| 摘要 |
PURPOSE:To enable a semiconductor laser drive circuit to operate at a high speed corresponding to the change speed of a laser beam intensity modulation signal by a method wherein a multiplication-type D/A converter, in which a laser beam intensity modulation signal is inputted into a digital input terminal, and a current set value is so provided into an analog input terminal as to obtain an operating maximum optical output when a laser beam intensity modulation signal is maximum, is provided. CONSTITUTION:Laser beam intensity modulation signal is inputted into a digital input terminal 4. A current setting value is so inputted as to obtain an operating maximum optical output when laser beam intensity modulation signal is maximum. Laser beam intensity modulation signal is directly inputted into the digital input terminal 5, and a current setting feedback signal is inputted into the analog input terminal 6. As digital laser beam intensity modulation signal is inputted into the digital input terminal 5, a D/A converter of high speed is not required to be provided. That is, only a multiplication-type D/A converter 4 is provided as a high speed operating circuit. |
