Byoung-Sung Kim

An efficient split-step time-domain dynamic modeling of DFB/DBR laser diodes

A novel and efficient approach for the numerical solution of time-dependent coupled-wave equations, which are frequently used for the modeling of distributed-feedback, distributed Bragg reflector, and Fabry-Perot laser diodes, is proposed. In this approach, the coupled-wave equations are split into two sets of equations. One of two sets of equations contains only the phase factors and time derivatives, and the other contains only the coupling terms. The separate sets of equations are solved exactly in their split form successively. This new numerical scheme, which we call the split-step time-domain model, is found to require an order of magnitude smaller number of subsections to get more accurate results than previous methods while the computation time for each time step is comparable to previous methods.

Time-domain large-signal analysis of widely tunable DBR laser diodes with periodically sampled and chirped gratings

The time-domain large-signal model is improved for analyzing the widely tunable laser diodes integrated with both active and passive sections. The wide tunability and the dynamic properties of sampled- and chirped-grating distributed Bragg reflector (DBR) laser diodes are successfully simulated using the new time-domain dynamic model.

Dynamic analysis of mode-locked sampled-grating distributed Bragg reflector laser diodes

A mode-locked sampled-grating distributed-Bragg-reflector (SGDBR) laser diode for generating a train of light pulses at terahertz repetition rates is proposed with a numerical analysis based on a time-domain large-signal model. The device consists of three parts: the saturable absorber section which serves as a mode-locker, the gain section as an amplifier, and the SGDBR as a spectrum filter. It is predicted that spectrum filtering of the SGDBR along with passive mode locking due to the saturable absorber is effective in generating a train of transform-limited mode-locked pulses at a high repetition rate.

Split-step time-domain analysis of optical waveguide devices composed of a directional coupler and gratings

An extended split-step time-domain model for composite coupling structures is reported. Time-dependent coupled-wave equations are solved by splitting of the operators for phase accumulation, forward directional coupling, and reverse Bragg reflection. Through an analysis of an add-drop filter based on a grating-written directional-coupler structure, the proposed modeling method is shown to be an order of magnitude more efficient than the previous methods.

Split-step time domain modeling of add-drop filters including a grating-written directional coupler

A novel time-domain model is proposed, which is demonstrated to be very useful for analyzing optical waveguide devices composed of gratings and a directional coupler structure, such as an add-drop filter including a grating-written directional coupler.