This Italian opera is set in Japan. It uses pentatonic scale…

This Italian opera is set in Japan. It uses pentatonic scales to display exoticism. In the aria we studied in class, the Japanese woman protagonist hopes her American husband will come back one day. However, when he does return, he comes with a new American wife and takes the protagonist’s son away with him. At the end of the opera the protagonist commits suicide. What is the name of the opera?