Semiconductor laser with two active layers and optical fiber amplifier using the same

摘要

A semiconductor laser device has two active layers (4A, 4B) laminated on different portions of a n-lnP substrate (1). Two stripes (15, 16) emit laser beams. Further, an electric current driving section (20) applies a bias current to the active layers (4A, 4B) via an electrode (8). A modulation signal applying section (21) generates a modulation signal that modulates the bias current, and superposes a modulation signal to the bias current.