SEMICONDUCTOR LASER DRIVER

摘要

PURPOSE:To obtain a prescribed extinction ratio and a peak value by detecting an optical output only when a pulse exists, controlling an LD drive circuit so as to make the output constant and controlling the LD current with the optical output at optical pulse output. CONSTITUTION:A light irradiated from a semiconductor laser LD1 is monitored by a photodetector (PD) 2 and its output is amplified by an amplifier 3. The output of the amplifier 3 is inputted to a sample-and-hold IC6. A sample-and- hold circuit 6 uses a signal 7 as a clock pulse and samples and holds the output of the amplifier 3 when the signal pulse exists. The output of the sample-and- hold circuit 6 controls the LD driver 4. As a result, the optical output with stable extinction ratio is obtained.