| 摘要 |
PURPOSE:To change over a main semiconductor laser to a spare semiconductor laser in a very short time by integrating the main laser, the spare laser and a photodiode for monitoring output beams on one optical guide in a monolithic manner. CONSTITUTION:A p-InP clad layer 2, a p-InGaAsP waveguide layer 3, a p-InP buffer layer 4, an n-InGaAsP active layer 5, an n-InP clad layer 6 and a p- InGaAsP gate layer 7 are grown in one groove on a semi-insulating InP substrate 1. A photodiode PD and laser diodes LD1, LD2 are formed on the same straight line through photolithography. Clad layers 6 in LD1 and LD2 and drains 11, 14 are conformed in a FET1 and a FET2 for driving the LDs. Gratings 17, 18, 19 are shaped to one parts of the buffer layers 4, and used as distributed Bragg reflestion type lasers. Laser beams are emitted as output beams to the outside from the front end surface 22 of an element, and one part is projected to the photodiode PD of a rear end surface. |
