FDTD Simulation of Femtosecond Optical Gating in Nonlinear Optical Waveguide Utilizing Intersubband Transition in AlGaN/GaN Quantum Wells(Special Issue on Advanced Optical Devices for Next Generation Photonic Networks)

概要

論文の詳細を見る
The propagation and the gate operation of femtosecond pulses in nonlinear optical waveguides utilizing the saturation of the intersubband absorption at 1.55μm in nitride multiple quantum wells are simulated for the first time. The calculation was carried out by a one-dimensional finite-difference time-domain(FD-TD) method combined with three-level rate equations describing the intersubband carrier dynamics. The absorption recovers within 1 ps when the pulse width is less than 200fs, which will allow 1-Tb/s operation. However, the pulse shape may be deformed with the propagation due to the coherent effect and the interference between the signal and the control pulses, and thus, optimization of the pulse widths and the incident timing is required. Since the transparent window(width of the control pulse)becomes shorter according to the propagation, the width of the control pulse should be set broader than that of the signal pulse. As an example, we assume the case where a 1.6-μm, 100-fs signal pulse is gated by a 300-fs control pulse at a wavelength of 1.5μm in a 500-μm length waveguide. A 140-fs gated signal pulse with a smooth envelope is expected to appear after the band-pass filter. The extinction ratio is expected to be greater than 15 dB.
社団法人電子情報通信学会の論文
2000-06-25