Patent ID: 6931039

Claim:
Optical transmitter equipment, comprising: a first semiconductor laser including an active layer for laser emission and a clad region for optical confinement; an emission device capable of supplying optical energy to the active layer in the first semiconductor laser, wherein the emission device is a second semiconductor laser; and a drive circuit for the first semiconductor laser, wherein an electrode for p-type semiconductor in the first semiconductor laser is for connection to a power supply side, and wherein an electrode for n-type semiconductor in the first semiconductor laser is connected to the drive circuit for the first semiconductor laser, and wherein the emission device is configured to supply optical energy corresponding to a bias current in the first semiconductor laser to the active layer in the first semiconductor laser, wherein the drive circuit for the first semiconductor laser comprises: a differential amplified circuit having a pair of transistors; a first constant current circuit connected to an n-type side of the first semiconductor laser; a second constant current circuit connected to the differential amplified circuit; a load circuit for the differential amplified circuit, the n-type side of the first semiconductor laser being connected to both an output end of the drive circuit and one end of the first constant current circuit; and a third constant current circuit connected to one end of the second semiconductor laser, wherein an output current of the third constant current circuit is larger than an output current of the first constant current circuit.