Jong Chang Yi

A PSPICE Circuit Modeling of Strained AlGaInN Laser Diode Based on the Multilevel Rate Equations

PSPICE circuit parameters of the blue laser diodes grown on wurtzite AlGaInN multiple quantum well structures were extracted directly from the three level rate equations. The relevant optical gain parameters were separately calculated from the self-consistent multiband Hamiltonian. The resulting equivalent circuit model for a blue laser diode was schematically presented, and its modulation characteristics, including the pulse response and the frequency response, have been demonstrated by using a conventional PSPICE.

Miniband Structure of Quantum Dots based on GaN/AlN Nanowire Arrays

The miniband structure of a quantum dot lattice based on GaN/AlN nanowire arrays has been investigated using the finite element method and Floquet theorem. The quantum dot modes and the quantum wire modes in the nanowire arrays were graphically verified. The optimum geometries of GaN/AlN quantum wire arrays were investigated by using a correlation between the width of nanowires and the separation of the minibandgap which is to be larger than the thermal energy at room temperature.

Epitaxial Structure Optimization for High Brightness InGaN Light Emitting Diodes by Using a Self-consistent Finite Element Method

The epitaxial layer structures for blue InGaN light emitting diodes have been optimized for high brightness applications with the output power levels exceeding 1000 W/cm 2 by using a self-consistent finite element method. The light-current-voltage relationship has been directly estimated from the multiband Hamiltonian for wurtzite crystals. To analyze the efficiency droop at high injection levels, the major nonradiative recombination processes and carrier spillover have also been taken into account. The wall-plug efficiency at high injection levels up to several thousand A/cm 2 has been successfully evaluated for various epilayer structures facilitating optimization of the epitaxial structures for desired output power levels.

Self-Consistent Analysis of the Relative Intensity Noise Characteristics in the Strained AlGaInN Laser Diodes with the High Frequency Current Modulation Effects

The relative intensity noise (RIN) characteristics in 405 nm blue laser diodes grown on wurtzite AlGaInN multiple quantum well structures were investigated using the rate equations with the quantum Langevin noise model. The device parameters were extracted from the optical gain properties of the MQW active region using the self-consistent numerical method developed for calculating the multiband Hamiltonian in the strained wurtzite crystal. These methods have been applied to laser diodes for various conditions including the external feedback and the high frequency current injection.

Nonlinear optical gain properties of GaN-based blue-violet LDs

The nonlinear gain suppression coefficients of GaN-based MQW LDs at high output power have been extracted from the measured optical spectra by using a self-consistent multiband Hamiltonian equations along with the density matrix formulation taking into account the strain effects and piezoelectric effects.

Nonlinear gain suppression coefficient of InAlGaN blue LDs

The optical characteristics of GaN-based MQW LDs such as the linear and nonlinear optical gain have been investigated by a self-consistent analysis of the multiband Hamiltonian taking into account the strain effects and piezoelectric effects in the wurtzite crystal. The nonlinear optical gain properties at high power density have also been investigated experimentally and the gain suppression coefficients were extracted by comparing measured spectra with the calculation results from the density matrix formulation.

Investigation of Intensity and Phase Feedback Effects on the Relative Intensity Noise in Blue Laser Diodes under High Frequency Modulation

The quantum noises in typical Blu‐ray laser diodes have been modeled after the quantum Langevin formalism into three level rate equations. The required material parameters have also been extracted by using the multiband Hamiltonian for strained wurtzite crystals. The results reveal the existence of an optimum current modulation level to minimize the relative intensity noise.

Strain Effects on Gain Properties of InGaAlN Blue LD

The strain effects on the optical gain properties of wurtzite InGaAIN multiple quantum well blue laser diode structures were investigated using the self-consistent method and the multiband Hamiltonian for the strained wurtzite crystal. 2% compressive strain gave up to 60% enhancement to the differential gain as well as 15 nm blue shift in the lasing wavelength.