LASER-DIODE DRIVING CIRCUIT

摘要

PURPOSE:To make the optical output of a laser diode variable, by making the reference voltage of an APC circuit variable. CONSTITUTION:The optical output of a laser diode 6 is varied based on an ambient temperature. Then part of the optical output undergoes optoelectronic transducing action in a photodetector 1. The result is converted into a voltage in a current-voltage converter 2. The voltage is compared with a reference voltage 7 in a differential amplifier 3. The driving current of the laser diode 6 is controlled through a driver 5. Thus the optical output is stabilized (therefore the circuit for this purpose is called an APC circuit). The reference voltage 7 can be varied. When the reference voltage 7 is varied, the optical output can be varied under a stable state. This operation is simple in its operation as compared with a conventional resistance control method.