Drive circuit for semiconductor laser

Abstract

Abstract PURPOSE:To transmit a signal without deteriorating the light receiving characteristics of a light receiver by preventing the decrease of the light erasing ratio while holding the light output of a semiconductor laser constant. CONSTITUTION:An electric signal which is inputted to a terminal 6 is converted from voltage to current by a pulse drive circuit 1, and superposed with a bias current by a current superposing circuit 2. A light output is obtained at a terminal 7 by driving the laser 3 with the current. On the other hand, the monitoring light of the laser outputted from a terminal 31 is converted to a current by a photoelectric converter 4. After this current is detected as the mean value or peak value by a bias current control circuit 5, it is compared with the reference voltage, and amplified, thereby controlling the bias current. As a result, the light output of the laser is stabilized. The bias current is applied to a signal pulse current control circuit 8. The circuit 8 controls the signal pulse current in response to the magnitude of the bias current, thereby preventing the decrease of the light erasing rate.

Inventors

• 👤 Nobumi Kuriyama
• 👤 宜巳 栗山

Bibliographic Details