A CRITIQUE ON THE USE OF WINDOW STRUCTURE IN TRAVELING-WAVE SEMICONDUCTOR OPTICAL AMPLIFIERS

The inclusion of window structure to the conventional design of travel ling wave semiconductor optical amplifier was thought to help signific antly reduce facet reflectivity. A theoretical study, in which wave pr opagation in the window region is also taken into consideration, shows that the significant reduction can be realized only if the window thi ckness can be as precisely controlled as the anti-reflection coating t hickness. Since this is not viable in practice, conventional design pr inciple and strategy are found necessary to be revised.