugate signals by four-wave mixing in SOA's

We present a complete large-signal dynamic model of a wavelength converter or optical phase conjugator based on four-wave mixing in semiconductor optical amplifiers. The modified transfer matrix method (TMM) is used for implementing the large-signal dynamic model. It is possible for this model to involve not only forward traveling waves, but also backward traveling waves. Also, this model includes longitudinal variation of carrier-induced reflective index, /spl alpha/-parameter, gain, carrier density, photon density, reflection, and amplified spontaneous emission noise at each small section. Therefore, we can accurately evaluate frequency chirping, optical pulse pattern, and extinction ratio of the conjugate signal. Th eye-opening penalty has been calculated to investigate the effects of frequency chirping and extinction ratio on transmission performance.

Charge distributions in EPDM/ATH compounds

Charge distributions in EPDM/ATH compounds were measured. Homocharge develops in a crosslinked pure EPDM (ethylene propylene diene terpolymer) and the addition of ATH (alumina tri-hydrate) increases the homocharge due to the trapping of charge at the EPDM-ATH interfaces. Details of the results are described.

Missing modes in 1.3 /spl mu/m InGaAsP/InP uncooled Fabry-Perot lasers and their effect on transmission performance

We report mode missing and modal instability of uncooled Fabry–Perot (FP) lasers for the temperature range from −45 to 85∘C and their effect on transmission performance. Using the time domain laser model (TDLM), mode missing has been modeled in FP lasers with structural defects in the active layer. Using this model, we have estimated eye opening penalty (EOP) due to missing modes up to 2.5 Gbps data rate. These simulation results suggest that FP lasers should have less than two missing modes for stable operation and high performance for optical data links.

Frequency chirping and dynamic characteristics of wavelength-converted optical signals by cross-gain and cross-phase modulation in semiconductor optical amplifiers

For all optical networks using wavelength division multiplexing (WDM), it is necessary to use wavelength converters for frequency reuse and wavelength/spatial routing. Wavelength converters based on cross-gain modulation (XGM) and cross-phase modulation (XPM) in semiconductor optical amplifier (SOA) have some advantages such as high conversion efficiency and insensitivity to polarization of input signals. A large-signal analysis was performed using a time developed TMM to calculate converted optical pulse waveforms and chirping in SOAs by self-consistently solving the pulse propagation equations and rate equation.