Structure of the quantum well for a broad-band semiconductor optical amplifier

For the Bat-gain characteristics of semiconductor optical amplifiers in the broad range, we used a non-uniform quantum well structure. The flat gain in the broad band is made possible by optimizing the variation of the well's thickness. We also showed the gain characteristics for different arrangements of the quantum wells from the p or the n side. As expected theoretically, the gain of the broad bandwidth was characterized by using a photoluminescence measurement.